hgbook: es/hook.tex annotate

hgbook

annotate es/hook.tex @ 429:e5c5918e8230

Started translation of cgi configuration section

author	Igor TAmara <igor@tamarapatino.org>
date	Sat Nov 29 19:46:33 2008 -0500 (2008-11-29)
parents	04c08ad7e92e
children	263a8436d72d

rev	line source
jerojasro@336	1 \chapter{Handling repository events with hooks}
jerojasro@336	2 \label{chap:hook}
jerojasro@336	3
jerojasro@336	4 Mercurial offers a powerful mechanism to let you perform automated
jerojasro@336	5 actions in response to events that occur in a repository. In some
jerojasro@336	6 cases, you can even control Mercurial's response to those events.
jerojasro@336	7
jerojasro@336	8 The name Mercurial uses for one of these actions is a \emph{hook}.
jerojasro@336	9 Hooks are called ``triggers'' in some revision control systems, but
jerojasro@336	10 the two names refer to the same idea.
jerojasro@336	11
jerojasro@336	12 \section{An overview of hooks in Mercurial}
jerojasro@336	13
jerojasro@336	14 Here is a brief list of the hooks that Mercurial supports. We will
jerojasro@336	15 revisit each of these hooks in more detail later, in
jerojasro@336	16 section~\ref{sec:hook:ref}.
jerojasro@336	17
jerojasro@336	18 \begin{itemize}
jerojasro@336	19 \item[\small\hook{changegroup}] This is run after a group of
jerojasro@336	20 changesets has been brought into the repository from elsewhere.
jerojasro@336	21 \item[\small\hook{commit}] This is run after a new changeset has been
jerojasro@336	22 created in the local repository.
jerojasro@336	23 \item[\small\hook{incoming}] This is run once for each new changeset
jerojasro@336	24 that is brought into the repository from elsewhere. Notice the
jerojasro@336	25 difference from \hook{changegroup}, which is run once per
jerojasro@336	26 \emph{group} of changesets brought in.
jerojasro@336	27 \item[\small\hook{outgoing}] This is run after a group of changesets
jerojasro@336	28 has been transmitted from this repository.
jerojasro@336	29 \item[\small\hook{prechangegroup}] This is run before starting to
jerojasro@336	30 bring a group of changesets into the repository.
jerojasro@336	31 \item[\small\hook{precommit}] Controlling. This is run before starting
jerojasro@336	32 a commit.
jerojasro@336	33 \item[\small\hook{preoutgoing}] Controlling. This is run before
jerojasro@336	34 starting to transmit a group of changesets from this repository.
jerojasro@336	35 \item[\small\hook{pretag}] Controlling. This is run before creating a tag.
jerojasro@336	36 \item[\small\hook{pretxnchangegroup}] Controlling. This is run after a
jerojasro@336	37 group of changesets has been brought into the local repository from
jerojasro@336	38 another, but before the transaction completes that will make the
jerojasro@336	39 changes permanent in the repository.
jerojasro@336	40 \item[\small\hook{pretxncommit}] Controlling. This is run after a new
jerojasro@336	41 changeset has been created in the local repository, but before the
jerojasro@336	42 transaction completes that will make it permanent.
jerojasro@336	43 \item[\small\hook{preupdate}] Controlling. This is run before starting
jerojasro@336	44 an update or merge of the working directory.
jerojasro@336	45 \item[\small\hook{tag}] This is run after a tag is created.
jerojasro@336	46 \item[\small\hook{update}] This is run after an update or merge of the
jerojasro@336	47 working directory has finished.
jerojasro@336	48 \end{itemize}
jerojasro@336	49 Each of the hooks whose description begins with the word
jerojasro@336	50 ``Controlling'' has the ability to determine whether an activity can
jerojasro@336	51 proceed. If the hook succeeds, the activity may proceed; if it fails,
jerojasro@336	52 the activity is either not permitted or undone, depending on the hook.
jerojasro@336	53
jerojasro@336	54 \section{Hooks and security}
jerojasro@336	55
jerojasro@336	56 \subsection{Hooks are run with your privileges}
jerojasro@336	57
jerojasro@336	58 When you run a Mercurial command in a repository, and the command
jerojasro@336	59 causes a hook to run, that hook runs on \emph{your} system, under
jerojasro@336	60 \emph{your} user account, with \emph{your} privilege level. Since
jerojasro@336	61 hooks are arbitrary pieces of executable code, you should treat them
jerojasro@336	62 with an appropriate level of suspicion. Do not install a hook unless
jerojasro@336	63 you are confident that you know who created it and what it does.
jerojasro@336	64
jerojasro@336	65 In some cases, you may be exposed to hooks that you did not install
jerojasro@336	66 yourself. If you work with Mercurial on an unfamiliar system,
jerojasro@336	67 Mercurial will run hooks defined in that system's global \hgrc\ file.
jerojasro@336	68
jerojasro@336	69 If you are working with a repository owned by another user, Mercurial
jerojasro@336	70 can run hooks defined in that user's repository, but it will still run
jerojasro@336	71 them as ``you''. For example, if you \hgcmd{pull} from that
jerojasro@336	72 repository, and its \sfilename{.hg/hgrc} defines a local
jerojasro@336	73 \hook{outgoing} hook, that hook will run under your user account, even
jerojasro@336	74 though you don't own that repository.
jerojasro@336	75
jerojasro@336	76 \begin{note}
jerojasro@336	77 This only applies if you are pulling from a repository on a local or
jerojasro@336	78 network filesystem. If you're pulling over http or ssh, any
jerojasro@336	79 \hook{outgoing} hook will run under whatever account is executing
jerojasro@336	80 the server process, on the server.
jerojasro@336	81 \end{note}
jerojasro@336	82
jerojasro@336	83 XXX To see what hooks are defined in a repository, use the
jerojasro@336	84 \hgcmdargs{config}{hooks} command. If you are working in one
jerojasro@336	85 repository, but talking to another that you do not own (e.g.~using
jerojasro@336	86 \hgcmd{pull} or \hgcmd{incoming}), remember that it is the other
jerojasro@336	87 repository's hooks you should be checking, not your own.
jerojasro@336	88
jerojasro@336	89 \subsection{Hooks do not propagate}
jerojasro@336	90
jerojasro@336	91 In Mercurial, hooks are not revision controlled, and do not propagate
jerojasro@336	92 when you clone, or pull from, a repository. The reason for this is
jerojasro@336	93 simple: a hook is a completely arbitrary piece of executable code. It
jerojasro@336	94 runs under your user identity, with your privilege level, on your
jerojasro@336	95 machine.
jerojasro@336	96
jerojasro@336	97 It would be extremely reckless for any distributed revision control
jerojasro@336	98 system to implement revision-controlled hooks, as this would offer an
jerojasro@336	99 easily exploitable way to subvert the accounts of users of the
jerojasro@336	100 revision control system.
jerojasro@336	101
jerojasro@336	102 Since Mercurial does not propagate hooks, if you are collaborating
jerojasro@336	103 with other people on a common project, you should not assume that they
jerojasro@336	104 are using the same Mercurial hooks as you are, or that theirs are
jerojasro@336	105 correctly configured. You should document the hooks you expect people
jerojasro@336	106 to use.
jerojasro@336	107
jerojasro@336	108 In a corporate intranet, this is somewhat easier to control, as you
jerojasro@336	109 can for example provide a ``standard'' installation of Mercurial on an
jerojasro@336	110 NFS filesystem, and use a site-wide \hgrc\ file to define hooks that
jerojasro@336	111 all users will see. However, this too has its limits; see below.
jerojasro@336	112
jerojasro@336	113 \subsection{Hooks can be overridden}
jerojasro@336	114
jerojasro@336	115 Mercurial allows you to override a hook definition by redefining the
jerojasro@336	116 hook. You can disable it by setting its value to the empty string, or
jerojasro@336	117 change its behaviour as you wish.
jerojasro@336	118
jerojasro@336	119 If you deploy a system-~or site-wide \hgrc\ file that defines some
jerojasro@336	120 hooks, you should thus understand that your users can disable or
jerojasro@336	121 override those hooks.
jerojasro@336	122
jerojasro@336	123 \subsection{Ensuring that critical hooks are run}
jerojasro@336	124
jerojasro@336	125 Sometimes you may want to enforce a policy that you do not want others
jerojasro@336	126 to be able to work around. For example, you may have a requirement
jerojasro@336	127 that every changeset must pass a rigorous set of tests. Defining this
jerojasro@336	128 requirement via a hook in a site-wide \hgrc\ won't work for remote
jerojasro@336	129 users on laptops, and of course local users can subvert it at will by
jerojasro@336	130 overriding the hook.
jerojasro@336	131
jerojasro@336	132 Instead, you can set up your policies for use of Mercurial so that
jerojasro@336	133 people are expected to propagate changes through a well-known
jerojasro@336	134 ``canonical'' server that you have locked down and configured
jerojasro@336	135 appropriately.
jerojasro@336	136
jerojasro@336	137 One way to do this is via a combination of social engineering and
jerojasro@336	138 technology. Set up a restricted-access account; users can push
jerojasro@336	139 changes over the network to repositories managed by this account, but
jerojasro@336	140 they cannot log into the account and run normal shell commands. In
jerojasro@336	141 this scenario, a user can commit a changeset that contains any old
jerojasro@336	142 garbage they want.
jerojasro@336	143
jerojasro@336	144 When someone pushes a changeset to the server that everyone pulls
jerojasro@336	145 from, the server will test the changeset before it accepts it as
jerojasro@336	146 permanent, and reject it if it fails to pass the test suite. If
jerojasro@336	147 people only pull changes from this filtering server, it will serve to
jerojasro@336	148 ensure that all changes that people pull have been automatically
jerojasro@336	149 vetted.
jerojasro@336	150
jerojasro@336	151 \section{Care with \texttt{pretxn} hooks in a shared-access repository}
jerojasro@336	152
jerojasro@336	153 If you want to use hooks to do some automated work in a repository
jerojasro@336	154 that a number of people have shared access to, you need to be careful
jerojasro@336	155 in how you do this.
jerojasro@336	156
jerojasro@336	157 Mercurial only locks a repository when it is writing to the
jerojasro@336	158 repository, and only the parts of Mercurial that write to the
jerojasro@336	159 repository pay attention to locks. Write locks are necessary to
jerojasro@336	160 prevent multiple simultaneous writers from scribbling on each other's
jerojasro@336	161 work, corrupting the repository.
jerojasro@336	162
jerojasro@336	163 Because Mercurial is careful with the order in which it reads and
jerojasro@336	164 writes data, it does not need to acquire a lock when it wants to read
jerojasro@336	165 data from the repository. The parts of Mercurial that read from the
jerojasro@336	166 repository never pay attention to locks. This lockless reading scheme
jerojasro@336	167 greatly increases performance and concurrency.
jerojasro@336	168
jerojasro@336	169 With great performance comes a trade-off, though, one which has the
jerojasro@336	170 potential to cause you trouble unless you're aware of it. To describe
jerojasro@336	171 this requires a little detail about how Mercurial adds changesets to a
jerojasro@336	172 repository and reads those changes.
jerojasro@336	173
jerojasro@336	174 When Mercurial \emph{writes} metadata, it writes it straight into the
jerojasro@336	175 destination file. It writes file data first, then manifest data
jerojasro@336	176 (which contains pointers to the new file data), then changelog data
jerojasro@336	177 (which contains pointers to the new manifest data). Before the first
jerojasro@336	178 write to each file, it stores a record of where the end of the file
jerojasro@336	179 was in its transaction log. If the transaction must be rolled back,
jerojasro@336	180 Mercurial simply truncates each file back to the size it was before the
jerojasro@336	181 transaction began.
jerojasro@336	182
jerojasro@336	183 When Mercurial \emph{reads} metadata, it reads the changelog first,
jerojasro@336	184 then everything else. Since a reader will only access parts of the
jerojasro@336	185 manifest or file metadata that it can see in the changelog, it can
jerojasro@336	186 never see partially written data.
jerojasro@336	187
jerojasro@336	188 Some controlling hooks (\hook{pretxncommit} and
jerojasro@336	189 \hook{pretxnchangegroup}) run when a transaction is almost complete.
jerojasro@336	190 All of the metadata has been written, but Mercurial can still roll the
jerojasro@336	191 transaction back and cause the newly-written data to disappear.
jerojasro@336	192
jerojasro@336	193 If one of these hooks runs for long, it opens a window of time during
jerojasro@336	194 which a reader can see the metadata for changesets that are not yet
jerojasro@336	195 permanent, and should not be thought of as ``really there''. The
jerojasro@336	196 longer the hook runs, the longer that window is open.
jerojasro@336	197
jerojasro@336	198 \subsection{The problem illustrated}
jerojasro@336	199
jerojasro@336	200 In principle, a good use for the \hook{pretxnchangegroup} hook would
jerojasro@336	201 be to automatically build and test incoming changes before they are
jerojasro@336	202 accepted into a central repository. This could let you guarantee that
jerojasro@336	203 nobody can push changes to this repository that ``break the build''.
jerojasro@336	204 But if a client can pull changes while they're being tested, the
jerojasro@336	205 usefulness of the test is zero; an unsuspecting someone can pull
jerojasro@336	206 untested changes, potentially breaking their build.
jerojasro@336	207
jerojasro@336	208 The safest technological answer to this challenge is to set up such a
jerojasro@336	209 ``gatekeeper'' repository as \emph{unidirectional}. Let it take
jerojasro@336	210 changes pushed in from the outside, but do not allow anyone to pull
jerojasro@336	211 changes from it (use the \hook{preoutgoing} hook to lock it down).
jerojasro@336	212 Configure a \hook{changegroup} hook so that if a build or test
jerojasro@336	213 succeeds, the hook will push the new changes out to another repository
jerojasro@336	214 that people \emph{can} pull from.
jerojasro@336	215
jerojasro@336	216 In practice, putting a centralised bottleneck like this in place is
jerojasro@336	217 not often a good idea, and transaction visibility has nothing to do
jerojasro@336	218 with the problem. As the size of a project---and the time it takes to
jerojasro@336	219 build and test---grows, you rapidly run into a wall with this ``try
jerojasro@336	220 before you buy'' approach, where you have more changesets to test than
jerojasro@336	221 time in which to deal with them. The inevitable result is frustration
jerojasro@336	222 on the part of all involved.
jerojasro@336	223
jerojasro@336	224 An approach that scales better is to get people to build and test
jerojasro@336	225 before they push, then run automated builds and tests centrally
jerojasro@336	226 \emph{after} a push, to be sure all is well. The advantage of this
jerojasro@336	227 approach is that it does not impose a limit on the rate at which the
jerojasro@336	228 repository can accept changes.
jerojasro@336	229
jerojasro@336	230 \section{A short tutorial on using hooks}
jerojasro@336	231 \label{sec:hook:simple}
jerojasro@336	232
jerojasro@336	233 It is easy to write a Mercurial hook. Let's start with a hook that
jerojasro@336	234 runs when you finish a \hgcmd{commit}, and simply prints the hash of
jerojasro@336	235 the changeset you just created. The hook is called \hook{commit}.
jerojasro@336	236
jerojasro@336	237 \begin{figure}[ht]
jerojasro@336	238 \interaction{hook.simple.init}
jerojasro@336	239 \caption{A simple hook that runs when a changeset is committed}
jerojasro@336	240 \label{ex:hook:init}
jerojasro@336	241 \end{figure}
jerojasro@336	242
jerojasro@336	243 All hooks follow the pattern in example~\ref{ex:hook:init}. You add
jerojasro@336	244 an entry to the \rcsection{hooks} section of your \hgrc. On the left
jerojasro@336	245 is the name of the event to trigger on; on the right is the action to
jerojasro@336	246 take. As you can see, you can run an arbitrary shell command in a
jerojasro@336	247 hook. Mercurial passes extra information to the hook using
jerojasro@336	248 environment variables (look for \envar{HG\_NODE} in the example).
jerojasro@336	249
jerojasro@336	250 \subsection{Performing multiple actions per event}
jerojasro@336	251
jerojasro@336	252 Quite often, you will want to define more than one hook for a
jerojasro@336	253 particular kind of event, as shown in example~\ref{ex:hook:ext}.
jerojasro@336	254 Mercurial lets you do this by adding an \emph{extension} to the end of
jerojasro@336	255 a hook's name. You extend a hook's name by giving the name of the
jerojasro@336	256 hook, followed by a full stop (the ``\texttt{.}'' character), followed
jerojasro@336	257 by some more text of your choosing. For example, Mercurial will run
jerojasro@336	258 both \texttt{commit.foo} and \texttt{commit.bar} when the
jerojasro@336	259 \texttt{commit} event occurs.
jerojasro@336	260
jerojasro@336	261 \begin{figure}[ht]
jerojasro@336	262 \interaction{hook.simple.ext}
jerojasro@336	263 \caption{Defining a second \hook{commit} hook}
jerojasro@336	264 \label{ex:hook:ext}
jerojasro@336	265 \end{figure}
jerojasro@336	266
jerojasro@336	267 To give a well-defined order of execution when there are multiple
jerojasro@336	268 hooks defined for an event, Mercurial sorts hooks by extension, and
jerojasro@336	269 executes the hook commands in this sorted order. In the above
jerojasro@336	270 example, it will execute \texttt{commit.bar} before
jerojasro@336	271 \texttt{commit.foo}, and \texttt{commit} before both.
jerojasro@336	272
jerojasro@336	273 It is a good idea to use a somewhat descriptive extension when you
jerojasro@336	274 define a new hook. This will help you to remember what the hook was
jerojasro@336	275 for. If the hook fails, you'll get an error message that contains the
jerojasro@336	276 hook name and extension, so using a descriptive extension could give
jerojasro@336	277 you an immediate hint as to why the hook failed (see
jerojasro@336	278 section~\ref{sec:hook:perm} for an example).
jerojasro@336	279
jerojasro@336	280 \subsection{Controlling whether an activity can proceed}
jerojasro@336	281 \label{sec:hook:perm}
jerojasro@336	282
jerojasro@336	283 In our earlier examples, we used the \hook{commit} hook, which is
jerojasro@336	284 run after a commit has completed. This is one of several Mercurial
jerojasro@336	285 hooks that run after an activity finishes. Such hooks have no way of
jerojasro@336	286 influencing the activity itself.
jerojasro@336	287
jerojasro@336	288 Mercurial defines a number of events that occur before an activity
jerojasro@336	289 starts; or after it starts, but before it finishes. Hooks that
jerojasro@336	290 trigger on these events have the added ability to choose whether the
jerojasro@336	291 activity can continue, or will abort.
jerojasro@336	292
jerojasro@336	293 The \hook{pretxncommit} hook runs after a commit has all but
jerojasro@336	294 completed. In other words, the metadata representing the changeset
jerojasro@336	295 has been written out to disk, but the transaction has not yet been
jerojasro@336	296 allowed to complete. The \hook{pretxncommit} hook has the ability to
jerojasro@336	297 decide whether the transaction can complete, or must be rolled back.
jerojasro@336	298
jerojasro@336	299 If the \hook{pretxncommit} hook exits with a status code of zero, the
jerojasro@336	300 transaction is allowed to complete; the commit finishes; and the
jerojasro@336	301 \hook{commit} hook is run. If the \hook{pretxncommit} hook exits with
jerojasro@336	302 a non-zero status code, the transaction is rolled back; the metadata
jerojasro@336	303 representing the changeset is erased; and the \hook{commit} hook is
jerojasro@336	304 not run.
jerojasro@336	305
jerojasro@336	306 \begin{figure}[ht]
jerojasro@336	307 \interaction{hook.simple.pretxncommit}
jerojasro@336	308 \caption{Using the \hook{pretxncommit} hook to control commits}
jerojasro@336	309 \label{ex:hook:pretxncommit}
jerojasro@336	310 \end{figure}
jerojasro@336	311
jerojasro@336	312 The hook in example~\ref{ex:hook:pretxncommit} checks that a commit
jerojasro@336	313 comment contains a bug ID. If it does, the commit can complete. If
jerojasro@336	314 not, the commit is rolled back.
jerojasro@336	315
jerojasro@336	316 \section{Writing your own hooks}
jerojasro@336	317
jerojasro@336	318 When you are writing a hook, you might find it useful to run Mercurial
jerojasro@336	319 either with the \hggopt{-v} option, or the \rcitem{ui}{verbose} config
jerojasro@336	320 item set to ``true''. When you do so, Mercurial will print a message
jerojasro@336	321 before it calls each hook.
jerojasro@336	322
jerojasro@336	323 \subsection{Choosing how your hook should run}
jerojasro@336	324 \label{sec:hook:lang}
jerojasro@336	325
jerojasro@336	326 You can write a hook either as a normal program---typically a shell
jerojasro@336	327 script---or as a Python function that is executed within the Mercurial
jerojasro@336	328 process.
jerojasro@336	329
jerojasro@336	330 Writing a hook as an external program has the advantage that it
jerojasro@336	331 requires no knowledge of Mercurial's internals. You can call normal
jerojasro@336	332 Mercurial commands to get any added information you need. The
jerojasro@336	333 trade-off is that external hooks are slower than in-process hooks.
jerojasro@336	334
jerojasro@336	335 An in-process Python hook has complete access to the Mercurial API,
jerojasro@336	336 and does not ``shell out'' to another process, so it is inherently
jerojasro@336	337 faster than an external hook. It is also easier to obtain much of the
jerojasro@336	338 information that a hook requires by using the Mercurial API than by
jerojasro@336	339 running Mercurial commands.
jerojasro@336	340
jerojasro@336	341 If you are comfortable with Python, or require high performance,
jerojasro@336	342 writing your hooks in Python may be a good choice. However, when you
jerojasro@336	343 have a straightforward hook to write and you don't need to care about
jerojasro@336	344 performance (probably the majority of hooks), a shell script is
jerojasro@336	345 perfectly fine.
jerojasro@336	346
jerojasro@336	347 \subsection{Hook parameters}
jerojasro@336	348 \label{sec:hook:param}
jerojasro@336	349
jerojasro@336	350 Mercurial calls each hook with a set of well-defined parameters. In
jerojasro@336	351 Python, a parameter is passed as a keyword argument to your hook
jerojasro@336	352 function. For an external program, a parameter is passed as an
jerojasro@336	353 environment variable.
jerojasro@336	354
jerojasro@336	355 Whether your hook is written in Python or as a shell script, the
jerojasro@336	356 hook-specific parameter names and values will be the same. A boolean
jerojasro@336	357 parameter will be represented as a boolean value in Python, but as the
jerojasro@336	358 number 1 (for ``true'') or 0 (for ``false'') as an environment
jerojasro@336	359 variable for an external hook. If a hook parameter is named
jerojasro@336	360 \texttt{foo}, the keyword argument for a Python hook will also be
jerojasro@336	361 named \texttt{foo}, while the environment variable for an external
jerojasro@336	362 hook will be named \texttt{HG\_FOO}.
jerojasro@336	363
jerojasro@336	364 \subsection{Hook return values and activity control}
jerojasro@336	365
jerojasro@336	366 A hook that executes successfully must exit with a status of zero if
jerojasro@336	367 external, or return boolean ``false'' if in-process. Failure is
jerojasro@336	368 indicated with a non-zero exit status from an external hook, or an
jerojasro@336	369 in-process hook returning boolean ``true''. If an in-process hook
jerojasro@336	370 raises an exception, the hook is considered to have failed.
jerojasro@336	371
jerojasro@336	372 For a hook that controls whether an activity can proceed, zero/false
jerojasro@336	373 means ``allow'', while non-zero/true/exception means ``deny''.
jerojasro@336	374
jerojasro@336	375 \subsection{Writing an external hook}
jerojasro@336	376
jerojasro@336	377 When you define an external hook in your \hgrc\ and the hook is run,
jerojasro@336	378 its value is passed to your shell, which interprets it. This means
jerojasro@336	379 that you can use normal shell constructs in the body of the hook.
jerojasro@336	380
jerojasro@336	381 An executable hook is always run with its current directory set to a
jerojasro@336	382 repository's root directory.
jerojasro@336	383
jerojasro@336	384 Each hook parameter is passed in as an environment variable; the name
jerojasro@336	385 is upper-cased, and prefixed with the string ``\texttt{HG\_}''.
jerojasro@336	386
jerojasro@336	387 With the exception of hook parameters, Mercurial does not set or
jerojasro@336	388 modify any environment variables when running a hook. This is useful
jerojasro@336	389 to remember if you are writing a site-wide hook that may be run by a
jerojasro@336	390 number of different users with differing environment variables set.
jerojasro@336	391 In multi-user situations, you should not rely on environment variables
jerojasro@336	392 being set to the values you have in your environment when testing the
jerojasro@336	393 hook.
jerojasro@336	394
jerojasro@336	395 \subsection{Telling Mercurial to use an in-process hook}
jerojasro@336	396
jerojasro@336	397 The \hgrc\ syntax for defining an in-process hook is slightly
jerojasro@336	398 different than for an executable hook. The value of the hook must
jerojasro@336	399 start with the text ``\texttt{python:}'', and continue with the
jerojasro@336	400 fully-qualified name of a callable object to use as the hook's value.
jerojasro@336	401
jerojasro@336	402 The module in which a hook lives is automatically imported when a hook
jerojasro@336	403 is run. So long as you have the module name and \envar{PYTHONPATH}
jerojasro@336	404 right, it should ``just work''.
jerojasro@336	405
jerojasro@336	406 The following \hgrc\ example snippet illustrates the syntax and
jerojasro@336	407 meaning of the notions we just described.
jerojasro@336	408 \begin{codesample2}
jerojasro@336	409 [hooks]
jerojasro@336	410 commit.example = python:mymodule.submodule.myhook
jerojasro@336	411 \end{codesample2}
jerojasro@336	412 When Mercurial runs the \texttt{commit.example} hook, it imports
jerojasro@336	413 \texttt{mymodule.submodule}, looks for the callable object named
jerojasro@336	414 \texttt{myhook}, and calls it.
jerojasro@336	415
jerojasro@336	416 \subsection{Writing an in-process hook}
jerojasro@336	417
jerojasro@336	418 The simplest in-process hook does nothing, but illustrates the basic
jerojasro@336	419 shape of the hook API:
jerojasro@336	420 \begin{codesample2}
jerojasro@336	421 def myhook(ui, repo, **kwargs):
jerojasro@336	422 pass
jerojasro@336	423 \end{codesample2}
jerojasro@336	424 The first argument to a Python hook is always a
jerojasro@336	425 \pymodclass{mercurial.ui}{ui} object. The second is a repository object;
jerojasro@336	426 at the moment, it is always an instance of
jerojasro@336	427 \pymodclass{mercurial.localrepo}{localrepository}. Following these two
jerojasro@336	428 arguments are other keyword arguments. Which ones are passed in
jerojasro@336	429 depends on the hook being called, but a hook can ignore arguments it
jerojasro@336	430 doesn't care about by dropping them into a keyword argument dict, as
jerojasro@336	431 with \texttt{**kwargs} above.
jerojasro@336	432
jerojasro@336	433 \section{Some hook examples}
jerojasro@336	434
jerojasro@336	435 \subsection{Writing meaningful commit messages}
jerojasro@336	436
jerojasro@336	437 It's hard to imagine a useful commit message being very short. The
jerojasro@336	438 simple \hook{pretxncommit} hook of figure~\ref{ex:hook:msglen.go}
jerojasro@336	439 will prevent you from committing a changeset with a message that is
jerojasro@336	440 less than ten bytes long.
jerojasro@336	441
jerojasro@336	442 \begin{figure}[ht]
jerojasro@336	443 \interaction{hook.msglen.go}
jerojasro@336	444 \caption{A hook that forbids overly short commit messages}
jerojasro@336	445 \label{ex:hook:msglen.go}
jerojasro@336	446 \end{figure}
jerojasro@336	447
jerojasro@336	448 \subsection{Checking for trailing whitespace}
jerojasro@336	449
jerojasro@336	450 An interesting use of a commit-related hook is to help you to write
jerojasro@336	451 cleaner code. A simple example of ``cleaner code'' is the dictum that
jerojasro@336	452 a change should not add any new lines of text that contain ``trailing
jerojasro@336	453 whitespace''. Trailing whitespace is a series of space and tab
jerojasro@336	454 characters at the end of a line of text. In most cases, trailing
jerojasro@336	455 whitespace is unnecessary, invisible noise, but it is occasionally
jerojasro@336	456 problematic, and people often prefer to get rid of it.
jerojasro@336	457
jerojasro@336	458 You can use either the \hook{precommit} or \hook{pretxncommit} hook to
jerojasro@336	459 tell whether you have a trailing whitespace problem. If you use the
jerojasro@336	460 \hook{precommit} hook, the hook will not know which files you are
jerojasro@336	461 committing, so it will have to check every modified file in the
jerojasro@336	462 repository for trailing white space. If you want to commit a change
jerojasro@336	463 to just the file \filename{foo}, but the file \filename{bar} contains
jerojasro@336	464 trailing whitespace, doing a check in the \hook{precommit} hook will
jerojasro@336	465 prevent you from committing \filename{foo} due to the problem with
jerojasro@336	466 \filename{bar}. This doesn't seem right.
jerojasro@336	467
jerojasro@336	468 Should you choose the \hook{pretxncommit} hook, the check won't occur
jerojasro@336	469 until just before the transaction for the commit completes. This will
jerojasro@336	470 allow you to check for problems only the exact files that are being
jerojasro@336	471 committed. However, if you entered the commit message interactively
jerojasro@336	472 and the hook fails, the transaction will roll back; you'll have to
jerojasro@336	473 re-enter the commit message after you fix the trailing whitespace and
jerojasro@336	474 run \hgcmd{commit} again.
jerojasro@336	475
jerojasro@336	476 \begin{figure}[ht]
jerojasro@336	477 \interaction{hook.ws.simple}
jerojasro@336	478 \caption{A simple hook that checks for trailing whitespace}
jerojasro@336	479 \label{ex:hook:ws.simple}
jerojasro@336	480 \end{figure}
jerojasro@336	481
jerojasro@336	482 Figure~\ref{ex:hook:ws.simple} introduces a simple \hook{pretxncommit}
jerojasro@336	483 hook that checks for trailing whitespace. This hook is short, but not
jerojasro@336	484 very helpful. It exits with an error status if a change adds a line
jerojasro@336	485 with trailing whitespace to any file, but does not print any
jerojasro@336	486 information that might help us to identify the offending file or
jerojasro@336	487 line. It also has the nice property of not paying attention to
jerojasro@336	488 unmodified lines; only lines that introduce new trailing whitespace
jerojasro@336	489 cause problems.
jerojasro@336	490
jerojasro@336	491 \begin{figure}[ht]
jerojasro@336	492 \interaction{hook.ws.better}
jerojasro@336	493 \caption{A better trailing whitespace hook}
jerojasro@336	494 \label{ex:hook:ws.better}
jerojasro@336	495 \end{figure}
jerojasro@336	496
jerojasro@336	497 The example of figure~\ref{ex:hook:ws.better} is much more complex,
jerojasro@336	498 but also more useful. It parses a unified diff to see if any lines
jerojasro@336	499 add trailing whitespace, and prints the name of the file and the line
jerojasro@336	500 number of each such occurrence. Even better, if the change adds
jerojasro@336	501 trailing whitespace, this hook saves the commit comment and prints the
jerojasro@336	502 name of the save file before exiting and telling Mercurial to roll the
jerojasro@336	503 transaction back, so you can use
jerojasro@336	504 \hgcmdargs{commit}{\hgopt{commit}{-l}~\emph{filename}} to reuse the
jerojasro@336	505 saved commit message once you've corrected the problem.
jerojasro@336	506
jerojasro@336	507 As a final aside, note in figure~\ref{ex:hook:ws.better} the use of
jerojasro@336	508 \command{perl}'s in-place editing feature to get rid of trailing
jerojasro@336	509 whitespace from a file. This is concise and useful enough that I will
jerojasro@336	510 reproduce it here.
jerojasro@336	511 \begin{codesample2}
jerojasro@336	512 perl -pi -e 's,\\s+\$,,' filename
jerojasro@336	513 \end{codesample2}
jerojasro@336	514
jerojasro@336	515 \section{Bundled hooks}
jerojasro@336	516
jerojasro@336	517 Mercurial ships with several bundled hooks. You can find them in the
jerojasro@336	518 \dirname{hgext} directory of a Mercurial source tree. If you are
jerojasro@336	519 using a Mercurial binary package, the hooks will be located in the
jerojasro@336	520 \dirname{hgext} directory of wherever your package installer put
jerojasro@336	521 Mercurial.
jerojasro@336	522
jerojasro@336	523 \subsection{\hgext{acl}---access control for parts of a repository}
jerojasro@336	524
jerojasro@336	525 The \hgext{acl} extension lets you control which remote users are
jerojasro@336	526 allowed to push changesets to a networked server. You can protect any
jerojasro@336	527 portion of a repository (including the entire repo), so that a
jerojasro@336	528 specific remote user can push changes that do not affect the protected
jerojasro@336	529 portion.
jerojasro@336	530
jerojasro@336	531 This extension implements access control based on the identity of the
jerojasro@336	532 user performing a push, \emph{not} on who committed the changesets
jerojasro@336	533 they're pushing. It makes sense to use this hook only if you have a
jerojasro@336	534 locked-down server environment that authenticates remote users, and
jerojasro@336	535 you want to be sure that only specific users are allowed to push
jerojasro@336	536 changes to that server.
jerojasro@336	537
jerojasro@336	538 \subsubsection{Configuring the \hook{acl} hook}
jerojasro@336	539
jerojasro@336	540 In order to manage incoming changesets, the \hgext{acl} hook must be
jerojasro@336	541 used as a \hook{pretxnchangegroup} hook. This lets it see which files
jerojasro@336	542 are modified by each incoming changeset, and roll back a group of
jerojasro@336	543 changesets if they modify ``forbidden'' files. Example:
jerojasro@336	544 \begin{codesample2}
jerojasro@336	545 [hooks]
jerojasro@336	546 pretxnchangegroup.acl = python:hgext.acl.hook
jerojasro@336	547 \end{codesample2}
jerojasro@336	548
jerojasro@336	549 The \hgext{acl} extension is configured using three sections.
jerojasro@336	550
jerojasro@336	551 The \rcsection{acl} section has only one entry, \rcitem{acl}{sources},
jerojasro@336	552 which lists the sources of incoming changesets that the hook should
jerojasro@336	553 pay attention to. You don't normally need to configure this section.
jerojasro@336	554 \begin{itemize}
jerojasro@336	555 \item[\rcitem{acl}{serve}] Control incoming changesets that are arriving
jerojasro@336	556 from a remote repository over http or ssh. This is the default
jerojasro@336	557 value of \rcitem{acl}{sources}, and usually the only setting you'll
jerojasro@336	558 need for this configuration item.
jerojasro@336	559 \item[\rcitem{acl}{pull}] Control incoming changesets that are
jerojasro@336	560 arriving via a pull from a local repository.
jerojasro@336	561 \item[\rcitem{acl}{push}] Control incoming changesets that are
jerojasro@336	562 arriving via a push from a local repository.
jerojasro@336	563 \item[\rcitem{acl}{bundle}] Control incoming changesets that are
jerojasro@336	564 arriving from another repository via a bundle.
jerojasro@336	565 \end{itemize}
jerojasro@336	566
jerojasro@336	567 The \rcsection{acl.allow} section controls the users that are allowed to
jerojasro@336	568 add changesets to the repository. If this section is not present, all
jerojasro@336	569 users that are not explicitly denied are allowed. If this section is
jerojasro@336	570 present, all users that are not explicitly allowed are denied (so an
jerojasro@336	571 empty section means that all users are denied).
jerojasro@336	572
jerojasro@336	573 The \rcsection{acl.deny} section determines which users are denied
jerojasro@336	574 from adding changesets to the repository. If this section is not
jerojasro@336	575 present or is empty, no users are denied.
jerojasro@336	576
jerojasro@336	577 The syntaxes for the \rcsection{acl.allow} and \rcsection{acl.deny}
jerojasro@336	578 sections are identical. On the left of each entry is a glob pattern
jerojasro@336	579 that matches files or directories, relative to the root of the
jerojasro@336	580 repository; on the right, a user name.
jerojasro@336	581
jerojasro@336	582 In the following example, the user \texttt{docwriter} can only push
jerojasro@336	583 changes to the \dirname{docs} subtree of the repository, while
jerojasro@336	584 \texttt{intern} can push changes to any file or directory except
jerojasro@336	585 \dirname{source/sensitive}.
jerojasro@336	586 \begin{codesample2}
jerojasro@336	587 [acl.allow]
jerojasro@336	588 docs/** = docwriter
jerojasro@336	589
jerojasro@336	590 [acl.deny]
jerojasro@336	591 source/sensitive/** = intern
jerojasro@336	592 \end{codesample2}
jerojasro@336	593
jerojasro@336	594 \subsubsection{Testing and troubleshooting}
jerojasro@336	595
jerojasro@336	596 If you want to test the \hgext{acl} hook, run it with Mercurial's
jerojasro@336	597 debugging output enabled. Since you'll probably be running it on a
jerojasro@336	598 server where it's not convenient (or sometimes possible) to pass in
jerojasro@336	599 the \hggopt{--debug} option, don't forget that you can enable
jerojasro@336	600 debugging output in your \hgrc:
jerojasro@336	601 \begin{codesample2}
jerojasro@336	602 [ui]
jerojasro@336	603 debug = true
jerojasro@336	604 \end{codesample2}
jerojasro@336	605 With this enabled, the \hgext{acl} hook will print enough information
jerojasro@336	606 to let you figure out why it is allowing or forbidding pushes from
jerojasro@336	607 specific users.
jerojasro@336	608
jerojasro@336	609 \subsection{\hgext{bugzilla}---integration with Bugzilla}
jerojasro@336	610
jerojasro@336	611 The \hgext{bugzilla} extension adds a comment to a Bugzilla bug
jerojasro@336	612 whenever it finds a reference to that bug ID in a commit comment. You
jerojasro@336	613 can install this hook on a shared server, so that any time a remote
jerojasro@336	614 user pushes changes to this server, the hook gets run.
jerojasro@336	615
jerojasro@336	616 It adds a comment to the bug that looks like this (you can configure
jerojasro@336	617 the contents of the comment---see below):
jerojasro@336	618 \begin{codesample2}
jerojasro@336	619 Changeset aad8b264143a, made by Joe User <joe.user@domain.com> in
jerojasro@336	620 the frobnitz repository, refers to this bug.
jerojasro@336	621
jerojasro@336	622 For complete details, see
jerojasro@336	623 http://hg.domain.com/frobnitz?cmd=changeset;node=aad8b264143a
jerojasro@336	624
jerojasro@336	625 Changeset description:
jerojasro@336	626 Fix bug 10483 by guarding against some NULL pointers
jerojasro@336	627 \end{codesample2}
jerojasro@336	628 The value of this hook is that it automates the process of updating a
jerojasro@336	629 bug any time a changeset refers to it. If you configure the hook
jerojasro@336	630 properly, it makes it easy for people to browse straight from a
jerojasro@336	631 Bugzilla bug to a changeset that refers to that bug.
jerojasro@336	632
jerojasro@336	633 You can use the code in this hook as a starting point for some more
jerojasro@336	634 exotic Bugzilla integration recipes. Here are a few possibilities:
jerojasro@336	635 \begin{itemize}
jerojasro@336	636 \item Require that every changeset pushed to the server have a valid
jerojasro@336	637 bug~ID in its commit comment. In this case, you'd want to configure
jerojasro@336	638 the hook as a \hook{pretxncommit} hook. This would allow the hook
jerojasro@336	639 to reject changes that didn't contain bug IDs.
jerojasro@336	640 \item Allow incoming changesets to automatically modify the
jerojasro@336	641 \emph{state} of a bug, as well as simply adding a comment. For
jerojasro@336	642 example, the hook could recognise the string ``fixed bug 31337'' as
jerojasro@336	643 indicating that it should update the state of bug 31337 to
jerojasro@336	644 ``requires testing''.
jerojasro@336	645 \end{itemize}
jerojasro@336	646
jerojasro@336	647 \subsubsection{Configuring the \hook{bugzilla} hook}
jerojasro@336	648 \label{sec:hook:bugzilla:config}
jerojasro@336	649
jerojasro@336	650 You should configure this hook in your server's \hgrc\ as an
jerojasro@336	651 \hook{incoming} hook, for example as follows:
jerojasro@336	652 \begin{codesample2}
jerojasro@336	653 [hooks]
jerojasro@336	654 incoming.bugzilla = python:hgext.bugzilla.hook
jerojasro@336	655 \end{codesample2}
jerojasro@336	656
jerojasro@336	657 Because of the specialised nature of this hook, and because Bugzilla
jerojasro@336	658 was not written with this kind of integration in mind, configuring
jerojasro@336	659 this hook is a somewhat involved process.
jerojasro@336	660
jerojasro@336	661 Before you begin, you must install the MySQL bindings for Python on
jerojasro@336	662 the host(s) where you'll be running the hook. If this is not
jerojasro@336	663 available as a binary package for your system, you can download it
jerojasro@336	664 from~\cite{web:mysql-python}.
jerojasro@336	665
jerojasro@336	666 Configuration information for this hook lives in the
jerojasro@336	667 \rcsection{bugzilla} section of your \hgrc.
jerojasro@336	668 \begin{itemize}
jerojasro@336	669 \item[\rcitem{bugzilla}{version}] The version of Bugzilla installed on
jerojasro@336	670 the server. The database schema that Bugzilla uses changes
jerojasro@336	671 occasionally, so this hook has to know exactly which schema to use.
jerojasro@336	672 At the moment, the only version supported is \texttt{2.16}.
jerojasro@336	673 \item[\rcitem{bugzilla}{host}] The hostname of the MySQL server that
jerojasro@336	674 stores your Bugzilla data. The database must be configured to allow
jerojasro@336	675 connections from whatever host you are running the \hook{bugzilla}
jerojasro@336	676 hook on.
jerojasro@336	677 \item[\rcitem{bugzilla}{user}] The username with which to connect to
jerojasro@336	678 the MySQL server. The database must be configured to allow this
jerojasro@336	679 user to connect from whatever host you are running the
jerojasro@336	680 \hook{bugzilla} hook on. This user must be able to access and
jerojasro@336	681 modify Bugzilla tables. The default value of this item is
jerojasro@336	682 \texttt{bugs}, which is the standard name of the Bugzilla user in a
jerojasro@336	683 MySQL database.
jerojasro@336	684 \item[\rcitem{bugzilla}{password}] The MySQL password for the user you
jerojasro@336	685 configured above. This is stored as plain text, so you should make
jerojasro@336	686 sure that unauthorised users cannot read the \hgrc\ file where you
jerojasro@336	687 store this information.
jerojasro@336	688 \item[\rcitem{bugzilla}{db}] The name of the Bugzilla database on the
jerojasro@336	689 MySQL server. The default value of this item is \texttt{bugs},
jerojasro@336	690 which is the standard name of the MySQL database where Bugzilla
jerojasro@336	691 stores its data.
jerojasro@336	692 \item[\rcitem{bugzilla}{notify}] If you want Bugzilla to send out a
jerojasro@336	693 notification email to subscribers after this hook has added a
jerojasro@336	694 comment to a bug, you will need this hook to run a command whenever
jerojasro@336	695 it updates the database. The command to run depends on where you
jerojasro@336	696 have installed Bugzilla, but it will typically look something like
jerojasro@336	697 this, if you have Bugzilla installed in
jerojasro@336	698 \dirname{/var/www/html/bugzilla}:
jerojasro@336	699 \begin{codesample4}
jerojasro@336	700 cd /var/www/html/bugzilla && ./processmail %s nobody@nowhere.com
jerojasro@336	701 \end{codesample4}
jerojasro@336	702 The Bugzilla \texttt{processmail} program expects to be given a
jerojasro@336	703 bug~ID (the hook replaces ``\texttt{\%s}'' with the bug~ID) and an
jerojasro@336	704 email address. It also expects to be able to write to some files in
jerojasro@336	705 the directory that it runs in. If Bugzilla and this hook are not
jerojasro@336	706 installed on the same machine, you will need to find a way to run
jerojasro@336	707 \texttt{processmail} on the server where Bugzilla is installed.
jerojasro@336	708 \end{itemize}
jerojasro@336	709
jerojasro@336	710 \subsubsection{Mapping committer names to Bugzilla user names}
jerojasro@336	711
jerojasro@336	712 By default, the \hgext{bugzilla} hook tries to use the email address
jerojasro@336	713 of a changeset's committer as the Bugzilla user name with which to
jerojasro@336	714 update a bug. If this does not suit your needs, you can map committer
jerojasro@336	715 email addresses to Bugzilla user names using a \rcsection{usermap}
jerojasro@336	716 section.
jerojasro@336	717
jerojasro@336	718 Each item in the \rcsection{usermap} section contains an email address
jerojasro@336	719 on the left, and a Bugzilla user name on the right.
jerojasro@336	720 \begin{codesample2}
jerojasro@336	721 [usermap]
jerojasro@336	722 jane.user@example.com = jane
jerojasro@336	723 \end{codesample2}
jerojasro@336	724 You can either keep the \rcsection{usermap} data in a normal \hgrc, or
jerojasro@336	725 tell the \hgext{bugzilla} hook to read the information from an
jerojasro@336	726 external \filename{usermap} file. In the latter case, you can store
jerojasro@336	727 \filename{usermap} data by itself in (for example) a user-modifiable
jerojasro@336	728 repository. This makes it possible to let your users maintain their
jerojasro@336	729 own \rcitem{bugzilla}{usermap} entries. The main \hgrc\ file might
jerojasro@336	730 look like this:
jerojasro@336	731 \begin{codesample2}
jerojasro@336	732 # regular hgrc file refers to external usermap file
jerojasro@336	733 [bugzilla]
jerojasro@336	734 usermap = /home/hg/repos/userdata/bugzilla-usermap.conf
jerojasro@336	735 \end{codesample2}
jerojasro@336	736 While the \filename{usermap} file that it refers to might look like
jerojasro@336	737 this:
jerojasro@336	738 \begin{codesample2}
jerojasro@336	739 # bugzilla-usermap.conf - inside a hg repository
jerojasro@336	740 [usermap]
jerojasro@336	741 stephanie@example.com = steph
jerojasro@336	742 \end{codesample2}
jerojasro@336	743
jerojasro@336	744 \subsubsection{Configuring the text that gets added to a bug}
jerojasro@336	745
jerojasro@336	746 You can configure the text that this hook adds as a comment; you
jerojasro@336	747 specify it in the form of a Mercurial template. Several \hgrc\
jerojasro@336	748 entries (still in the \rcsection{bugzilla} section) control this
jerojasro@336	749 behaviour.
jerojasro@336	750 \begin{itemize}
jerojasro@336	751 \item[\texttt{strip}] The number of leading path elements to strip
jerojasro@336	752 from a repository's path name to construct a partial path for a URL.
jerojasro@336	753 For example, if the repositories on your server live under
jerojasro@336	754 \dirname{/home/hg/repos}, and you have a repository whose path is
jerojasro@336	755 \dirname{/home/hg/repos/app/tests}, then setting \texttt{strip} to
jerojasro@336	756 \texttt{4} will give a partial path of \dirname{app/tests}. The
jerojasro@336	757 hook will make this partial path available when expanding a
jerojasro@336	758 template, as \texttt{webroot}.
jerojasro@336	759 \item[\texttt{template}] The text of the template to use. In addition
jerojasro@336	760 to the usual changeset-related variables, this template can use
jerojasro@336	761 \texttt{hgweb} (the value of the \texttt{hgweb} configuration item
jerojasro@336	762 above) and \texttt{webroot} (the path constructed using
jerojasro@336	763 \texttt{strip} above).
jerojasro@336	764 \end{itemize}
jerojasro@336	765
jerojasro@336	766 In addition, you can add a \rcitem{web}{baseurl} item to the
jerojasro@336	767 \rcsection{web} section of your \hgrc. The \hgext{bugzilla} hook will
jerojasro@336	768 make this available when expanding a template, as the base string to
jerojasro@336	769 use when constructing a URL that will let users browse from a Bugzilla
jerojasro@336	770 comment to view a changeset. Example:
jerojasro@336	771 \begin{codesample2}
jerojasro@336	772 [web]
jerojasro@336	773 baseurl = http://hg.domain.com/
jerojasro@336	774 \end{codesample2}
jerojasro@336	775
jerojasro@336	776 Here is an example set of \hgext{bugzilla} hook config information.
jerojasro@336	777 \begin{codesample2}
jerojasro@336	778 [bugzilla]
jerojasro@336	779 host = bugzilla.example.com
jerojasro@336	780 password = mypassword
jerojasro@336	781 version = 2.16
jerojasro@336	782 # server-side repos live in /home/hg/repos, so strip 4 leading
jerojasro@336	783 # separators
jerojasro@336	784 strip = 4
jerojasro@336	785 hgweb = http://hg.example.com/
jerojasro@336	786 usermap = /home/hg/repos/notify/bugzilla.conf
jerojasro@336	787 template = Changeset \{node\|short\}, made by \{author\} in the \{webroot\}
jerojasro@336	788 repo, refers to this bug.\\nFor complete details, see
jerojasro@336	789 \{hgweb\}\{webroot\}?cmd=changeset;node=\{node\|short\}\\nChangeset
jerojasro@336	790 description:\\n\\t\{desc\|tabindent\}
jerojasro@336	791 \end{codesample2}
jerojasro@336	792
jerojasro@336	793 \subsubsection{Testing and troubleshooting}
jerojasro@336	794
jerojasro@336	795 The most common problems with configuring the \hgext{bugzilla} hook
jerojasro@336	796 relate to running Bugzilla's \filename{processmail} script and mapping
jerojasro@336	797 committer names to user names.
jerojasro@336	798
jerojasro@336	799 Recall from section~\ref{sec:hook:bugzilla:config} above that the user
jerojasro@336	800 that runs the Mercurial process on the server is also the one that
jerojasro@336	801 will run the \filename{processmail} script. The
jerojasro@336	802 \filename{processmail} script sometimes causes Bugzilla to write to
jerojasro@336	803 files in its configuration directory, and Bugzilla's configuration
jerojasro@336	804 files are usually owned by the user that your web server runs under.
jerojasro@336	805
jerojasro@336	806 You can cause \filename{processmail} to be run with the suitable
jerojasro@336	807 user's identity using the \command{sudo} command. Here is an example
jerojasro@336	808 entry for a \filename{sudoers} file.
jerojasro@336	809 \begin{codesample2}
jerojasro@336	810 hg_user = (httpd_user) NOPASSWD: /var/www/html/bugzilla/processmail-wrapper %s
jerojasro@336	811 \end{codesample2}
jerojasro@336	812 This allows the \texttt{hg\_user} user to run a
jerojasro@336	813 \filename{processmail-wrapper} program under the identity of
jerojasro@336	814 \texttt{httpd\_user}.
jerojasro@336	815
jerojasro@336	816 This indirection through a wrapper script is necessary, because
jerojasro@336	817 \filename{processmail} expects to be run with its current directory
jerojasro@336	818 set to wherever you installed Bugzilla; you can't specify that kind of
jerojasro@336	819 constraint in a \filename{sudoers} file. The contents of the wrapper
jerojasro@336	820 script are simple:
jerojasro@336	821 \begin{codesample2}
jerojasro@336	822 #!/bin/sh
jerojasro@336	823 cd `dirname $0` && ./processmail "$1" nobody@example.com
jerojasro@336	824 \end{codesample2}
jerojasro@336	825 It doesn't seem to matter what email address you pass to
jerojasro@336	826 \filename{processmail}.
jerojasro@336	827
jerojasro@336	828 If your \rcsection{usermap} is not set up correctly, users will see an
jerojasro@336	829 error message from the \hgext{bugzilla} hook when they push changes
jerojasro@336	830 to the server. The error message will look like this:
jerojasro@336	831 \begin{codesample2}
jerojasro@336	832 cannot find bugzilla user id for john.q.public@example.com
jerojasro@336	833 \end{codesample2}
jerojasro@336	834 What this means is that the committer's address,
jerojasro@336	835 \texttt{john.q.public@example.com}, is not a valid Bugzilla user name,
jerojasro@336	836 nor does it have an entry in your \rcsection{usermap} that maps it to
jerojasro@336	837 a valid Bugzilla user name.
jerojasro@336	838
jerojasro@336	839 \subsection{\hgext{notify}---send email notifications}
jerojasro@336	840
jerojasro@336	841 Although Mercurial's built-in web server provides RSS feeds of changes
jerojasro@336	842 in every repository, many people prefer to receive change
jerojasro@336	843 notifications via email. The \hgext{notify} hook lets you send out
jerojasro@336	844 notifications to a set of email addresses whenever changesets arrive
jerojasro@336	845 that those subscribers are interested in.
jerojasro@336	846
jerojasro@336	847 As with the \hgext{bugzilla} hook, the \hgext{notify} hook is
jerojasro@336	848 template-driven, so you can customise the contents of the notification
jerojasro@336	849 messages that it sends.
jerojasro@336	850
jerojasro@336	851 By default, the \hgext{notify} hook includes a diff of every changeset
jerojasro@336	852 that it sends out; you can limit the size of the diff, or turn this
jerojasro@336	853 feature off entirely. It is useful for letting subscribers review
jerojasro@336	854 changes immediately, rather than clicking to follow a URL.
jerojasro@336	855
jerojasro@336	856 \subsubsection{Configuring the \hgext{notify} hook}
jerojasro@336	857
jerojasro@336	858 You can set up the \hgext{notify} hook to send one email message per
jerojasro@336	859 incoming changeset, or one per incoming group of changesets (all those
jerojasro@336	860 that arrived in a single pull or push).
jerojasro@336	861 \begin{codesample2}
jerojasro@336	862 [hooks]
jerojasro@336	863 # send one email per group of changes
jerojasro@336	864 changegroup.notify = python:hgext.notify.hook
jerojasro@336	865 # send one email per change
jerojasro@336	866 incoming.notify = python:hgext.notify.hook
jerojasro@336	867 \end{codesample2}
jerojasro@336	868
jerojasro@336	869 Configuration information for this hook lives in the
jerojasro@336	870 \rcsection{notify} section of a \hgrc\ file.
jerojasro@336	871 \begin{itemize}
jerojasro@336	872 \item[\rcitem{notify}{test}] By default, this hook does not send out
jerojasro@336	873 email at all; instead, it prints the message that it \emph{would}
jerojasro@336	874 send. Set this item to \texttt{false} to allow email to be sent.
jerojasro@336	875 The reason that sending of email is turned off by default is that it
jerojasro@336	876 takes several tries to configure this extension exactly as you would
jerojasro@336	877 like, and it would be bad form to spam subscribers with a number of
jerojasro@336	878 ``broken'' notifications while you debug your configuration.
jerojasro@336	879 \item[\rcitem{notify}{config}] The path to a configuration file that
jerojasro@336	880 contains subscription information. This is kept separate from the
jerojasro@336	881 main \hgrc\ so that you can maintain it in a repository of its own.
jerojasro@336	882 People can then clone that repository, update their subscriptions,
jerojasro@336	883 and push the changes back to your server.
jerojasro@336	884 \item[\rcitem{notify}{strip}] The number of leading path separator
jerojasro@336	885 characters to strip from a repository's path, when deciding whether
jerojasro@336	886 a repository has subscribers. For example, if the repositories on
jerojasro@336	887 your server live in \dirname{/home/hg/repos}, and \hgext{notify} is
jerojasro@336	888 considering a repository named \dirname{/home/hg/repos/shared/test},
jerojasro@336	889 setting \rcitem{notify}{strip} to \texttt{4} will cause
jerojasro@336	890 \hgext{notify} to trim the path it considers down to
jerojasro@336	891 \dirname{shared/test}, and it will match subscribers against that.
jerojasro@336	892 \item[\rcitem{notify}{template}] The template text to use when sending
jerojasro@336	893 messages. This specifies both the contents of the message header
jerojasro@336	894 and its body.
jerojasro@336	895 \item[\rcitem{notify}{maxdiff}] The maximum number of lines of diff
jerojasro@336	896 data to append to the end of a message. If a diff is longer than
jerojasro@336	897 this, it is truncated. By default, this is set to 300. Set this to
jerojasro@336	898 \texttt{0} to omit diffs from notification emails.
jerojasro@336	899 \item[\rcitem{notify}{sources}] A list of sources of changesets to
jerojasro@336	900 consider. This lets you limit \hgext{notify} to only sending out
jerojasro@336	901 email about changes that remote users pushed into this repository
jerojasro@336	902 via a server, for example. See section~\ref{sec:hook:sources} for
jerojasro@336	903 the sources you can specify here.
jerojasro@336	904 \end{itemize}
jerojasro@336	905
jerojasro@336	906 If you set the \rcitem{web}{baseurl} item in the \rcsection{web}
jerojasro@336	907 section, you can use it in a template; it will be available as
jerojasro@336	908 \texttt{webroot}.
jerojasro@336	909
jerojasro@336	910 Here is an example set of \hgext{notify} configuration information.
jerojasro@336	911 \begin{codesample2}
jerojasro@336	912 [notify]
jerojasro@336	913 # really send email
jerojasro@336	914 test = false
jerojasro@336	915 # subscriber data lives in the notify repo
jerojasro@336	916 config = /home/hg/repos/notify/notify.conf
jerojasro@336	917 # repos live in /home/hg/repos on server, so strip 4 "/" chars
jerojasro@336	918 strip = 4
jerojasro@336	919 template = X-Hg-Repo: \{webroot\}
jerojasro@336	920 Subject: \{webroot\}: \{desc\|firstline\|strip\}
jerojasro@336	921 From: \{author\}
jerojasro@336	922
jerojasro@336	923 changeset \{node\|short\} in \{root\}
jerojasro@336	924 details: \{baseurl\}\{webroot\}?cmd=changeset;node=\{node\|short\}
jerojasro@336	925 description:
jerojasro@336	926 \{desc\|tabindent\|strip\}
jerojasro@336	927
jerojasro@336	928 [web]
jerojasro@336	929 baseurl = http://hg.example.com/
jerojasro@336	930 \end{codesample2}
jerojasro@336	931
jerojasro@336	932 This will produce a message that looks like the following:
jerojasro@336	933 \begin{codesample2}
jerojasro@336	934 X-Hg-Repo: tests/slave
jerojasro@336	935 Subject: tests/slave: Handle error case when slave has no buffers
jerojasro@336	936 Date: Wed, 2 Aug 2006 15:25:46 -0700 (PDT)
jerojasro@336	937
jerojasro@336	938 changeset 3cba9bfe74b5 in /home/hg/repos/tests/slave
jerojasro@336	939 details: http://hg.example.com/tests/slave?cmd=changeset;node=3cba9bfe74b5
jerojasro@336	940 description:
jerojasro@336	941 Handle error case when slave has no buffers
jerojasro@336	942 diffs (54 lines):
jerojasro@336	943
jerojasro@336	944 diff -r 9d95df7cf2ad -r 3cba9bfe74b5 include/tests.h
jerojasro@336	945 --- a/include/tests.h Wed Aug 02 15:19:52 2006 -0700
jerojasro@336	946 +++ b/include/tests.h Wed Aug 02 15:25:26 2006 -0700
jerojasro@336	947 @@ -212,6 +212,15 @@ static __inline__ void test_headers(void *h)
jerojasro@336	948 [...snip...]
jerojasro@336	949 \end{codesample2}
jerojasro@336	950
jerojasro@336	951 \subsubsection{Testing and troubleshooting}
jerojasro@336	952
jerojasro@336	953 Do not forget that by default, the \hgext{notify} extension \emph{will
jerojasro@336	954 not send any mail} until you explicitly configure it to do so, by
jerojasro@336	955 setting \rcitem{notify}{test} to \texttt{false}. Until you do that,
jerojasro@336	956 it simply prints the message it \emph{would} send.
jerojasro@336	957
jerojasro@336	958 \section{Information for writers of hooks}
jerojasro@336	959 \label{sec:hook:ref}
jerojasro@336	960
jerojasro@336	961 \subsection{In-process hook execution}
jerojasro@336	962
jerojasro@336	963 An in-process hook is called with arguments of the following form:
jerojasro@336	964 \begin{codesample2}
jerojasro@336	965 def myhook(ui, repo, **kwargs):
jerojasro@336	966 pass
jerojasro@336	967 \end{codesample2}
jerojasro@336	968 The \texttt{ui} parameter is a \pymodclass{mercurial.ui}{ui} object.
jerojasro@336	969 The \texttt{repo} parameter is a
jerojasro@336	970 \pymodclass{mercurial.localrepo}{localrepository} object. The
jerojasro@336	971 names and values of the \texttt{**kwargs} parameters depend on the
jerojasro@336	972 hook being invoked, with the following common features:
jerojasro@336	973 \begin{itemize}
jerojasro@336	974 \item If a parameter is named \texttt{node} or
jerojasro@336	975 \texttt{parent\emph{N}}, it will contain a hexadecimal changeset ID.
jerojasro@336	976 The empty string is used to represent ``null changeset ID'' instead
jerojasro@336	977 of a string of zeroes.
jerojasro@336	978 \item If a parameter is named \texttt{url}, it will contain the URL of
jerojasro@336	979 a remote repository, if that can be determined.
jerojasro@336	980 \item Boolean-valued parameters are represented as Python
jerojasro@336	981 \texttt{bool} objects.
jerojasro@336	982 \end{itemize}
jerojasro@336	983
jerojasro@336	984 An in-process hook is called without a change to the process's working
jerojasro@336	985 directory (unlike external hooks, which are run in the root of the
jerojasro@336	986 repository). It must not change the process's working directory, or
jerojasro@336	987 it will cause any calls it makes into the Mercurial API to fail.
jerojasro@336	988
jerojasro@336	989 If a hook returns a boolean ``false'' value, it is considered to have
jerojasro@336	990 succeeded. If it returns a boolean ``true'' value or raises an
jerojasro@336	991 exception, it is considered to have failed. A useful way to think of
jerojasro@336	992 the calling convention is ``tell me if you fail''.
jerojasro@336	993
jerojasro@336	994 Note that changeset IDs are passed into Python hooks as hexadecimal
jerojasro@336	995 strings, not the binary hashes that Mercurial's APIs normally use. To
jerojasro@336	996 convert a hash from hex to binary, use the
jerojasro@336	997 \pymodfunc{mercurial.node}{bin} function.
jerojasro@336	998
jerojasro@336	999 \subsection{External hook execution}
jerojasro@336	1000
jerojasro@336	1001 An external hook is passed to the shell of the user running Mercurial.
jerojasro@336	1002 Features of that shell, such as variable substitution and command
jerojasro@336	1003 redirection, are available. The hook is run in the root directory of
jerojasro@336	1004 the repository (unlike in-process hooks, which are run in the same
jerojasro@336	1005 directory that Mercurial was run in).
jerojasro@336	1006
jerojasro@336	1007 Hook parameters are passed to the hook as environment variables. Each
jerojasro@336	1008 environment variable's name is converted in upper case and prefixed
jerojasro@336	1009 with the string ``\texttt{HG\_}''. For example, if the name of a
jerojasro@336	1010 parameter is ``\texttt{node}'', the name of the environment variable
jerojasro@336	1011 representing that parameter will be ``\texttt{HG\_NODE}''.
jerojasro@336	1012
jerojasro@336	1013 A boolean parameter is represented as the string ``\texttt{1}'' for
jerojasro@336	1014 ``true'', ``\texttt{0}'' for ``false''. If an environment variable is
jerojasro@336	1015 named \envar{HG\_NODE}, \envar{HG\_PARENT1} or \envar{HG\_PARENT2}, it
jerojasro@336	1016 contains a changeset ID represented as a hexadecimal string. The
jerojasro@336	1017 empty string is used to represent ``null changeset ID'' instead of a
jerojasro@336	1018 string of zeroes. If an environment variable is named
jerojasro@336	1019 \envar{HG\_URL}, it will contain the URL of a remote repository, if
jerojasro@336	1020 that can be determined.
jerojasro@336	1021
jerojasro@336	1022 If a hook exits with a status of zero, it is considered to have
jerojasro@336	1023 succeeded. If it exits with a non-zero status, it is considered to
jerojasro@336	1024 have failed.
jerojasro@336	1025
jerojasro@336	1026 \subsection{Finding out where changesets come from}
jerojasro@336	1027
jerojasro@336	1028 A hook that involves the transfer of changesets between a local
jerojasro@336	1029 repository and another may be able to find out information about the
jerojasro@336	1030 ``far side''. Mercurial knows \emph{how} changes are being
jerojasro@336	1031 transferred, and in many cases \emph{where} they are being transferred
jerojasro@336	1032 to or from.
jerojasro@336	1033
jerojasro@336	1034 \subsubsection{Sources of changesets}
jerojasro@336	1035 \label{sec:hook:sources}
jerojasro@336	1036
jerojasro@336	1037 Mercurial will tell a hook what means are, or were, used to transfer
jerojasro@336	1038 changesets between repositories. This is provided by Mercurial in a
jerojasro@336	1039 Python parameter named \texttt{source}, or an environment variable named
jerojasro@336	1040 \envar{HG\_SOURCE}.
jerojasro@336	1041
jerojasro@336	1042 \begin{itemize}
jerojasro@336	1043 \item[\texttt{serve}] Changesets are transferred to or from a remote
jerojasro@336	1044 repository over http or ssh.
jerojasro@336	1045 \item[\texttt{pull}] Changesets are being transferred via a pull from
jerojasro@336	1046 one repository into another.
jerojasro@336	1047 \item[\texttt{push}] Changesets are being transferred via a push from
jerojasro@336	1048 one repository into another.
jerojasro@336	1049 \item[\texttt{bundle}] Changesets are being transferred to or from a
jerojasro@336	1050 bundle.
jerojasro@336	1051 \end{itemize}
jerojasro@336	1052
jerojasro@336	1053 \subsubsection{Where changes are going---remote repository URLs}
jerojasro@336	1054 \label{sec:hook:url}
jerojasro@336	1055
jerojasro@336	1056 When possible, Mercurial will tell a hook the location of the ``far
jerojasro@336	1057 side'' of an activity that transfers changeset data between
jerojasro@336	1058 repositories. This is provided by Mercurial in a Python parameter
jerojasro@336	1059 named \texttt{url}, or an environment variable named \envar{HG\_URL}.
jerojasro@336	1060
jerojasro@336	1061 This information is not always known. If a hook is invoked in a
jerojasro@336	1062 repository that is being served via http or ssh, Mercurial cannot tell
jerojasro@336	1063 where the remote repository is, but it may know where the client is
jerojasro@336	1064 connecting from. In such cases, the URL will take one of the
jerojasro@336	1065 following forms:
jerojasro@336	1066 \begin{itemize}
jerojasro@336	1067 \item \texttt{remote:ssh:\emph{ip-address}}---remote ssh client, at
jerojasro@336	1068 the given IP address.
jerojasro@336	1069 \item \texttt{remote:http:\emph{ip-address}}---remote http client, at
jerojasro@336	1070 the given IP address. If the client is using SSL, this will be of
jerojasro@336	1071 the form \texttt{remote:https:\emph{ip-address}}.
jerojasro@336	1072 \item Empty---no information could be discovered about the remote
jerojasro@336	1073 client.
jerojasro@336	1074 \end{itemize}
jerojasro@336	1075
jerojasro@336	1076 \section{Hook reference}
jerojasro@336	1077
jerojasro@336	1078 \subsection{\hook{changegroup}---after remote changesets added}
jerojasro@336	1079 \label{sec:hook:changegroup}
jerojasro@336	1080
jerojasro@336	1081 This hook is run after a group of pre-existing changesets has been
jerojasro@336	1082 added to the repository, for example via a \hgcmd{pull} or
jerojasro@336	1083 \hgcmd{unbundle}. This hook is run once per operation that added one
jerojasro@336	1084 or more changesets. This is in contrast to the \hook{incoming} hook,
jerojasro@336	1085 which is run once per changeset, regardless of whether the changesets
jerojasro@336	1086 arrive in a group.
jerojasro@336	1087
jerojasro@336	1088 Some possible uses for this hook include kicking off an automated
jerojasro@336	1089 build or test of the added changesets, updating a bug database, or
jerojasro@336	1090 notifying subscribers that a repository contains new changes.
jerojasro@336	1091
jerojasro@336	1092 Parameters to this hook:
jerojasro@336	1093 \begin{itemize}
jerojasro@336	1094 \item[\texttt{node}] A changeset ID. The changeset ID of the first
jerojasro@336	1095 changeset in the group that was added. All changesets between this
jerojasro@336	1096 and \index{tags!\texttt{tip}}\texttt{tip}, inclusive, were added by
jerojasro@336	1097 a single \hgcmd{pull}, \hgcmd{push} or \hgcmd{unbundle}.
jerojasro@336	1098 \item[\texttt{source}] A string. The source of these changes. See
jerojasro@336	1099 section~\ref{sec:hook:sources} for details.
jerojasro@336	1100 \item[\texttt{url}] A URL. The location of the remote repository, if
jerojasro@336	1101 known. See section~\ref{sec:hook:url} for more information.
jerojasro@336	1102 \end{itemize}
jerojasro@336	1103
jerojasro@336	1104 See also: \hook{incoming} (section~\ref{sec:hook:incoming}),
jerojasro@336	1105 \hook{prechangegroup} (section~\ref{sec:hook:prechangegroup}),
jerojasro@336	1106 \hook{pretxnchangegroup} (section~\ref{sec:hook:pretxnchangegroup})
jerojasro@336	1107
jerojasro@336	1108 \subsection{\hook{commit}---after a new changeset is created}
jerojasro@336	1109 \label{sec:hook:commit}
jerojasro@336	1110
jerojasro@336	1111 This hook is run after a new changeset has been created.
jerojasro@336	1112
jerojasro@336	1113 Parameters to this hook:
jerojasro@336	1114 \begin{itemize}
jerojasro@336	1115 \item[\texttt{node}] A changeset ID. The changeset ID of the newly
jerojasro@336	1116 committed changeset.
jerojasro@336	1117 \item[\texttt{parent1}] A changeset ID. The changeset ID of the first
jerojasro@336	1118 parent of the newly committed changeset.
jerojasro@336	1119 \item[\texttt{parent2}] A changeset ID. The changeset ID of the second
jerojasro@336	1120 parent of the newly committed changeset.
jerojasro@336	1121 \end{itemize}
jerojasro@336	1122
jerojasro@336	1123 See also: \hook{precommit} (section~\ref{sec:hook:precommit}),
jerojasro@336	1124 \hook{pretxncommit} (section~\ref{sec:hook:pretxncommit})
jerojasro@336	1125
jerojasro@336	1126 \subsection{\hook{incoming}---after one remote changeset is added}
jerojasro@336	1127 \label{sec:hook:incoming}
jerojasro@336	1128
jerojasro@336	1129 This hook is run after a pre-existing changeset has been added to the
jerojasro@336	1130 repository, for example via a \hgcmd{push}. If a group of changesets
jerojasro@336	1131 was added in a single operation, this hook is called once for each
jerojasro@336	1132 added changeset.
jerojasro@336	1133
jerojasro@336	1134 You can use this hook for the same purposes as the \hook{changegroup}
jerojasro@336	1135 hook (section~\ref{sec:hook:changegroup}); it's simply more convenient
jerojasro@336	1136 sometimes to run a hook once per group of changesets, while other
jerojasro@336	1137 times it's handier once per changeset.
jerojasro@336	1138
jerojasro@336	1139 Parameters to this hook:
jerojasro@336	1140 \begin{itemize}
jerojasro@336	1141 \item[\texttt{node}] A changeset ID. The ID of the newly added
jerojasro@336	1142 changeset.
jerojasro@336	1143 \item[\texttt{source}] A string. The source of these changes. See
jerojasro@336	1144 section~\ref{sec:hook:sources} for details.
jerojasro@336	1145 \item[\texttt{url}] A URL. The location of the remote repository, if
jerojasro@336	1146 known. See section~\ref{sec:hook:url} for more information.
jerojasro@336	1147 \end{itemize}
jerojasro@336	1148
jerojasro@336	1149 See also: \hook{changegroup} (section~\ref{sec:hook:changegroup}) \hook{prechangegroup} (section~\ref{sec:hook:prechangegroup}), \hook{pretxnchangegroup} (section~\ref{sec:hook:pretxnchangegroup})
jerojasro@336	1150
jerojasro@336	1151 \subsection{\hook{outgoing}---after changesets are propagated}
jerojasro@336	1152 \label{sec:hook:outgoing}
jerojasro@336	1153
jerojasro@336	1154 This hook is run after a group of changesets has been propagated out
jerojasro@336	1155 of this repository, for example by a \hgcmd{push} or \hgcmd{bundle}
jerojasro@336	1156 command.
jerojasro@336	1157
jerojasro@336	1158 One possible use for this hook is to notify administrators that
jerojasro@336	1159 changes have been pulled.
jerojasro@336	1160
jerojasro@336	1161 Parameters to this hook:
jerojasro@336	1162 \begin{itemize}
jerojasro@336	1163 \item[\texttt{node}] A changeset ID. The changeset ID of the first
jerojasro@336	1164 changeset of the group that was sent.
jerojasro@336	1165 \item[\texttt{source}] A string. The source of the of the operation
jerojasro@336	1166 (see section~\ref{sec:hook:sources}). If a remote client pulled
jerojasro@336	1167 changes from this repository, \texttt{source} will be
jerojasro@336	1168 \texttt{serve}. If the client that obtained changes from this
jerojasro@336	1169 repository was local, \texttt{source} will be \texttt{bundle},
jerojasro@336	1170 \texttt{pull}, or \texttt{push}, depending on the operation the
jerojasro@336	1171 client performed.
jerojasro@336	1172 \item[\texttt{url}] A URL. The location of the remote repository, if
jerojasro@336	1173 known. See section~\ref{sec:hook:url} for more information.
jerojasro@336	1174 \end{itemize}
jerojasro@336	1175
jerojasro@336	1176 See also: \hook{preoutgoing} (section~\ref{sec:hook:preoutgoing})
jerojasro@336	1177
jerojasro@336	1178 \subsection{\hook{prechangegroup}---before starting to add remote changesets}
jerojasro@336	1179 \label{sec:hook:prechangegroup}
jerojasro@336	1180
jerojasro@336	1181 This controlling hook is run before Mercurial begins to add a group of
jerojasro@336	1182 changesets from another repository.
jerojasro@336	1183
jerojasro@336	1184 This hook does not have any information about the changesets to be
jerojasro@336	1185 added, because it is run before transmission of those changesets is
jerojasro@336	1186 allowed to begin. If this hook fails, the changesets will not be
jerojasro@336	1187 transmitted.
jerojasro@336	1188
jerojasro@336	1189 One use for this hook is to prevent external changes from being added
jerojasro@336	1190 to a repository. For example, you could use this to ``freeze'' a
jerojasro@336	1191 server-hosted branch temporarily or permanently so that users cannot
jerojasro@336	1192 push to it, while still allowing a local administrator to modify the
jerojasro@336	1193 repository.
jerojasro@336	1194
jerojasro@336	1195 Parameters to this hook:
jerojasro@336	1196 \begin{itemize}
jerojasro@336	1197 \item[\texttt{source}] A string. The source of these changes. See
jerojasro@336	1198 section~\ref{sec:hook:sources} for details.
jerojasro@336	1199 \item[\texttt{url}] A URL. The location of the remote repository, if
jerojasro@336	1200 known. See section~\ref{sec:hook:url} for more information.
jerojasro@336	1201 \end{itemize}
jerojasro@336	1202
jerojasro@336	1203 See also: \hook{changegroup} (section~\ref{sec:hook:changegroup}),
jerojasro@336	1204 \hook{incoming} (section~\ref{sec:hook:incoming}), ,
jerojasro@336	1205 \hook{pretxnchangegroup} (section~\ref{sec:hook:pretxnchangegroup})
jerojasro@336	1206
jerojasro@336	1207 \subsection{\hook{precommit}---before starting to commit a changeset}
jerojasro@336	1208 \label{sec:hook:precommit}
jerojasro@336	1209
jerojasro@336	1210 This hook is run before Mercurial begins to commit a new changeset.
jerojasro@336	1211 It is run before Mercurial has any of the metadata for the commit,
jerojasro@336	1212 such as the files to be committed, the commit message, or the commit
jerojasro@336	1213 date.
jerojasro@336	1214
jerojasro@336	1215 One use for this hook is to disable the ability to commit new
jerojasro@336	1216 changesets, while still allowing incoming changesets. Another is to
jerojasro@336	1217 run a build or test, and only allow the commit to begin if the build
jerojasro@336	1218 or test succeeds.
jerojasro@336	1219
jerojasro@336	1220 Parameters to this hook:
jerojasro@336	1221 \begin{itemize}
jerojasro@336	1222 \item[\texttt{parent1}] A changeset ID. The changeset ID of the first
jerojasro@336	1223 parent of the working directory.
jerojasro@336	1224 \item[\texttt{parent2}] A changeset ID. The changeset ID of the second
jerojasro@336	1225 parent of the working directory.
jerojasro@336	1226 \end{itemize}
jerojasro@336	1227 If the commit proceeds, the parents of the working directory will
jerojasro@336	1228 become the parents of the new changeset.
jerojasro@336	1229
jerojasro@336	1230 See also: \hook{commit} (section~\ref{sec:hook:commit}),
jerojasro@336	1231 \hook{pretxncommit} (section~\ref{sec:hook:pretxncommit})
jerojasro@336	1232
jerojasro@336	1233 \subsection{\hook{preoutgoing}---before starting to propagate changesets}
jerojasro@336	1234 \label{sec:hook:preoutgoing}
jerojasro@336	1235
jerojasro@336	1236 This hook is invoked before Mercurial knows the identities of the
jerojasro@336	1237 changesets to be transmitted.
jerojasro@336	1238
jerojasro@336	1239 One use for this hook is to prevent changes from being transmitted to
jerojasro@336	1240 another repository.
jerojasro@336	1241
jerojasro@336	1242 Parameters to this hook:
jerojasro@336	1243 \begin{itemize}
jerojasro@336	1244 \item[\texttt{source}] A string. The source of the operation that is
jerojasro@336	1245 attempting to obtain changes from this repository (see
jerojasro@336	1246 section~\ref{sec:hook:sources}). See the documentation for the
jerojasro@336	1247 \texttt{source} parameter to the \hook{outgoing} hook, in
jerojasro@336	1248 section~\ref{sec:hook:outgoing}, for possible values of this
jerojasro@336	1249 parameter.
jerojasro@336	1250 \item[\texttt{url}] A URL. The location of the remote repository, if
jerojasro@336	1251 known. See section~\ref{sec:hook:url} for more information.
jerojasro@336	1252 \end{itemize}
jerojasro@336	1253
jerojasro@336	1254 See also: \hook{outgoing} (section~\ref{sec:hook:outgoing})
jerojasro@336	1255
jerojasro@336	1256 \subsection{\hook{pretag}---before tagging a changeset}
jerojasro@336	1257 \label{sec:hook:pretag}
jerojasro@336	1258
jerojasro@336	1259 This controlling hook is run before a tag is created. If the hook
jerojasro@336	1260 succeeds, creation of the tag proceeds. If the hook fails, the tag is
jerojasro@336	1261 not created.
jerojasro@336	1262
jerojasro@336	1263 Parameters to this hook:
jerojasro@336	1264 \begin{itemize}
jerojasro@336	1265 \item[\texttt{local}] A boolean. Whether the tag is local to this
jerojasro@336	1266 repository instance (i.e.~stored in \sfilename{.hg/localtags}) or
jerojasro@336	1267 managed by Mercurial (stored in \sfilename{.hgtags}).
jerojasro@336	1268 \item[\texttt{node}] A changeset ID. The ID of the changeset to be tagged.
jerojasro@336	1269 \item[\texttt{tag}] A string. The name of the tag to be created.
jerojasro@336	1270 \end{itemize}
jerojasro@336	1271
jerojasro@336	1272 If the tag to be created is revision-controlled, the \hook{precommit}
jerojasro@336	1273 and \hook{pretxncommit} hooks (sections~\ref{sec:hook:commit}
jerojasro@336	1274 and~\ref{sec:hook:pretxncommit}) will also be run.
jerojasro@336	1275
jerojasro@336	1276 See also: \hook{tag} (section~\ref{sec:hook:tag})
jerojasro@336	1277
jerojasro@336	1278 \subsection{\hook{pretxnchangegroup}---before completing addition of
jerojasro@336	1279 remote changesets}
jerojasro@336	1280 \label{sec:hook:pretxnchangegroup}
jerojasro@336	1281
jerojasro@336	1282 This controlling hook is run before a transaction---that manages the
jerojasro@336	1283 addition of a group of new changesets from outside the
jerojasro@336	1284 repository---completes. If the hook succeeds, the transaction
jerojasro@336	1285 completes, and all of the changesets become permanent within this
jerojasro@336	1286 repository. If the hook fails, the transaction is rolled back, and
jerojasro@336	1287 the data for the changesets is erased.
jerojasro@336	1288
jerojasro@336	1289 This hook can access the metadata associated with the almost-added
jerojasro@336	1290 changesets, but it should not do anything permanent with this data.
jerojasro@336	1291 It must also not modify the working directory.
jerojasro@336	1292
jerojasro@336	1293 While this hook is running, if other Mercurial processes access this
jerojasro@336	1294 repository, they will be able to see the almost-added changesets as if
jerojasro@336	1295 they are permanent. This may lead to race conditions if you do not
jerojasro@336	1296 take steps to avoid them.
jerojasro@336	1297
jerojasro@336	1298 This hook can be used to automatically vet a group of changesets. If
jerojasro@336	1299 the hook fails, all of the changesets are ``rejected'' when the
jerojasro@336	1300 transaction rolls back.
jerojasro@336	1301
jerojasro@336	1302 Parameters to this hook:
jerojasro@336	1303 \begin{itemize}
jerojasro@336	1304 \item[\texttt{node}] A changeset ID. The changeset ID of the first
jerojasro@336	1305 changeset in the group that was added. All changesets between this
jerojasro@336	1306 and \index{tags!\texttt{tip}}\texttt{tip}, inclusive, were added by
jerojasro@336	1307 a single \hgcmd{pull}, \hgcmd{push} or \hgcmd{unbundle}.
jerojasro@336	1308 \item[\texttt{source}] A string. The source of these changes. See
jerojasro@336	1309 section~\ref{sec:hook:sources} for details.
jerojasro@336	1310 \item[\texttt{url}] A URL. The location of the remote repository, if
jerojasro@336	1311 known. See section~\ref{sec:hook:url} for more information.
jerojasro@336	1312 \end{itemize}
jerojasro@336	1313
jerojasro@336	1314 See also: \hook{changegroup} (section~\ref{sec:hook:changegroup}),
jerojasro@336	1315 \hook{incoming} (section~\ref{sec:hook:incoming}),
jerojasro@336	1316 \hook{prechangegroup} (section~\ref{sec:hook:prechangegroup})
jerojasro@336	1317
jerojasro@336	1318 \subsection{\hook{pretxncommit}---before completing commit of new changeset}
jerojasro@336	1319 \label{sec:hook:pretxncommit}
jerojasro@336	1320
jerojasro@336	1321 This controlling hook is run before a transaction---that manages a new
jerojasro@336	1322 commit---completes. If the hook succeeds, the transaction completes
jerojasro@336	1323 and the changeset becomes permanent within this repository. If the
jerojasro@336	1324 hook fails, the transaction is rolled back, and the commit data is
jerojasro@336	1325 erased.
jerojasro@336	1326
jerojasro@336	1327 This hook can access the metadata associated with the almost-new
jerojasro@336	1328 changeset, but it should not do anything permanent with this data. It
jerojasro@336	1329 must also not modify the working directory.
jerojasro@336	1330
jerojasro@336	1331 While this hook is running, if other Mercurial processes access this
jerojasro@336	1332 repository, they will be able to see the almost-new changeset as if it
jerojasro@336	1333 is permanent. This may lead to race conditions if you do not take
jerojasro@336	1334 steps to avoid them.
jerojasro@336	1335
jerojasro@336	1336 Parameters to this hook:
jerojasro@336	1337 \begin{itemize}
jerojasro@336	1338 \item[\texttt{node}] A changeset ID. The changeset ID of the newly
jerojasro@336	1339 committed changeset.
jerojasro@336	1340 \item[\texttt{parent1}] A changeset ID. The changeset ID of the first
jerojasro@336	1341 parent of the newly committed changeset.
jerojasro@336	1342 \item[\texttt{parent2}] A changeset ID. The changeset ID of the second
jerojasro@336	1343 parent of the newly committed changeset.
jerojasro@336	1344 \end{itemize}
jerojasro@336	1345
jerojasro@336	1346 See also: \hook{precommit} (section~\ref{sec:hook:precommit})
jerojasro@336	1347
jerojasro@336	1348 \subsection{\hook{preupdate}---before updating or merging working directory}
jerojasro@336	1349 \label{sec:hook:preupdate}
jerojasro@336	1350
jerojasro@336	1351 This controlling hook is run before an update or merge of the working
jerojasro@336	1352 directory begins. It is run only if Mercurial's normal pre-update
jerojasro@336	1353 checks determine that the update or merge can proceed. If the hook
jerojasro@336	1354 succeeds, the update or merge may proceed; if it fails, the update or
jerojasro@336	1355 merge does not start.
jerojasro@336	1356
jerojasro@336	1357 Parameters to this hook:
jerojasro@336	1358 \begin{itemize}
jerojasro@336	1359 \item[\texttt{parent1}] A changeset ID. The ID of the parent that the
jerojasro@336	1360 working directory is to be updated to. If the working directory is
jerojasro@336	1361 being merged, it will not change this parent.
jerojasro@336	1362 \item[\texttt{parent2}] A changeset ID. Only set if the working
jerojasro@336	1363 directory is being merged. The ID of the revision that the working
jerojasro@336	1364 directory is being merged with.
jerojasro@336	1365 \end{itemize}
jerojasro@336	1366
jerojasro@336	1367 See also: \hook{update} (section~\ref{sec:hook:update})
jerojasro@336	1368
jerojasro@336	1369 \subsection{\hook{tag}---after tagging a changeset}
jerojasro@336	1370 \label{sec:hook:tag}
jerojasro@336	1371
jerojasro@336	1372 This hook is run after a tag has been created.
jerojasro@336	1373
jerojasro@336	1374 Parameters to this hook:
jerojasro@336	1375 \begin{itemize}
jerojasro@336	1376 \item[\texttt{local}] A boolean. Whether the new tag is local to this
jerojasro@336	1377 repository instance (i.e.~stored in \sfilename{.hg/localtags}) or
jerojasro@336	1378 managed by Mercurial (stored in \sfilename{.hgtags}).
jerojasro@336	1379 \item[\texttt{node}] A changeset ID. The ID of the changeset that was
jerojasro@336	1380 tagged.
jerojasro@336	1381 \item[\texttt{tag}] A string. The name of the tag that was created.
jerojasro@336	1382 \end{itemize}
jerojasro@336	1383
jerojasro@336	1384 If the created tag is revision-controlled, the \hook{commit} hook
jerojasro@336	1385 (section~\ref{sec:hook:commit}) is run before this hook.
jerojasro@336	1386
jerojasro@336	1387 See also: \hook{pretag} (section~\ref{sec:hook:pretag})
jerojasro@336	1388
jerojasro@336	1389 \subsection{\hook{update}---after updating or merging working directory}
jerojasro@336	1390 \label{sec:hook:update}
jerojasro@336	1391
jerojasro@336	1392 This hook is run after an update or merge of the working directory
jerojasro@336	1393 completes. Since a merge can fail (if the external \command{hgmerge}
jerojasro@336	1394 command fails to resolve conflicts in a file), this hook communicates
jerojasro@336	1395 whether the update or merge completed cleanly.
jerojasro@336	1396
jerojasro@336	1397 \begin{itemize}
jerojasro@336	1398 \item[\texttt{error}] A boolean. Indicates whether the update or
jerojasro@336	1399 merge completed successfully.
jerojasro@336	1400 \item[\texttt{parent1}] A changeset ID. The ID of the parent that the
jerojasro@336	1401 working directory was updated to. If the working directory was
jerojasro@336	1402 merged, it will not have changed this parent.
jerojasro@336	1403 \item[\texttt{parent2}] A changeset ID. Only set if the working
jerojasro@336	1404 directory was merged. The ID of the revision that the working
jerojasro@336	1405 directory was merged with.
jerojasro@336	1406 \end{itemize}
jerojasro@336	1407
jerojasro@336	1408 See also: \hook{preupdate} (section~\ref{sec:hook:preupdate})
jerojasro@336	1409
jerojasro@336	1410 %%% Local Variables:
jerojasro@336	1411 %%% mode: latex
jerojasro@336	1412 %%% TeX-master: "00book"
jerojasro@336	1413 %%% End: