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1 <!-- vim: set filetype=docbkxml shiftwidth=2 autoindent expandtab tw=77 : -->
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2
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3 <chapter id="chap:branch">
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4 <?dbhtml filename="managing-releases-and-branchy-development.html"?>
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5 <title>Managing releases and branchy development</title>
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6
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7 <para id="x_369">Mercurial provides several mechanisms for you to manage a
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8 project that is making progress on multiple fronts at once. To
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9 understand these mechanisms, let's first take a brief look at a
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10 fairly normal software project structure.</para>
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11
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12 <para id="x_36a">Many software projects issue periodic <quote>major</quote>
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13 releases that contain substantial new features. In parallel, they
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14 may issue <quote>minor</quote> releases. These are usually
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15 identical to the major releases off which they're based, but with
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16 a few bugs fixed.</para>
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17
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18 <para id="x_36b">In this chapter, we'll start by talking about how to keep
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19 records of project milestones such as releases. We'll then
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20 continue on to talk about the flow of work between different
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21 phases of a project, and how Mercurial can help you to isolate and
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22 manage this work.</para>
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23
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24 <sect1>
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25 <title>Giving a persistent name to a revision</title>
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26
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27 <para id="x_36c">Once you decide that you'd like to call a particular
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28 revision a <quote>release</quote>, it's a good idea to record
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29 the identity of that revision. This will let you reproduce that
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30 release at a later date, for whatever purpose you might need at
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31 the time (reproducing a bug, porting to a new platform, etc).
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32 &interaction.tag.init;</para>
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33
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34 <para id="x_36d">Mercurial lets you give a permanent name to any revision
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35 using the <command role="hg-cmd">hg tag</command> command. Not
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36 surprisingly, these names are called <quote>tags</quote>.</para>
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37
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38 &interaction.tag.tag;
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39
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40 <para id="x_36e">A tag is nothing more than a <quote>symbolic name</quote>
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41 for a revision. Tags exist purely for your convenience, so that
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42 you have a handy permanent way to refer to a revision; Mercurial
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43 doesn't interpret the tag names you use in any way. Neither
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44 does Mercurial place any restrictions on the name of a tag,
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45 beyond a few that are necessary to ensure that a tag can be
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46 parsed unambiguously. A tag name cannot contain any of the
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47 following characters:</para>
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48 <itemizedlist>
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49 <listitem><para id="x_36f">Colon (ASCII 58,
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50 <quote><literal>:</literal></quote>)</para>
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51 </listitem>
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52 <listitem><para id="x_370">Carriage return (ASCII 13,
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53 <quote><literal>\r</literal></quote>)</para>
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54 </listitem>
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55 <listitem><para id="x_371">Newline (ASCII 10,
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56 <quote><literal>\n</literal></quote>)</para>
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57 </listitem></itemizedlist>
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58
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59 <para id="x_372">You can use the <command role="hg-cmd">hg tags</command>
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60 command to display the tags present in your repository. In the
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61 output, each tagged revision is identified first by its name,
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62 then by revision number, and finally by the unique hash of the
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63 revision.</para>
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64
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65 &interaction.tag.tags;
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66
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67 <para id="x_373">Notice that <literal>tip</literal> is listed in the output
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68 of <command role="hg-cmd">hg tags</command>. The
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69 <literal>tip</literal> tag is a special <quote>floating</quote>
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70 tag, which always identifies the newest revision in the
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71 repository.</para>
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72
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73 <para id="x_374">In the output of the <command role="hg-cmd">hg
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74 tags</command> command, tags are listed in reverse order, by
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75 revision number. This usually means that recent tags are listed
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76 before older tags. It also means that <literal>tip</literal> is
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77 always going to be the first tag listed in the output of
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78 <command role="hg-cmd">hg tags</command>.</para>
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79
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80 <para id="x_375">When you run <command role="hg-cmd">hg log</command>, if it
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81 displays a revision that has tags associated with it, it will
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82 print those tags.</para>
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83
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84 &interaction.tag.log;
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85
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86 <para id="x_376">Any time you need to provide a revision ID to a Mercurial
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87 command, the command will accept a tag name in its place.
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88 Internally, Mercurial will translate your tag name into the
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89 corresponding revision ID, then use that.</para>
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90
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91 &interaction.tag.log.v1.0;
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92
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93 <para id="x_377">There's no limit on the number of tags you can have in a
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94 repository, or on the number of tags that a single revision can
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95 have. As a practical matter, it's not a great idea to have
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96 <quote>too many</quote> (a number which will vary from project
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97 to project), simply because tags are supposed to help you to
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98 find revisions. If you have lots of tags, the ease of using
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99 them to identify revisions diminishes rapidly.</para>
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100
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101 <para id="x_378">For example, if your project has milestones as frequent as
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102 every few days, it's perfectly reasonable to tag each one of
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103 those. But if you have a continuous build system that makes
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104 sure every revision can be built cleanly, you'd be introducing a
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105 lot of noise if you were to tag every clean build. Instead, you
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106 could tag failed builds (on the assumption that they're rare!),
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107 or simply not use tags to track buildability.</para>
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108
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109 <para id="x_379">If you want to remove a tag that you no longer want, use
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110 <command role="hg-cmd">hg tag --remove</command>.</para>
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111
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112 &interaction.tag.remove;
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113
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114 <para id="x_37a">You can also modify a tag at any time, so that it identifies
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115 a different revision, by simply issuing a new <command
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116 role="hg-cmd">hg tag</command> command. You'll have to use the
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117 <option role="hg-opt-tag">-f</option> option to tell Mercurial
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118 that you <emphasis>really</emphasis> want to update the
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119 tag.</para>
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120
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121 &interaction.tag.replace;
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122
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123 <para id="x_37b">There will still be a permanent record of the previous
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124 identity of the tag, but Mercurial will no longer use it.
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125 There's thus no penalty to tagging the wrong revision; all you
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126 have to do is turn around and tag the correct revision once you
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127 discover your error.</para>
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128
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129 <para id="x_37c">Mercurial stores tags in a normal revision-controlled file
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130 in your repository. If you've created any tags, you'll find
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131 them in a file in the root of your repository named <filename
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132 role="special">.hgtags</filename>. When you run the <command
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133 role="hg-cmd">hg tag</command> command, Mercurial modifies
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134 this file, then automatically commits the change to it. This
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135 means that every time you run <command role="hg-cmd">hg
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136 tag</command>, you'll see a corresponding changeset in the
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137 output of <command role="hg-cmd">hg log</command>.</para>
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138
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139 &interaction.tag.tip;
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140
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141 <sect2>
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142 <title>Handling tag conflicts during a merge</title>
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143
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144 <para id="x_37d">You won't often need to care about the <filename
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145 role="special">.hgtags</filename> file, but it sometimes
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146 makes its presence known during a merge. The format of the
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147 file is simple: it consists of a series of lines. Each line
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148 starts with a changeset hash, followed by a space, followed by
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149 the name of a tag.</para>
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150
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151 <para id="x_37e">If you're resolving a conflict in the <filename
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152 role="special">.hgtags</filename> file during a merge,
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153 there's one twist to modifying the <filename
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154 role="special">.hgtags</filename> file: when Mercurial is
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155 parsing the tags in a repository, it
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156 <emphasis>never</emphasis> reads the working copy of the
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157 <filename role="special">.hgtags</filename> file. Instead, it
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158 reads the <emphasis>most recently committed</emphasis>
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159 revision of the file.</para>
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160
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161 <para id="x_37f">An unfortunate consequence of this design is that you
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162 can't actually verify that your merged <filename
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163 role="special">.hgtags</filename> file is correct until
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164 <emphasis>after</emphasis> you've committed a change. So if
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165 you find yourself resolving a conflict on <filename
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166 role="special">.hgtags</filename> during a merge, be sure to
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167 run <command role="hg-cmd">hg tags</command> after you commit.
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168 If it finds an error in the <filename
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169 role="special">.hgtags</filename> file, it will report the
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170 location of the error, which you can then fix and commit. You
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171 should then run <command role="hg-cmd">hg tags</command>
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172 again, just to be sure that your fix is correct.</para>
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173 </sect2>
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174
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175 <sect2>
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176 <title>Tags and cloning</title>
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177
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178 <para id="x_380">You may have noticed that the <command role="hg-cmd">hg
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179 clone</command> command has a <option
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180 role="hg-opt-clone">-r</option> option that lets you clone
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181 an exact copy of the repository as of a particular changeset.
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182 The new clone will not contain any project history that comes
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183 after the revision you specified. This has an interaction
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184 with tags that can surprise the unwary.</para>
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185
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186 <para id="x_381">Recall that a tag is stored as a revision to
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187 the <filename role="special">.hgtags</filename> file. When you
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188 create a tag, the changeset in which its recorded refers to an
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189 older changeset. When you run <command role="hg-cmd">hg clone
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190 -r foo</command> to clone a repository as of tag
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191 <literal>foo</literal>, the new clone <emphasis>will not
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192 contain any revision newer than the one the tag refers to,
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193 including the revision where the tag was created</emphasis>.
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194 The result is that you'll get exactly the right subset of the
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195 project's history in the new repository, but
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196 <emphasis>not</emphasis> the tag you might have
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197 expected.</para>
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198 </sect2>
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199
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200 <sect2>
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201 <title>When permanent tags are too much</title>
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202
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203 <para id="x_382">Since Mercurial's tags are revision controlled and carried
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204 around with a project's history, everyone you work with will
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205 see the tags you create. But giving names to revisions has
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206 uses beyond simply noting that revision
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207 <literal>4237e45506ee</literal> is really
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208 <literal>v2.0.2</literal>. If you're trying to track down a
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209 subtle bug, you might want a tag to remind you of something
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210 like <quote>Anne saw the symptoms with this
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211 revision</quote>.</para>
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212
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213 <para id="x_383">For cases like this, what you might want to use are
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214 <emphasis>local</emphasis> tags. You can create a local tag
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215 with the <option role="hg-opt-tag">-l</option> option to the
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216 <command role="hg-cmd">hg tag</command> command. This will
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217 store the tag in a file called <filename
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218 role="special">.hg/localtags</filename>. Unlike <filename
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219 role="special">.hgtags</filename>, <filename
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220 role="special">.hg/localtags</filename> is not revision
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221 controlled. Any tags you create using <option
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222 role="hg-opt-tag">-l</option> remain strictly local to the
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223 repository you're currently working in.</para>
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224 </sect2>
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225 </sect1>
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226
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227 <sect1>
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228 <title>The flow of changes&emdash;big picture vs. little</title>
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229
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230 <para id="x_384">To return to the outline I sketched at the
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231 beginning of the chapter, let's think about a project that has
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232 multiple concurrent pieces of work under development at
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233 once.</para>
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234
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235 <para id="x_385">There might be a push for a new <quote>main</quote> release;
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236 a new minor bugfix release to the last main release; and an
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237 unexpected <quote>hot fix</quote> to an old release that is now
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238 in maintenance mode.</para>
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239
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240 <para id="x_386">The usual way people refer to these different concurrent
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241 directions of development is as <quote>branches</quote>.
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242 However, we've already seen numerous times that Mercurial treats
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243 <emphasis>all of history</emphasis> as a series of branches and
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244 merges. Really, what we have here is two ideas that are
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245 peripherally related, but which happen to share a name.</para>
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246 <itemizedlist>
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247 <listitem><para id="x_387"><quote>Big picture</quote> branches represent
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248 the sweep of a project's evolution; people give them names,
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249 and talk about them in conversation.</para>
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250 </listitem>
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251 <listitem><para id="x_388"><quote>Little picture</quote> branches are
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252 artefacts of the day-to-day activity of developing and
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253 merging changes. They expose the narrative of how the code
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254 was developed.</para>
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255 </listitem></itemizedlist>
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256 </sect1>
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257
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258 <sect1>
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259 <title>Managing big-picture branches in repositories</title>
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260
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261 <para id="x_389">The easiest way to isolate a <quote>big picture</quote>
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262 branch in Mercurial is in a dedicated repository. If you have
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263 an existing shared repository&emdash;let's call it
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264 <literal>myproject</literal>&emdash;that reaches a
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265 <quote>1.0</quote> milestone, you can start to prepare for
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266 future maintenance releases on top of version 1.0 by tagging the
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267 revision from which you prepared the 1.0 release.</para>
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268
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269 &interaction.branch-repo.tag;
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270
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271 <para id="x_38a">You can then clone a new shared
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272 <literal>myproject-1.0.1</literal> repository as of that
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273 tag.</para>
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274
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275 &interaction.branch-repo.clone;
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276
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277 <para id="x_38b">Afterwards, if someone needs to work on a bug fix that ought
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278 to go into an upcoming 1.0.1 minor release, they clone the
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279 <literal>myproject-1.0.1</literal> repository, make their
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280 changes, and push them back.</para>
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281
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282 &interaction.branch-repo.bugfix;
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283
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284 <para id="x_38c">Meanwhile, development for
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285 the next major release can continue, isolated and unabated, in
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286 the <literal>myproject</literal> repository.</para>
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287
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288 &interaction.branch-repo.new;
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289 </sect1>
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290
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291 <sect1>
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292 <title>Don't repeat yourself: merging across branches</title>
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bos@559
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293
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294 <para id="x_38d">In many cases, if you have a bug to fix on a maintenance
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295 branch, the chances are good that the bug exists on your
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296 project's main branch (and possibly other maintenance branches,
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297 too). It's a rare developer who wants to fix the same bug
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298 multiple times, so let's look at a few ways that Mercurial can
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299 help you to manage these bugfixes without duplicating your
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300 work.</para>
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301
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bos@584
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302 <para id="x_38e">In the simplest instance, all you need to do is pull changes
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303 from your maintenance branch into your local clone of the target
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304 branch.</para>
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305
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306 &interaction.branch-repo.pull;
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307
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bos@584
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308 <para id="x_38f">You'll then need to merge the heads of the two branches, and
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309 push back to the main branch.</para>
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310
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311 &interaction.branch-repo.merge;
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312 </sect1>
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313
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bos@559
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314 <sect1>
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bos@559
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315 <title>Naming branches within one repository</title>
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316
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bos@584
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317 <para id="x_390">In most instances, isolating branches in repositories is the
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318 right approach. Its simplicity makes it easy to understand; and
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319 so it's hard to make mistakes. There's a one-to-one
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320 relationship between branches you're working in and directories
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321 on your system. This lets you use normal (non-Mercurial-aware)
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322 tools to work on files within a branch/repository.</para>
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323
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bos@584
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324 <para id="x_391">If you're more in the <quote>power user</quote> category
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325 (<emphasis>and</emphasis> your collaborators are too), there is
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326 an alternative way of handling branches that you can consider.
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327 I've already mentioned the human-level distinction between
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328 <quote>small picture</quote> and <quote>big picture</quote>
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329 branches. While Mercurial works with multiple <quote>small
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330 picture</quote> branches in a repository all the time (for
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331 example after you pull changes in, but before you merge them),
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332 it can <emphasis>also</emphasis> work with multiple <quote>big
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333 picture</quote> branches.</para>
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334
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bos@584
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335 <para id="x_392">The key to working this way is that Mercurial lets you
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336 assign a persistent <emphasis>name</emphasis> to a branch.
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337 There always exists a branch named <literal>default</literal>.
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338 Even before you start naming branches yourself, you can find
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339 traces of the <literal>default</literal> branch if you look for
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340 them.</para>
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341
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bos@584
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342 <para id="x_393">As an example, when you run the <command role="hg-cmd">hg
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343 commit</command> command, and it pops up your editor so that
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344 you can enter a commit message, look for a line that contains
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345 the text <quote><literal>HG: branch default</literal></quote> at
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346 the bottom. This is telling you that your commit will occur on
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347 the branch named <literal>default</literal>.</para>
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348
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bos@584
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349 <para id="x_394">To start working with named branches, use the <command
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bos@559
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350 role="hg-cmd">hg branches</command> command. This command
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bos@559
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351 lists the named branches already present in your repository,
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bos@567
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352 telling you which changeset is the tip of each.</para>
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353
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354 &interaction.branch-named.branches;
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355
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bos@584
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356 <para id="x_395">Since you haven't created any named branches yet, the only
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bos@567
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357 one that exists is <literal>default</literal>.</para>
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358
|
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bos@584
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359 <para id="x_396">To find out what the <quote>current</quote> branch is, run
|
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bos@559
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360 the <command role="hg-cmd">hg branch</command> command, giving
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361 it no arguments. This tells you what branch the parent of the
|
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bos@567
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362 current changeset is on.</para>
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363
|
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bos@567
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364 &interaction.branch-named.branch;
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365
|
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bos@584
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366 <para id="x_397">To create a new branch, run the <command role="hg-cmd">hg
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bos@559
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367 branch</command> command again. This time, give it one
|
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bos@567
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368 argument: the name of the branch you want to create.</para>
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bos@567
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369
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bos@567
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370 &interaction.branch-named.create;
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bos@559
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371
|
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bos@584
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372 <para id="x_398">After you've created a branch, you might wonder what effect
|
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bos@559
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373 the <command role="hg-cmd">hg branch</command> command has had.
|
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bos@559
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374 What do the <command role="hg-cmd">hg status</command> and
|
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bos@567
|
375 <command role="hg-cmd">hg tip</command> commands report?</para>
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bos@567
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376
|
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bos@567
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377 &interaction.branch-named.status;
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bos@567
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378
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bos@584
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379 <para id="x_399">Nothing has changed in the
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bos@559
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380 working directory, and there's been no new history created. As
|
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bos@559
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381 this suggests, running the <command role="hg-cmd">hg
|
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bos@559
|
382 branch</command> command has no permanent effect; it only
|
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bos@559
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383 tells Mercurial what branch name to use the
|
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bos@559
|
384 <emphasis>next</emphasis> time you commit a changeset.</para>
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bos@559
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385
|
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bos@584
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386 <para id="x_39a">When you commit a change, Mercurial records the name of the
|
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bos@559
|
387 branch on which you committed. Once you've switched from the
|
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bos@559
|
388 <literal>default</literal> branch to another and committed,
|
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bos@559
|
389 you'll see the name of the new branch show up in the output of
|
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bos@559
|
390 <command role="hg-cmd">hg log</command>, <command
|
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bos@559
|
391 role="hg-cmd">hg tip</command>, and other commands that
|
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bos@567
|
392 display the same kind of output.</para>
|
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bos@567
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393
|
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bos@567
|
394 &interaction.branch-named.commit;
|
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bos@567
|
395
|
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bos@584
|
396 <para id="x_39b">The <command role="hg-cmd">hg log</command>-like commands
|
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bos@567
|
397 will print the branch name of every changeset that's not on the
|
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bos@559
|
398 <literal>default</literal> branch. As a result, if you never
|
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bos@559
|
399 use named branches, you'll never see this information.</para>
|
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bos@559
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400
|
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bos@584
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401 <para id="x_39c">Once you've named a branch and committed a change with that
|
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bos@559
|
402 name, every subsequent commit that descends from that change
|
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bos@559
|
403 will inherit the same branch name. You can change the name of a
|
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bos@559
|
404 branch at any time, using the <command role="hg-cmd">hg
|
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bos@567
|
405 branch</command> command.</para>
|
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bos@567
|
406
|
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bos@567
|
407 &interaction.branch-named.rebranch;
|
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bos@567
|
408
|
|
bos@584
|
409 <para id="x_39d">In practice, this is something you won't do very often, as
|
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bos@567
|
410 branch names tend to have fairly long lifetimes. (This isn't a
|
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bos@567
|
411 rule, just an observation.)</para>
|
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bos@675
|
412 </sect1>
|
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bos@675
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413
|
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bos@559
|
414 <sect1>
|
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bos@559
|
415 <title>Dealing with multiple named branches in a
|
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bos@559
|
416 repository</title>
|
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bos@559
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417
|
|
bos@584
|
418 <para id="x_39e">If you have more than one named branch in a repository,
|
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bos@559
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419 Mercurial will remember the branch that your working directory
|
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bos@701
|
420 is on when you start a command like <command role="hg-cmd">hg
|
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bos@559
|
421 update</command> or <command role="hg-cmd">hg pull
|
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bos@559
|
422 -u</command>. It will update the working directory to the tip
|
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bos@559
|
423 of this branch, no matter what the <quote>repo-wide</quote> tip
|
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bos@559
|
424 is. To update to a revision that's on a different named branch,
|
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bos@559
|
425 you may need to use the <option role="hg-opt-update">-C</option>
|
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bos@559
|
426 option to <command role="hg-cmd">hg update</command>.</para>
|
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bos@559
|
427
|
|
bos@672
|
428 <para id="x_39f">This behavior is a little subtle, so let's see it in
|
|
bos@559
|
429 action. First, let's remind ourselves what branch we're
|
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bos@567
|
430 currently on, and what branches are in our repository.</para>
|
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bos@567
|
431
|
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bos@567
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432 &interaction.branch-named.parents;
|
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bos@567
|
433
|
|
bos@584
|
434 <para id="x_3a0">We're on the <literal>bar</literal> branch, but there also
|
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bos@567
|
435 exists an older <command role="hg-cmd">hg foo</command>
|
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bos@567
|
436 branch.</para>
|
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bos@559
|
437
|
|
bos@584
|
438 <para id="x_3a1">We can <command role="hg-cmd">hg update</command> back and
|
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bos@559
|
439 forth between the tips of the <literal>foo</literal> and
|
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bos@559
|
440 <literal>bar</literal> branches without needing to use the
|
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bos@559
|
441 <option role="hg-opt-update">-C</option> option, because this
|
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bos@559
|
442 only involves going backwards and forwards linearly through our
|
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bos@567
|
443 change history.</para>
|
|
bos@567
|
444
|
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bos@567
|
445 &interaction.branch-named.update-switchy;
|
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bos@559
|
446
|
|
bos@584
|
447 <para id="x_3a2">If we go back to the <literal>foo</literal> branch and then
|
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bos@559
|
448 run <command role="hg-cmd">hg update</command>, it will keep us
|
|
bos@559
|
449 on <literal>foo</literal>, not move us to the tip of
|
|
bos@567
|
450 <literal>bar</literal>.</para>
|
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bos@567
|
451
|
|
bos@567
|
452 &interaction.branch-named.update-nothing;
|
|
bos@559
|
453
|
|
bos@584
|
454 <para id="x_3a3">Committing a new change on the <literal>foo</literal> branch
|
|
bos@567
|
455 introduces a new head.</para>
|
|
bos@567
|
456
|
|
bos@567
|
457 &interaction.branch-named.foo-commit;
|
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bos@675
|
458 </sect1>
|
|
bos@675
|
459
|
|
bos@559
|
460 <sect1>
|
|
bos@559
|
461 <title>Branch names and merging</title>
|
|
bos@559
|
462
|
|
bos@584
|
463 <para id="x_3a4">As you've probably noticed, merges in Mercurial are not
|
|
bos@559
|
464 symmetrical. Let's say our repository has two heads, 17 and 23.
|
|
bos@559
|
465 If I <command role="hg-cmd">hg update</command> to 17 and then
|
|
bos@559
|
466 <command role="hg-cmd">hg merge</command> with 23, Mercurial
|
|
bos@559
|
467 records 17 as the first parent of the merge, and 23 as the
|
|
bos@559
|
468 second. Whereas if I <command role="hg-cmd">hg update</command>
|
|
bos@559
|
469 to 23 and then <command role="hg-cmd">hg merge</command> with
|
|
bos@559
|
470 17, it records 23 as the first parent, and 17 as the
|
|
bos@559
|
471 second.</para>
|
|
bos@559
|
472
|
|
bos@584
|
473 <para id="x_3a5">This affects Mercurial's choice of branch name when you
|
|
bos@559
|
474 merge. After a merge, Mercurial will retain the branch name of
|
|
bos@559
|
475 the first parent when you commit the result of the merge. If
|
|
bos@559
|
476 your first parent's branch name is <literal>foo</literal>, and
|
|
bos@559
|
477 you merge with <literal>bar</literal>, the branch name will
|
|
bos@559
|
478 still be <literal>foo</literal> after you merge.</para>
|
|
bos@559
|
479
|
|
bos@584
|
480 <para id="x_3a6">It's not unusual for a repository to contain multiple heads,
|
|
bos@559
|
481 each with the same branch name. Let's say I'm working on the
|
|
bos@559
|
482 <literal>foo</literal> branch, and so are you. We commit
|
|
bos@559
|
483 different changes; I pull your changes; I now have two heads,
|
|
bos@559
|
484 each claiming to be on the <literal>foo</literal> branch. The
|
|
bos@559
|
485 result of a merge will be a single head on the
|
|
bos@559
|
486 <literal>foo</literal> branch, as you might hope.</para>
|
|
bos@559
|
487
|
|
bos@584
|
488 <para id="x_3a7">But if I'm working on the <literal>bar</literal> branch, and
|
|
bos@559
|
489 I merge work from the <literal>foo</literal> branch, the result
|
|
bos@567
|
490 will remain on the <literal>bar</literal> branch.</para>
|
|
bos@567
|
491
|
|
bos@567
|
492 &interaction.branch-named.merge;
|
|
bos@559
|
493
|
|
bos@584
|
494 <para id="x_3a8">To give a more concrete example, if I'm working on the
|
|
bos@559
|
495 <literal>bleeding-edge</literal> branch, and I want to bring in
|
|
bos@559
|
496 the latest fixes from the <literal>stable</literal> branch,
|
|
bos@559
|
497 Mercurial will choose the <quote>right</quote>
|
|
bos@559
|
498 (<literal>bleeding-edge</literal>) branch name when I pull and
|
|
bos@559
|
499 merge from <literal>stable</literal>.</para>
|
|
bos@675
|
500 </sect1>
|
|
bos@675
|
501
|
|
bos@559
|
502 <sect1>
|
|
bos@559
|
503 <title>Branch naming is generally useful</title>
|
|
bos@559
|
504
|
|
bos@584
|
505 <para id="x_3a9">You shouldn't think of named branches as applicable only to
|
|
bos@559
|
506 situations where you have multiple long-lived branches
|
|
bos@559
|
507 cohabiting in a single repository. They're very useful even in
|
|
bos@559
|
508 the one-branch-per-repository case.</para>
|
|
bos@559
|
509
|
|
bos@584
|
510 <para id="x_3aa">In the simplest case, giving a name to each branch gives you
|
|
bos@559
|
511 a permanent record of which branch a changeset originated on.
|
|
bos@559
|
512 This gives you more context when you're trying to follow the
|
|
bos@559
|
513 history of a long-lived branchy project.</para>
|
|
bos@559
|
514
|
|
bos@584
|
515 <para id="x_3ab">If you're working with shared repositories, you can set up a
|
|
bos@559
|
516 <literal role="hook">pretxnchangegroup</literal> hook on each
|
|
bos@559
|
517 that will block incoming changes that have the
|
|
bos@559
|
518 <quote>wrong</quote> branch name. This provides a simple, but
|
|
bos@559
|
519 effective, defence against people accidentally pushing changes
|
|
bos@559
|
520 from a <quote>bleeding edge</quote> branch to a
|
|
bos@559
|
521 <quote>stable</quote> branch. Such a hook might look like this
|
|
bos@559
|
522 inside the shared repo's <filename role="special">
|
|
bos@559
|
523 /.hgrc</filename>.</para>
|
|
bos@580
|
524 <programlisting>[hooks]
|
|
bos@580
|
525 pretxnchangegroup.branch = hg heads --template '{branches} ' | grep mybranch</programlisting>
|
|
bos@559
|
526 </sect1>
|
|
bos@559
|
527 </chapter>
|
|
bos@559
|
528
|
|
bos@559
|
529 <!--
|
|
bos@559
|
530 local variables:
|
|
bos@559
|
531 sgml-parent-document: ("00book.xml" "book" "chapter")
|
|
bos@559
|
532 end:
|
|
bos@559
|
533 -->
|
