1Git::Repository::TutoriUasle(r3)Contributed Perl DocumenGtiatt:i:oRnepository::Tutorial(3)
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6 Git::Repository::Tutorial - Control git from Perl using Git::Repository
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9 use Git::Repository;
10 # do cool stuff with Git, using the following advice
12
14 A Git::Repository object represents an actual Git repository, against
15 which you can run commands.
16 Obtain a Git::Repository object from an existing repository
18 If your script is expected to run against a repository in the current
19 directory (like most Git commands), let Git::Repository handle the
20 magic:
21 $r = Git::Repository->new();
23 If the repository has a working copy (work tree):
25 $r = Git::Repository->new( work_tree => $dir );
27 In this case, the git dir is computed as the output of "git rev-parse
29 --git-dir", and the the work tree is normalized using "git rev-parse
30 --show-cdup". To force the use of a different work tree, set the
31 "GIT_WORK_TREE" environment variable in the option hash.
32 If the repository is a bare repository, or you prefer to provide the
34 location of the .git directory:
35 $r = Git::Repository->new( git_dir => $gitdir );
37 If the work tree and the git directory are in unrelated locations, you
39 can also provide both:
40 $r = Git::Repository->new( work_tree => $dir, git_dir => $gitdir );
42 The constructor also accepts an option hash. The various options are
44 detailed in the manual page for Git::Repository::Command.
45 Run any git command
47 Git commands can be run against an existing Git::Repository object, or
48 against the class itself (in which case, git will try to deduce its
49 context from the current directory and the environment).
50 The pattern for running commands is always the same:
52 $r->run( $command => @arguments, \%options );
54 The $command and @arguments are identical to those you'd pass to the
56 "git" command-line tool. The options hash contains options, as
57 described in the manual page for Git::Repository::Command.
58 Create a new repository
60 Sometime, you'll need to create the Git repository from scratch:
61 # git version 1.6.5 and above
63 Git::Repository->run( init => $dir );
64 $r = Git::Repository->new( work_tree => $dir );
65 Any git older than 1.6.5 requires the command to be run in the work
67 tree, so we use the "cwd" option:
68 # git version 1.5.0.rc1 and above
70 Git::Repository->run( init => { cwd => $dir } );
71 $r = Git::Repository->new( work_tree => $dir );
72 # older git versions
74 Git::Repository->run( 'init-db' => { cwd => $dir } );
75 $r = Git::Repository->new( work_tree => $dir );
76 Note that the old "create()" method is obsolete (as of Git::Repository
78 1.18, from April 16, 2011) and has been removed (as of Git::Repository
79 1.301, January 21, 2013).
80 Clone a repository
82 Cloning works the same way:
83 Git::Repository->run( clone => $url => $dir );
85 $r = Git::Repository->new( work_tree => $dir );
86 Run a simple command
88 When you don't really care about the output of the command, just call
89 it:
90 $r->run( add => '.' );
92 $r->run( commit => '-m', 'my commit message' );
93 In case of an error or warning, Git::Repository will "croak()" or
95 "carp()" appropriately.
96 Properly quote options
98 It's common to work out the proper string of Git commands needed to
99 achieve your goal in the shell, before actually turning them into calls
100 to "Git::Repository->run".
101 Some options might require quoting, to properly get the arguments to
103 Git through the shell:
104 # shell
106 $ git log --since='Fri Jul 26 19:34:15 2013 +0200' --grep='report ticket'
107 Such quoting is of course not needed with Git::Repository:
109 $since = 'Fri Jul 26 19:34:15 2013 +0200';
111 $grep = 'report ticket';
112 my $cmd = $r->command( log => "--since=$since", "--grep=$grep" );
113 Be careful with spaces in options
115 For the same reasons as above (individual arguments to "run" or
116 "command" are turned into individual "argv" elements for git,
117 whitespace included), some command-line usages of git need to be
118 slightly reformatted to make them suitable for "run()".
119 For example, these two commands have the same effect when run from the
121 shell:
122 shell> git checkout -b sometopic
124 shell> git checkout -bsometopic
125 In the first case, git receives three arguments in "argv": "checkout",
127 "-b" and "sometopic". In the second case, it receives two arguments:
128 "checkout" and "-bsometopic", and then git recognizes the beginning of
129 the -b option and splits "sometopic" out of the second argument.
130 So, in a call such as:
132 $command = $repo->run( checkout => "-b$branch_name", { quiet => 0 } );
134 If $branch_name contains an initial space character, the call will be
136 equivalent the following shell command:
137 shell> git checkout -b\ sometopic
139 and git will receive two arguments: "checkout" and "-b sometopic", from
141 which it will split out " sometopic" (note the initial space).
142 The space after -b must be removed, as otherwise the code attempts to
144 create a branch called " sometopic", which git rejects.
145 Silence warnings for some Git commands
147 Some Git porcelain commands provide additional information on "STDERR".
148 One typical example is "git checkout":
149 $ git checkout mybranch
151 Switched to branch 'mybranch'
152 The "run()" method of Git::Repository treats all output on "STDERR" as
154 a warning. Therefore, the following code:
155 $r->run( checkout => 'mybranch' );
157 will output a warning like this one:
159 Switched to branch 'mybranch' at myscript.pl line 10.
161 In such a case, you can use the "quiet" option to silence the warning
163 for a single command:
164 $r->run( checkout => 'mybranch', { quiet => 1 } );
166 To silence all warnings, you can pass the "quiet" option during the
168 creation of the original repository object:
169 my $r = Git::Repository->new( { quiet => 1 } );
171 This is not recommended, as it might hide important information from
173 you.
174 Process normal and error output
176 The "run()" command doesn't capture "STDERR": it only warns (or dies)
177 if something was printed on it. To be able to actually capture error
178 output, "command()" must be used.
179 my $cmd = $r->command( @cmd );
181 my @errput = $cmd->stderr->getlines();
182 $cmd->close;
183 "run()" also captures all output at once, which can lead to unnecessary
185 memory consumption when capturing the output of some really verbose
186 commands.
187 my $cmd = $r->command( log => '--pretty=oneline', '--all' );
189 my $log = $cmd->stdout;
190 while (<$log>) {
191 ...;
192 }
193 $cmd->close;
194 Of course, as soon as one starts reading and writing to an external
196 process' communication handles, a risk of blocking exists. Caveat
197 emptor.
198 Provide input on standard input
200 Use the "input" option:
201 my $commit = $r->run( 'commit-tree', $tree, '-p', $parent,
203 { input => $message } );
204 Change the environment of a command
206 Use the "env" option:
207 $r->run(
209 'commit', '-m', 'log message',
210 { env => {
211 GIT_COMMITTER_NAME => 'Git::Repository',
212 GIT_COMMITTER_EMAIL => 'book@cpan.org',
213 },
214 },
215 );
216 Note that Git::Repository::Command does small changes to the
218 environment a command before running it. Specifically, it:
219 • deletes "GIT_DIR" and "GIT_WORK_TREE", and sets them to the
221 corresponding values from the current Git::Repository object
222 • deletes "TERM"
224 • replaces "PATH" with the value of the "env->{PATH}" option
226 The easiest way to preserve en environment variable is to pass it with
228 the "env" option, for example:
229 $r->run( qw( config --get-colorbool githooks.color true ),
231 { env => { TERM => $ENV{TERM} } } );
232 See Git::Repository::Command and System::Command for other available
234 options.
235 Ignore the system and global configuration files
237 Git has three levels of configuration files that can change the output
238 of porcelain commands: system ($(prefix)/etc/gitconfig), global
239 ($HOME/.gitconfig and $XDG_CONFIG_HOME/git/config) and local
240 (.git/config inside the repository).
241 To ensure the system and global configuration files will be ignored and
243 won't interfere with the expected output of your Git commands, you can
244 add the following keys to the "env" option:
245 GIT_CONFIG_NOSYSTEM => 1,
247 XDG_CONFIG_HOME => undef,
248 HOME => undef,
249 Ensure the output from Git commands is not localized
251 Since version 1.7.9, Git translates its most common interface messages
252 into the user's language if translations are available and the locale
253 is appropriately set.
254 This means that naively parsing the output "porcelain" commands might
256 fail if the program is unexpectedly run under an unexpected locale.
257 The easiest way to ensure your Git commands will be run in a "locale-
259 safe" environment, is to set the "LC_ALL" environment variable to "C".
260 The brutal way:
262 $ENV{LC_ALL} = 'C';
264 The temporary way:
266 local $ENV{LC_ALL} = 'C';
268 The subtle way (restricted to the commands run on a given
270 Git::Repository instance):
271 my $r = Git::Repository->new( { env => { LC_ALL => 'C' } } );
273 The stealthiest way (restricted to a single command):
275 $r->run( ..., { env => { LC_ALL => 'C' } } );
277 Ensure the Git commands are run from the current working directory
279 By default, Git::Repository::Command will "chdir()" to the root of the
280 work tree before launching the requested Git command.
281 This means that no matter where your program "chdir()" to, commands on
283 the Git::Repository instance will by default be run from the root of
284 the work tree. So, commands such as "add" need to use the "full" path
285 (relative to "GIT_WORK_TREE") of the files to be added.
286 The "cwd" option can be used to define where Git::Repository::Command
288 will "chdir()" to. To instruct Git::Repository::Command to not
289 "chdir()" (and therefore run the Git command from the current working
290 directory), set the option to "undef":
291 # run from cwd for this command only
293 $r->run( ..., { cwd => undef } );
294 # always run git from cwd
296 my $r = Git::Repository->new( { cwd => undef } );
297 Finely control when "run()" dies
299 By default, "Git::Repository->run( ... )" dies if the Git command
300 exited with a status code of 128 (fatal error) or 129 (usage message).
301 Some commands will throw an error and exit with a status different from
303 the previous two:
304 $r->run( checkout => 'does-not-exist' ); # exit status: 1
306 The above "run()" call does not die, and output the following warning:
308 error: pathspec 'does-not-exist' did not match any file(s) known to git.
310 The exit status (as given by "$? >> 8") is 1.
312 To force "run()" to die when the Git command exits with status 1, use
314 the "fatal" option (added in version 1.304, May 25, 2013):
315 $r->run( checkout => 'does-not-exist', { fatal => 1 } );
317 By default, 128 and 129 remain in the list of fatal codes.
319 Here are a few examples:
321 # set the fatal codes for all call to run() on this object
323 $r = Git::Repository->new( { fatal => [ 1 .. 255 ] } );
324 As usual, setting the option to the Git::Repository object will set it
326 for all commands run for it:
327 # "!0" is a shortcut for 1 .. 255
329 $r = Git::Repository->new( { fatal => [ "!0" ] } );
330 Using negative codes will make these values non-fatal:
332 # the above call to new() makes all exit codes fatal
334 # but 3 and 7 won't be fatal for this specific run
335 $r->run( ..., { fatal => [ -3, -7 ] } );
336 When the list contains a single item, there is no need to use an array
338 reference:
339 # same as [ "!0" ]
341 $r = Git::Repository->new( { fatal => "!0" } );
342 # remove 17 from the list of fatal exit codes for this run only
344 $r->run( ..., { fatal => -17 } );
345 See Git::Repository::Command for other available options.
347 Process the output of git log
349 When creating a tool that needs to process the output of git log, you
350 should always define precisely the expected format using the --pretty
351 option, and choose a format that is easy to parse.
352 Assuming git log will output the default format will eventually lead to
354 problems, for example when the user's git configuration defines
355 "format.pretty" to be something else than the default of "medium".
356 See also Git::Repository::Plugin::Log for adding to your
358 Git::Repository objects a "log()" method that will parse the log output
359 for you.
360 Understanding the various options for git log can make it very simple
362 to obtain a lot of information.
363 For example:
365 # all tags reachable from $committish
367 my @tags = map {
368 s/^ \((.*)\)/$1/;
369 ( map +( split /: / )[1], grep /^tag: /, split /, / )
370 }
371 $_->run( qw( log --simplify-by-decoration --pretty=%d ), $committish );
372 Process the output of git shortlog
374 git shortlog behaves differently when it detects it's not attached to a
375 terminal. In that case, it just tries to read some git log output from
376 its standard input.
377 So this oneliner will hang, because git shortlog is waiting for some
379 data from the program connected to its standard input (the oneliner):
380 perl -MGit::Repository -le 'print scalar Git::Repository->run( shortlog => -5 )'
382 Whereas this one will "work" (as in "immediately return with no
384 output"):
385 perl -MGit::Repository -le 'print scalar Git::Repository->run( shortlog => -5, { input => "" } )'
387 So, you need to give git shortlog some input (from git log):
389 perl -MGit::Repository -le 'print scalar Git::Repository->run( shortlog => { input => scalar Git::Repository->run( log => -5 ) } )'
391 If the log output is large, you'll probably be better off with
393 something like the following:
394 use Git::Repository;
396 # start both git commands
398 my $log = Git::Repository->command('log')->stdout;
399 my $cmd = Git::Repository->command( shortlog => -ens );
400 # feed one with the output of the other
402 my $in = $cmd->stdin;
403 print {$in} $_ while <$log>;
404 close $in;
405 # and do something with the output
407 print $cmd->stdout->getlines;
408 Wrap git in a sudo call
410 If for a given repository you want to wrap all calls to git in a "sudo"
411 call, you can use the "git" option with an array ref:
412 my $r = Git::Repository->new( { git => [qw( sudo -u nobody git )] } );
414 In this case, every call to git from $r will actually call "sudo -u
416 nobody git".
417 Use submodules
419 Because Git::Repository automatically sets the "GIT_DIR" and
420 "GIT_WORK_TREE" environment variables, some "submodule" sub-commands
421 may fail. For example:
422 $r->run( submodule => add => $repository => 'sub' );
424 will give the following error:
426 error: pathspec 'sub' did not match any file(s) known to git.
428 To avoid this error, you should enforce the removal of the
430 "GIT_WORK_TREE" variable from the environment in which the command is
431 run:
432 $r->run(
434 submodule => add => $repository => 'sub',
435 { env => { GIT_WORK_TREE => undef } }
436 );
437 Note that System::Command version 1.04 is required to be able to remove
439 variables from the environment.
440 Sort git versions
442 Since version 1.318, Git::Repository lets Git::Version::Compare handle
443 all version comparisons.
444 Sorting version numbers is therefore as simple as:
446 use Git::Version::Compare qw( cmp_git );
448 @sort_verson = sort cmp_git @versions;
450 Add specialized methods to your Git::Repository objects
452 Have a look at Git::Repository::Plugin and
453 Git::Repository::Plugin::Log, to learn how to add your own methods to
454 Git::Repository.
455 Run code on the output of a git command through callback
457 Sometimes you need to process the output of a command by running a
458 callback on each line of the output.
459 # code inspiration:
461 # https://github.com/dolmen/github-keygen/blob/24c501072ba7d890810de3008434c1fe1f757286/release.pl#L178
462 my %tree;
464 $r->run( 'ls-tree' => $commit, sub {
465 my ($mode, $type, $object, $file) = split;
466 $tree{$file} = [ $mode, $type, $object ];
467 } );
468 Note that the value returned by the callback will be returned as part
470 of the "run()" output, instead of the original line.
471 Initialize a test repository with a bundle
473 Instead of creating a test repository using a series of file editions
474 and commits, one can simply import data into the test repository using
475 a bundle. Bundles are created with the "git bundle create" command (see
476 the Git documentation for details).
477 First create a temporary repository with the help of Test::Git:
479 use Test::Git;
481 my $r = test_repository();
482 then import the bundle data in your repository, and collect the
484 references:
485 my @refs = $r->run( bundle => 'unbundle', $bundle_file );
487 and finally update the references:
489 for my $line (@refs) {
491 my ( $sha1, $ref ) = split / /, $line;
492 $r->run( 'update-ref', $ref => $sha1 );
493 }
494 Since Git version 1.6.5, it's also possible to clone directly from a
496 bundle (this creates an "origin" remote pointing to the bundle file):
497 my $r = test_repository( clone => [ $bundle_file ] );
499 A bundle from a recipient repository's point of view is just like a
501 regular remote repository. See the documentation of git bundle for
502 details of what's possible (e.g. incremental bundles).
503
505 Philippe Bruhat (BooK) <book@cpan.org>
506
508 Copyright 2010-2016 Philippe Bruhat (BooK), all rights reserved.
509
511 This program is free software; you can redistribute it and/or modify it
512 under the same terms as Perl itself.
513perl v5.34.0 2021-07-22 Git::Repository::Tutorial(3)