NAME¶
Git::Repository - Perl interface to Git repositories
SYNOPSIS¶
use Git::Repository;
# start from an existing repository
$r = Git::Repository->new( git_dir => $gitdir );
# start from an existing working copy
$r = Git::Repository->new( work_tree => $dir );
# or init our own repository first
Git::Repository->run( init => $dir, ... );
$r = Git::Repository->new( work_tree => $dir );
# or clone from a URL first
Git::Repository->run( clone => $url, $dir, ... );
$r = Git::Repository->new( work_tree => $dir );
# run commands
# - get the full output (no errput)
$output = $r->run(@cmd);
# - get the full output as a list of lines (no errput)
@output = $r->run(@cmd);
# - obtain a Git::Repository::Command object
$cmd = $r->command(@cmd);
# obtain version information
my $version = $r->version();
# compare current git version
if ( $r->version_gt('1.6.5') ) {
...;
}
DESCRIPTION¶
"Git::Repository" is a Perl interface to Git, for scripted
interactions with repositories. It's a low-level interface that allows calling
any Git command, whether
porcelain or
plumbing, including
bidirectional commands such as "git commit-tree".
A "Git::Repository" object simply provides context to the git commands
being run. It is possible to call the "command()" and
"run()" methods against the class itself, and the context (typically
current working directory) will be obtained from the options and
environment.
As a low-level interface, it provides no sugar for particular Git commands.
Specifically, it will not prepare environment variables that individual Git
commands may need or use.
However, the "GIT_DIR" and "GIT_WORK_TREE" environment
variables are special: if the command is run in the context of a
"Git::Repository" object, they will be overridden by the object's
"git_dir" and "work_tree" attributes, respectively. It is
however still possible to override them if necessary, using the
"env" option.
"Git::Repository" requires at least Git 1.5.0, and is expected to
support any later version.
See "Git::Repository::Tutorial" for more code examples.
CONSTRUCTORS¶
There are two ways to create "Git::Repository" objects:
new( %args, $options )¶
Create a new "Git::Repository" object, based on an existing Git
repository.
Parameters are:
- git_dir => $gitdir
- The location of the git repository (.git directory
or equivalent).
For backward compatibility with versions 1.06 and before,
"repository" is accepted in place of "git_dir" (but
the newer name takes precedence).
- work_tree => $dir
- The location of the git working copy (for a non-bare
repository).
If "work_tree" actually points to a subdirectory of the work tree,
"Git::Repository" will automatically recompute the proper value.
For backward compatibility with versions 1.06 and before,
"working_copy" is accepted in place of "work_tree"
(but the newer name takes precedence).
At least one of the two parameters is required. Usually, one is enough, as
"Git::Repository" can work out where the other directory (if any)
is.
"new()" also accepts a reference to an option hash which will be used
as the default by "Git::Repository::Command" when working with the
corresponding "Git::Repository" instance.
So this:
my $options = {
git => '/path/to/some/other/git',
env => {
GIT_COMMITTER_EMAIL => 'book@cpan.org',
GIT_COMMITTER_NAME => 'Philippe Bruhat (BooK)',
},
};
my $r = Git::Repository->new(
work_tree => $dir,
$options
);
is equivalent to explicitly passing the option hash to each "run()" or
"command()".
It probably makes no sense to set the "input" option in
"new()", but Git::Repository won't stop you. Note that on some
systems, some git commands may close standard input on startup, which will
cause a "SIGPIPE". Git::Repository::Command will raise an exception.
create( @cmd )¶
The "create()" method is deprecated, and will go away
in the future.
Runs a repository initialization command (like "init" or
"clone") and returns a "Git::Repository" object pointing
to it. @cmd may contain a hashref with options (see Git::Repository::Command.
Do not use the
-q option on such commands. "create()" needs to
parse their output to find the path to the repository.
"create()" also accepts a reference to an option hash which will be
used to set up the returned "Git::Repository" instance.
Now that "create()" is deprecated, instead of:
$r = Git::Repository->create( ... );
simply do it in two steps:
Git::Repository->run( ... );
$r = Git::Repository->new( ... );
METHODS¶
"Git::Repository" supports the following methods:
command( @cmd )¶
Runs the git sub-command and options, and returns a
"Git::Repository::Command" object pointing to the sub-process
running the command.
As described in the Git::Repository::Command documentation, @cmd may also
contain a hashref containing options for the command.
run( @cmd )¶
Runs the command and returns the output as a string in scalar context, or as a
list of lines in list context. Also accepts a hashref of options.
Lines are automatically "chomp"ed.
If the git command printed anything on stderr, it will be printed as warnings.
If the git sub-process exited with status 128 (fatal error), or 129 (usage
message), "run()" will "die()".
git_dir()¶
Returns the repository path.
repo_path()¶
For backward compatibility with versions 1.06 and before,
"repo_path()" it provided as an alias to "git_dir()".
work_tree()¶
Returns the working copy path. Used as current working directory by
"Git::Repository::Command".
wc_path()¶
For backward compatibility with versions 1.06 and before, "wc_path()"
it provided as an alias to "work_tree()".
options()¶
Return the option hash that was passed to "Git::Repository->new()".
version()¶
Return the version of git, as given by "git --version".
Version-comparison "operators"¶
Git evolves very fast, and new features are constantly added. To facilitate the
creation of programs that can properly handle the wide variety of Git versions
seen in the wild, a number of version comparison "operators" are
available.
They are named "version_
op" where
op is the equivalent
of the Perl operators "lt", "gt", "le",
"ge", "eq", "ne". They return a boolean value,
obtained by comparing the version of the git binary and the version string
passed as parameter.
The methods are:
- version_lt( $version )
- version_gt( $version )
- version_le( $version )
- version_ge( $version )
- version_eq( $version )
- version_ne( $version )
All those methods also accept an option hash, just like the others.
Note that there are a small number of cases where the version comparison
operators will
not compare versions correctly for
very old
versions of Git. Typical example is "1.0.0a gt 1.0.0" which should
return true, but doesn't. This only matters in comparisons, only for version
numbers prior to "1.4.0-rc1" (June 2006), and only when the compared
versions are very close.
Other issues exist when comparing development version numbers with one another.
For example, 1.7.1.1 is greater than both "1.7.1.1.gc8c07" and
"1.7.1.1.g5f35a", and 1.7.1 is less than both. Obviously,
"1.7.1.1.gc8c07" will compare as greater than
"1.7.1.1.g5f35a" (asciibetically), but in fact these two version
numbers cannot be compared, as they are two siblings children of the commit
tagged "v1.7.1").
If one were to compute the set of all possible version numbers (as returned by
"git --version") for all git versions that can be compiled from each
commit in the
git.git repository, the result would not be a totally
ordered set. Big deal.
Also, don't be too precise when requiring the minimum version of Git that
supported a given feature. The precise commit in git.git at which a given
feature was added doesn't mean as much as the release branch in which that
commit was merged.
PLUGIN SUPPORT¶
"Git::Repository" intentionally has only few methods. The idea is to
provide a lightweight wrapper around git, to be used to create interesting
tools based on Git.
However, people will want to add extra functionality to
"Git::Repository", the obvious example being a "log()"
method that returns simple objects with useful attributes.
Taking the hypothetical "Git::Repository::Plugin::Hello" module which
source code is listed in the previous reference, the methods it provides would
be loaded and used as follows:
use Git::Repository qw( Hello );
my $r = Git::Repository->new();
print $r->hello();
print $r->hello_gitdir();
It's possible to load only a selection of methods from the plugin:
use Git::Repository [ Hello => 'hello' ];
my $r = Git::Repository->new();
print $r->hello();
# dies: Can't locate object method "hello_gitdir"
print $r->hello_gitdir();
If your plugin lives in another namespace than
"Git::Repository::Plugin::", just prefix the fully qualified class
name with a "+". For example:
use Git::Repository qw( +MyGit::Hello );
See Git::Repository::Plugin about how to create a new plugin.
OTHER PERL GIT WRAPPERS¶
A number of Perl git wrappers already exist. Why create a new one?
I have a lot of ideas of nice things to do with Git as a tool to manipulate
blobs, trees, and tags, that may or may not represent revision history of a
project. A lot of those commands can output huge amounts of data, which I need
to be able to process in chunks. Some of these commands also expect to receive
input.
What follows is a short list of "missing features" that I was looking
for when I looked at the existing Git wrappers on CPAN. They are the
"rational" reason for writing my own (the real reason being of
course "I thought it would be fun, and I enjoyed doing it").
Even though it works well for me and others, "Git::Repository" has its
own shortcomings: it
is a
low-level interface to Git commands,
anything complex requires you to deal with input/output handles, it provides
no high-level interface to generate actual Git commands or process the output
of commands (but have a look at the plugins), it doesn't fully work under
Win32 yet, etc. One the following modules may therefore be better suited for
your needs, depending on what you're trying to achieve.
Git.pm¶
Git.pm is not on CPAN. It is usually packaged with Git, and installed with the
system Perl libraries. Not being on CPAN makes it harder to install in any
Perl. It makes it harder for a CPAN library to depend on it.
It doesn't allow calling "git init" or "git clone".
The "command_bidi_pipe" function especially has problems:
<
http://kerneltrap.org/mailarchive/git/2008/10/24/3789584>
Git::Class¶
Depends on Moose, which seems an unnecessary dependency for a simple wrapper
around Git. The startup penalty could become significant for command-line
tools.
Although it supports "git init" and "git clone" (and has
methods to call any Git command), it is mostly aimed at porcelain commands,
and provides no way to control bidirectional commands (such as "git
commit-tree").
Git::Wrapper¶
Doesn't support streams or bidirectional commands.
AUTHOR¶
Philippe Bruhat (BooK), "<book at cpan.org>"
BUGS¶
Since version 1.17, "Git::Repository" delegates the actual command
execution to "System::Command". Win32 support for that module is
currently very bad (the test suite hangs in a few places). If you'd like
better Win32 support for "Git::Repository", help me improve
"System::Command"!
Please report any bugs or feature requests to "bug-git-repository at
rt.cpan.org", or through the web interface at
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Git-Repository
<
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Git-Repository>. I will
be notified, and then you'll automatically be notified of progress on your bug
as I make changes.
SUPPORT¶
You can find documentation for this module with the perldoc command.
perldoc Git::Repository
You can also look for information at:
- •
- RT: CPAN's request tracker
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Git-Repository
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Git-Repository>
- •
- AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/Git-Repository
<http://annocpan.org/dist/Git-Repository>
- •
- CPAN Ratings
http://cpanratings.perl.org/d/Git-Repository
<http://cpanratings.perl.org/d/Git-Repository>
- •
- Search CPAN
http://search.cpan.org/dist/Git-Repository
<http://search.cpan.org/dist/Git-Repository>
ACKNOWLEDGEMENTS¶
Thanks to Todd Rinalo, who wanted to add more methods to
"Git::Repository", which made me look for a solution that would
preserve the minimalism of "Git::Repository". The
"::Plugin" interface is what I came up with.
COPYRIGHT¶
Copyright 2010-2011 Philippe Bruhat (BooK), all rights reserved.
LICENSE¶
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.