GitHub - libgit2/libgit2: A cross-platform, linkable library implementation of Git that you can use in your application.
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libgit2 is a portable, pure C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application.
libgit2 is used in a variety of places, from GUI clients to hosting providers ("forges") and countless utilities and applications in between. Because it's written in C, it can be made available to any other programming language through "bindings", so you can use it in
,
,
,
,
, and more.
libgit2 is licensed under a very permissive license (GPLv2 with a special Linking Exception). This means that you can link against the library with any kind of software without making that software fall under the GPL. Changes to libgit2 would still be covered under its GPL license.
Table of Contents
Building libgit2 - Using CMake
Using libgit2
Most of these instructions assume that you're writing an application in C and want to use libgit2 directly. If you're not using C, and you're writing in a different language or platform like .NET, Node.js, or Ruby, then there is probably a "
" that you can use to take care of the messy tasks of calling into native code.
But if you do want to use libgit2 directly - because you're building an application in C - then you may be able use an existing binary. There are packages for the
and
package managers. And libgit2 is available in
and most Linux distributions.
However, these versions may be outdated and we recommend using the latest version if possible. Thankfully libgit2 is not hard to compile.
Quick Start
Prerequisites for building libgit2:
, and is recommended to be installed into your PATH.
is used by our test framework, and should be installed into your PATH.
C compiler: libgit2 is C90 and should compile on most compilers. Windows: Visual Studio is recommended
Mac: Xcode is recommended
Unix: gcc or clang is recommended.
Build
Create a build directory beneath the libgit2 source directory, and change into it: mkdir build && cd build
Create the cmake build environment: cmake ..
Build libgit2: cmake --build .
Trouble with these steps? Read our
. More detailed build guidance is available below.
Getting Help
Chat with us
via IRC: join
on
.
via Slack: visit
to sign up, then join us in #libgit2
Getting Help
If you have questions about the library, please be sure to check out the
. If you still have questions, reach out to us on Slack or post a question on
(with the libgit2 tag).
Reporting Bugs
Please open a
and include as much information as possible. If possible, provide sample code that illustrates the problem you're seeing. If you're seeing a bug only on a specific repository, please provide a link to it if possible.
We ask that you not open a GitHub Issue for help, only for bug reports.
Reporting Security Issues
Please have a look at SECURITY.md.
What It Can Do
libgit2 provides you with the ability to manage Git repositories in the programming language of your choice. It's used in production to power many applications including GitHub.com, Plastic SCM and Azure DevOps.
It does not aim to replace the git tool or its user-facing commands. Some APIs resemble the plumbing commands as those align closely with the concepts of the Git system, but most commands a user would type are out of scope for this library to implement directly.
The library provides:
SHA conversions, formatting and shortening
abstracted ODB backend system
commit, tag, tree and blob parsing, editing, and write-back
tree traversal
revision walking
index file (staging area) manipulation
reference management (including packed references)
config file management
high level repository management
thread safety and reentrancy
descriptive and detailed error messages
...and more (over 175 different API calls)
As libgit2 is purely a consumer of the Git system, we have to adjust to changes made upstream. This has two major consequences:
Some changes may require us to change provided interfaces. While we try to implement functions in a generic way so that no future changes are required, we cannot promise a completely stable API.
As we have to keep up with changes in behavior made upstream, we may lag behind in some areas. We usually to document these incompatibilities in our issue tracker with the label "git change".
Optional dependencies
While the library provides git functionality with very few dependencies, some recommended dependencies are used for performance or complete functionality.
Hash generation: Git uses SHA1DC (collision detecting SHA1) for its default hash generation. SHA256 support is experimental, and optimized support is provided by system libraries on macOS and Windows, or by the HTTPS library on Unix systems when available.
Threading: is provided by the system libraries on Windows, and pthreads on Unix systems.
HTTPS: is provided by the system libraries on macOS and Windows, or by OpenSSL or mbedTLS on other Unix systems.
SSH: is provided by
or by invoking
.
Unicode: is provided by the system libraries on Windows and macOS.
Initialization
The library needs to keep track of some global state. Call
git_libgit2_init(); before calling any other libgit2 functions. You can call this function many times. A matching number of calls to
git_libgit2_shutdown(); will free the resources. Note that if you have worker threads, you should call git_libgit2_shutdownafter those threads have exited. If you require assistance coordinating this, simply have the worker threads call git_libgit2_init at startup and git_libgit2_shutdown at shutdown.
Threading
See
for information
Conventions
See
for an overview of the external and internal API/coding conventions we use.
Building libgit2 - Using CMake
Building
libgit2 builds cleanly on most platforms without any external dependencies as a requirement. libgit2 is built using
(version 2.8 or newer) on all platforms.
On most systems you can build the library using the following commands
$ mkdir build && cd build $ cmake .. $ cmake --build . To include the examples in the build, use cmake -DBUILD_EXAMPLES=ON .. instead of cmake ... The built executable for the examples can then be found in build/examples, relative to the toplevel directory.
Alternatively you can point the CMake GUI tool to the CMakeLists.txt file and generate platform specific build project or IDE workspace.
If you're not familiar with CMake,
may be helpful.
Advanced Options
You can specify a number of options to cmake that will change the way libgit2 is built. To use this, specify -Doption=value during the initial cmake configuration. For example, to build the fuzzer suite:
$ mkdir build && cd build $ cmake -DBUILD_FUZZERS=ON .. $ cmake --build . Build options:
BUILD_EXAMPLES=ON: builds the suite of example code
BUILD_FUZZERS=ON: builds the fuzzing suite
ENABLE_WERROR=ON: build with -Werror or the equivalent, which turns compiler warnings into errors in the libgit2 codebase (but not its dependencies)
Dependency options:
USE_SSH=type: enables SSH support and optionally selects the provider; type can be set to libssh2 or exec (which will execute an external OpenSSH command). ON implies libssh2; defaults to OFF.
USE_HTTPS=type: enables HTTPS support and optionally selects the provider; type can be set to OpenSSL, OpenSSL-Dynamic (to not link against OpenSSL, but load it dynamically), SecureTransport, Schannel or WinHTTP; the default is SecureTransport on macOS, WinHTTP on Windows, and whichever of OpenSSL or mbedTLS is detected on other platforms. Defaults to ON.
USE_SHA1=type: selects the SHA1 mechanism to use; type can be set to CollisionDetection, HTTPS to use the system or HTTPS provider, or one of OpenSSL, OpenSSL-Dynamic, OpenSSL-FIPS (to use FIPS compliant routines in OpenSSL), CommonCrypto, or Schannel. Defaults to CollisionDetection. This option is retained for backward compatibility and should not be changed.
USE_SHA256=type: selects the SHA256 mechanism to use; type can be set to HTTPS to use the system or HTTPS driver, builtin, or one of OpenSSL, OpenSSL-Dynamic, OpenSSL-FIPS (to use FIPS compliant routines in OpenSSL), CommonCrypto, or Schannel. Defaults to HTTPS.
USE_GSSAPI=<on/off>: enables GSSAPI for SPNEGO authentication on Unix. Defaults to OFF.
USE_HTTP_PARSER=type: selects the HTTP Parser; either http-parser for an external
dependency, llhttp for an external
dependency, or builtin. Defaults to builtin.
REGEX_BACKEND=type: selects the regular expression backend to use; one of regcomp_l, pcre2, pcre, regcomp, or builtin. The default is to use regcomp_l where available, PCRE if found, otherwise, to use the builtin.
USE_BUNDLED_ZLIB=type: selects the bundled zlib; either ON or OFF. Defaults to using the system zlib if available, falling back to the bundled zlib.
Locating Dependencies
The libgit2 project uses cmake since it helps with cross-platform projects, especially those with many dependencies. If your dependencies are in non-standard places, you may want to use the _ROOT_DIR options to specify their location. For example, to specify an OpenSSL location:
$ cmake -DOPENSSL_ROOT_DIR=/tmp/openssl-3.3.2 .. Since these options are general to CMake, their
may be helpful. If you have questions about dependencies, please
.
Running Tests
Once built, you can run the tests from the build directory with the command
$ ctest -V Alternatively you can run the test suite directly using,
$ ./libgit2_tests Invoking the test suite directly is useful because it allows you to execute individual tests, or groups of tests using the -s flag. For example, to run the index tests:
$ ./libgit2_tests -sindex To run a single test named index::racy::diff, which corresponds to the test function
:
$ ./libgit2_tests -sindex::racy::diff The test suite will print a . for every passing test, and an F for any failing test. An S indicates that a test was skipped because it is not applicable to your platform or is particularly expensive.
Note: There should be no failing tests when you build an unmodified source tree from a
, or from the
. Please contact us or
if you see test failures.
Installation
To install the library you can specify the install prefix by setting:
$ cmake .. -DCMAKE_INSTALL_PREFIX=/install/prefix $ cmake --build . --target install Advanced Usage
For more advanced use or questions about CMake please read the
.
The following CMake variables are declared:
CMAKE_INSTALL_BINDIR: Where to install binaries to.
CMAKE_INSTALL_LIBDIR: Where to install libraries to.
CMAKE_INSTALL_INCLUDEDIR: Where to install headers to.
BUILD_SHARED_LIBS: Build libgit2 as a Shared Library (defaults to ON)
BUILD_TESTS: Build the unit and integration test suites (defaults to ON)
USE_THREADS: Build libgit2 with threading support (defaults to ON)
To list all build options and their current value, you can do the following:
# Create and set up a build directory $ mkdir build && cd build $ cmake .. # List all build options and their values $ cmake -L Compiler and linker options
There are several options that control the behavior of the compiler and linker. These flags may be useful for cross-compilation or specialized setups.
CMAKE_C_FLAGS: Set your own compiler flags
CMAKE_C_STANDARD: the C standard to compile against; defaults to C90
CMAKE_C_EXTENSIONS: whether compiler extensions are supported; defaults to OFF
CMAKE_FIND_ROOT_PATH: Override the search path for libraries
ZLIB_LIBRARY, OPENSSL_SSL_LIBRARY AND OPENSSL_CRYPTO_LIBRARY: Tell CMake where to find those specific libraries
LINK_WITH_STATIC_LIBRARIES: Link only with static versions of system libraries
macOS
If you'd like to work with Xcode, you can generate an Xcode project with "-G Xcode".
# Create and set up a build directory $ mkdir build && cd build $ cmake -G Xcode .. Tip
Universal binary support:
If you want to build a universal binary for macOS 11.0+, CMake sets it all up for you if you use -DCMAKE_OSX_ARCHITECTURES="x86_64;arm64" when configuring.
[Deprecated] If you want to build a universal binary for Mac OS X (10.4.4 ~ 10.6), CMake sets it all up for you if you use -DCMAKE_OSX_ARCHITECTURES="i386;x86_64" when configuring.
iOS
Get an iOS cmake toolchain File:
You can use a pre-existing toolchain file like
or write your own.
Specify the toolchain and system Name:
The CMAKE_TOOLCHAIN_FILE variable points to the toolchain file for iOS.
The CMAKE_SYSTEM_NAME should be set to iOS.
Example Command:
Assuming you're using the ios-cmake toolchain, the command might look like this:
cmake -G Xcode -DCMAKE_TOOLCHAIN_FILE=path/to/ios.toolchain.cmake -DCMAKE_SYSTEM_NAME=iOS -DPLATFORM=OS64 .. Build the Project:
After generating the project, open the .xcodeproj file in Xcode, select your iOS device or simulator as the target, and build your project.
Android
Extract toolchain from NDK using, make-standalone-toolchain.sh script. Optionally, crosscompile and install OpenSSL inside of it. Then create CMake toolchain file that configures paths to your crosscompiler (substitute {PATH} with full path to the toolchain):
SET(CMAKE_SYSTEM_NAME Linux) SET(CMAKE_SYSTEM_VERSION Android) SET(CMAKE_C_COMPILER {PATH}/bin/arm-linux-androideabi-gcc) SET(CMAKE_CXX_COMPILER {PATH}/bin/arm-linux-androideabi-g++) SET(CMAKE_FIND_ROOT_PATH {PATH}/sysroot/) SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER) SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY) SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY) Add -DCMAKE_TOOLCHAIN_FILE={pathToToolchainFile} to cmake command when configuring.
MinGW
If you want to build the library in MinGW environment with SSH support enabled, you may need to pass -DCMAKE_LIBRARY_PATH="${MINGW_PREFIX}/${MINGW_CHOST}/lib/" flag to CMake when configuring. This is because CMake cannot find the Win32 libraries in MinGW folders by default and you might see an error message stating that CMake could not resolve ws2_32 library during configuration.
Another option would be to install msys2-w32api-runtime package before configuring. This package installs the Win32 libraries into /usr/lib folder which is by default recognized as the library path by CMake. Please note though that this package is meant for MSYS subsystem which is different from MinGW.
Language Bindings
Here are the bindings to libgit2 that are currently available:
C++ libqgit2, Qt bindings
https://projects.kde.org/projects/playground/libs/libqgit2/repository/
Chicken Scheme chicken-git
https://wiki.call-cc.org/egg/git
D dlibgit
https://github.com/s-ludwig/dlibgit
Dart git2dart
https://github.com/DartGit-dev/git2dart
Delphi GitForDelphi
https://github.com/libgit2/GitForDelphi
libgit2-delphi
https://github.com/todaysoftware/libgit2-delphi
Erlang Geef
https://github.com/carlosmn/geef
Go git2go
https://github.com/libgit2/git2go
GObject libgit2-glib
https://wiki.gnome.org/Projects/Libgit2-glib
Guile Guile-Git
https://gitlab.com/guile-git/guile-git
Haskell hgit2
https://github.com/jwiegley/gitlib
Java Jagged
https://github.com/ethomson/jagged
Git24j
https://github.com/git24j/git24j
Javascript / WebAssembly ( browser and nodejs ) WASM-git
https://github.com/petersalomonsen/wasm-git
Julia LibGit2.jl
https://github.com/JuliaLang/julia/tree/master/stdlib/LibGit2
Lua luagit2
https://github.com/libgit2/luagit2
.NET libgit2sharp
https://github.com/libgit2/libgit2sharp
Node.js nodegit
https://github.com/nodegit/nodegit
Objective-C objective-git
https://github.com/libgit2/objective-git
OCaml ocaml-libgit2
https://github.com/fxfactorial/ocaml-libgit2
Parrot Virtual Machine parrot-libgit2
https://github.com/letolabs/parrot-libgit2
Perl Git-Raw
https://github.com/jacquesg/p5-Git-Raw
Pharo Smalltalk libgit2-pharo-bindings
https://github.com/pharo-vcs/libgit2-pharo-bindings
PHP php-git2
https://github.com/RogerGee/php-git2
Python pygit2
https://github.com/libgit2/pygit2
R gert
https://docs.ropensci.org/gert
git2r
https://github.com/ropensci/git2r
Ruby Rugged
https://github.com/libgit2/rugged
Rust git2-rs
https://github.com/rust-lang/git2-rs
Swift SwiftGit2
https://github.com/SwiftGit2/SwiftGit2
SwiftGitX
https://github.com/ibrahimcetin/SwiftGitX
swift-libgit2
https://github.com/swift-developer-tools/swift-libgit2
Tcl lg2
https://github.com/apnadkarni/tcl-libgit2
Vala libgit2.vapi
https://github.com/apmasell/vapis/blob/master/libgit2.vapi
If you start another language binding to libgit2, please let us know so we can add it to the list.
How Can I Contribute?
We welcome new contributors! We have a number of issues marked as
and
that are good places to jump in and get started. There's much more detailed information in our list of
.
Please be sure to check the
to understand our workflow, and the libgit2
.
License
libgit2 is under GPL2 with linking exception. This means you can link to and use the library from any program, proprietary or open source; paid or gratis. However, if you modify libgit2 itself, you must distribute the source to your modified version of libgit2.
See the
for the full license text.