1 libgit2 - the Git linkable library
2 ==================================
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11 `libgit2` is a portable, pure C implementation of the Git core methods
12 provided as a linkable library with a solid API, allowing to build Git
13 functionality into your application. Language bindings like
14 [Rugged](https://github.com/libgit2/rugged) (Ruby),
15 [LibGit2Sharp](https://github.com/libgit2/libgit2sharp) (.NET),
16 [pygit2](http://www.pygit2.org/) (Python) and
17 [NodeGit](http://nodegit.org) (Node) allow you to build Git tooling
18 in your favorite language.
20 `libgit2` is used to power Git GUI clients like
21 [GitKraken](https://gitkraken.com/) and [gmaster](https://gmaster.io/)
22 and on Git hosting providers like [GitHub](https://github.com/),
23 [GitLab](https://gitlab.com/) and
24 [Azure DevOps](https://azure.com/devops).
25 We perform the merge every time you click "merge pull request".
27 `libgit2` is licensed under a **very permissive license** (GPLv2 with a special
28 Linking Exception). This basically means that you can link it (unmodified)
29 with any kind of software without having to release its source code.
30 Additionally, the example code has been released to the public domain (see the
31 [separate license](examples/COPYING) for more information).
36 * [Using libgit2](#using-libgit2)
37 * [Quick Start](#quick-start)
38 * [Getting Help](#getting-help)
39 * [What It Can Do](#what-it-can-do)
40 * [Optional dependencies](#optional-dependencies)
41 * [Initialization](#initialization)
42 * [Threading](#threading)
43 * [Conventions](#conventions)
44 * [Building libgit2 - Using CMake](#building-libgit2---using-cmake)
45 * [Building](#building)
46 * [Installation](#installation)
47 * [Advanced Usage](#advanced-usage)
48 * [Compiler and linker options](#compiler-and-linker-options)
52 * [Language Bindings](#language-bindings)
53 * [How Can I Contribute?](#how-can-i-contribute)
59 Most of these instructions assume that you're writing an application
60 in C and want to use libgit2 directly. If you're _not_ using C,
61 and you're writing in a different language or platform like .NET,
62 Node.js, or Ruby, then there is probably a
63 "[language binding](#language-bindings)" that you can use to take care
64 of the messy tasks of calling into native code.
66 But if you _do_ want to use libgit2 directly - because you're building
67 an application in C - then you may be able use an existing binary.
68 There are packages for the
69 [vcpkg](https://github.com/Microsoft/vcpkg) and
70 [conan](https://conan.io/center/libgit2)
71 package managers. And libgit2 is available in
72 [Homebrew](https://formulae.brew.sh/formula/libgit2) and most Linux
75 However, these versions _may_ be outdated and we recommend using the
76 latest version if possible. Thankfully libgit2 is not hard to compile.
81 **Prerequisites** for building libgit2:
83 1. [CMake](https://cmake.org/), and is recommended to be installed into
85 2. [Python](https://www.python.org) is used by our test framework, and
86 should be installed into your `PATH`.
87 3. C compiler: libgit2 is C90 and should compile on most compilers.
88 * Windows: Visual Studio is recommended
89 * Mac: Xcode is recommended
90 * Unix: gcc or clang is recommended.
94 1. Create a build directory beneath the libgit2 source directory, and change
95 into it: `mkdir build && cd build`
96 2. Create the cmake build environment: `cmake ..`
97 3. Build libgit2: `cmake --build .`
99 Trouble with these steps? Read our [troubleshooting guide](docs/troubleshooting.md).
100 More detailed build guidance is available below.
107 - via IRC: join [#libgit2](https://web.libera.chat/#libgit2) on
108 [libera](https://libera.chat).
109 - via Slack: visit [slack.libgit2.org](http://slack.libgit2.org/) to sign up,
110 then join us in `#libgit2`
114 If you have questions about the library, please be sure to check out the
115 [API documentation](http://libgit2.github.com/libgit2/). If you still have
116 questions, reach out to us on Slack or post a question on
117 [StackOverflow](http://stackoverflow.com/questions/tagged/libgit2) (with the `libgit2` tag).
121 Please open a [GitHub Issue](https://github.com/libgit2/libgit2/issues) and
122 include as much information as possible. If possible, provide sample code
123 that illustrates the problem you're seeing. If you're seeing a bug only
124 on a specific repository, please provide a link to it if possible.
126 We ask that you not open a GitHub Issue for help, only for bug reports.
128 **Reporting Security Issues**
130 Please have a look at SECURITY.md.
135 libgit2 provides you with the ability to manage Git repositories in the
136 programming language of your choice. It's used in production to power many
137 applications including GitHub.com, Plastic SCM and Azure DevOps.
139 It does not aim to replace the git tool or its user-facing commands. Some APIs
140 resemble the plumbing commands as those align closely with the concepts of the
141 Git system, but most commands a user would type are out of scope for this
142 library to implement directly.
144 The library provides:
146 * SHA conversions, formatting and shortening
147 * abstracted ODB backend system
148 * commit, tag, tree and blob parsing, editing, and write-back
151 * index file (staging area) manipulation
152 * reference management (including packed references)
153 * config file management
154 * high level repository management
155 * thread safety and reentrancy
156 * descriptive and detailed error messages
157 * ...and more (over 175 different API calls)
159 As libgit2 is purely a consumer of the Git system, we have to
160 adjust to changes made upstream. This has two major consequences:
162 * Some changes may require us to change provided interfaces. While we try to
163 implement functions in a generic way so that no future changes are required,
164 we cannot promise a completely stable API.
165 * As we have to keep up with changes in behavior made upstream, we may lag
166 behind in some areas. We usually to document these incompatibilities in our
167 issue tracker with the label "git change".
169 Optional dependencies
170 =====================
172 While the library provides git functionality without the need for
173 dependencies, it can make use of a few libraries to add to it:
175 - pthreads (non-Windows) to enable threadsafe access as well as multi-threaded pack generation
176 - OpenSSL (non-Windows) to talk over HTTPS and provide the SHA-1 functions
177 - LibSSH2 to enable the SSH transport
178 - iconv (OSX) to handle the HFS+ path encoding peculiarities
183 The library needs to keep track of some global state. Call
187 before calling any other libgit2 functions. You can call this function many times. A matching number of calls to
189 git_libgit2_shutdown();
191 will free the resources. Note that if you have worker threads, you should
192 call `git_libgit2_shutdown` *after* those threads have exited. If you
193 require assistance coordinating this, simply have the worker threads call
194 `git_libgit2_init` at startup and `git_libgit2_shutdown` at shutdown.
199 See [threading](docs/threading.md) for information
204 See [conventions](docs/conventions.md) for an overview of the external
205 and internal API/coding conventions we use.
207 Building libgit2 - Using CMake
208 ==============================
213 `libgit2` builds cleanly on most platforms without any external dependencies.
214 Under Unix-like systems, like Linux, \*BSD and Mac OS X, libgit2 expects `pthreads` to be available;
215 they should be installed by default on all systems. Under Windows, libgit2 uses the native Windows API
218 The `libgit2` library is built using [CMake](<https://cmake.org/>) (version 2.8 or newer) on all platforms.
220 On most systems you can build the library using the following commands
222 $ mkdir build && cd build
226 Alternatively you can point the CMake GUI tool to the CMakeLists.txt file and generate platform specific build project or IDE workspace.
228 If you're not familiar with CMake, [a more detailed explanation](https://preshing.com/20170511/how-to-build-a-cmake-based-project/) may be helpful.
233 Once built, you can run the tests from the `build` directory with the command
237 Alternatively you can run the test suite directly using,
241 Invoking the test suite directly is useful because it allows you to execute
242 individual tests, or groups of tests using the `-s` flag. For example, to
245 $ ./libgit2_tests -sindex
247 To run a single test named `index::racy::diff`, which corresponds to the test
248 function [`test_index_racy__diff`](https://github.com/libgit2/libgit2/blob/main/tests/index/racy.c#L23):
250 $ ./libgit2_tests -sindex::racy::diff
252 The test suite will print a `.` for every passing test, and an `F` for any
253 failing test. An `S` indicates that a test was skipped because it is not
254 applicable to your platform or is particularly expensive.
256 **Note:** There should be _no_ failing tests when you build an unmodified
257 source tree from a [release](https://github.com/libgit2/libgit2/releases),
258 or from the [main branch](https://github.com/libgit2/libgit2/tree/main).
259 Please contact us or [open an issue](https://github.com/libgit2/libgit2/issues)
260 if you see test failures.
265 To install the library you can specify the install prefix by setting:
267 $ cmake .. -DCMAKE_INSTALL_PREFIX=/install/prefix
268 $ cmake --build . --target install
273 For more advanced use or questions about CMake please read <https://cmake.org/Wiki/CMake_FAQ>.
275 The following CMake variables are declared:
277 - `CMAKE_INSTALL_BINDIR`: Where to install binaries to.
278 - `CMAKE_INSTALL_LIBDIR`: Where to install libraries to.
279 - `CMAKE_INSTALL_INCLUDEDIR`: Where to install headers to.
280 - `BUILD_SHARED_LIBS`: Build libgit2 as a Shared Library (defaults to ON)
281 - `BUILD_TESTS`: Build the unit and integration test suites (defaults to ON)
282 - `USE_THREADS`: Build libgit2 with threading support (defaults to ON)
284 To list all build options and their current value, you can do the
287 # Create and set up a build directory
290 # List all build options and their values
293 Compiler and linker options
294 ---------------------------
296 CMake lets you specify a few variables to control the behavior of the
297 compiler and linker. These flags are rarely used but can be useful for
298 64-bit to 32-bit cross-compilation.
300 - `CMAKE_C_FLAGS`: Set your own compiler flags
301 - `CMAKE_FIND_ROOT_PATH`: Override the search path for libraries
302 - `ZLIB_LIBRARY`, `OPENSSL_SSL_LIBRARY` AND `OPENSSL_CRYPTO_LIBRARY`:
303 Tell CMake where to find those specific libraries
304 - `LINK_WITH_STATIC_LIBRARIES`: Link only with static versions of
310 If you want to build a universal binary for Mac OS X, CMake sets it
311 all up for you if you use `-DCMAKE_OSX_ARCHITECTURES="i386;x86_64"`
317 Extract toolchain from NDK using, `make-standalone-toolchain.sh` script.
318 Optionally, crosscompile and install OpenSSL inside of it. Then create CMake
319 toolchain file that configures paths to your crosscompiler (substitute `{PATH}`
320 with full path to the toolchain):
322 SET(CMAKE_SYSTEM_NAME Linux)
323 SET(CMAKE_SYSTEM_VERSION Android)
325 SET(CMAKE_C_COMPILER {PATH}/bin/arm-linux-androideabi-gcc)
326 SET(CMAKE_CXX_COMPILER {PATH}/bin/arm-linux-androideabi-g++)
327 SET(CMAKE_FIND_ROOT_PATH {PATH}/sysroot/)
329 SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
330 SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
331 SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
333 Add `-DCMAKE_TOOLCHAIN_FILE={pathToToolchainFile}` to cmake command
339 If you want to build the library in MinGW environment with SSH support enabled,
340 you may need to pass `-DCMAKE_LIBRARY_PATH="${MINGW_PREFIX}/${MINGW_CHOST}/lib/"` flag
341 to CMake when configuring. This is because CMake cannot find the Win32 libraries in
342 MinGW folders by default and you might see an error message stating that CMake
343 could not resolve `ws2_32` library during configuration.
345 Another option would be to install `msys2-w32api-runtime` package before configuring.
346 This package installs the Win32 libraries into `/usr/lib` folder which is by default
347 recognized as the library path by CMake. Please note though that this package is meant
348 for MSYS subsystem which is different from MinGW.
351 ==================================
353 Here are the bindings to libgit2 that are currently available:
356 * libqgit2, Qt bindings <https://projects.kde.org/projects/playground/libs/libqgit2/repository/>
358 * chicken-git <https://wiki.call-cc.org/egg/git>
360 * dlibgit <https://github.com/s-ludwig/dlibgit>
362 * GitForDelphi <https://github.com/libgit2/GitForDelphi>
363 * libgit2-delphi <https://github.com/todaysoftware/libgit2-delphi>
365 * Geef <https://github.com/carlosmn/geef>
367 * git2go <https://github.com/libgit2/git2go>
369 * libgit2-glib <https://wiki.gnome.org/Projects/Libgit2-glib>
371 * Guile-Git <https://gitlab.com/guile-git/guile-git>
373 * hgit2 <https://github.com/jwiegley/gitlib>
375 * Jagged <https://github.com/ethomson/jagged>
376 * Git24j <https://github.com/git24j/git24j>
377 * Javascript / WebAssembly ( browser and nodejs )
378 * WASM-git <https://github.com/petersalomonsen/wasm-git>
380 * LibGit2.jl <https://github.com/JuliaLang/julia/tree/master/stdlib/LibGit2>
382 * luagit2 <https://github.com/libgit2/luagit2>
384 * libgit2sharp <https://github.com/libgit2/libgit2sharp>
386 * nodegit <https://github.com/nodegit/nodegit>
388 * objective-git <https://github.com/libgit2/objective-git>
390 * ocaml-libgit2 <https://github.com/fxfactorial/ocaml-libgit2>
391 * Parrot Virtual Machine
392 * parrot-libgit2 <https://github.com/letolabs/parrot-libgit2>
394 * Git-Raw <https://github.com/jacquesg/p5-Git-Raw>
396 * php-git <https://github.com/libgit2/php-git>
398 * pygit2 <https://github.com/libgit2/pygit2>
400 * gert <https://docs.ropensci.org/gert>
401 * git2r <https://github.com/ropensci/git2r>
403 * Rugged <https://github.com/libgit2/rugged>
405 * git2-rs <https://github.com/rust-lang/git2-rs>
407 * SwiftGit2 <https://github.com/SwiftGit2/SwiftGit2>
409 * libgit2.vapi <https://github.com/apmasell/vapis/blob/master/libgit2.vapi>
411 If you start another language binding to libgit2, please let us know so
412 we can add it to the list.
414 How Can I Contribute?
415 ==================================
417 We welcome new contributors! We have a number of issues marked as
418 ["up for grabs"](https://github.com/libgit2/libgit2/issues?q=is%3Aissue+is%3Aopen+label%3A%22up+for+grabs%22)
420 ["easy fix"](https://github.com/libgit2/libgit2/issues?utf8=✓&q=is%3Aissue+is%3Aopen+label%3A%22easy+fix%22)
421 that are good places to jump in and get started. There's much more detailed
422 information in our list of [outstanding projects](docs/projects.md).
424 Please be sure to check the [contribution guidelines](docs/contributing.md) to
425 understand our workflow, and the libgit2 [coding conventions](docs/conventions.md).
428 ==================================
430 `libgit2` is under GPL2 **with linking exception**. This means you can link to
431 and use the library from any program, proprietary or open source; paid or
432 gratis. However, if you modify libgit2 itself, you must distribute the
433 source to your modified version of libgit2.
435 See the [COPYING file](COPYING) for the full license text.