Contributing to Neovim ====================== Getting started --------------- If you want to help but don't know where to start, here are some low-risk/isolated tasks: - Try a [complexity:low] issue. - Fix bugs found by [Clang](#clang-scan-build), [PVS](#pvs-studio) or [Coverity](#coverity). - [Improve documentation](#documentation) - [Merge a Vim patch] (requires strong familiarity with Vim) - NOTE: read the above link before sending improvements to "runtime files" (anything in `runtime/`). - Vimscript and documentation files are (mostly) maintained by [Vim](https://github.com/vim/vim), not Nvim. - Lua files are maintained by Nvim. Reporting problems ------------------ - [Check the FAQ][wiki-faq]. - [Search existing issues][github-issues] (including closed!) - Update Neovim to the latest version to see if your problem persists. - Try to reproduce with `nvim --clean` ("factory defaults"). - [Bisect](https://neovim.io/doc/user/starting.html#bisect) your config: disable plugins incrementally, to narrow down the cause of the issue. - [Bisect][git-bisect] Neovim's source code to find the cause of a regression, if you can. This is _extremely_ helpful. - When reporting a crash, [include a stacktrace](https://github.com/neovim/neovim/wiki/FAQ#backtrace-linux). - Use [ASAN/UBSAN](#clang-sanitizers-asan-and-ubsan) to get detailed errors for segfaults and undefined behavior. - Check the logs. `:edit $NVIM_LOG_FILE` - Include `cmake --system-information` for build-related issues. Developer guidelines -------------------- - Read [:help dev](https://neovim.io/doc/user/develop.html#dev) and [:help dev-doc][dev-doc-guide] if you are working on Nvim core. - Read [:help dev-ui](https://neovim.io/doc/user/develop.html#dev-ui) if you are developing a UI. - Read [:help dev-api-client](https://neovim.io/doc/user/develop.html#dev-api-client) if you are developing an API client. - Install `ninja` for faster builds of Nvim. ```bash sudo apt-get install ninja-build make distclean make # Nvim build system uses ninja automatically, if available. ``` - Install `ccache` for faster rebuilds of Nvim. Nvim will use it automatically if it's found. To disable caching use: ```bash CCACHE_DISABLE=true make ``` Pull requests (PRs) --------------------- - To avoid duplicate work, create a draft pull request. - Your PR must include [test coverage][run-tests]. - Avoid cosmetic changes to unrelated files in the same commit. - Use a [feature branch][git-feature-branch] instead of the master branch. - Use a _rebase workflow_ for all PRs. - After addressing review comments, it's fine to force-push. ### Merging to master For maintainers: when a PR is ready to merge to master, - prefer _Squash Merge_ for "single-commit PRs" (when the PR has only one meaningful commit). - prefer _Merge_ for "multi-commit PRs" (when the PR has multiple meaningful commits). ### Stages: Draft and Ready for review Pull requests have two stages: Draft and Ready for review. 1. [Create a Draft PR][pr-draft] while you are _not_ requesting feedback as you are still working on the PR. - You can skip this if your PR is ready for review. 2. [Change your PR to ready][pr-ready] when the PR is ready for review. - You can convert back to Draft at any time. Do __not__ add labels like `[RFC]` or `[WIP]` in the title to indicate the state of your PR: this just adds noise. Non-Draft PRs are assumed to be open for comments; if you want feedback from specific people, `@`-mention them in a comment. ### Commit messages Follow the [conventional commits guidelines][conventional_commits] to *make reviews easier* and to make the VCS/git logs more valuable. The general structure of a commit message is: ``` ([optional scope]): [optional body] [optional footer(s)] ``` - Prefix the commit subject with one of these [_types_](https://github.com/commitizen/conventional-commit-types/blob/master/index.json): - `build`, `ci`, `docs`, `feat`, `fix`, `perf`, `refactor`, `revert`, `test`, `vim-patch` - You can **ignore this for "fixup" commits** or any commits you expect to be squashed. - Append optional scope to _type_ such as `(lsp)`, `(treesitter)`, `(float)`, … - _Description_ shouldn't start with a capital letter or end in a period. - Use the _imperative voice_: "Fix bug" rather than "Fixed bug" or "Fixes bug." - Try to keep the first line under 72 characters. - A blank line must follow the subject. - Breaking API changes must be indicated by 1. "!" after the type/scope, and 2. a "BREAKING CHANGE" footer describing the change. Example: ``` refactor(provider)!: drop support for Python 2 BREAKING CHANGE: refactor to use Python 3 features since Python 2 is no longer supported. ``` ### News High level release notes are maintained in [news.txt](runtime/doc/news.txt). A PR is not required to add a news item but is generally recommended. ### Automated builds (CI) Each pull request must pass the automated builds on [Cirrus CI] and [GitHub Actions]. - CI builds are compiled with [`-Werror`][gcc-warnings], so compiler warnings will fail the build. - If any tests fail, the build will fail. See [test/README.md#running-tests][run-tests] to run tests locally. - CI runs [ASan] and other analyzers. - To run valgrind locally: `VALGRIND=1 make test` - To run Clang ASan/UBSan locally: `CC=clang make CMAKE_FLAGS="-DENABLE_ASAN_UBSAN=ON"` - The [lint](#lint) build checks modified lines _and their immediate neighbors_, to encourage incrementally updating the legacy style to meet our [style](#style). (See [#3174][3174] for background.) - CI for FreeBSD runs on [Cirrus CI]. - To see CI results faster in your PR, you can temporarily set `TEST_FILE` in [test.yml](https://github.com/neovim/neovim/blob/e35b9020b16985eee26e942f9a3f6b045bc3809b/.github/workflows/test.yml#L29). ### Clang scan-build View the [Clang report] to see potential bugs found by the Clang [scan-build](https://clang-analyzer.llvm.org/scan-build.html) analyzer. - Search the Neovim commit history to find examples: ```bash git log --oneline --no-merges --grep clang ``` - To verify a fix locally, run `scan-build` like this: ```bash rm -rf build/ scan-build --use-analyzer=/usr/bin/clang make ``` ### PVS-Studio View the [PVS report](https://neovim.io/doc/reports/pvs/PVS-studio.html.d/) to see potential bugs found by [PVS Studio](https://www.viva64.com/en/pvs-studio/). - Use this format for commit messages (where `{id}` is the PVS warning-id)): ``` fix(PVS/V{id}): {description} ``` - Search the Neovim commit history to find examples: ```bash git log --oneline --no-merges --grep PVS ``` - Try `./scripts/pvscheck.sh` to run PVS locally. ### Coverity [Coverity](https://scan.coverity.com/projects/neovim-neovim) runs against the master build. To view the defects, just request access; you will be approved. - Use this format for commit messages (where `{id}` is the CID (Coverity ID); ([example](https://github.com/neovim/neovim/pull/804))): ``` fix(coverity/{id}): {description} ``` - Search the Neovim commit history to find examples: ```bash git log --oneline --no-merges --grep coverity ``` ### Clang sanitizers (ASAN and UBSAN) ASAN/UBSAN can be used to detect memory errors and other common forms of undefined behavior at runtime in debug builds. - To build Neovim with sanitizers enabled, use ``` rm -rf build && CMAKE_EXTRA_FLAGS="-DCMAKE_C_COMPILER=clang -DENABLE_ASAN_UBSAN=1" make ``` - When running Neovim, use ``` ASAN_OPTIONS=log_path=/tmp/nvim_asan nvim args... ``` - If Neovim exits unexpectedly, check `/tmp/nvim_asan.{PID}` (or your preferred `log_path`) for log files with error messages. Coding ------ ### Lint You can run the linter locally by: ```bash make lint ``` ### Style - You can format files by using: ```bash make format # or formatc, formatlua ``` This will format changed Lua and C files with all appropriate flags set. - Style rules are (mostly) defined by `src/uncrustify.cfg` which tries to match the [style-guide]. To use the Nvim `gq` command with `uncrustify`: ```vim if !empty(findfile('src/uncrustify.cfg', ';')) setlocal formatprg=uncrustify\ -q\ -l\ C\ -c\ src/uncrustify.cfg\ --no-backup endif ``` The required version of `uncrustify` is specified in `uncrustify.cfg`. - There is also `.clang-format` which has drifted from the [style-guide], but is available for reference. To use the Nvim `gq` command with `clang-format`: ```vim if !empty(findfile('.clang-format', ';')) setlocal formatprg=clang-format\ -style=file endif ``` ### Navigate - Set `blame.ignoreRevsFile` to ignore [noisy commits](https://github.com/neovim/neovim/commit/2d240024acbd68c2d3f82bc72cb12b1a4928c6bf) in git blame: ```bash git config blame.ignoreRevsFile .git-blame-ignore-revs ``` - Recommendation is to use **[clangd]**. Can use the maintained config in [nvim-lspconfig/clangd]. - Explore the source code [on the web](https://sourcegraph.com/github.com/neovim/neovim). ### Includes For managing includes in C files, use [include-what-you-use]. - [Install include-what-you-use][include-what-you-use-install] - To see which includes needs fixing use the cmake preset `iwyu`: ```bash cmake --preset iwyu cmake --build build ``` - There's also a make target that automatically fixes the suggestions from IWYU: ```bash make iwyu ``` See [#549][549] for more details. ### Lua runtime files Most of the Lua core [`runtime/`](./runtime) modules are precompiled to bytecode, so changes to those files won't get used unless you rebuild Nvim or by passing `--luamod-dev` and `$VIMRUNTIME`. For example, try adding a function to `runtime/lua/vim/_editor.lua` then: ```bash VIMRUNTIME=./runtime ./build/bin/nvim --luamod-dev ``` Documentation ------------- Read [:help dev-doc][dev-doc-guide] to understand the expected documentation style and conventions. ### Generating :help Many `:help` docs are autogenerated from (C or Lua) docstrings. To generate the documentation run: ```bash make doc ``` If you need to modify or debug the documentation flow, these are the main files: - `./scripts/gen_vimdoc.py`: Main doc generator. Drives doxygen to generate xml files, and scrapes those xml files to render vimdoc files. - `./scripts/lua2dox.lua`: Used by `gen_vimdoc.py` to transform Lua files into a format compatible with doxygen. - `./scripts/gen_eval_files.lua`: Generates documentation and Lua type files from metadata files: ``` runtime/lua/vim/* => runtime/doc/lua.txt runtime/lua/vim/* => runtime/doc/lua.txt runtime/lua/vim/lsp/ => runtime/doc/lsp.txt src/nvim/api/* => runtime/doc/api.txt src/nvim/eval.lua => runtime/doc/builtin.txt src/nvim/options.lua => runtime/doc/options.txt ``` ### Lua docstrings Use [LuaLS] annotations in Lua docstrings to annotate parameter types, return types, etc. See [:help dev-doc-lua][dev-doc-lua]. - The template for function documentation is: ```lua --- {Brief} --- --- {Long explanation} --- --- @param arg1 type {description} --- @param arg2 type {description} --- ... --- --- @return type {description} ``` - If possible, add type information (`table`, `string`, `number`, ...). Multiple valid types are separated by a bar (`string|table`). Indicate optional parameters via `type|nil`. - If a function in your Lua module should _not_ be documented, add `@nodoc`. - If the function is internal or otherwise non-public add `@private`. - Private functions usually should be underscore-prefixed (named "_foo", not "foo"). - Mark deprecated functions with `@deprecated`. Reviewing --------- To help review pull requests, start with [this checklist][review-checklist]. Reviewing can be done on GitHub, but you may find it easier to do locally. Using [GitHub CLI][gh], you can create a new branch with the contents of a pull request, e.g. [#1820][1820]: ```bash gh pr checkout https://github.com/neovim/neovim/pull/1820 ``` Use [`git log -p master..FETCH_HEAD`][git-history-filtering] to list all commits in the feature branch which aren't in the `master` branch; `-p` shows each commit's diff. To show the whole surrounding function of a change as context, use the `-W` argument as well. [549]: https://github.com/neovim/neovim/issues/549 [1820]: https://github.com/neovim/neovim/pull/1820 [3174]: https://github.com/neovim/neovim/issues/3174 [ASan]: http://clang.llvm.org/docs/AddressSanitizer.html [Cirrus CI]: https://cirrus-ci.com/github/neovim/neovim [Clang report]: https://neovim.io/doc/reports/clang/ [GitHub Actions]: https://github.com/neovim/neovim/actions [clangd]: https://clangd.llvm.org [Merge a Vim patch]: https://github.com/neovim/neovim/wiki/Merging-patches-from-upstream-Vim [complexity:low]: https://github.com/neovim/neovim/issues?q=is%3Aopen+is%3Aissue+label%3Acomplexity%3Alow [conventional_commits]: https://www.conventionalcommits.org [dev-doc-guide]: https://neovim.io/doc/user/develop.html#dev-doc [dev-doc-lua]: https://neovim.io/doc/user/develop.html#dev-lua-doc [LuaLS]: https://github.com/LuaLS/lua-language-server/wiki/Annotations [gcc-warnings]: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html [gh]: https://cli.github.com/ [git-bisect]: http://git-scm.com/book/en/v2/Git-Tools-Debugging-with-Git [git-feature-branch]: https://www.atlassian.com/git/tutorials/comparing-workflows [git-history-filtering]: https://www.atlassian.com/git/tutorials/git-log/filtering-the-commit-history [git-history-rewriting]: http://git-scm.com/book/en/v2/Git-Tools-Rewriting-History [git-rebasing]: http://git-scm.com/book/en/v2/Git-Branching-Rebasing [github-issues]: https://github.com/neovim/neovim/issues [include-what-you-use-install]: https://github.com/include-what-you-use/include-what-you-use#how-to-install [include-what-you-use]: https://github.com/include-what-you-use/include-what-you-use#using-with-cmake [lua-language-server]: https://github.com/sumneko/lua-language-server/ [master error list]: https://raw.githubusercontent.com/neovim/doc/gh-pages/reports/clint/errors.json [nvim-lspconfig/clangd]: https://github.com/neovim/nvim-lspconfig/blob/master/doc/server_configurations.md#clangd [pr-draft]: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request [pr-ready]: https://docs.github.com/en/github/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/changing-the-stage-of-a-pull-request [review-checklist]: https://github.com/neovim/neovim/wiki/Code-review-checklist [run-tests]: https://github.com/neovim/neovim/blob/master/test/README.md#running-tests [style-guide]: https://neovim.io/doc/user/dev_style.html#dev-style [uncrustify]: http://uncrustify.sourceforge.net/ [wiki-contribute-help]: https://github.com/neovim/neovim/wiki/contribute-%3Ahelp [wiki-faq]: https://github.com/neovim/neovim/wiki/FAQ