diff options
| -rw-r--r-- | CONTRIBUTING.md | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md new file mode 100644 index 0000000..ff502b4 --- /dev/null +++ b/CONTRIBUTING.md @@ -0,0 +1,167 @@ +Contributing +============ + +License +------- + +`bfs` is licensed under the [Zero-Clause BSD License](https://opensource.org/licenses/0BSD), a maximally permissive license. +Contributions must use the same license. + + +Building +-------- + +`bfs` uses [GNU Make](https://www.gnu.org/software/make/) as its build system. +A simple invocation of + + $ make + +should build `bfs` successfully, with no additional steps necessary. +As usual with `make`, you can run a [parallel build](https://www.gnu.org/software/make/manual/html_node/Parallel.html) with `-j`. +For example, to use all your cores, run `make -j$(nproc)`. + +### Targets + +| Command | Description | +|------------------|---------------------------------------------------------------| +| `make` | Builds just the `bfs` binary | +| `make all` | Builds everything, including the tests (but doesn't run them) | +| `make check` | Builds everything, and runs the tests | +| `make install` | Installs `bfs` (with man page, shell completions, etc.) | +| `make uninstall` | Uninstalls `bfs` | + +### Flag-like targets + +The build system provides a few shorthand targets for handy configurations: + +| Command | Description | +|----------------|-------------------------------------------------------------| +| `make release` | Build `bfs` with optimizations, LTO, and without assertions | +| `make asan` | Enable [AddressSanitizer] | +| `make lsan` | Enable [LeakSanitizer] | +| `make msan` | Enable [MemorySanitizer] | +| `make tsan` | Enable [ThreadSanitizer] | +| `make ubsan` | Enable [UndefinedBehaviorSanitizer] | +| `make gcov` | Enable [code coverage] | + +[AddressSanitizer]: https://github.com/google/sanitizers/wiki/AddressSanitizer +[LeakSanitizer]: https://github.com/google/sanitizers/wiki/AddressSanitizerLeakSanitizer#stand-alone-mode +[MemorySanitizer]: https://github.com/google/sanitizers/wiki/MemorySanitizer +[ThreadSanitizer]: https://github.com/google/sanitizers/wiki/ThreadSanitizerCppManual +[UndefinedBehaviorSanitizer]: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html +[code coverage]: https://gcc.gnu.org/onlinedocs/gcc/Gcov.html + +You can combine multiple flags and other targets (e.g. `make asan ubsan check`), but not all of them will work together. + +### Flags + +Other flags are controlled with `make` variables and/or environment variables. +Here are some of the common ones; check the [`Makefile`](/Makefile) for more. + +| Flag | Description | +|----------------------------------|---------------------------------------------| +| `CC` | The C compiler to use, e.g. `make CC=clang` | +| `CFLAGS`<br>`EXTRA_CFLAGS` | Override/add to the default compiler flags | +| `LDFLAGS`<br>`EXTRA_LDFLAGS` | Override/add to the linker flags | +| `WITH_ACL`<br>`WITH_ATTR`<br>... | Enable/disable optional dependencies | +| `TEST_FLAGS` | `tests.sh` flags for `make check` | +| `DESTDIR` | The root directory for `make install` | +| `PREFIX` | The installation prefix (default: `/usr`) | +| `MANDIR` | The man page installation directory | + +### Dependency tracking + +The build system automatically tracks header dependencies with the `-M` family of compiler options (see `DEPFLAGS` in the `Makefile`). +So if you edit a header file, `make` will rebuild the necessary object files ensuring they don't go out of sync. + +We go one step further than most build systems by tracking the flags that were used for the previous compilation. +That means you can change configurations without having to `make clean`. +For example, + + $ make + $ make release + +will build the project in debug mode and then rebuild it in release mode. + +A side effect of this may be surprising: `make check` by itself will rebuild the project in the default configuration. +To test a different configuration, you'll have to repeat it (e.g. `make release check`). + + +Testing +------- + +`bfs` comes with an extensive testsuite which can be run with + + $ make check + +Most of the testsuite is implemented in the file [`tests.sh`](/tests.sh). +This script contains hundreds of separate test cases. +Most of them are *snapshot tests* which compare `bfs`'s output to a known-good copy saved under [`tests`](/tests). + +You can pass the name of a particular test case (or a few) to run just those tests. +For example: + + $ ./tests.sh test_basic + +If you need to update the reference snapshot, pass `--update`. +It can be handy to generate the snapshot with a different `find` implementation to ensure the output is correct, for example: + + $ ./tests.sh test_basic --bfs=find --update + +But keep in mind, other `find` implementations may not be correct. +To my knowledge, no other implementation passes even the POSIX-compatible subset of the tests: + + $ ./tests.sh --bfs=find --posix + ... + tests passed: 89 + tests failed: 5 + +Run + + $ ./tests.sh --help + +for more details. + +### Validation + +A more thorough testsuite is run by the [CI](https://github.com/tavianator/bfs/actions) and to validate releases. +It builds `bfs` in multiple configurations to test for latent bugs, memory leaks, 32-bit compatibility, etc. +You can run it yourself with + + $ make distcheck + +Some of these tests require `sudo`, and will prompt for your password if necessary. + + +Hacking +------- + +`bfs` is written in [C](https://en.wikipedia.org/wiki/C_(programming_language)), specifically [C99](https://en.wikipedia.org/wiki/C99). +You can get a feel for the coding style by skimming the source code. +[`main.c`](/main.c) contains an overview of the rest of source files. +A quick summary: + +- Tabs for indentation, spaces for alignment. +- Most types and functions should be namespaced with `bfs_`. + Exceptions are made for things that could be generally useful outside of `bfs`. +- Error handling follows the C standard library conventions: return a nonzero `int` or a `NULL` pointer, with the error code in `errno`. + All failure cases should be handled, including `malloc()` failures. +- `goto` is not harmful for cleaning up in error paths. + +### Adding tests + +Both new features and bug fixes should have associated tests. +To add a test, create a new function in `tests.sh` called `test_<something>`. +Snapshot tests use the `bfs_diff` function to automatically compare the generated and expected outputs. +For example, + +```bash +function test_something() { + bfs_diff basic -name something +} +``` + +`basic` is one of the directory trees generated for test cases; others include `links`, `loops`, `deep`, and `rainbow`. + +Run `./tests.sh test_something --update` to generate the reference snapshot (and don't forget to `git add` it). +Finally, add the test case to one of the arrays `posix_tests`, `bsd_tests`, `gnu_tests`, or `bfs_tests` depending on which `find` implementations it should be compatible with. |