1# Checklist for making changes to `libpldm` 2 3## Philosophy and influences 4 5- [Good Practices in Library Design, Implementation, and Maintenance - Ulrich 6 Drepper][goodpractice] 7 8[goodpractice]: https://www.akkadia.org/drepper/goodpractice.pdf 9 10- [How Do I Make This Hard to Misuse? - Rusty Russell][rusty-api-scale-good] 11 12[rusty-api-scale-good]: https://ozlabs.org/~rusty/index.cgi/tech/2008-03-30.html 13 14- [What If I Don't Actually Like My Users? - Rusty Russell][rusty-api-scale-bad] 15 16[rusty-api-scale-bad]: https://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html 17 18- [Red flags that indicate questionable quality - Lennart 19 Poettering][poettering-library-red-flags] 20 21[poettering-library-red-flags]: 22 https://mastodon.social/@pid_eins/112517953375791453 23 24- [Not sure if this is a gcc bug or some weird corner of UB or what... - Andrew 25 Zonenberg][azonenberg-packed-struct] 26 27[azonenberg-packed-struct]: https://ioc.exchange/@azonenberg/112535511250395148 28 29## References 30 31- [C17 draft standard][c17-draft-standard] 32 33[c17-draft-standard]: 34 https://web.archive.org/web/20181230041359if_/http://www.open-std.org/jtc1/sc22/wg14/www/abq/c17_updated_proposed_fdis.pdf 35 36## Definitions 37 38- **Error condition**: An invalid state reached at runtime, caused either by 39 resource exhaustion, or incorrect use of the library's public APIs and data 40 types. 41 42- **Invariant**: A condition in the library's implementation that must never 43 evaluate false. 44 45- **Public API**: Any definitions and declarations under `include/libpldm`. 46 47- **Wire format**: Any message structure defined in the DMTF PLDM protocol 48 specifications. 49 50## Elaborations 51 52- Resource exhaustion is always an error condition and never an invariant 53 violation. 54 55- An invariant violation is always a programming failure of the library's 56 implementation, and never the result of incorrect use of the library's public 57 APIs (see error condition). 58 59- Corollaries of the above two points: 60 61 - Incorrect use of public API functions is always an error condition, and is 62 dealt with by returning an error code. 63 64 - Incorrect use of static functions in the library's implementation is an 65 invariant violation which may be established using `assert()`. 66 67- `assert()` is the recommended way to demonstrate invariants are upheld. 68 69## Adding a new API 70 71- [ ] My new public `struct` definitions are _not_ marked 72 `__attribute__((packed))` 73 74- [ ] If my work interacts with the PLDM wire format, then I have done so using 75 the `msgbuf` APIs found in `src/msgbuf.h` (and under `src/msgbuf/`) to 76 minimise concerns around spatial memory safety and endian-correctness. 77 78- [ ] All my error conditions are handled by returning an error code to the 79 caller. 80 81- [ ] All my invariants are tested using `assert()`. 82 83- [ ] I have not used `assert()` to evaluate any error conditions without also 84 handling the error condition by returning an error code the the caller. 85 86 - Release builds of the library are configured with `assert()` disabled 87 (`-Db_ndebug=if-release`, which provides `-DNDEBUG` in `CFLAGS`). 88 89- [ ] My new APIs return negative `errno` values on error and not PLDM 90 completion codes. 91 92 - [ ] The specific error values my function returns and their meaning in the 93 context of the function call are listed in the API documentation. 94 95- [ ] If I've added support for a new PLDM message type, then I've implemented 96 both the encoder and decoder for that message. Note this applies for both 97 request _and_ response message types. 98 99- [ ] My new function symbols are marked with `LIBPLDM_ABI_TESTING` in the 100 implementation 101 102- [ ] I've implemented test cases with reasonable branch coverage of each new 103 function I've added 104 105- [ ] I've guarded the test cases of functions marked `LIBPLDM_ABI_TESTING` so 106 that they are not compiled when the corresponding function symbols aren't 107 visible 108 109- [ ] If I've added support for a new message type, then my commit message 110 specifies all of: 111 112 - [ ] The relevant DMTF specification by its DSP number and title 113 - [ ] The relevant version of the specification 114 - [ ] The section of the specification that defines the message type 115 116- [ ] If my work impacts the public API of the library, then I've added an entry 117 to `CHANGELOG.md` describing my work 118 119## Stabilising an existing API 120 121- [ ] The API of interest is currently marked `LIBPLDM_ABI_TESTING` 122 123- [ ] My commit message links to a publicly visible patch that makes use of the 124 API 125 126- [ ] My commit updates the annotation from `LIBPLDM_ABI_TESTING` to 127 `LIBPLDM_ABI_STABLE` only for the function symbols demonstrated by the 128 patch linked in the commit message. 129 130- [ ] I've removed guards from the function's tests so they are always compiled 131 132- [ ] If I've updated the ABI dump, then I've used the OpenBMC CI container to 133 do so. 134 135## Updating an ABI dump 136 137Each of the following must succeed: 138 139- [ ] Enter the OpenBMC CI Docker container 140 - Approximately: 141 `docker run --cap-add=sys_admin --rm=true --privileged=true -u $USER -w $(pwd) -v $(pwd):$(pwd) -e MAKEFLAGS= -it openbmc/ubuntu-unit-test:2024-W21-ce361f95ff4fa669` 142- [ ] `CC=gcc CXX=g++; [ $(uname -m) = 'x86_64' ] && meson setup -Dabi=deprecated,stable build` 143- [ ] `meson compile -C build` 144- [ ] `./scripts/abi-dump-formatter < build/src/current.dump > abi/x86_64/gcc.dump` 145 146## Removing an API 147 148- [ ] If the function is marked `LIBPLDM_ABI_TESTING`, then I have removed it 149 150- [ ] If the function is marked `LIBPLDM_ABI_STABLE`, then I have changed the 151 annotation to `LIBPLDM_ABI_DEPRECATED` and left it in-place. 152 153- [ ] If the function is marked `LIBPLDM_ABI_DEPRECATED`, then I have removed it 154 only after satisfying myself that each of the following is true: 155 156 - [ ] There are no known users of the function left in the community 157 - [ ] There has been at least one tagged release of `libpldm` subsequent to 158 the API being marked deprecated 159 160## Testing my changes 161 162Each of the following must succeed when executed in order. Note that to avoid 163[googletest bug #4232][googletest-issue-4232] you must avoid using GCC 12 164(shipped in Debian Bookworm). 165 166[googletest-issue-4232]: https://github.com/google/googletest/issues/4232 167 168- [ ] `meson setup -Dabi-compliance-check=disabled build` 169- [ ] `meson compile -C build && meson test -C build` 170 171- [ ] `meson configure --buildtype=release build` 172- [ ] `meson compile -C build && meson test -C build` 173 174- [ ] `meson configure --buildtype=debug build` 175- [ ] `meson configure -Dabi=deprecated,stable build` 176- [ ] `meson compile -C build && meson test -C build` 177