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libakstdlib/AGENTS.md
Andrew Kesterson 95e5002512
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Version the library at 0.1.0
project() now carries VERSION 0.1.0, and is the single place a version number
is spelled. It flows into generated version macros, the shared library's
VERSION/SOVERSION, the Version: field in akstdlib.pc, and a new
akstdlibConfigVersion.cmake. Before this @PROJECT_VERSION@ expanded to
nothing, so akstdlib.pc shipped an empty Version: and libakstdlib.so carried
no soname at all.

0.x on purpose: TODO.md section 2.1 still records four confirmed defects whose
fixes change documented behaviour, so the API is not being promised yet. While
the major version is 0 the soname carries MAJOR.MINOR -- 0.1 and 0.2 are
different ABIs -- and becomes MAJOR alone at 1.0. The if() in CMakeLists.txt
and the #if in tests/test_version.c encode that rule and are tested against
each other.

include/akstdlib_version.h.in is configured into the build tree as
akstdlib_version.h and installed beside akstdlib.h. It defines
AKSL_VERSION_MAJOR/MINOR/PATCH/STRING/NUMBER and AKSL_VERSION_SONAME.
AKSL_VERSION_NUMBER is computed rather than written as a literal, because a
literal 000100 is octal in C and would make 0.1.0 compare as 64;
test_version.c asserts it against the runtime components, so a rewrite to a
literal fails.

Those macros record what a caller was compiled against. aksl_version(),
aksl_version_string() and aksl_version_soname() report what actually loaded,
and AKSL_VERSION_CHECK() compares the two, raising AKERR_VALUE naming both.
It is a macro so that it expands at the caller's site and captures the
caller's numbers; the function compares them against the ones baked into the
library. Compatibility is "same soname", so patch is ignored -- a caller built
against 0.1.0 keeps working against 0.1.7.

Normally the soname catches a mismatch at load time and the check never fires.
It earns its keep when the soname is bypassed: a 0.2.0 build dropped in under
the 0.1 filename loads happily, and only the check notices.

write_basic_package_version_file() uses SameMinorVersion to mirror the soname,
falling back to ExactVersion below CMake 3.11 where that mode does not exist.
The fallback is stricter than the soname rule -- it pins the patch level too --
but never laxer, and wrongly refusing a good pairing beats wrongly accepting a
bad one.

Coverage of src/stdlib.c rose to 99.1% of lines (217/219), 45.1% of branches
and 25/25 functions. That puts branch coverage back over the old 45 gate, but
the gate stays at 40: 0.1 points of headroom is not a ratchet.

ctest 14/14, ASan+UBSan 14/14, coverage 16/16 at 90/40. Also verified out of
tree: SONAME libakstdlib.so.0.1 recorded in consumers, pkg-config
--modversion reporting 0.1.0, find_package(akstdlib 0.1) accepted with 0.2 and
1.0 refused, a patch-bumped 0.1.1 loading and passing the check, a 0.2.0
dropped in under the 0.1 filename caught by it, and an embedded
add_subdirectory build keeping its own version rather than the parent's.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-30 22:40:49 -04:00

83 lines
3.5 KiB
Markdown

# Repository Guidelines
## Project Structure & Module Organization
`libakstdlib` is a C shared library that wraps libc calls and small data
structures in `libakerror` error contexts. Public API declarations live in
`include/akstdlib.h`; implementation lives in `src/stdlib.c`. Tests are
one-file CTest executables under `tests/test_<name>.c`, with shared test helpers
in `tests/aksl_capture.h`. CMake package templates are in `cmake/` and
`akstdlib.pc.in`. The vendored dependency is `deps/libakerror`; update it as a
submodule rather than editing generated files under `build/`, `build-asan/` or
`build-coverage/`.
## Build, Test, and Development Commands
Initialize dependencies before a fresh build:
```sh
git submodule update --init --recursive
cmake -S . -B build
cmake --build build
```
Run the normal suite with `ctest --test-dir build --output-on-failure`. Use the
instrumented build for memory and undefined-behavior checks:
```sh
cmake -S . -B build-asan -DAKSL_SANITIZE=ON
cmake --build build-asan
ctest --test-dir build-asan --output-on-failure
```
For coverage, configure a third tree; the report is part of that suite (the
`coverage_reset` / `coverage_report` CTest entries) and also lands in
`build-coverage/coverage-summary.txt`:
```sh
cmake -S . -B build-coverage -DAKSL_COVERAGE=ON
cmake --build build-coverage --target coverage
```
Run `cmake --build build --target mutation` only when you need the slower
mutation harness. `rebuild.sh` installs to `/home/andrew/local` and removes the
local build directory, so treat it as a local convenience script.
## Coding Style & Naming Conventions
Use C with 4-space indentation; existing files sometimes use tabs for continued
statements, so match the surrounding block. Public symbols use the `aksl_`
prefix, structs use `aksl_<Name>`, and tests use `test_<feature>.c` plus static
`test_<case>` functions. Preserve the `akerr_ErrorContext AKERR_NOIGNORE *`
return convention and the `PREPARE_ERROR` / `FAIL_*` / `SUCCEED_RETURN` pattern.
## Testing Guidelines
Add a new test by creating `tests/test_mything.c` and adding `mything` to the
right list in `CMakeLists.txt`. `AKSL_TESTS` must exit zero.
`AKSL_WILL_FAIL_TESTS` are deliberate abort/contract tests.
`AKSL_KNOWN_FAILING_TESTS` assert documented defects from `TODO.md`; when one
starts unexpectedly passing, move it into `AKSL_TESTS` with the fix.
`src/stdlib.c` is at 99.1% line coverage and CI gates it at 90 (line) / 40
(branch), so new code needs tests in the same commit. Run
`cmake --build build-coverage --target coverage` and check the uncovered-line
listing before proposing a change. Tests for behaviour that `TODO.md` records as
defective belong in `AKSL_KNOWN_FAILING_TESTS` asserting the *correct* contract —
do not pin current-but-wrong behaviour in `AKSL_TESTS`, since that turns the
eventual fix into a test failure.
## Commit & Pull Request Guidelines
Recent commits use short imperative summaries, for example `Add memory wrapper
tests` and `Make error-status assertions authoritative`. Keep commits focused
and include tests with behavior changes. Pull requests should describe the
changed API or behavior, list the CTest/sanitizer/mutation commands run, and
link the relevant `TODO.md` item or issue when fixing a known defect.
## Agent-Specific Instructions
Do not modify generated build trees, profiling artifacts, or untracked scratch
files unless explicitly asked. Prefer small, test-backed changes and update
`README.md` or `TODO.md` when changing documented workflows or known failures.