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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

3.5 KiB

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:

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:

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:

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.