The front end hardcoded /opt/homebrew/opt/llvm and lib/libclang.dylib, so
on Linux it died before parsing anything:
FileNotFoundError: [Errno 2] No such file or directory:
'/opt/homebrew/opt/llvm/bin/clang'
PIPE_LLVM could move the prefix but not the file name, so no value of it
made the tool run there.
Discovery is now per platform: Homebrew's LLVM on macOS, the system prefix
elsewhere, PIPE_LLVM still winning over both. The library is looked up as
.dylib or .so, exact name first and then highest version, and under
lib/*-linux-gnu as well, because distributions ship
libclang.so.<major>.<minor> without always adding the unversioned symlink
and Debian keeps it in a multiarch subdirectory. -print-resource-dir falls
back to clang on PATH when the prefix ships only the library. When nothing
matches, the conventional name is handed to clang.cindex so its own error
names the library rather than a path this code invented.
_sdk_root already degrades to None off macOS, since xcrun is absent.
test/cpp_front_test.dart looked for the same Homebrew dylib, so on Linux
it reported "All tests skipped" rather than failing. That is why the gap
went unnoticed: the suite was green because it ran nothing. Its detection
now mirrors the front end's, and on this Linux machine the four cases go
from skipped to run and passing.
Verified end to end against an unrelated 87-translation-unit C++ project:
87/87 parsed, 0 TUs failed, 0 clang errors, 26 state enums and 879
emissions recovered.
Both suites fail test/stdout_json_test.dart under the parallel runner on
this machine, pristine main included, and it passes in isolation on both
branches; a serial run failed a different test instead. Pre-existing and
unrelated.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
tool/cpp_front.py is a second front end written against the state model,
not the rules: it reads a compile database with libclang (Homebrew LLVM)
and writes the JSON that `pipe check --model` takes. Every rule,
baseline and gate works on it unchanged.
Mapping, per project `enum class` (identity from clang's resolved AST,
so two enums both named QueryIntent are never confused):
- a reference that produces a value (assignment, atomic store, argument,
return, initialiser) is an emission; a cast from an int is an indirect
one;
- a `case`, `==` or `!=` is an observation;
- a busy enumerator written to the method's OWN state, followed by a
top-level try whose catch neither writes state nor rethrows, is a
swallowed failure;
- sources the build does not compile are recorded as unresolved, so
findings naming them drop a confidence step.
One rule-side change, optional and Dart-neutral: an EmissionSite may name
its stateType. rendered-not-emitted attributed indirect emissions by owner
(a bloc owns one state type), so a cast to one enum made "never emitted"
unprovable for every other enum in the same C++ class. With stateType
set, the suppression is scoped to that enum. Dart output is still byte
identical on the fixture and all four dogfood apps.
Run on ~/work/tools/yams (375 translation units from build/debug, 0 clang
errors, about two minutes): 118 state enums, 82 findings. A grep-based
hand check of 13 found 12 factually correct - e.g. the IPC connection FSM
never enters ImplState::ReadingHeader, the downloader never reports
ProgressStage::Verifying though three CLI commands render it,
ExtractScopeType qualifiers are parsed but never acted on - and one false
positive (a nested JSON-parse fallback taken for a stuck busy state),
now excluded by requiring the method's own state and a top-level try.
Bugs found on the way and fixed: ccache/compiler wrappers passed as
inputs, relative -I paths resolved against the wrong directory (7 TUs
silently lost third_party headers), a symlinked path putting every TU
"outside" the project, and an empty compile database producing an empty
"clean" model with exit 0 - all now fail loudly or are handled.
test/cpp_front_test.dart runs the front end on test/fixtures/cpp_state
with positive and negative controls for each rule; skipped without LLVM.
138 tests pass.
