fix: instrument library crates and impl methods in lib+bin projects#626
Merged
rocketman-code merged 5 commits intomainfrom Apr 24, 2026
Merged
fix: instrument library crates and impl methods in lib+bin projects#626rocketman-code merged 5 commits intomainfrom
rocketman-code merged 5 commits intomainfrom
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Support cargo example targets via --example flag, mutually exclusive with --bin. Generalize find_bin_target to find_target accepting a target kind parameter. Update build_instrumented to accept CargoTarget enum (Bin or Example). Extend find_latest_binary to scan the examples subdirectory. Add unit test for example target discovery.
…ntation Single-package projects with both [lib] and [[bin]] (the most common Rust project structure) don't get library functions instrumented. The wrapper gate at wrapper.rs:138 skips lib.rs because it has no measured functions (only mod declarations), causing the entire library crate to be passed through without instrumentation. This test creates a lib+bin fixture and asserts that library functions (compute::add, compute::multiply) record calls. It currently fails with empty keys, proving the bug.
…jects The wrapper gate (wrapper.rs:138) checked only whether the crate root file was directly in config.targets or matched the entry point. For lib+bin packages, lib.rs contains no functions (just mod declarations) so it was absent from targets, causing the gate to skip the entire library crate. All library functions went uninstrumented. The fix adds a fallback: when the simple checks fail, check if any target file starts_with(source_parent) of the crate root. This mirrors the logic already used inside rewrite_and_compile (line 206) to determine which files belong to a crate. Path::starts_with is component-level, so no cross-package false positives are possible.
The rewriter looked up bare AST names (e.g., "check") in the measured
map, but the build pipeline stores impl-qualified names ("Frame::check").
Standalone functions matched (bare == qualified), but impl methods
never did -- their guards were silently never injected.
Add qualified_fn_name() that walks up the AST to find the enclosing
impl block and constructs the same qualified name that the resolve
module uses (via naming::render_impl_name). Both lookup sites in the
rewriter now use this function.
This is a hotfix using the same naming::render_impl_name as resolve.
The proper fix extracts a shared function so the name construction is
a single code path (MISU: make disagreement impossible, not improbable).
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Summary
Frame::check) matching the resolve module's format, so impl methods get guards injectedVerified on mini-redis: all 33 active functions now report wall time, CPU time, call counts, and allocation data under realistic load (50 clients x 1000 ops).
Test Plan
single_package_lib_bin_instruments_library_functionspasses