Module fs_probe 

Counted filesystem probe funnel, shared by every ecosystem crate’s config-file cache.

crate::mtime_cache::MtimeFileCache claims “one stat, zero reads on a cache hit” — a claim Arc::ptr_eq on the returned value cannot verify, since that only proves the parsed value was reused, not that no syscall ran to get there. Counting actual stat/read calls needs a single chokepoint every cache implementation routes through, so the count is trustworthy across crate boundaries.

Most wrappers below are a bare passthrough to their std::fs equivalent in a shipped build (the exception is read_to_string_capped, which adds a real size bound on top of File::open/Read::take); the counters are compiled out entirely unless this crate is built for its own tests or with the test-util feature, so counting one function’s calls costs nothing in production. cfg(test) alone cannot gate the public snapshot function, because deps-core is an ordinary (non-dev) dependency of deps-cargo/deps-npm — it is never compiled with cfg(test) when a downstream crate’s own tests build, so the test-util feature is what those crates enable in their dev-dependencies instead.

Constants

MAX_CONFIG_ANCESTOR_DEPTH

Shared upper bound on how many ancestor directories a config-file discovery walk climbs, independent of whether the filesystem root has been reached.

Functions

exists

Whether path exists — false on any error, including a missing path.

is_file

Whether path exists and is a regular file — false on any error, including a missing path.

metadata

Counted wrapper around std::fs::metadata.

read_to_string_capped

Counted, size-bounded wrapper around std::fs::File::open + Read::take.

snapshot

The current (stat_count, read_count) totals.