fix: carry module path segments instead of re-deriving them

[SteveSolvesProblems]

Fixes #38. Blocks the 0.24.0 release — I cancelled the tag for this.

A module name is segments joined by the language separator, and resolution needs them back. Recovering them by splitting the name made any component containing the separator ambiguous, which produced two bugs pointing in opposite directions:

specifier	before	cause
./app.js	never resolved	extension not stripped. Pre-existing
./app.config	regressed in 0.24.0	safe_seg renamed the module to app-config, but the specifier still split to ["app","config"]

The second is a regression in the unreleased 0.24.0, caught before it shipped — diagnosed by the session that wrote the original dotted-filename fix.

safe_seg is deleted, not patched

Patching it would have kept the mangled names. app.config.ts becoming module app-config is a translation rule a human and an agent each have to learn and neither can guess — ctx def app.config wouldn't match the file in front of them, and nothing in the output explains why.

module_name already built the segments and joined them away one line later. They're now carried on Module::path_segs and returned by resolve_segs directly. Names match filenames again, and the whole class of separator-in-a-component bugs stops being expressible rather than being fixed one instance at a time.

resolve_name is gone, subsumed. It meant two things — Go's package directory, and "the name before collision renaming" — and both were always really "the segments to resolve against". Disambiguation now touches the display name only, because resolution no longer reads it.

The specifier side strips a source extension from any component, because the binding is specifier/symbol (./app.js/boot) so the filename isn't reliably last. It's an allowlist — ts, tsx, js, jsx, mjs, cjs — not "text after the last dot". That distinction is the whole fix: it's what lets ./app.config keep .config while ./app.js loses .js.

Four new regression tests cover exactly that matrix, plus one asserting ./app.config and ./app.js resolve to different modules when both files exist.

Recall is unchanged on every benchmark repo

The gains this class of fix bought earlier are fully intact:

repo	recall
preact (js)	78.1%
got (ts)	78.9%
ripgrep (rust)	65.4%
requests (py)	83.6%
cobra (go)	99.8%
chi (go)	89.6%

Also: the benchmark's grep figures were not reproducible

fair_grep searched an absolute path, and cost is counted in bytes — so every hit carried the clone directory's name, and the numbers depended on where the corpus happened to sit. On ripgrep the path prefix alone was 9,322 tokens, 21% of that row.

It also biased the comparison toward ctx, which already reports paths relative to its root. Searching from inside the tree fixes both. Verified by running the harness twice from two different cache paths — now byte-identical.

This shrinks ctx's headline advantage, which is the honest direction:

row	before	after
ripgrep new	4.6x	2.0x
ripgrep unwrap	184.8x	81.6x
requests get	2.7x	1.4x

BENCHMARK.md regenerated. Recall figures did not move; only the cost ratios.

Release-note consequence

Drop the "module names change for files with a dot" line. It's no longer true — naming reverts to what 0.23.0 already produced, so anyone upgrading 0.23.0 → 0.24.0 sees no naming change at all. That's why this belongs before the tag rather than in a 0.24.1: otherwise names would change twice across two releases for no user-visible reason.

Verified

• cargo fmt --all --check — clean
• cargo clippy --all-targets --locked under RUSTFLAGS=-D warnings — clean
• cargo test --all-targets --locked — 172 passed, 0 failed (4 new)
• cargo +1.90 check --all-targets --locked — clean
• cargo audit — 0 vulnerabilities
• dogfood — 95.3%, no broken links
• EXAMPLES.md regenerated against a clean build; all eight non-pinned blocks diffed byte-for-byte

Module names in EXAMPLES.md are unchanged, since no file in this repo has a dot in its name — which is also why this repo's own figures could never have caught either bug.

🤖 Generated with Claude Code

https://claude.ai/code/session_01UZYZbC55c7yC2YnrL5WBZx