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findings: wasmparser case-folding gap extends to interface names #246

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33 changes: 22 additions & 11 deletions upstream-component-model-repo-findings.md
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Expand Up @@ -125,20 +125,31 @@ entry on resolution — see git history.)
versions, not a component-model repo defect. Handled by docs/architecture.md §4.1/§9
version-pinning discipline (the translator's wasmparser is the single
validation authority).
- **wasmparser skips case-folding when comparing `[method]`/`[static]` names**
(candidate bytecodealliance/wasm-tools issue; found 2026-08-22 validating our
#185): Explainer.md §Name Uniqueness requires strongly-unique — lowercase
- **wasmparser skips case-folding when comparing `[method]`/`[static]` and
interface names** (candidate bytecodealliance/wasm-tools issue; found
2026-08-22 validating our #185, extended 2026-08-25; fix tracked on our side
as #238): Explainer.md §Name Uniqueness requires strongly-unique — lowercase
acronyms, strip the `[...]` prefix, compare — and explicitly lists
`[method]foo.BAR` vs `[method]foo.bar` as a validation error. wasmparser
implements the fold for plain labels (`KebabStr`'s case-insensitive
`Eq`/`Hash`) but `ResourceFunc` derives them on the raw `a.b` string
(`src/validator/names.rs`; verified identical in 0.251/0.252/0.256), so
`[method]r.a-b` + `[method]r.a-B` in one scope validates (wasm-tools 1.247
`validate --features component-model`, wasmtime 47 `compile`, and our
translator-shim all accept; plain-label and record-field folded collisions
are correctly rejected). Consequence for us: spec-invalid method/static
case-collisions can reach the runtime's conventions layer — one of the
triggers tracked in #185.
`Eq`/`Hash`) but `ResourceFunc` *and* `InterfaceName` derive them on the raw
string (`src/validator/names.rs`; verified identical in 0.251/0.252/0.256
and on wasm-tools `main` as of 2026-08-25), so `[method]r.a-b` +
`[method]r.a-B` in one scope validates, as does `test:i/x-y` + `test:i/x-Y`
(wasm-tools 1.247 `validate --features component-model`, wasmtime 47
`compile`, and our translator-shim all accept; plain-label and record-field
folded collisions are correctly rejected). Searched both upstream trackers
2026-08-25: no existing issue covers it. Spec-side note: upstream
WebAssembly/component-model#703 (merged 2026-08-18, after our submodule pin)
rewrote strongly-unique as canonicalize-then-compare per
WebAssembly/component-model#702 (non-transitivity); the acronym fold is
retained and applies to all names — the new invalid-examples list adds
`[static]foo-BAR.FOO-bar` and `foo:bar/BAZ` — so the divergence conclusion
is unchanged under both wordings. Re-verify wording/line numbers against
post-#703 Explainer.md before filing. Consequence for us: spec-invalid
method/static and interface-name case-collisions can reach the runtime's
conventions layer — one of the triggers tracked in #185; translator-side
enforcement is #238.

[WebAssembly/component-model]: https://github.com/WebAssembly/component-model

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