fix(wrap): route lift lookup via export name + propagate string encoding (LS-A-16)#158
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fix(wrap): route lift lookup via export name + propagate string encoding (LS-A-16)#158avrabe wants to merge 2 commits into
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…ing (LS-A-16)
`find_lift_type_for_interface_func` took (iface, func) parameters but
never compared them — `let _ = target_export_name` suppressed the unused
warning. For a multi-export component, every export silently received
the first lift's type and canonical options (including string_encoding).
A guest compiled with `--string-encoding=utf16` had every export
downgraded to UTF-8 because the encoding was also hardcoded in emission
paths. Wasm validator accepts the output; downstream wasmtime transcodes
against the wrong encoding, producing mojibake / truncated strings with
no trap. Same family as the wasmtime 2026-04-09 CM-transcoding CVE wave.
Fix:
- find_lift_type_for_interface_func matches export names against the
wit-bindgen `{iface}#{func}` convention; resolves through
component_func_defs to the right canon Lift entry.
- New `source_string_encoding_option` helper maps the source
CanonStringEncoding to the wasm_encoder::CanonicalOption.
- Lift emission paths use the source-derived encoding instead of
hardcoded UTF8.
- Single-lift fallback retained for simple-fixture compatibility but
only when exactly one lift exists; multi-lift without matching
export now returns None instead of guessing.
Tests (4 new):
- ls_a_16_find_lift_distinguishes_between_two_exports
- ls_a_16_find_lift_single_lift_fallback_still_works
- ls_a_16_find_lift_two_lifts_without_matching_export_returns_none
- ls_a_16_source_string_encoding_option_round_trips
Deferred to a follow-up under the same UCA-W-2:
- Lower-side encoding propagation (canon.lower options threaded from
source canon.lower entries)
- Lift-side Memory(0) hardcoding in multi-memory mode (uncertain
reachability since assemble_component is called with a single source)
LS-A-16 added to safety/stpa/loss-scenarios.yaml. Discovered by the
post-v0.8.0 Mythos delta-pass on component_wrap.rs.
Refs: LS-A-16 (UCA-W-2, H-1, H-4)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
avrabe
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Mythos delta-pass evidence (re-posted from closed #155) Tier-5 file touched: A fresh agent ran This is the re-open of stuck PR #155 (GitHub-Actions glitch); workflow_runs failed to trigger on multiple synchronize events for that PR. |
Whitespace-only change to generate a fresh SHA. The C5 LS-A-16 fix was stuck behind a GitHub-Actions glitch — workflow_runs not firing on multiple synchronize events. Adding this trivial commit produces a new SHA that GH should treat as a fresh push. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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Re-opened version of #155 — that PR's CI workflows were stuck in a GitHub-Actions glitch (synchronize events not generating workflow runs). Same code, fresh PR number to clear the webhook state.
Summary
Fixes from the post-v0.8.0 Mythos delta-pass sweep on `component_wrap.rs`:
A guest compiled with `--string-encoding=utf16` had every export downgraded to UTF-8 → mojibake / truncated strings downstream with no trap. Same family as the wasmtime 2026-04-09 CM-transcoding CVE wave.
Fix
Tests (4 new)
Refs
🤖 Generated with Claude Code