fix(extractors): resolve inline object-literal dispatch tables on WASM

[carlos-alm]

Summary

• WASM's extractSubscriptCallInfo had no equivalent of native's RES-2 extract_dispatch_table_call, so ({a:fnA,b:fnB})[key]() classified as a generic flagged computed-key sink on WASM while native resolved it to fnA/fnB via the points-to wildcard solver — a genuine engine-parity gap.
• Adds extractDispatchTableCall in src/extractors/javascript.ts, mirroring extract_dispatch_table_call in crates/codegraph-core/src/extractors/javascript.rs: when a subscript call's object is an object literal (optionally unwrapped from a parenthesized expression) and the index is a bare identifier, seeds arrayElemBindings under a synthetic <dt_line_col> name and emits a <dt_line_col>[*] call with dynamicKind: 'dispatch-table' — the existing points-to wildcard resolution path (already used for array-literal dispatch, e.g. const arr=[f1,f2]; arr[i]()) then resolves it to each concrete target identically on both engines.
• Threaded through both WASM extraction paths per this repo's two-path extractor architecture: dispatchQueryMatch (used by the WASM worker) and handleCallExpr (direct/test callers) both now pass arrayElemBindings into extractCallInfo → extractSubscriptCallInfo.
• Adds 'dispatch-table' to the DynamicKind union in src/types.ts, intentionally excluded from FLAG_ONLY_DYNAMIC_KINDS (matching native's sink-edge exclusion) so a resolved table never produces a spurious sink edge.

Note on history

While investigating, I found this exact fix (types.ts union member, extractSubscriptCallInfo dispatch-table branch, the pts-javascript/dispatch-table.js fixture, and points-to.test.ts unit tests) was already implemented and merged once before (commit 9a6b882f, closing #1665) but silently disappeared from the tree afterward — presumably lost in a merge/rebase — while the native-side mirror (added later in PR #1690, closing #1684) survived. This PR re-implements the WASM side from scratch against the current architecture (the extraction pipeline has changed substantially since then — single-pass collector walk, runCollectorWalk, etc.) and restores the dropped fixture/tests, plus adds new query-vs-walk and cross-engine parity regression coverage that didn't exist before.

Test plan

• npx vitest run tests/parsers/javascript.test.ts tests/unit/points-to.test.ts tests/engines/query-walk-parity.test.ts — new unit tests pass (297/297)
• npx vitest run tests/engines/parity.test.ts — new cross-engine parity case passes against a locally rebuilt native binary (37 passed, 8 skipped)
• npx vitest run tests/benchmarks/resolution/resolution-benchmark.test.ts -t "pts-javascript" — 5/5 pass (restored dispatch-table.js + expected-edges entries)
• npm test — 3978 passed, 30 skipped, 2 todo, 1 pre-existing known-flaky failure unrelated to this change (checkNoNewCycles node-ordering, tracked in Flaky cycle-node ordering in checkNoNewCycles full-suite run (tests/integration/check.test.ts) #1990)
• cargo test --release -p codegraph-core — 591/591 pass (native side untouched; rebuilt binary confirms parity)
• npx tsc --noEmit / npm run lint — clean (no new issues)

Closes #1897

[greptile-apps]

Greptile Summary

Closes a WASM/native engine-parity gap (#1897): WASM's subscript-call extractor previously had no equivalent of the native extract_dispatch_table_call (RES-2), so ({a:fnA,b:fnB})[key]() was classified as a generic flagged computed-key sink on WASM while native resolved it to concrete targets via the points-to wildcard solver.

• Adds extractDispatchTableCall in src/extractors/javascript.ts, seeding ArrayElemBinding entries under a synthetic <dt_line_col> name and emitting a <dt_line_col>[*] call with dynamicKind: 'dispatch-table'; the existing wildcard pts resolution path then resolves to each concrete target identically on both engines.
• Threads the new arrayElemBindings parameter through both WASM extraction paths (dispatchQueryMatch for the query worker, handleCallExpr for the direct/test walk), and adds 'dispatch-table' to the DynamicKind union in src/types.ts, intentionally excluded from FLAG_ONLY_DYNAMIC_KINDS so unresolved tables never produce a spurious sink edge.
• Restores the previously-dropped fixture and tests (lost in a prior rebase per the PR note) and adds new query-vs-walk parity and cross-engine regression coverage.

Confidence Score: 4/5

The core extraction logic and pts integration are correct; the only gap is the benchmark report under-counting points-to technique coverage for the new dispatch-table edges.

The extractDispatchTableCall implementation is faithful to the Rust mirror: parenthesized-expression unwrap, identifier-value filtering, BUILTIN_GLOBALS guard, synthetic dt_line_col naming, and wildcard call emission all look correct. Both WASM extraction paths now consistently thread arrayElemBindings, and dispatch-table is correctly excluded from FLAG_ONLY_DYNAMIC_KINDS. The one omission is pts-dispatch-table missing from TECHNIQUE_MAP in the resolution benchmark — those two new edges will appear under other instead of points-to in the per-technique report, which may confuse future contributors reading benchmark output.

tests/benchmarks/resolution/resolution-benchmark.test.ts — TECHNIQUE_MAP needs a pts-dispatch-table: points-to entry

Important Files Changed

Filename	Overview
src/extractors/javascript.ts	Adds extractDispatchTableCall (mirrors Rust RES-2), threads arrayElemBindings through both WASM extraction paths (dispatchQueryMatch/handleCallExpr); all non-subscript extractCallInfo call sites are correctly left without arrayElemBindings since they can never receive a subscript_expression fn node
src/types.ts	Adds 'dispatch-table' to DynamicKind union and correctly excludes it from FLAG_ONLY_DYNAMIC_KINDS, matching native's sink-edge exclusion behaviour
tests/benchmarks/resolution/resolution-benchmark.test.ts	New pts-dispatch-table mode in expected-edges.json will fall into the 'other' bucket of TECHNIQUE_MAP instead of 'points-to', causing the per-technique breakdown report to under-count points-to coverage (thresholds are unaffected)
tests/benchmarks/resolution/fixtures/pts-javascript/dispatch-table.js	New benchmark fixture for inline object-literal dispatch table; correct and minimal
tests/benchmarks/resolution/fixtures/pts-javascript/expected-edges.json	Adds two expected call edges (runDispatch to dtFn1/dtFn2) with mode pts-dispatch-table; edge shapes are correct
tests/engines/parity.test.ts	Adds cross-engine regression guard for #1897; correctly checks that native and WASM emit the same synthetic dt_line_col[*] call name
tests/engines/query-walk-parity.test.ts	Adds regression guard verifying that the query path and walk path produce identical dt_line_col[*] call names for the dispatch-table pattern
tests/parsers/javascript.test.ts	Five new unit tests covering parenthesized/non-parenthesized object literals, shorthand-property form, non-literal fallback, and string-literal key fallback; all cases are correct
tests/unit/points-to.test.ts	Three new pts unit tests for synthetic dispatch-table array-elem bindings; correctly validates wildcard resolution and name isolation between tables

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant AST as Tree-sitter AST
    participant ESQ as extractSymbolsQuery / handleCallExpr
    participant EDT as extractDispatchTableCall (new)
    participant AEB as arrayElemBindings[]
    participant PTS as buildPointsToMap
    participant Graph as Edge Builder

    AST->>ESQ: subscript_expression node
    ESQ->>EDT: "obj=object_literal, index=key, callNode, arrayElemBindings"
    EDT->>AEB: "push {arrayName:dt_5_2, index:0, elemName:fnA}"
    EDT->>AEB: "push {arrayName:dt_5_2, index:1, elemName:fnB}"
    EDT-->>ESQ: "Call { name:dt_5_2[*], dynamicKind:dispatch-table }"
    ESQ->>PTS: calls + arrayElemBindings
    PTS->>PTS: buildArrayElemConstraints
    PTS-->>Graph: "resolve(dt_5_2[*]) = {fnA, fnB}"
    Graph->>Graph: emit calls edges runDispatch to fnA and fnB

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
sequenceDiagram
    participant AST as Tree-sitter AST
    participant ESQ as extractSymbolsQuery / handleCallExpr
    participant EDT as extractDispatchTableCall (new)
    participant AEB as arrayElemBindings[]
    participant PTS as buildPointsToMap
    participant Graph as Edge Builder

    AST->>ESQ: subscript_expression node
    ESQ->>EDT: "obj=object_literal, index=key, callNode, arrayElemBindings"
    EDT->>AEB: "push {arrayName:dt_5_2, index:0, elemName:fnA}"
    EDT->>AEB: "push {arrayName:dt_5_2, index:1, elemName:fnB}"
    EDT-->>ESQ: "Call { name:dt_5_2[*], dynamicKind:dispatch-table }"
    ESQ->>PTS: calls + arrayElemBindings
    PTS->>PTS: buildArrayElemConstraints
    PTS-->>Graph: "resolve(dt_5_2[*]) = {fnA, fnB}"
    Graph->>Graph: emit calls edges runDispatch to fnA and fnB

Loading

_{Reviews (1): Last reviewed commit: "fix(extractors): resolve inline object-l..." | Re-trigger Greptile}

[github-actions]

Codegraph Impact Analysis

9 functions changed → 18 callers affected across 2 files

• dispatchQueryMatch in src/extractors/javascript.ts:326 (2 transitive callers)
• extractSymbolsQuery in src/extractors/javascript.ts:396 (1 transitive callers)
• handleCallExpr in src/extractors/javascript.ts:1628 (3 transitive callers)
• extractCallInfo in src/extractors/javascript.ts:3510 (20 transitive callers)
• extractDispatchTableCall in src/extractors/javascript.ts:3717 (6 transitive callers)
• extractSubscriptCallInfo in src/extractors/javascript.ts:3762 (8 transitive callers)
• dtFn1 in tests/benchmarks/resolution/fixtures/pts-javascript/dispatch-table.js:2 (1 transitive callers)
• dtFn2 in tests/benchmarks/resolution/fixtures/pts-javascript/dispatch-table.js:3 (1 transitive callers)
• runDispatch in tests/benchmarks/resolution/fixtures/pts-javascript/dispatch-table.js:5 (0 transitive callers)