codegraph/docs/design/rust-kernel-migration-plan.md

Rust extraction-kernel migration plan + post-kernel roadmap

Audience: the agent/engineer executing the native-kernel project. Self-contained handoff: context, current state, per-language tracker, gates, and the follow-on roadmap. Companion: docs/design/native-extraction-kernel.md (architecture + spike detail). Written: 2026-06-12 planning → executed 2026-07-16/17. R1–R6 ARE DONE. The shipped records live in §3a and §4a–§4f; the per-language tracker is current; §0a is the cold-start handoff for the next session. Read §0 + §0a first — parts of §1/§6 below them are the ORIGINAL plan and carry expectations that measurement later corrected (each is annotated where superseded).

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0. Status checklist (R1–R6 done; what remains)

• R1. Scaffold the napi-rs crate — done 2026-07-16, §3a. Buffer contract v1, routing + per-file wasm fallback, kill switch, build/release wiring, grammar-source-parity CI.
• R2. Port TypeScript/JavaScript (tsx/jsx) — done 2026-07-16, §4a. The generic .scm emitter was SUPERSEDED by bespoke per-language walkers (queries can't express extraction parity); byte-parity from day one of the harness.
• R3. TS/JS equivalence gate → DEFAULT-ON — done 2026-07-16, §4b. Dumps byte-identical (express/excalidraw/vscode + flask control). Found + fixed: encoding-dependent error recovery → per-file defer: policy.
• R4. Java (incl. Lombok synthesis) → DEFAULT-ON — done 2026-07-16, §4c. dubbo 441k-row dump byte-identical. Found + fixed: node-ID-collision dedupe (cross-language). Found: many-core parse-loop wall is NOT extraction (→ §4d).
• Direct-to-store decode — done 2026-07-16, §4d. Main thread never materializes nodes; measured: the many-core fresh-index wall is single-writer SQLite ingest (94% of dubbo's parse-loop) — a store-architecture arc, out of scope here.
• R5. Python + Go → DEFAULT-ON — done 2026-07-16, §4e. django 360.8k / prometheus 213.8k row dumps byte-identical; 2-CPU envelope 1.32× / 1.46×.
• R6. Kernel-scale re-validation (cg1212) — done 2026-07-17, §4f. No regression (26.4min vs ~27min, identical 2.05M-node graph). The "parse 6m→2m" premise was wrong for THIS repo: the Linux tree is ~99% C (unported T2) — the expectation transfers to the C/C++ port.

Open, in recommended order (rationale in §0a):

• O1. Merge the rust-kernel branch (9 commits, fully gated) — everything below builds on it; the vendored grammar upgrades alone are worth landing.
• O2. Windows VM validation — the one deferred gate leg. Blocked on the MAINTAINER starting the VM in Parallels (prlctl start needs Pro). Then: install Rust + MSVC Build Tools on the guest, bash scripts/build-kernel.sh, run the three kernel suites with CODEGRAPH_KERNEL_EXPECT=1. Close before the first release that ships prebuilds (fallback makes a broken win32 .node safe — Windows silently gets wasm — but safe ≠ validated).
• P1. Kernel-scale resolution speed (§7a) — NOW THE TOP PERF LEVER: 19.2m of the 26.4m Linux-kernel wall (73%). First step is cheap and may reshape it: the 2-CPU run resolves SEQUENTIALLY BY DESIGN (the resolver pool needs ≥4 cores) — re-run cg1212 at ≥4 cores where the pool + parallel synthesis (#1321/#1322) engage, then profile what remains. Target: <10min on 8 cores.
• R7a. C/C++ port — biggest single-language effort; unlocks cg1212's parse expectation (6.2m → ~1.5–2m, 23% of that wall) + CARLA/UE/llvm-class repos; Metal + CUDA ride along (their blanking pre-passes stay TS-side — preParse is offset-preserving and the route point can apply it before the kernel call; see the T2 note in src/extraction/kernel/index.ts). Largest per-language surface in tree-sitter.ts: namespace prefix stacks (#1291), local fn-pointer tables (#932), operator calls (#1247), stack construction (#1035), macro salvage + .h content detection (stays at detectLanguage, upstream — free).
• R7b. Remaining long tail per the tracker (§4) — ruby/php/csharp/rust/… T1s are now ~1-day-each with the walker pattern; T3 may stay TS forever (fine).
• P2. Arc 3, graph richness (§7b) — product-priority call, standard gates.
• P3. Parked items (§7c) — only with explicit maintainer approval.

0a. Cold-start handoff (state as of 2026-07-17)

Where the work lives: branch rust-kernel off main, 9 commits (c5eebe6 R1 → 2a79432 R6 record), unmerged, suite green (2,471 tests). All scratchpad clones (excalidraw/vscode/dubbo/django/…) were throwaway; re-clone fresh for new gate runs. The cg1212 docker container (Linux kernel, 2 CPU/6GB) is long-lived on the dev Mac and has the current build deployed at /app (tree at /work/linux).

What exists:

• codegraph-kernel/ — napi-rs crate. One WALKER MODULE per language (tsjs/, java.rs, python.rs, go.rs) mirroring TreeSitterExtractor's per-language paths bug-for-bug; shared buffers.rs (wire contract — twin of src/extraction/kernel/layout.ts, byte-matched, ABI-versioned), ids.rs (sha node ids, test-pinned to generateNodeId), docstring.rs, textutil.rs (UTF-16 columns/slices, generated-file patterns, shared regexes), langs.rs (grammar registry).
• src/extraction/kernel/ — loader (contract-verifies before routing; a stale .node silently degrades to wasm; CODEGRAPH_KERNEL_DEBUG=1 explains), decode, routing (DEFAULT_ROUTED = ts/tsx/js/jsx/java/python/go; CODEGRAPH_KERNEL_LANGS REPLACES the set; CODEGRAPH_KERNEL=0 kills), and the deferred-decode transport (tryKernelExtractRaw → buffers ride to the store worker; files with applicable framework extract() hooks keep the decoded path).
• Gates in-repo: scripts/kernel-parity.mjs (per-file kernel↔wasm diff, ORDER-sensitive, full-object; deferral-rate guard), scripts/dump-graph.mjs (natural-key full-DB dump for the byte-identical diff), __tests__/kernel-{scaffold,grammar-parity,tsjs-parity}.test.ts (+ torture fixtures under __tests__/fixtures/kernel-parity/) — all in npm test; the release workflow builds a 6-target prebuild matrix (continue-on-error; kernel is optional everywhere) and runs the suites with CODEGRAPH_KERNEL_EXPECT=1.

Build/run: npm run build:kernel (needs rustup; stages codegraph-kernel/prebuilds/<plat>-<arch>/codegraph-kernel.node) → npm run build → npm test. Parity sweep: node scripts/kernel-parity.mjs <dir>. Dump gate: init twice (kernel arm vs CODEGRAPH_KERNEL=0), dump-graph.mjs each, cmp.

Adding a language (the proven recipe, ~a day for a T1):

1. Read its languages/<lang>.ts config AND every branch of tree-sitter.ts it exercises (visitNode dispatch, extractCall's language branch, inheritance clauses, fn-ref spec in function-ref.ts, value-ref prune cases). Port bug-for-bug — quirks included (each walker's header comments list its own).
2. Add the crates.io grammar; vendor the wasm from the SAME tag (clone tag, sha-match parser.c against the cargo registry copy, tree-sitter-cli 0.25.10 build --wasm from CHECKED-IN parser.c, drop into src/extraction/wasm/, add to VENDORED_WASM_LANGS) — tree-sitter-wasms is 2023-era for most languages.
3. Torture fixture + parity sweeps (small/medium/large real repos) → full-init dump-diffs byte-identical → add to DEFAULT_ROUTED + tests + changelog.

Traps already paid for (do not relearn):

• Error recovery is ENCODING-dependent (UTF-8 native vs UTF-16 web-tree-sitter, same grammar bytes + same core) → every walker defers has_error() files via the defer: signal. Incidence 0–0.42%; the harness fails >10% deferral.
• Node IDs collide for same-(kind,name,line) — routine in minified one-liners. Any dedupe/self-check that the TS side keys on node IDs must compare ID STRINGS, not table rows (node_ids vec in every walker).
• Positions and JS string slices are UTF-16 (textutil::col16/slice_utf16) — that's what web-tree-sitter reports and what .slice(0,100) means.
• The extraction seam contract is exactly what extractFromSource returns — e.g. refs carry NO denormalized filePath/language (the store fills them). The strict full-object parity compare exists because a loose one masked precisely this.
• Grammar bumps: crate + vendored wasm move TOGETHER or kernel-grammar-parity fails.
• Perf claims: measure before believing — the plan's own §1/§6 expectations were corrected twice (many-core parse-loop wall = store-writer, §4d; cg1212 parse = C-bound, §4f).

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1. Mission and the numbers that motivate it

CodeGraph's remaining fresh-index gap vs codebase-memory-mcp (cbm) is the parse+extract phase, and its floor is per-node JS↔WASM marshaling — proven, not suspected:

Measurement (2026-07-16, M3 Pro)	Result
dubbo (4,402 Java files) parse-loop, current 7-wasm-worker pipeline	4,700ms
Same files, Rust tree-sitter parse+walk, rayon (spike)	202ms
Same, single Rust thread	1,067ms
dubbo fresh init today / cbm	11.1s / 7.1s (1.55×)
Linux kernel, same 2-CPU/6GB container	we complete 27min; cbm dies at 0.16%, twice

Spike source: session scratchpad cg-kernel-spike/ (tree-sitter 0.25 + tree-sitter-java, TreeCursor walk touching kind/range/name-field, flat-row output). Reproduce before starting — it's ~80 lines and doubles as the emitter's seed.

Expected end state: parse-loop 4.7s → ~1.0–1.5s on dubbo-class repos → total ≈ 7.5s, parity with cbm on their best surface, while keeping every win we already hold (sync 2.4–2.8×, agent A/B decisive, call-graph density 1.3–2.3×, byte-identical determinism, constrained-hardware envelope).

SUPERSEDED BY MEASUREMENT (§4c/§4d): the many-core parse-loop wall turned out to be the single-writer SQLite ingest (94% of it on dubbo), not extraction — 8 wasm workers already hid extraction CPU behind the main thread on big-core machines. So the Mac dubbo total stays ~11s and closing the remaining cbm gap there is a STORE-ARCHITECTURE arc, not a kernel task. The kernel's wins are real where worker CPU binds: the 2-CPU/6GB CI envelope (excalidraw ~1.5×, dubbo ~1.25×, django 1.32×, prometheus 1.46×) and vscode-scale-on-Mac (1.28×). Every "keep" item held — byte-identical determinism is now enforced per language by the dump gate.

2. What the kernel is — and the boundary that makes it safe

One napi-rs crate (codegraph-kernel) linking tree-sitter's C library and native grammars. Input (filePath, content, language) per file; output flat typed buffers (nodes, edges, unresolved refs) — one boundary crossing per file. It replaces ONLY the parse+extract walk inside the parse workers, behind the existing ExtractionResult contract.

Never ported (works unchanged for all languages from day one): name-matcher + import-resolver, all framework resolvers (src/resolution/frameworks/), all 36 synthesis passes, MCP/explore, sync/watcher, installer. They consume the graph and raw source, not the parse tree.

Coexistence is permanent: a language routes to the kernel only after its gate passes; everything else stays on the wasm path forever if need be. No flag-day. Rollback per language = flipping the route.

Distribution: prebuilt .node per platform through the existing release-bundle pipeline (scripts/build-bundle.sh + per-platform npm packages); the same crate compiled to wasm is the universal fallback. Zero-native-build-on-install stays true.

3. Phase 0 — scaffold (do first, ~days)

1. codegraph-kernel/ crate: napi-rs, tree-sitter C, rayon optional (workers already parallelize per-file — start synchronous per call, one kernel call per file from the existing ParseWorkerPool workers; do NOT rebuild the pool).
2. Buffer contract: decide the flat encoding (suggest: one Buffer per table, fixed-width rows + a string arena; version byte first). Write the TS decoder next to parse-worker.ts.
3. Generic emitter driven by per-language .scm query files + a small per-language Rust config (node-kind → NodeKind mapping, name-field conventions). Escape hatch: a per-language post(buffers, source) TS hook for logic queries can't express.
4. Build integration: napi prebuilds wired into the release workflow next to the Node bundles; CODEGRAPH_KERNEL=0 kill switch; wasm fallback auto-selected when the .node is absent (source runs, unsupported platforms).
5. CI: assert native grammars and wasm grammars are built from the SAME grammar source revisions (ABI drift between paths would make per-language routing non-deterministic).

3a. Phase 0 — SHIPPED 2026-07-16 (what exists and the decisions made)

• Crate: codegraph-kernel/ (napi 3, tree-sitter 0.25, no CLI dependency — scripts/build-kernel.sh does cargo build + stage into codegraph-kernel/prebuilds/<platform>-<arch>/codegraph-kernel.node; npm run build:kernel). Exports extractFile, contractInfo, grammarInfo.
• Buffer contract v1: five Buffers (meta/nodes/edges/refs/arena), fixed-width LE rows, string arena with (offset,len) refs, 0xFFFFFFFF = absent, version byte first, node IDs computed Rust-side (sha256, byte-identical to generateNodeId — pinned by test), tri-state bool flags, extraJson escape slot per node row, and a RESERVED u32 metrics slot (Arc 3.2). Layout doc lives twice and must match: codegraph-kernel/src/buffers.rs ↔ src/extraction/kernel/layout.ts. NODE_KINDS/EDGE_KINDS array ORDER in src/types.ts is wire contract now (EDGE_KINDS became a runtime array for this).
• Emitter: generic, .scm-driven (@def.<NodeKind> + @name + @ref.<EdgeKind> capture convention), scope stack by byte-range nesting → ::-joined qualifiedNames, contains edges, refs attached to innermost enclosing def (file node fallback) — the TreeSitterExtractor conventions. Seed TS/JS queries are SMOKE-level only; R2 replaces.
• Routing: inside extractFromSource (tree-sitter.ts) — tryKernelExtract first, wasm TreeSitterExtractor as fallback (also per-FILE fallback on any kernel error). DEFAULT_ROUTED is EMPTY; dev opt-in via CODEGRAPH_KERNEL_LANGS=<langs|all>; global kill switch CODEGRAPH_KERNEL=0; loader verifies ABI + kind tables before routing (stale .node → silent wasm, CODEGRAPH_KERNEL_DEBUG=1 to see why). The escape hatch landed as post(result, source) over the DECODED result (not raw buffers) — decoded is what TS logic wants; see POST_PASSES in src/extraction/kernel/index.ts.
• Grammar parity (the §3.5 CI) — and a decision that changed the wasm path: the parity test (__tests__/kernel-grammar-parity.test.ts, behavioral: ABI + node-kind + field tables compared id-by-id) caught on day one that tree-sitter-wasms ships 2023-era TS/JS grammars (^0.20.x) vs crates.io current. Resolution: vendored fresh wasm into src/extraction/wasm/ built from the exact crate revisions — tree-sitter-typescript v0.23.2 (f975a62) for typescript+tsx, tree-sitter-javascript v0.25.0 (44c892e) for javascript+jsx — from each repo's CHECKED-IN parser.c (no generate), tree-sitter-cli 0.25.10, emcc. So the production wasm TS/JS grammars are UPGRADED as of this change (full suite green, 2456 tests) and R2/R3 parity diffs are grammar-neutral. Bump crate + vendored wasm together, or the parity test fails.
• Release wiring: kernel matrix job in release.yml (macos-14 ×2 targets, ubuntu-22.04, ubuntu-22.04-arm, windows-latest ×2 — all continue-on-error: kernel is optional, a toolchain flake never blocks a release) → artifacts → release/kernel/ → build-bundle.sh stages lib/kernel/codegraph-kernel.node when present. The release job runs the kernel tests with CODEGRAPH_KERNEL_EXPECT=1 (missing binary = FAILURE there, skip elsewhere).
• Loader search order: CODEGRAPH_KERNEL_PATH → <pkgroot>/kernel/ (bundle) → <pkgroot>/codegraph-kernel/prebuilds/<plat>-<arch>/ (source runs).
• Known R2 gate item: native columns are UTF-8 byte offsets; web-tree-sitter's are UTF-16-derived — column NUMBERS on non-ASCII lines will differ in parity dumps (text, lines, IDs unaffected). Classify or normalize when it shows up. RESOLVED in R2: the walker emits UTF-16 columns natively (util::col16), and JS string-slicing semantics (signature truncation at 100/80/120 units) are reproduced in UTF-16 units too — no column/slice diff class exists.

4a. R2 — TS/JS port SHIPPED 2026-07-16 (and a §3 design revision)

• The generic .scm emitter is superseded. Real TS/JS parity needs logic queries can't express (extractCall's receiver-qualified callees, store/RTK/component recognition, fn-ref capture+gating, value-ref shadow pruning, docstring wrapper climbs) — so R2 replaced the R1 query emitter with a bespoke per-language walker (codegraph-kernel/src/tsjs/, ~1,900 lines) that mirrors TreeSitterExtractor's TS/JS paths function-for-function, bug-for-bug. emitter.rs + queries/ are deleted (git has them); expect T1 languages (java/python/go) to be walkers too. The post(result, source) TS escape hatch remains available but TS/JS needed none.
• Parity evidence (macOS): scripts/kernel-parity.mjs (multiset diff of canonicalized nodes/edges/refs per file, FULL objects) — this repo 353/353 files, excalidraw 643/643 files (10,650 nodes / 10,726 edges / 68,307 refs), plus checked-in torture fixtures (__tests__/fixtures/kernel-parity/) covering components/HOCs/styled, zustand-through-middleware, RTK endpoints+hooks, vuex/pinia, fn-refs (incl this.x + shadowing gates), value-refs (incl the shadow prune), decorators, enums, type-alias members + tuple contracts, re-exports, JSX. Kept alive in npm test by __tests__/kernel-tsjs-parity.test.ts (strict full-object compare).
• One decoder bug found by the strict compare: decode.ts pre-filled filePath/language on refs; wasm extractors leave them unset (the store denormalizes via ?? filePath). Fixed — the seam contract is "exactly what extractFromSource returns", not "what the store makes of it".
• Perf (M3 Pro, excalidraw 643 files / 7MB): extraction single-thread 487ms kernel vs 1,255ms wasm (2.6×, identical outputs). End-to-end init on an 11-core host moves only ~3.4s → ~3.2s — parse is a small, already-pool-parallelized slice there; the win concentrates on constrained hardware (2-core CI class) and kernel-scale parse (R6). Headroom if R4's dubbo target needs it: arena interning, memoized UTF-16 line prefixes, and skipping wasm-grammar loads in workers for kernel-routed languages (worker cold-start).
• Not yet done (R3 gate): large-repo parity (vscode-class), full-repo dump-diff through the DB, retrieval invariants, agent A/B, Linux docker + Windows VM parity runs, control-repo perf. Routing stays opt-in (CODEGRAPH_KERNEL_LANGS) until then. → Done same day, §4b.

4b. R3 — gate PASSED, TS/JS DEFAULT-ON (2026-07-16)

Evidence (tools: scripts/kernel-parity.mjs now ORDER-sensitive — identical multisets in a different emission order would shift rowids and change resolution — and scripts/dump-graph.mjs, natural-key full-DB dumps):

1. Graph parity — byte-identical, not ≤0.5%: full init dump-diff kernel-vs-wasm: express (13,712 rows), excalidraw (89,898), vscode (2,378,238 rows) — all byte-identical. Control repo (flask, Python) byte-identical + timing unchanged. Extraction-level order-sensitive sweeps: repo 352/354 (+2 deferred), express 141/141, excalidraw 643/643, vscode 12,055/12,106 (+51 deferred), 0 diffs.
2. The one real find — encoding-dependent error recovery: same grammar bytes (sha-verified parser.c/scanner.h), same tree-sitter core (0.25.10), but error RECOVERY on files with parse errors differs between UTF-8 (native) and UTF-16 (web-tree-sitter) parsing — proven by parsing the divergent vscode file natively in UTF-16, which reproduced the wasm tree exactly. Incidence: 0% (express) / 0.31% (excalidraw) / 0.42% (vscode) of files. Policy: the kernel defers any file whose tree has_error() to the wasm extractor (defer: signal, silent, per-file) — parity by construction on erroring files, 99.6%+ keep the fast path, and the harness fails if deferrals exceed 10% (a broken kernel can't hide).
3. Retrieval invariants: kernel-indexed excalidraw — mutateElement → renderStaticScene connects end-to-end via explore (callback + react-render + jsx hops shown); synthesized-edge families present (408 jsx-render / 46 react-render / 14 interface-impl / 1 callback); byte-identical DB ⇒ counts equal by construction.
4. Agent A/B: byte-identical DBs make the A/B vacuous (identical graph, identical MCP server) — same justification as the #1320–#1322 perf PRs, which shipped on the dump-diff gate. Not burned.
5. Perf: vscode init 105.4s → 82.1s (1.28×) on the 11-core Mac; excalidraw on a 2-CPU/6GB Linux container (the CI-runner envelope) 6.2–7.1s → 4.3–4.8s (~1.5×, n=2 interleaved); Mac excalidraw ≈ neutral-to-slightly-better (parse already a small pool-parallelized slice at 11 cores). Control unchanged.
6. Platforms: Linux (arm64 bookworm container, in-container cargo build): all 22 kernel tests green under CODEGRAPH_KERNEL_EXPECT=1. Windows VM: deferred — VM stopped and prlctl start needs Parallels Pro; benign because a missing/broken .node falls back to wasm, and the release workflow builds + gates win32 prebuilds. Run the kernel suites on the VM when it's next up.
7. Suite: 2,465 tests pass WITH default-on routing — the entire extraction test corpus now exercises the kernel for TS/JS on machines with a staged .node.

Default routing: DEFAULT_ROUTED = {typescript, tsx, javascript, jsx} in src/extraction/kernel/index.ts. CODEGRAPH_KERNEL_LANGS REPLACES the set; CODEGRAPH_KERNEL=0 kills. Changelog entry added under [Unreleased].

4c. R4 — Java PORTED + gate PASSED + DEFAULT-ON (2026-07-16)

• Walker: codegraph-kernel/src/java.rs (self-contained, sharing the crate-level docstring/textutil modules) — package namespaces, imports, javadoc, annotations → decorates, type_list inheritance, fields/constants (static-final → constant), enum_constant members, anonymous classes (<T$anon@line> incl. the TS side's 0-based-line quirk, mirrored bug-for-bug), method_invocation calls with the this.field unwrap + the Foo.getInstance().bar() chain encoding, static-member value reads, method_reference fn-refs (this::x / Type::m), value refs, and the full Lombok member synthesizer (#912: @Getter/@Setter/@Data/@Value/@Builder/ @ToString/@EqualsAndHashCode/@Slf4j-family, taken-member dedup by exact classQN::name). Grammar: tree-sitter-java crate 0.23.5; wasm vendored from the SAME tag (94703d5, parser.c sha-matched), replacing tree-sitter-wasms' ^0.20.2 build.
• Parity: extraction sweeps — gson 262/262, retrofit 341/341, dubbo 4,048/4,048, torture fixture (__tests__/fixtures/kernel-parity/Torture.java, in npm test). Full-init dump-diffs byte-identical: gson (49,766 rows), retrofit (62,735), dubbo (441,266 rows). All R2/R3 repos re-verified after the fix below.
• The gate caught a REAL cross-language bug: retrofit's minified website JS exposed that fn-ref dedupe and value-ref self-checks must compare node ID strings, not table rows — IDs collide for same-(kind,name,line) nodes (routine in minified one-liners: many function e on line 3) and the TS side keys on ${fromNodeId}|${name}. Fixed in BOTH walkers (node_ids per row); this affected tsjs too (latent since R2, never released).
• Benchmark honesty (the §6 expectation was wrong about WHERE the win lands): dubbo fresh-init on the 11-core M3 Pro is ~FLAT end-to-end (11.3–11.5 wasm → 11.0–11.6 kernel; parse-loop wall 5,020→4,394ms) because that phase's wall is main-thread-bound (file reads + result store + SQLite), not worker-CPU-bound — 8 wasm workers already hide extraction CPU behind the main thread on big-core machines. Where worker CPU binds, the kernel delivers: dubbo on 2-CPU/6GB Linux 27.8–28.6s → 22.3–22.8s (~1.25×); excalidraw same envelope ~1.5×; vscode-on-Mac 1.28×. The cbm-parity Mac headline therefore needs the next lever: decode the kernel's buffers DIRECTLY into store rows (skip per-node JS object materialization on the main thread) — buffer contract already carries everything; tracked as the top §7a-adjacent follow-up.
• Platforms: Linux container (arm64): all 23 kernel tests green EXPECT=1; Windows VM still deferred (same fallback rationale as §4b).
• Default routing now includes java.

4e. R5 — Python + Go PORTED + gates PASSED + DEFAULT-ON (2026-07-16)

• Walkers: codegraph-kernel/src/python.rs + src/go.rs (the java.rs pattern). Python: decorated_definition docstring/decorator handling (decorates only for bare-identifier decorators — the call-kind quirk mirrored), fn-in-class → method, module assignments always variable (no isConst hook), from-import binding refs, self.x fn-ref candidates as BARE names, attribute callees via the namedChild(1) fallback. Go: receiver methods with Recv::name QNs + first-earlier-struct contains edges, type_spec → struct/interface classification (embedding → extends; interface method_elems → method nodes), composite-literal instantiates keeping the package qualifier, top-level var/const initializer walks attributed to the symbol (#693), 2-hop field chains (#1276), New().Method() re-encode (#645/#608), GO_SPEC fn-ref layers (literal_element/expression_list fan-out).
• Grammars: crates tree-sitter-python 0.23.6 (bffb65a) + tree-sitter-go 0.23.4 (3c3775f); wasm vendored from the same tags, parser.c sha-matched (both were 2023-era in tree-sitter-wasms).
• Parity: extraction sweeps 100% — flask 83/83, django 3,035/3,038 (+3 error-file deferrals), gin 99/99, prometheus 978/979 (+1). Full-init dumps byte-identical: flask (10,833 rows), gin (17,540), django (360,794), prometheus (213,758). Torture fixtures in npm test. Even Mac-side init already moves where extraction matters: prometheus 5.7→4.5s, django 9.0→8.7s. On the 2-CPU/6GB envelope (the CI-runner class): django 22.0→16.7s (1.32×), prometheus 15.0→10.3s (1.46×).
• Default routing now: typescript, tsx, javascript, jsx, java, python, go.

4f. R6 — kernel-scale re-validation (2026-07-17)

Fresh init of the Linux kernel in the cg1212 container (2 CPUs / 6GB), current build (R5 kernel + direct-to-store active), CODEGRAPH_SYNTH_TIMINGS:

• Completes, exit 0: 1,586s (26.4min) vs the ~27min #1212/#1323 baseline — no regression with per-file routing checks, error-file deferral, and the d2s store path live. Graph scale identical: 2,048,664 nodes / 6,405,964 edges (baseline 2.05M/6.4M).
• Phase walls: scan 1.3s (70,239 files), parse-loop 371.9s (6.2m — unchanged), fts-rebuild 6.4s, edge-index-recreate 78.9s, callback-synthesis 350.3s, resolution 1,149.7s (19.2m — the wall, P1's territory), maintenance 47.2s.
• The §6 parse expectation (6m → ~2m) was mis-premised: the Linux tree is 63,810 C/H files vs 422 Python — ~99% C, an UNPORTED T2 language, so the kernel can't touch its parse time. The expectation transfers to the C/C++ port (R7, with the blanking pre-passes staying TS-side per §4). The tree's own Python tooling: 99/99 files byte-parity.
• Kernel-scale priority order after this run: P1 resolution (73% of the wall) > C/C++ port (23%) > everything else.

4d. Direct-to-store decode (2026-07-16) — and where the wall ACTUALLY is

Kernel-routed files now ship their flat buffers from the parse worker all the way to the STORE WORKER, which decodes + finalizes them there (tryKernelExtractRaw → ExtractionResult.kernelBuffers → KernelStoreBundle → decodeKernelBundle; filter semantics shared via finalizeStoreBundle). The main thread's per-file work drops to O(1) + the content hash — it never materializes per-node objects, and both postMessage hops move flat bytes instead of object graphs. Files whose applicable frameworks carry an extract() hook keep the decoded path (hooks merge into decoded results); non-writer paths (main-thread store, tests) materialize via materializeKernelResult. Byte-identical dumps re-verified on dubbo, excalidraw, express, gson.

Measurement that closes the §4c question: with the store worker instrumented, dubbo's parse-loop wall is 94% store-writer busy time (4,202ms of 4,493ms on the kernel arm). The many-core fresh-index wall is the single-writer SQLite ingest — not extraction, not main-thread work. d2s still improves the writer lane ~11% (4,726→4,202ms: buffers skip structured-clone deserialization ON the writer) and frees the main thread, but the remaining cbm gap on many-core medium repos is a STORE-ARCHITECTURE question (their RAM-first design defers all durability). Next levers there (a separate perf arc, not this project): deferred/bulk index builds during the parse phase, multi-file write transactions, buffer→bind without object materialization. Note the #1320-arc post-mortem already measured statement batching and sorted inserts as ~zero on this path — B-tree maintenance is the floor.

4. Per-language tracker

Tiers: T1 = mostly .scm + mapping config. T2 = needs bespoke pre/post passes kept in TS (listed). T3 = not a plain tree-sitter walk (standalone/multi-grammar extractor) — migrate last or never; wasm/TS path is a fine permanent home.

The user-facing language contract is README.md → Language Support (34 logos incl. Metal, CUDA, Terraform/OpenTofu, Pascal/Delphi). Keep this tracker in sync with it — every README language must have a row here, even the ones that only ride another language's port.

Grammar column: crates.io = mainstream native grammar crate exists; vendored = we ship a rebuilt/patched wasm (ABI-15) and the kernel must compile OUR fork natively — verify parity before porting the language.

Language(s)	Today	Tier	Grammar source	Migration notes / known traps	Status
typescript, tsx, javascript, jsx	languages/typescript.ts, javascript.ts + shared branches	T1	crates.io	First target. Value-reference edges (#895/#897) and component recognition (#841 forwardRef/memo/styled) must survive — they're extraction-side. Largest test surface; gate is strictest here. PORTED + GATE PASSED + DEFAULT-ON (§4a/§4b); erroring files defer to wasm per-file.	✅
java	languages/java.ts	T1	crates.io	Second target; unlocks the dubbo-parity claim. Lombok member synthesis (#912) is a NODE synthesizer hook in extraction (synthesizeMembers) — port or keep as TS post-pass. PORTED incl. Lombok + gate passed + DEFAULT-ON (§4c).	✅
python	languages/python.ts	T1	crates.io	Third. Decorator extraction feeds framework route detection — parity required. PORTED + DEFAULT-ON (§4e).	✅
go	languages/go.ts	T1	crates.io	Third (tie). Value-reference edges ship here too (#897). PORTED + DEFAULT-ON (§4e).	✅
ruby, php	dedicated files	T1	crates.io	Straightforward; PHP property-receiver shapes (#1220/#1251) are RESOLUTION-side, unaffected.	☐
csharp	languages/csharp.ts	T1	crates.io	Plain.	☐
rust, dart, scala, lua, luau, r	dedicated files	T1	crates.io (luau/r/scala: verify crate freshness vs our wasm)	Long-tail T1; port opportunistically after the big five.	☐
kotlin	languages/kotlin.ts	T1½	crates.io	Expect/actual pairing is synthesis-side (fine); extraction is clean but validate against a KMP repo.	☐
swift	shared + dedicated branch	T1½	crates.io	Trap: in-class property extraction lives in tree-sitter.ts's DEDICATED branch, not swift.ts (#1020 — Alamofire went 0→348 props). Gate on Alamofire.	☐
c, cpp	languages/c-cpp.ts	T2	crates.io	Keep as TS pre-passes: blankCppExportMacros/blankCppInlineMacros (UE class MACRO Name phantom-function misparse, #1096–#1102, CARLA 440→6), in-body reflection collapse guard (#1206), content-based .h C-vs-C++ detection.	☐
metal, cuda	dialects over the cpp grammar	T2 (rides c/cpp)	crates.io (cpp)	README-listed as first-class languages. Both are dialect-gated cpp: Metal = specifier/[[attribute]] blanking (#1121, the preParse-takes-filePath pattern); CUDA = <<<>>> blanking + content-gated .h (#1172). Their pre-passes must run before the kernel parse or stay TS-side; gate them WITH the c/cpp port, not separately.	☐
objc	languages/objc.ts	T2	crates.io	Rides the c-cpp trap family; RN bridge extraction feeds rnCrossPlatformEdges (synthesis-side, fine).	☐
arkts	languages/arkts.ts	T2	vendored (harmony-contrib)	Dot-prefixed refs + decorator-gated matching fixed 36,840 wrong edges — that logic must port exactly or stay TS-side. Compile our grammar fork natively.	☐
pascal	languages/pascal.ts	T2	vendored	Paired with dfm-extractor (T3); extractPascalDefProc indexed lookups.	☐
vbnet	languages/vbnet.ts	T2	vendored, patched + external scanner	Our wasm is a patched grammar WITH a C external scanner — the kernel must build that scanner; ts-cli 0.24 dropped \p{...} classes during the original build (#1164). Highest grammar-build risk of any language.	☐
cobol	languages/cobol.ts	T2	vendored fork	Paragraph-extent reconstruction + copybook resolution are extraction logic (#1161, CardDemo 43/44). Port carefully or keep TS post-pass.	☐
erlang	languages/erlang.ts	T2	vendored (WhatsApp/ELP)	npm tree-sitter-erlang is HIJACKED — never source from it (#1165). gen_server dispatch is synthesis-side (fine).	☐
nix	languages/nix.ts	T2	vendored (ABI-15 rebuild)	Option-path synthesizer is synthesis-side; the ===-always-false → .equals() lesson (#1190) is wasm-binding-specific and disappears natively — still gate on nixpkgs (44k files).	☐
solidity	languages/solidity.ts	T2	vendored	modifier_invocation outside body walk (#1170) is extraction-side; port it.	☐
terraform	languages/terraform.ts	T2	vendored	:-scoped refs for module-boundary bridging (#1173); metadata does NOT persist — re-read source (#1174).	☐
cfml, cfscript, cfquery	cfml-extractor.ts + 3 grammar files	T3	vendored ×3	3-grammar family with BOM-sensitive dialect sniffing (#1118/#1153–55). Leave on wasm until the very end, possibly forever.	☐
svelte, vue, astro, liquid	standalone extractors	T3	n/a (custom/embedded parsing)	Not tree-sitter walks. Permanent TS home is acceptable — file counts are small and these repos are small.	☐
dfm (Delphi forms), razor, mybatis XML	standalone extractors	T3	n/a	Same as above. mybatis pairs with a synthesis pass (fine).	☐

Do-not-regress invariants during any port (extraction-side, will show up in the gate): node metadata is re-read from source, never persisted; parse commits stay in FILE ORDER (#1015); MAX_FILE_SIZE skip; generated-file detection; CODEGRAPH_PARSE_WORKERS semantics; framework extract() hooks keep running TS-side per file after the kernel pass.

5. Equivalence gate (run per language, no exceptions)

Byte-identity vs hand-written extractors is NOT expected — the gate is behavioral parity:

1. Graph parity: fresh-index 3 real repos (small/medium/large for the language) on wasm-path vs kernel-path builds. Dump with the dump-graph.mjs pattern (natural keys). Node/edge/ref deltas ≤0.5% AND every diff category manually classified (the 13-edge supertype-visibility bug this week was caught exactly this way — small diffs are real).
2. Retrieval invariants: the language's canonical flows still connect end-to-end in codegraph_explore (playbook: docs/design/dynamic-dispatch-coverage-playbook.md); node counts stable; synthesized-edge spot-check.
3. Agent A/B non-regression per the standard methodology (CLAUDE.md): --model sonnet --effort high ALWAYS, ≥2 runs/arm, pre-warmed daemon, CODEGRAPH_NO_PROMPT_HOOK=1, forbid subagent delegation in the prompt.
4. Perf: fresh-index improves on the language's repos; a NON-migrated control repo is unchanged; suite green; Linux docker + Windows VM passes for platform-sensitive bits.

6. Rollout order and expected wins

Executed 2026-07-16/17; outcomes vs these expectations are in §4a–§4f. Two expectations below were corrected by measurement: (2) the dubbo-on-Mac headline is store-writer-bound, not extraction-bound (§4c/§4d — the win lands on the low-core envelope instead); (4) cg1212 is ~99% C, an unported T2 language, so its parse expectation belongs to the C/C++ port (§4f).

1. TS/JS/TSX/JSX — most indexed files in the funnel; excalidraw 3.3s → ~2.3s expected.
2. Java — dubbo 11.1s → ~7.5s expected (the cbm-parity headline).
3. Python, Go — rounds out ~90% of real-world indexed files.
4. Kernel-scale re-run in the cg1212 container after (2): parse 6.0m → ~1.5–2m expected.
5. Long tail opportunistically; T3 possibly never — that's fine by design.

Measurement discipline (hard-won this week — do NOT relearn these):

• Profile first. Ideas killed by measurement this week: sorted-chunk inserts (zero), statement-batching the persist (zero — B-tree maintenance is the cost), RAM-disk/ in-memory DB build (SLOWER — fastInit already writes at page-cache speed).
• CODEGRAPH_SYNTH_TIMINGS=1 now emits full phase walls ([phase-timing]) + pool/batch timings. UI distorts phase walls — pipe stdout away.
• Check host load before timing (iOS simulators inflated every phase ~30%); the Monitor-on-loadavg pattern (fire <3.5) gives clean windows.
• grep is aliased to ugrep and silently treats callback-synthesizer.ts as binary — use grep -a.

7. AFTER the kernel: the follow-on roadmap (in order)

7a. Kernel-scale resolution speed — NOW THE TOP OPEN PERF ITEM

Confirmed by the R6 run (§4f): resolution is 19.2min of the 26.4min Linux-kernel wall (73%) — sequential BY DESIGN in the 2-CPU container (the resolver pool requires ≥4 cores to engage). Parse is 6.2min (23%) and belongs to the C/C++ port (R7a). Steps: re-run cg1212 validation on ≥4-core allocation (pool + parallel synthesis #1321/#1322 engage — this first measurement is cheap and may reshape the whole problem); profile; likely levers: worker count scaling, batch size at scale, warmCachesYielding on multi-GB DBs. Target: kernel <10min on a normal 8-core host.

7b. Arc 3 — graph richness (forensics-backed; adopt cbm's real extras, skip inflation)

Priority order, each gated by the standard A/B + node-explosion probes:

1. Test→subject edges (first-class tests edges at index time; we compute covering tests at query time today; cbm materializes 14.8k on dubbo). Feeds test-gap detection (Lite headline) + Pro risk signals. Cheapest, do first.
2. Per-node code metrics (complexity, cognitive, is_test, is_entry_point, param counts) — computed during extraction (the kernel makes this nearly free — design the buffer contract with a metrics slot!). Feeds Pro risk-ranking verdicts + explore ranking de-noise.
3. Read/write distinction on references (USAGE vs WRITES). The measured agent frontier ("who mutates this state" — the canvasNonce class). HIGHEST value, HIGHEST risk: scope to exported/state-relevant symbols; the tracking-every-local explosion is the known failure mode (#999/#1212 class). Full validation methodology.
4. Exception-flow edges (raises) — throw→handler; moderate.
5. Doc Section nodes (markdown headings as nodes, linked to code) — maps onto Pro's synced-business-docs story.
6. IaC nodes (k8s/docker/kustomize as graph nodes with cross-references). NOT worth chasing (verified in their cache schema): per-variable node inflation (85% of their node count), DB size parity (theirs is ~60% allocation slack), similarity vectors in the core engine.

7c. Deferred/parked (needs explicit approval before starting)

• Single-file SEA binary (distribution polish; zero speed).
• Team-shared graph artifact (cbm's graph.db.zst idea — good, but design it for the Pro shared-worker story, not as an OSS clone).
• Full native rewrite: rejected with data — the moat (2,444 tests, byte-identical determinism, this week's two caught-by-gate bugs) lives in the TS reference.

8. Context for the executing agent

• House rules live in CLAUDE.md (repo root) — the retrieval invariants, A/B model policy, release rules (never npm publish/push tags), changelog format.
• This week's PR trail tells the story and the style: #1305, #1320 (checkpoint deferral + double-buffered persist; THE invariant: batch k+1 READS batch k's edges — supertype walks — so edges insert before fan-out), #1321 (parallel synthesis via pool reuse, registry order = merge order), #1322 (bulk edge load, identity index stays), #1323 (kernel-scale hardening: skip-don't-retry-on-main >1.5M nodes, yielding index recreate).
• Every perf PR shipped byte-identical with the dump-diff gate; keep that bar.
• Competitive context (validated 2026-07-16): cbm wins medium-repo fresh index 1.55–1.8× (their RAM-first design); we win sync 2.4–2.8×, agent A/B (their 14 tools drew ZERO calls in 8/8 runs), call-graph density 1.3–2.3×, and the constrained-hardware envelope (Linux kernel on 2-CPU/6GB: we complete in 27min, they die at 0.16% — their speed IS their memory floor). The kernel project closes their last number without giving up any of ours.