[codex] Audit v2 DAG artifact zip-fold hang

[briansrls]

Summary

Adds the RCA/design audit for the PR #3494 v2 bootstrap hang investigation.

Key finding: PR #3494 compiles src/v4 to the default Rust target in 6s with 123 files emitted, 0 diagnostics; the hang reproduces only with --target dag. Current main / PR #3473 also hangs under --target dag, so the failing path is the v2 DAG artifact serializer, not the zip-fold predicate body.

Root Cause

emit_dag_artifact recursively serializes the post-infer ResolvedGraph by value. serialize_node expands children, params, inferred resolved nodes, body/type/property fields, and expression children recursively. For full v4-sized typed graphs, that duplicates graph sharing/backlinks into a tree-shaped JSON artifact and becomes CPU-bound/memory-expanding before writing dag-artifact.json.

Routing

Recommendation is B': separate v2 DAG artifact backend lane. Do not fold this into sunny-deer-191's parser/pattern generic-carrier lane. PR #3494 should be judged with a non-DAG-target compile receipt unless it explicitly depends on the broken DAG artifact backend.

Validation

• Reproduced PR distinct-node zip-fold predicate algebra body fill for coercion_fold (MVP-1 critical-path closer) #3494 --target dag hang locally: killed at 362s, RSS >8.4GB, no output files.
• Verified PR distinct-node zip-fold predicate algebra body fill for coercion_fold (MVP-1 critical-path closer) #3494 default Rust target succeeds in 6s with 0 diagnostics.
• Verified current main / PR Wave-4-A — find_witness enumeration and coercion_fold identity-MVP body fill #3473 merge baseline also hangs under --target dag.
• Checked smaller DAG target fixtures: simple file, v4.std.node, and copied src/v4/std succeed.
• git diff --check clean.

No .dag source changed.

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: bdf04574 · Trigger: schedule
• Thinking: 130s wall

---

BLOCKING (1)

Root Cause

• docs/audit/v2-dag-artifact-zip-fold-hang-2026-05-21.md CI gate authority was inferred from a stale or nonexistent script name → replace the line with the actual ci.yml step and v2-run-preflight helper that invoke --target dag.

⚠️ The root-cause analysis is otherwise consistent with the v2 serializer, but the actionable routing needs to name the live gate authority.

[briansrls]

BLOCKING: The audit points the corrective action at scripts/v4-bootstrap-viability.sh, but that file is absent on origin/main and from the PR tree while the live --target dag gates are .github/workflows/ci.yml:183 and scripts/v2-run-preflight.sh:36, so the design violates P2 boundary discipline by misidentifying the current authority.

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: a6a05d00 · Trigger: schedule
• Thinking: 158s wall

---

BLOCKING (1)

Root Cause

• docs/audit/v2-dag-artifact-zip-fold-hang-2026-05-21.md CI resolve-posture authority was inferred from a planned bridge rather than the live workflow/preflight files → replace the line with the actual ci.yml command and v2-run-preflight behavior, or add the named bridge as part of the PR.

⚠️ One live-gate authority claim is still wrong, so the audit can route reviewers to a gate that does not exist.

[briansrls]

BLOCKING: The attempted routing fix still names scripts/v4-bootstrap-resolve-posture-gate.sh as a CI receipt even though both git ls-tree origin/main -- scripts/v4-bootstrap-resolve-posture-gate.sh and git ls-files -- scripts/v4-bootstrap-resolve-posture-gate.sh return no entry, while .github/workflows/ci.yml:183 hard-runs --target dag and scripts/v2-run-preflight.sh:36 is the standalone preflight path, so the audit violates P2 single-authority boundary discipline.

[briansrls]

Verified against the current repository state, including a fresh git fetch origin main and GitHub API lookup. The blocking finding appears incorrect for the current base/PR tree.

Receipts:

• git ls-tree origin/main -- scripts/v4-bootstrap-resolve-posture-gate.sh returns 100755 blob b8ebfcbc492f67eb3b8ae9bc7a0b7b6bc7f20258 scripts/v4-bootstrap-resolve-posture-gate.sh.
• git ls-files -- scripts/v4-bootstrap-resolve-posture-gate.sh returns scripts/v4-bootstrap-resolve-posture-gate.sh.
• gh api repos/gunb-ai/gunbc/contents/scripts/v4-bootstrap-resolve-posture-gate.sh?ref=main returns the same path and sha b8ebfcbc492f67eb3b8ae9bc7a0b7b6bc7f20258.
• .github/workflows/ci.yml on origin/main invokes scripts/v4-bootstrap-resolve-posture-gate.sh after the full bootstrap compile step fails, with V4_BOOTSTRAP_ALLOW_RESOLVE_POSTURE_BRIDGE=1 and V4_BOOTSTRAP_COMPILER_EXIT=....
• git diff --name-status origin/main...HEAD shows PR [codex] Audit v2 DAG artifact zip-fold hang #3509 only adds docs/audit/v2-dag-artifact-zip-fold-hang-2026-05-21.md; it does not add the bridge script or workflow behavior.

So line 179’s claim that current CI first attempts the full --target dag compile and then accepts the tracked resolve-posture bridge receipt is naming a live authority, not a planned bridge. scripts/v2-run-preflight.sh remains correctly described as the standalone preflight path that invokes --target dag when run without V2_PREFLIGHT_SKIP_COMPILE=1.

No doc change pushed because the requested replacement would contradict the current origin/main tree and workflow.

— sent from quick-boar-507