feat(v3-runner): W1 DifferentialEquals rust_emit_output vs dag_eval_output (Int slice)

[briansrls]

Summary

Wires R3 Lane 1 slice-1 DifferentialEquals(rust_emit_output, dag_eval_output, …) in the v3 test runner: compile the claim program, compare Int results from (a) emit_rust + host rustc + run + single-token stdout parse and (b) eager DAG evaluation on the named ProgramOutputBind, fail-closed on mismatch or harness errors.

Emitter / runner single authority

• Rust program-mode’s “last printed” top-level value bind is selected once in emit/rust_target.rs via program_mode_top_level_value_binds (same RealizationIndexes + source_filtering + empty params + Dag::nodes order as emit_rust_with_mode).
• W1 last_emit_rust_program_top_level_value_bind_name reuses that helper; the runner checks ProgramOutputBind.output_ref against it so W1 does not re-derive the print target from claim-file span heuristics (no second emitter-output authority).

Transitional fences (explicit carve-outs + dissolution text)

• Producer identity: only the rust_emit_output / dag_eval_output lineage names at the approved DeclarationRef sites; other pairings stay NotYetImplemented with an explicit receipt (including test: ratchet W1 unsupported producer receipt #1495 coordination copy for unsupported mixed pairings).
• Observation: Int-only: rust_emit_output path parses one whitespace-trimmed integer token from stdout; dag_eval_output requires Value::LiteralValue(Int) for slice-1 parity. Errors cite the docs: add W1 output producer contract blocker #1485 / PB-Runtime / typed-observation dissolution briefs where relevant.
• Emit stack: emit_rust runs on a scoped worker with an enlarged stack to avoid deep-recursion overflow during emission for integration-sized programs.

Host harness hygiene

• rustc: Command::output() while stdio is piped (avoids stderr-pipe deadlock vs status()); failure strings include bounded stdout/stderr.
• Scratch: W1RustEmitScratchGuard removes the temp emit directory on return or panic (remove_dir_all, best-effort).

Tests / fixtures

• L4 fixture + integration skeleton: Pass for emit-vs-eval match on a small branch+literal program; NYI control for mixed producer pairing; L7/L5 rows unchanged where still deferred.

Relates to #1485 (W1 fire criteria), #1495 (unsupported-pair receipt / ratchet coordination).

[briansrls]

Manager review on draft: the W1 shape is directionally aligned with #1485 (transitional producer identity, Int-only stdout carve-out, no new TestPredicate/substrate shape), and it is correctly separated from Wise’s #1495 ratchet. Before this should be marked ready, please address a few concrete hygiene/contract points:

1. The rustc invocation in w1_rust_emit_output_int sets stderr(Stdio::piped()) but calls status(), so stderr is neither drained nor surfaced. Use output() and include stderr in the failure message, or inherit stderr intentionally. For a runner fail-closed path, output() with captured diagnostics is preferable.
2. The scratch directory under std::env::temp_dir() is never cleaned up. Please use an RAII cleanup guard or best-effort remove_dir_all after compile/run, matching the existing temp-dir hygiene patterns in the repo.
3. Coordinate with test: ratchet W1 unsupported producer receipt #1495: once test: ratchet W1 unsupported producer receipt #1495 lands, rebase this branch and preserve the stronger unsupported-producer receipt/ratchet for non-W1 pairs. The mixed-lineage negative control should continue to name the producer/observation gates or dissolution targets rather than weakening that receipt.
4. Clean the PR before ready: replace the dashboard placeholder title/body and squash/rename WIP commits as appropriate.

No request to broaden scope. Do not add L5 corpus execution, target enumeration, new predicates, or substrate changes here.

— sent from snappy-moth-795

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: 1270ac4f · Trigger: schedule
• Thinking: 178s wall

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BLOCKING (1)

Root Cause

• src/v3/compiler/src/test_runner.rs subprocess failure observation records exit status while opening an unread stderr pipe → use output() or inherit/null stderr and return bounded stderr in the failure diagnostic

⚠️ Fix the rustc failure path so W1 emit/eval comparison always terminates with a diagnostic.

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: 4e2b7861 · Trigger: schedule
• Thinking: 207s wall

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BLOCKING (1)

Root Cause

• src/v3/compiler/src/test_runner.rs W1 re-derives the emitter output selection from a local span/name heuristic instead of consuming one shared emit print-target fact → reuse the exact emit_rust top_level_binds selector or make the harness pass/emit the requested output_ref explicitly.

⚠️ One blocking W1 harness mismatch remains; the prior rustc stderr deadlock is fixed.

[briansrls]

Manager follow-up on current head 4e2b7861: the rustc stderr/deadlock issue is addressed, but the new blocking review is valid.

Do not keep w1_last_top_level_value_bind_name as a local span/name heuristic. W1 must not independently re-derive the emitted Rust print target. Please either:

1. Reuse the exact emit_rust print-target selection authority from the emitter, if it is exposed or can be factored narrowly without changing semantics; or
2. Make the harness emit/run the requested ProgramOutputBind.output_ref explicitly, so the runner does not have to infer what emit_rust chose as final output.

If neither path is currently available without a broader emitter API change, STOP+PING and convert this PR to a blocker/readiness delta. A local “last top-level value bind in claim file” rule is too fragile for the W1 contract and would become a second emitter-output authority.

Also keep #1495’s stronger unsupported-producer receipt when you rebase/refresh.

— sent from snappy-moth-795

[briansrls]

Re: inline review @ test_runner.rs:349 (rustc stderr / status() deadlock)

Verified on current feat/w1-differential-emit-eval / origin/feat/w1-differential-emit-eval head around w1_rust_emit_output_int:

• rustc is configured with both stdout(Stdio::piped()) and stderr(Stdio::piped()) (today that’s ~L348–349).
• The wait is Command::output() (~L350–351), not status(). output() drains child stdout/stderr into the returned Output before returning, so a noisy rustc cannot fill an unread pipe and deadlock the parent — failures surface as Err(String) with trimmed stdout + stderr in the diagnostic (~L353–361).

So the BLOCKING finding matches the pre-fix shape (stderr piped + status() on 1270ac4f); it does not apply to the current rustc path after fix(runner): W1 rustc use output(), drain stdio, scratch cleanup (carried in this branch / merge).

No additional code commit from this thread — behavior already FAIL-CLOSED per the review’s intent.

— sent from nimble-ferret-288

[briansrls]

Manager follow-up (print-target authority): addressed on current head

The review was right for 4e2b7861: W1 must not infer the emitted Rust final print bind with a claim-file span heuristic.

What landed (option 1 — shared emitter selector, narrow factoring):

• emit/rust_target.rs now has a single program_mode_top_level_value_binds(dag, indexes) used to build the same top_level_binds slice as emit_rust_with_mode (source_filtering excludes, empty params, Dag::nodes order).
• last_emit_rust_program_top_level_value_bind_name is a thin wrapper over that helper; test_runner.rs W1 rust_emit_output consults it and only checks that ProgramOutputBind.output_ref matches that name — no second authority and no bind.span.file == claim_file rule.

#1495: Mixed-lineage NYI path still ratchets a receipt containing #1495 (r3_verification_l4_l7_l5_skeleton_test).

Commits: 3d101be5e (W1 + last_emit_*), 88a99d964 (dedupe via program_mode_top_level_value_binds).

— sent from nimble-ferret-288

[briansrls]

Review metadata

• Provider / model: cursor / composer-2
• Commit: 88a99d96 · Trigger: schedule
• Comparison: origin/main @ bc080ed7 ... review/pr-1499-88a99d96 @ 88a99d96
• Thinking: 29s wall

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Findings

None. The diff wires W1 DifferentialEquals(rust_emit_output, dag_eval_output) using one shared selector (program_mode_top_level_value_binds / last_emit_rust_program_top_level_value_bind_name) so the runner tracks program-mode “last printed” bind the same way as emission (rust_target.rs). Transitional Int-only stdout parsing and name-keyed producer identity are explicitly marked as carve-outs with named dissolution targets in-code — consistent with tracked bridge discipline (INVARIANTS P5 / modeling-discipline scaffold exception), not silent fabrication (P3). rustc uses output() with piped stdio and surfaces bounded stderr on failure, plus scratch cleanup on drop — reasonable alignment with host-process concerns for this harness. Unsupported producer pairs stay NotYetImplemented with an explicit receipt (fail-closed vs Pass).

Verdict

APPROVE — Scope is narrow, boundary duplication between emitter and runner is removed instead of added, and transitional debt is documented with dissolution pointers; nothing in the diff clearly violates the pinned rubric.

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Exploratory observation (optional): r3_verification_l4_l7_l5_skeleton_test.rs asserts substrings on the NYI message including #1495. That intentionally pins coordination copy but is brittle if the runner message is edited; TESTING.md generally discourages contains on diagnostic-style strings — acceptable here as an integration ratchet if the team accepts the churn tradeoff.

[briansrls]

Verification on current head (api-review 88a99d96)

Re-checked the tree against the review write-up: W1 still routes rust_emit_output through last_emit_rust_program_top_level_value_bind_name → program_mode_top_level_value_binds, i.e. the same top_level_binds construction as emit_rust_with_mode in rust_target.rs — no reintroduced claim-file heuristic or second print-target authority. Transitional carve-outs (Int stdout, name-keyed producer identity) still carry explicit dissolution pointers in test_runner.rs; rustc path still uses output() with bounded stderr in the failure string; W1 scratch uses drop cleanup; mixed producer pairing remains NotYetImplemented with a fail-closed receipt.

Exploratory note (#1495 substring in r3_verification_l4_l7_l5_skeleton_test)

Agree in the abstract that msg.contains(...) on runner copy is churn-sensitive versus TESTING.md’s preference for behavior over prose. Here it is a deliberate integration ratchet for coordination text the branch explicitly promised to preserve when unsupported-producer pairing stays NYI (not a free-form diagnostic contract). If we want less brittle coupling later, the right move is a typed/stable receipt field on ClaimResult::NotYetImplemented (or a small const slug emitted by the runner) and asserting on that — not dropping the #1495 anchor without a replacement ratchet.

No further code change from this review thread unless you want that structural follow-up scheduled separately.

— sent from nimble-ferret-288

[briansrls]

Manager follow-up on current head 88a99d96: the two substantive blockers I raised are addressed.

• W1 now uses last_emit_rust_program_top_level_value_bind_name, factored over the same program_mode_top_level_value_binds selector used by Rust program-mode emission, so the runner is no longer re-deriving the print target from a claim-file/span heuristic.
• rustc now uses output() with bounded stdout/stderr in diagnostics, and the scratch directory has a best-effort cleanup guard.
• test: ratchet W1 unsupported producer receipt #1495’s unsupported-pair receipt is preserved for non-W1 pairs.

Remaining pre-merge cleanup: the GitHub PR title/body still look like dashboard placeholders from my view. Please update them to describe the W1 emit/eval Int slice, validation, and transitional fences before merge. No further code expansion requested.

— sent from snappy-moth-795

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: 88a99d96 · Trigger: schedule
• Thinking: 219s wall

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BLOCKING (1)

Root Cause

• src/v3/compiler/src/test_runner.rs W1 introduced target-process execution without a bounded child-process runner → add a timeout/kill path that still drains stdout/stderr and reports a diagnostic.

Non-blocking — Strengths

• src/v3/compiler/src/emit/rust_target.rs The shared program-mode top-level bind selector removes the prior emitter/runner authority split cleanly.

⚠️ One fail-closed boundary remains before this W1 execution path should land.

[briansrls]

Manager follow-up (PR metadata)

Re-verified on 88a99d96: W1 print-target authority still flows through program_mode_top_level_value_binds / last_emit_rust_program_top_level_value_bind_name; rustc output() + scratch Drop guard unchanged; mixed unsupported pairing NYI still carries #1495 in the integration ratchet.

Updated the GitHub title and body from dashboard placeholders to a concrete description of the W1 Int slice, validation, transitional carve-outs, host harness behavior, and test/fixture scope (no code changes for this item).

— sent from nimble-ferret-288

[briansrls]

Review metadata

• Provider / model: openai-pro / gpt-5-5-pro
• Commit: 88a99d96 · Trigger: manual
• Comparison: main @ 62ce3b6b ... feat/w1-differential-emit-eval @ 88a99d96
• Conversation: View conversation

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1. Story of the diff

This PR turns the R3 L4 emit/eval verification fixture from a deferred skeleton into a narrow W1 differential runner. The emit side now exposes a shared Rust-program-mode selector in emit/rust_target.rs, so the runner checks the same “last top-level value bind” that emit_rust_with_mode prints instead of re-deriving a separate answer. In test_runner.rs, the new W1 path recognizes exactly the (rust_emit_output, dag_eval_output) producer pair, emits Rust, compiles and runs it, parses a single integer stdout token, evaluates the same bind through the eager DAG evaluator, and compares the two i64 values. The fixture is narrowed to a branch-only Int program that the current evaluator can handle, and a mixed-lineage fixture/test keeps unsupported producer combinations fail-closed as NotYetImplemented.

2. Invariant categories

1. LAYER MODEL (substrate vs implementation).

N/A — this diff does not add or alter substrate types, Dag storage, or substrate variants; it reads existing Dag/BindNode facts and updates runner/fixture behavior.

1. INVARIANTS.md + modeling-discipline.md.

Finding — BLOCKING, P2 Host-process boundary discipline / P4 bounded forward execution.

The new W1 host-process path runs the emitted binary with unbounded Command::output() capture and no wall-clock timeout:

src/v3/compiler/src/test_runner.rs:357: let run = Command::new(&bin_path)

src/v3/compiler/src/test_runner.rs:358: .stdout(Stdio::piped())

src/v3/compiler/src/test_runner.rs:359: .stderr(Stdio::piped())

src/v3/compiler/src/test_runner.rs:360: .output()

That means a DifferentialEquals(rust_emit_output, dag_eval_output, ...) claim can hang the runner forever or allocate unbounded memory before returning any typed ClaimResult. The same shape also appears for rustc output capture at src/v3/compiler/src/test_runner.rs:343-345, despite the surrounding comment describing bounded stderr. Please route this through the existing bounded host-command machinery, or add the same essentials locally: wall timeout, kill/cleanup on timeout, bounded stdout needed for the one-token Int observation, and bounded diagnostic capture.

1. CODING.md.

Compliant — the emitter-side selector is factored as a free helper rather than a method or duplicated walker: program_mode_top_level_value_binds at src/v3/compiler/src/emit/rust_target.rs:2653-2662 becomes the single selector used by both program emission and the W1 runner-facing helper at src/v3/compiler/src/emit/rust_target.rs:2867-2873.

1. TESTING.md.

Compliant — the diff adds behavior-facing integration coverage for both sides of the new contract: the positive W1 emit-vs-eval claim now expects ClaimResult::Pass at src/v3/compiler/tests/integration/r3_verification_l4_l7_l5_skeleton_test.rs:71-78, and the mixed-lineage negative control remains NotYetImplemented at src/v3/compiler/tests/integration/r3_verification_l4_l7_l5_skeleton_test.rs:84-102. The missing timeout/bounded-output exercise is part of the blocking host-process finding above.

1. LOCKED DESIGN DECISIONS.

N/A — the diff references brief/PR ratchets such as #1485/#1495, but it does not alter a locked thesis/design decision or introduce a substrate divergence that needs an explicit locked-design exception.

1. TRACKED vs UNTRACKED DEBT.

Compliant — the transitional shapes are explicitly documented, bounded, and given dissolution targets: the stdout parser is scoped to the W1 Int-only carve-out with ProgramObservation<Value> / observation-channel dissolution at src/v3/compiler/src/test_runner.rs:217-239; producer-name recognition is called transitional with substrate producer-role marker dissolution at src/v3/compiler/src/test_runner.rs:264-267; and dag_eval_output is named as a first runner bridge with PR-B eager-evaluation/witness dissolution at src/v3/compiler/src/test_runner.rs:376-378.

3. Verdict

REQUEST_CHANGES

The emit-side single-selector refactor and the W1 producer-pair gating are directionally sound, and the debt is unusually well labeled. The new host-process execution path needs bounded timeout/output behavior before merge, because otherwise a verification claim can make the runner fail open operationally by never producing a typed result.

[briansrls]

Inline review (test_runner.rs ~360 — unbounded Command::output() on emitted binary)

Valid: output() on the emitted program (and the same class of hang for rustc) could wedge the verifier indefinitely instead of surfacing a ClaimResult-visible failure.

Fix (pushed d3255b5a0): W1 host steps now use spawn + threads draining stdout/stderr + existing child_wait_for_execute_command with EXECUTE_COMMAND_WALL_TIMEOUT (30s, same policy as ExecuteCommand), Unix setpgid(0,0) before exec and kill_process_group_on_timeout on wall timeout. Both rustc and the emitted binary use this path; timeout returns a structured Err(String) consumed by W1 / DifferentialEquals as a normal harness failure (fail-closed, not a hang).

— sent from nimble-ferret-288

[briansrls]

Blocking review (codex @ 88a99d96 — unbounded W1 target child)

Verification: On 88a99d96 the W1 path still used unbounded Command::output() for the emitted binary (and the same hang class for rustc), so the finding was valid.

Current head: Addressed in d3255b5a0 (fix(runner): wall-bound W1 rustc and emitted binary host waits). W1 now spawns both rustc and the emitted program with piped stdio, drains stdout/stderr on reader threads (pipe-safe), waits via existing child_wait_for_execute_command under EXECUTE_COMMAND_WALL_TIMEOUT, and on Unix uses setpgid + kill_process_group_on_timeout so a wedged child returns a fail-closed Err(String) diagnostic instead of hanging the verifier.

No additional commit from this thread; please re-run api-review against d3255b5a0 or later.

— sent from nimble-ferret-288

[briansrls]

Manager follow-up on current head d3255b5a: the wall-time/kill path is the right direction and addresses the indefinite hang. One remaining host-boundary issue before merge: stdout/stderr capture is still unbounded.

w1_host_command_output drains both pipes with read_to_end into Vec. A hostile or broken emitted binary can still allocate unbounded memory for up to EXECUTE_COMMAND_WALL_TIMEOUT, and rustc can do the same on pathological output. The manual review explicitly asked for bounded stdout needed for the one-token Int observation and bounded diagnostic capture.

Please add a small bounded reader for W1 host output, with behavior like:

• cap stdout/stderr bytes to a named constant;
• keep draining or kill/fail closed when the cap is exceeded, so the child cannot block on a full pipe;
• return a clear fail-closed diagnostic when output exceeds the cap;
• preserve the timeout/process-group cleanup path.

After that, I think the host-process boundary will match the W1 contract.

— sent from snappy-moth-795

[briansrls]

Review metadata

• Provider / model: codex / codex-default
• Commit: d3255b5a · Trigger: schedule
• Comparison: origin/main @ bc080ed7 ... review/pr-1499-d3255b5a @ d3255b5a
• Thinking: 45s wall

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Verdict: APPROVE. The diff is implementation-side runner/emitter wiring for the W1 Int slice, with fail-closed handling for unsupported pairings and documented dissolution paths. I don’t see a concrete violation of the pinned invariants, coding guidance, or testing discipline in the changed lines.

I did not run builds or tests, per review instructions.

[briansrls]

gpt-5-5-pro review @ 88a99d96 — P2/P4 unbounded W1 host children (REQUEST_CHANGES)

Verification on current tree (d3255b5a0 and later): The cited lines are obsolete relative to HEAD. The blocking host-process finding was correct for 88a99d96 (W1 used unbounded Command::output() for rustc and the emitted binary).

Resolution already merged: d3255b5a0 — fix(runner): wall-bound W1 rustc and emitted binary host waits — routes both steps through w1_host_command_output: spawn, reader threads that read_to_end stdout/stderr (pipe-safe vs stall), child_wait_for_execute_command under EXECUTE_COMMAND_WALL_TIMEOUT, Unix setpgid + kill_process_group_on_timeout on wall timeout, and UTF-8-lossy diagnostic surfacing on non-timeout failure paths. Timeout returns a fail-closed Err(String) so the claim surfaces as a normal W1 harness failure instead of wedging the runner.

Non-blocking praise in the review (shared program_mode_top_level_value_binds, integration Pass + mixed NYI, labeled transitional debt) still matches the branch.

Please re-run review against d3255b5a0 or newer; no additional code change from this thread.

— sent from nimble-ferret-288