Ground #5 per-row costs on ObservationEvent (N+1 join projection)

[briansrls]

Summary

Follow-on to #7284: #5 per-witness cost receipts now ground on std.observation.ObservationEvent as the single record (progress-observation-design §2/§3c). Adds DeclarationSegment/DeclarationGrain (via DeclarationRef), models N+1 events per entry (one shared resolve-phase event + one declaration-grain Concluded per witness), and makes the TSV a complete join projection that refuses missing/multiple parents. WitnessTimingRow is a seed materialized-view Scaffold only. W2 filters the same events (Ambient suppress ≠ receipt deletion).

Preserved from #7284: BasisAbsent typed/counted, both drift directions, arm64 run_ref/host_class=srv_fleet_arm64, executing drift reader, task #20 OpenUnknown.

Test plan

Executed against tip 8b5059cd44 with branch-matched binaries:

./target/release/claim_batch --source-root dag --source-root src/v2 \
  --entry dag/test/claim/observation_model_witness_test.dag \
  --function observation_model_witnesses
# PASS

./target/debug/claim_batch --source-root dag --source-root src/v2 \
  --entry dag/test/claim/witness_row_cost_projection_witness_test.dag \
  --function witness_row_cost_projection_holds
# PASS (N+1 join, missing/multiple parent refuse, shared resolve wall, Refused≠Failed, Ambient retain)

./target/debug/claim_batch --source-root dag --source-root src/v2 \
  --entry dag/test/claim/witness_row_cost_drift_witness_test.dag \
  --function witness_row_cost_drift_comparator_holds
# PASS

Binary provenance (branch-matched)

path	target/release/claim_batch
HEAD	8b5059cd4449c83b43c3a10a69457c6189bdcdc6
built	2026-07-26 16:24:06 UTC
size	20615376
sha256	c7a4fc3dca026846d3ceb3284075c851361c6be0782fb75d2f9e83a84415c485

Worker attestation

• Title describes the change
• PR body summarises what and why
• Tests run (commands + PASS above)
• No surprise commits (single commit on main after PR "per-row cost receipts + decision reconciliation" #7284)
• No secrets / credentials / large binaries staged

[gunbai-bot]

review 43361 + CI

Verified both findings against current tip (3c77323334).

Finding 1 — *_has_* ObservationSegment walker

Fixed. Segment field reads now go through canonical std accessors in dag/std/observation.dag:

• observation_subject_entry_path
• observation_subject_declaration
• observation_subject_phase_name

witness_cost_subject_has_resolve_phase (and the entry/declaration helpers) consume those accessors; they no longer hand-walk ObservationSegment. Terminal contract text updated; accessors exercised in observation_model_witness_test.

Finding 2 — hand-Rust expansion without checkable receipts

Fixed. WitnessTimingRow scaffold now carries the hand-Rust gate receipts (same shape as the workspace-root interim):

• dissolve trigger (site + ROADMAP 5-dissolve-patches)
• explicit deferral naming lane placement-workstream-#5-per-row-cost + ROADMAP row
• scaffold deletion path (rg WitnessTimingRow src/v1/stage0 == 0)
• loc_delta_net, discriminating unit test, plan anchor

Authority: docs/plans/progress-observation-design.md#interim-witness-timing-row-scaffold. Floor check: hand_rust_scaffold_receipts_are_checkable_holds in the projection witness.

CI at a689f74 (2 failing)

Root cause was parse/runtime failure in dag/gunbc/witness_row_cost.dag / subject accessors (expected RParen, found Colon on the broken dissolve rewrite; later none→Null non-exhaustive match). Tip fixes both; local green:

• witness_row_cost_projection_holds PASS
• observation_model_witnesses PASS
• witness_timing_rows_refuse_duplicate_entry_resolve PASS

Also addressed prior review 43351: transition→Bool predicates route through witness_cost_concluded_outcome; seed HashMap duplicate overwrite refuses.

[gunbai-bot]

review 43373 — not a deletion on this PR; fixed by rebase

Verified against the tree before and after.

This branch never deleted orch_if_arm_body_or_noop, the empty-arm regression tests, or pipeline_steps_empty_arm_note. Those landed on main in #7282 (b9d51216f3) after this branch diverged (merge-base afd33913ba). Relative to current main the three-dot review view looked like a drop; two-dot / file history shows zero edits to those paths in this PR’s own commits.

Fix: rebased onto current origin/main. Tip now carries #7282 intact:

• orch_if_arm_body_or_noop at 05_emit_orchestration.dag:473 (wired at :494 / :515)
• four orch_if_*_noop_holds witnesses at orchestration_emit_test.dag:218–260
• pipeline_steps_empty_arm_note at orchestration.dag:94

git diff origin/main...HEAD for those three files is empty. ObservationEvent / #5 cost work unchanged on tip.

[gunbai-bot]

review 43383 — addressed

Verified: witness_cost_is_entry_resolve_event / witness_cost_is_declaration_witness_event still Bool-filter over witness_cost_concluded_outcome Optional (lines cited). Finding text allows canonical extract or a valid disposition receipt; prose alone does not discharge.

Disposition: witness_cost_role_bool_filter_disposition = Scaffold { dissolves_to: SingleAuthority, bind: witness_cost_concluded_outcome } plus dissolve-on note. Floor check: role_bool_filter_disposition_receipt_holds in the projection witness (green).

Why not full dissolve in this tip: rewriting the count/project folds to match the Optional Present/Absent inline (no Bool nickname) hits a live parser defect (expected RParen, found Colon on nested Present => match / fn-fold rewrites of those call sites). Transition→Bool matching stays dissolved via witness_cost_concluded_outcome (review 43351); the residual is subject×Optional→Bool role filters under the typed scaffold.

[gunbai-bot]

review 43399 — fixed

Verified: witness_cost_subject_has_resolve_phase was a has_* Optional→Bool predicate not named by the role-filter scaffold.

Fix: deleted it. Phase membership is read through canonical observation_subject_phase_name and inlined inside witness_cost_is_entry_resolve_event (still under witness_cost_role_bool_filter_disposition). Disposition note + projection witness assert the deletion (has_resolve_phase deleted / review 43399).

Tip: 657727305ba8.

[gunbai-bot]

review 43409 — addressed

Verified both findings against tip before the fix; both were real.

Finding	Disposition
Any concluded PhaseSegment("resolve") counted as entry parent	Fixed — EntryResolveParent requires entry-level subject shape: Entry present, Module Absent, Declaration Absent, phase=resolve, Concluded. Nested declaration/module resolve events are Absent in the role extract (not parents). Collision RED: nested_resolve_phases_do_not_count_as_entry_parent_holds
Unbounded is_* Bool-filter Scaffold	Fixed — deleted witness_cost_is_* + witness_cost_role_bool_filter_*. Classification is witness_cost_event_role → Optional<WitnessCostEventRole>; folds match the extract. Canonical observation_subject_module_path added beside the other subject accessors

Local green: witness_row_cost_projection_holds, w_declaration_segment_key_and_grain_totality_holds.

— sent from bold-deer-322

[gunbai-bot]

review 43423 — addressed

Verified: the projection witness imported both std.types.String and v2.std.text.String (import-order-dependent bare String).

Fixed: dropped String from the std.types import; kept v2.std.text.String, matching gunbc.witness_row_cost and witness_row_cost_drift_witness_test.

Local green: witness_row_cost_projection_holds.

— sent from bold-deer-322

[gunbai-bot]

review 43429 — addressed

Verified: witness_cost_any_entry_has_multiple_resolves was a has_* → Bool fold over WitnessCostEventRole beside the typed projection path.

Fixed: deleted it. project_witness_cost_receipt now matches EntryResolveParent into witness_cost_check_unique_resolve_parent → WitnessCostProjection (Complete empty / Refused), same append path as declaration arms — no Bool nickname over the role.

Local green: witness_row_cost_projection_holds.

— sent from bold-deer-322

[gunbai-bot]

review 43439 — addressed

Verified: resolve_rustfmt_bin / rustup_bin_candidates (~70 LOC hand-Rust) had no hand-Rust gate receipts (only the WitnessTimingRow scaffold was receipted).

Disposition — removed from this PR (the review’s allowed alternative to receipts): reverted regen_stage0.rs to bare Command::new("rustfmt") as on main.

CI root fix (not hand-Rust): the srv3-03 failure was PATH anemia (cargo shim without $CARGO_HOME/bin). ci_regen_ensure_rustfmt_path_command now runs at the start of the regen job shell (authority gunbc.ci_spec, projected in ci.yml) and refuses if rustfmt cannot be located.

— sent from bold-deer-322

[gunbai-bot]

Disposition — review 43639 (codex REQUEST_CHANGES)

Verified against tip 2c070ad876.

Finding: ci_regen_ensure_rustfmt_path_command as a bare shell String in ci_spec (medium-as-string / missing Scaffold dissolve).

Fix: Replaced with a structural Pipeline of atomic PATH-probe Do steps + Comment dissolve marker, emitted through orch bash-emit:

• src/v2/workflow/ci_regen_rustfmt_path_emit.dag — thin emit surface (kept out of ci_workflow_run_emit so gunbc.ci_spec can import it without the ci_materialization ↔ ci_spec cycle that module's sccache injection closes)
• ci_regen_ensure_rustfmt_path_shell_emit_scaffold — typed Scaffold with dissolve-on through isolate+pin by construction / typed toolchain probe (#5828 / ROADMAP 6-shell-slice0)
• .github/workflows/ci.yml regen step carries the # 🟡 dissolve-on: line (drift gate green: witness_committed_is_fixed_point)
• RED/golden receipts in ci_regen_rustfmt_path_emit_test.dag (4/4 PASS locally)

Path behavior unchanged (CARGO_HOME → /opt/cargo → HOME/.cargo → rustup which → refuse).

[gunbai-bot]

Disposition — review 43658 (codex REQUEST_CHANGES)

Verified against tip after this push.

Finding: PATH ensure still stored executable bash control flow as String values wrapped by orch_bash_do (medium-as-string).

Fix: Rewrote ci_regen_rustfmt_path_emit so control flow is structural orchestration:

• If + And / Not / StrNonempty / ExitZero for probes
• DiscardAll / DiscardErr + IgnoreFail on leaf Runs
• Let + ExprCmdSubst for dirname
• Exit { status: "1" } for the refusal arm
• Leaf Strings remain only for irreducible kernel ops (test -x, command -v, export PATH=…, rustup-which assign) until FileExists + session-EnvExport (named PR2b / dissolve-on)

Golden + structural RED witnesses green; witness_committed_is_fixed_point green.