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phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed
phase plan subsystem tags requires provides affects tech-stack key-files key-decisions patterns-established requirements-completed duration completed
08-alt-landmark-preprocessing-routing-backend-v2 04 routing
alt
landmarks
preprocessing
build-tool
overpass
fail-honest
coverage-gate
quantum-ceiling
scaling-rule
phase provides
08-alt-landmark-preprocessing-routing-backend-v2 (plan 08-02) the ONE landmark module (LANDMARK_QUANTUM_S + farthestPointAnchors + landmarkTables + landmarkCoverage) and the ARG2 encodeGraph that REQUIRES a landmarks block
phase provides
08-alt-landmark-preprocessing-routing-backend-v2 (plan 08-03) the live ALT consumer (routeAstar potentials) these build-time tables feed
phase provides
06-turn-by-turn-guidance-live-driving the measured real-graph facts the gates lean on (311,325 nodes / 677,068 edges / 14.7 MB base / one giant SCC ≈ 0.98 coverage)
the staged build tool
a preprocessing stage between edge compaction and encode that feeds the graph's edges to the ONE landmark module — the script quantizes and implements nothing itself (single-authority law)
the D-02 scaling rule in code
L = clamp(round(N/13000), 16, 32) (~24 at KL's 311k nodes) + the --landmarks <n> measured knob (positive int, hard cap 128, parsed before --check)
honest pre-write gates
quantum-ceiling throw → fail with the raise-quantum hint (Pitfall 5); per-anchor coverage ≥ 0.9 with the SAME fraction for any L (T-08-11); anchor shortfall fails loud
extended stats gate (L/quantum/coverage min-mean/table bytes/sentinel totals BEFORE the size gates) and --check landmark facts decoded from the binary (count/quantum/anchors/coverage/sentinels, no network)
A1 LADDER HISTORY rung (c2) recorded in the script header
EXECUTED in this preprocessing stage
08-05 (the campaign gates on the ARG2 binary this plan's rebuild leg must produce)
future Malaysia-wide fork builds (re-derive L from the same rule)
docs/ROAD-GRAPH.md quantum-knob documentation
added patterns
collect-then-write extends to the landmark stage: coverage/quantum gates run BEFORE encode, the write stays the last statement after every gate
gate constants are override-proof: --landmarks changes the count, never LANDMARK_MIN_COVERAGE_FRACTION (T-08-11 enforced structurally)
created modified
routing/scripts/build-road-graph.mjs (the preprocessing stage + --check landmark facts + --landmarks knob + ladder rung c2)
Task 2's real rebuild STOPPED at Overpass HTTP 502 per the plan's own honest-failure path (no retry beyond the script's one-request law, no query change, no fabrication); the previous ARG1 binary is byte-untouched — the rebuild is a maintainer-time re-run of the same command
Anchor shortfall (farthestPointAnchors returning fewer than requested) fails loud instead of encoding a weaker ALT than the rule asked for — printed L must equal carried L (input validation, Rule 2)
--check mirrors the build's printed facts from the written bytes (landmarkCoverage re-computed off the decoded u16 tables) — the print-the-measurement law extends to the artifact audit
~6min 2026-10-25

Phase 8 Plan 08-04: Build-Side ALT Preprocessing Summary

The build tool now produces ARG2 through the ONE landmark module — D-02 scaling rule (L ≈ 24 at KL scale), hard coverage/quantum gates before any write, a --landmarks measured knob, and --check landmark facts — but the real KL rebuild is PENDING: Overpass returned HTTP 502 and the plan's honest-failure path stopped there with the previous ARG1 binary untouched.

Performance

  • Duration: ~6 min (11:08–11:14 UTC)
  • Started: 2026-10-25T11:08:00Z
  • Completed: 2026-10-25T11:13:25Z
  • Tasks: 1/2 complete (task 1 committed; task 2 stopped at the plan's own honest-failure path)
  • Files modified: 1

Accomplishments

  • The preprocessing stage landed with zero second implementations: after degree-0 compaction and before the encode, the script projects the edge array once ({from, to, seconds, flags} — the module's input shape, no mutation of the encode side) and feeds it to farthestPointAnchors → landmarkTables → landmarkCoverage from ../src/landmark.ts. No local Dijkstra, no local priority queue, no local quantization — grep -ci "dijkstra\|priorityqueue" hits only 3 doc-comment lines (the module's Dijkstras, by name).
  • D-02 is code, not custom: L = clamp(round(N/13000), 16, 32) with named, rationale-commented constants; --landmarks <n> replaces the rule wholesale for measured retries (validated positive integer, hard cap 128 — fail-loud beyond; parsed BEFORE --check dispatch so the knob composes with both modes).
  • The gates are honest and override-proof: a landmarkTables throw → fail(... raise LANDMARK_QUANTUM_S in routing/src/landmark.ts ... (Pitfall 5: raise the quantum, never clamp)); coverage min < 0.9 → fail naming L, the offending anchor index/id, its fraction, and the giant-SCC expectation; anchor shortfall → fail rather than encode fewer anchors than the rule asked. The SAME coverage fraction gates any --landmarks value (T-08-11).
  • The measurement prints exist at both ends: the stats gate prints L (rule vs override), quantum, coverage min/mean, table bytes (2·L·N·2 + 4·L), and sentinel totals BEFORE the size gates; --check now prints landmarkCount / landmarkQuantumS / landmarkNodes / coverage min-mean / sentinel totals decoded from the binary (verified live on the committed ARG2 mini-graph: L=2, quantum 0.100, coverage 1.000/1.000, sentinels 0).
  • Collect-then-write preserved: writeFileSync(OUT_PATH, ...) remains the single call site, after every gate — the failed rebuild proved it (exit 1, binary byte-identical).
  • The fail-honest ARG1 path is proven, not assumed: --check routing/data/kl-roadgraph.v1.bin exits 1 at this commit with is NOT a valid GRAPH_VERSION CSR binary (decodeGraph null) — the on-disk binary is still ARG1 exactly as the plan's acceptance criteria require at this stage.
  • No coupling leaked: npm run routing:test stays 79/79 green (the suite never imports the build script).

Task Commits

Each completed task was committed atomically:

  1. task 1: The preprocessing stage + --check landmark facts (code) — 698fdf4 (feat)
  2. task 2: The real rebuild (network, maintainer-time) — NO COMMIT — stopped at Overpass HTTP 502 per the plan's honest-failure path; no file changed, nothing to commit

Files Created/Modified

  • routing/scripts/build-road-graph.mjs (+173/−16) — the ALT preprocessing stage, the landmark constants block (D-02 rule + coverage gate + override cap), the --landmarks argv parse, the encodeGraph call carrying landmarks: { quantumS, nodes, to, from }, the extended stats/--check prints, the usage/exit-code docs, and A1 LADDER HISTORY rung (c2)

Decisions Made

  • Stopped at the first 502 instead of retrying: the plan pre-commits "Overpass unreachable → the script exits 1, the previous binary untouched. STOP: record the failure. Do NOT fabricate, shrink the query, or retry beyond the script's own law," and the orchestrator confirmed "record it honestly in SUMMARY.md as a deviation and stop at that point." A 502 IS a fetch failure; an executor quietly hammering a rate-limited public API is exactly what the STOP rule exists to prevent. Wave 5's maintainer-time campaign can rebuild with one command.
  • Anchor-shortfall fail-loud (Rule 2, input validation): farthestPointAnchors may legitimately return fewer than requested (candidates exhausted / fragmentation); silently encoding fewer landmarks than the printed L would break the print-the-measurement law, so the shortfall exits 1 with a fragmentation hint. Degenerate zero-anchor case covered separately.

Deviations from Plan

Honest-Stop (pre-planned path, not an auto-fix)

1. Task 2's real rebuild blocked by Overpass HTTP 502 — stopped per the plan's own failure path

  • Found during: task 2 (the real rebuild)

  • What happened: node routing/scripts/build-road-graph.mjs fetched the corpus bbox, hit Overpass, and got HTTP 502 (server-side transient); the script exited 1 at its own !res.ok gate

  • Action taken: NO retry, NO query change, NO fabrication — recorded and stopped, per task 2's HONEST FAILURE PATHS and the plan's collect-then-write law

  • State left behind: routing/data/kl-roadgraph.v1.bin byte-untouched (ARG1, 15,449,343 B, mtime 2026-10-24 13:45); git status clean for routing/src/, routing/test/, routing/scripts/** (task-2 acceptance: zero source drift — holds)

  • Full build stdout (the measurement that exists outside the terminal):

    bbox (corpus extremes ± 0.05 deg): [2.9397, 101.5569, 3.2268, 101.7876]
fetching ways from https://overpass-api.de/api/interpreter (this can take minutes)…
build-road-graph: Overpass returned HTTP 502

    (exit 1 — the bbox line matches the 2026-10-24 build: computed from the COMMITTED corpus ± margin, mechanical pinning intact)

Total deviations: 1 (the pre-planned honest stop; 0 auto-fixed bugs) Impact on plan: Task 1 shipped complete and verified. Task 2's deliverable (a checked-green ARG2 binary on disk) is PENDING — produce it by re-running node routing/scripts/build-road-graph.mjs (minutes, Overpass willing), then node routing/scripts/build-road-graph.mjs --check routing/data/kl-roadgraph.v1.bin must exit 0 printing landmarkCount ≥ 16 / quantum 0.1 / coverage ≥ 0.9. Expected ≈ 43 MB (14.7 MB base + ~28 MB tables at L=24), inside the envelope and the 30–80 MB advisory band.

Issues Encountered

  • Overpass HTTP 502 (task 2) — the public endpoint's well-known transient failure mode. Handled by the plan's pre-committed honest stop (see Deviations). The binary rebuild is the ONLY outstanding deliverable of this plan; everything needed for it is staged and committed.
  • Nothing else — task 1's full verification battery passed on the first run (syntax, ARG1 honest-refuse exit 1, all grep gates, single writeFileSync call site, zero Dijkstra code hits, routing:test 79/79).

Verification Record (as-run)

  • node --check routing/scripts/build-road-graph.mjs → SYNTAX-OK
  • node routing/scripts/build-road-graph.mjs --check routing/data/kl-roadgraph.v1.bin → exit 1, --check: routing/data/kl-roadgraph.v1.bin is NOT a valid GRAPH_VERSION CSR binary (decodeGraph null) — ARG1-HONEST-REFUSE proven (the rebuild is the pending task 2)
  • node routing/scripts/build-road-graph.mjs --check routing/test/fixtures/mini-graph.bin → prints landmarkCount: 2 / landmarkQuantumS: 0.100 / landmarkNodes: 0, 18 / landmark coverage min/mean: 1.000 / 1.000 / landmark sentinel cells: 0 to / 0 from (exit 1 solely at the pre-existing 1 MB floor gate — a fixture, not a road graph)
  • --landmarks 0 → exit 1 (positive-integer law); --landmarks 999 → exit 1 at the 128 cap
  • grep gates: farthestPointAnchors 6, landmarkTables 5, landmarkCoverage 6, LANDMARK_MIN_COVERAGE_FRACTION 6, NODES_PER_LANDMARK 3, --landmarks 10, landmarks: { 1, writeFileSync(OUT_PATH 1 (after the gates), Dijkstra/priority-queue CODE hits 0 (3 doc-comment lines)
  • npm run routing:test → 79 passed, 0 failed

User Setup Required

None - no external service configuration required. (The pending rebuild needs only network access to the public Overpass API — no keys, no accounts.)

Next Phase Readiness

  • 08-05 (campaign): BLOCKED on the rebuild leg — the campaign's first act should be the maintainer-time re-run: node routing/scripts/build-road-graph.mjs (expect the landmark block: L = 24 by the rule at ~311k nodes, quantum 0.1, coverage min ≈ 0.98 per the giant-SCC fact, table bytes ≈ 28 MB, total ≈ 43 MB, no below-band WARNING), then --check exit 0. If Overpass fails again, that is the campaign's first honest data point, not a blocker to work around.
  • The staged tool is campaign-ready: every gate number prints before the write; the --landmarks knob is the D-02 remediation lever (raise toward 32) without touching any search code; RO1/RO2's rollout pins are untouched by this plan.
  • Known state: the real KL binary on disk is still ARG1 → decodes null → router-pending (designed, D-01) until the rebuild + re-upload; all committed fixtures carry tables, so every suite surface runs ALT live.

Phase: 08-alt-landmark-preprocessing-routing-backend-v2 Completed: 2026-10-25 (task 1; task 2 pending Overpass availability)

Self-Check: PASSED

  • routing/scripts/build-road-graph.mjs exists with the stage (grep-verified counts above) — FOUND
  • Task commit 698fdf4 exists in git history — FOUND
  • routing:test 79/79 at HEAD — FOUND (run post-commit)
  • Task 2 has intentionally NO commit (honest stop, zero file changes) — VERIFIED (git status clean on all routing paths; binary md5 6a94156aaa1d58542cef98c4ffc52b7e, byte-untouched)
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