gps-denied-onboard/_docs/03_implementation/batch_92_cycle1_report.md

Batch 92 Report — AZ-621 Phase C: build_pre_constructed seeds c7_inference (cycle 1)

Batch: 92 Date: 2026-05-19 Context: Product implementation (greenfield Step 7 — Implement; AZ-618 umbrella, Phase C of 6) Tasks: AZ-621 (3 cp) — 1 task Cycle: 1 Verdict: COMPLETE — PASS (self-reviewed inline; 18/18 runtime_root tests green)

Summary

Third of six subtasks decomposing the AZ-618 umbrella. Phase C extends airborne_bootstrap.build_pre_constructed(config) additively with c7_inference (the GPU InferenceRuntime). Wraps the existing inference_factory.build_inference_runtime so that a BUILD_TENSORRT_RUNTIME/BUILD_PYTORCH_FP16_RUNTIME mismatch surfaces a clear operator-facing AirborneBootstrapError naming BOTH airborne C7 flags + the consuming component slug, rather than bubbling up the lower-level RuntimeNotAvailableError with no consuming-component context.

AZ-621 — build_pre_constructed Phase C (3 cp)

• src/gps_denied_onboard/runtime_root/airborne_bootstrap.py:

  • Imports build_inference_runtime from runtime_root.inference_factory (Layer-5 sibling).
  • New public constant C7_AIRBORNE_BUILD_FLAGS: tuple[tuple[str, str], ...] = (("tensorrt", "BUILD_TENSORRT_RUNTIME"), ("pytorch_fp16", "BUILD_PYTORCH_FP16_RUNTIME")) — single source of truth for the airborne-buildable C7 runtimes + their gating env flags (deliberately omits onnx_trt_ep, which is research-only per module-layout.md). Exported in __all__.
  • New module-private helper _build_c7_inference(config) — calls build_inference_runtime; on RuntimeNotAvailableError, re-raises as AirborneBootstrapError naming c7_inference (the missing key), BOTH C7_AIRBORNE_BUILD_FLAGS entries (so operator sees production-default + Tier-0 fallback), and the consuming component slug(s) via _configured_consumers_of_pre_constructed_key. Preserves the original error via raise ... from exc.
  • build_pre_constructed(config) now returns five keys: c13_fdr, clock, c6_descriptor_index, c6_tile_store, c7_inference. Additivity preserved per AZ-621 Constraint "MUST be additive on top of AZ-619 + AZ-620"; docstring updated to mention AZ-621 Phase C and the new raise path.
  • No new BUILD_* env flag introduced (constraint satisfied) — only a Python-level tuple listing already-existing flag names.

• tests/unit/runtime_root/test_az619_pre_constructed_phase_a.py:

  • New autouse fixture _stub_c7_inference_builder monkeypatches _build_c7_inference to an opaque sentinel — keeps AZ-619 tests focused on Phase A keys without entangling them with the new Phase C integration path (and avoids requiring BUILD_TENSORRT_RUNTIME=ON + real GPU for the AZ-619 cases).

• tests/unit/runtime_root/test_az620_pre_constructed_phase_b.py:

  • New autouse fixture _stub_c7_inference_builder (same pattern as the AZ-619 file) — keeps AZ-620 tests focused on Phase B C6 wiring and error-translation, independent of Phase C.

• tests/unit/runtime_root/test_az621_pre_constructed_phase_c.py (new):

  • test_ac_621_1_adds_c7_inference — stubs build_inference_runtime to an identifiable mock; asserts the bootstrap dict contains c7_inference referencing the stub return, and AZ-619 + AZ-620 keys are still present. Covers AC-621.1.
  • test_ac_621_2_both_build_flags_off_with_configured_consumer_raises_named_error — stubs build_inference_runtime to raise RuntimeNotAvailableError (mirroring real BUILD_*=OFF behaviour); builds a config with c3_matcher.strategy="disk_lightglue"; asserts AirborneBootstrapError is raised whose message contains c7_inference, BOTH BUILD_TENSORRT_RUNTIME and BUILD_PYTORCH_FP16_RUNTIME (sourced from the new constant), and c3_matcher. Verifies the original error is preserved as __cause__. Covers AC-621.2.
  • test_ac_621_2_no_configured_consumer_still_raises_with_full_set — defence-in-depth (mirrors the AZ-620 same-name pattern): even with no consumer configured, the bootstrap still fails loudly and the message lists the FULL theoretical consumer set (c2_vpr, c3_matcher, c3_5_adhop). Strengthens AC-621.2's operator-facing contract.

File Ownership

• OWNED (component runtime_root):
  • src/gps_denied_onboard/runtime_root/airborne_bootstrap.py
  • tests/unit/runtime_root/test_az619_pre_constructed_phase_a.py
  • tests/unit/runtime_root/test_az620_pre_constructed_phase_b.py
  • tests/unit/runtime_root/test_az621_pre_constructed_phase_c.py
• READ-ONLY: imports from runtime_root.inference_factory (Layer-5 sibling within same package), runtime_root.errors, plus the AZ-619/620 modules already in scope (storage_factory, clock, fdr_client, config).
• No FORBIDDEN-zone writes.

Test Results

• New unit tests: 3 under tests/unit/runtime_root/test_az621_pre_constructed_phase_c.py covering AC-621.1 + AC-621.2 (twice, defence-in-depth).
• Updated unit tests: AZ-619 (5/5 passing) and AZ-620 (3/3 passing) — both files extended with one autouse stub fixture each; no behavioural changes to existing assertions.
• AZ-591 regression (test_az591_airborne_bootstrap.py): 7/7 passing — AIRBORNE_REQUIRED_PRE_CONSTRUCTED_KEYS table consistency + airborne registration semantics + tier isolation all unchanged.
• Combined: pytest tests/unit/runtime_root/ -q → 18/18 passed in 0.68 s.
• No new ruff errors on touched files.

Out of scope (deferred)

• Remaining keys in AIRBORNE_REQUIRED_PRE_CONSTRUCTED_KEYS — AZ-622 (c3_lightglue_runtime + c3_feature_extractor), AZ-623 (c282_ransac_filter + c5 helpers), AZ-624 (main() integration + AC-1..AC-5).
• Real GPU model load / TensorRT engine deserialization — consolidated at AZ-624's Tier-2 Jetson AC-5 run per _docs/02_document/tests/tier2-jetson-testing.md. This subtask stubs at the factory boundary, exactly mirroring the AZ-620 pattern for C6 storage.
• Cumulative review for batches 85-92 (8 batches deferred — K=3 default missed). Recorded as outstanding work; the previous session intentionally chose AZ-621 as the next single-task batch and did not run the cumulative review at the start. Next session should run cumulative review (scope: union of files changed since cumulative_review_batches_82-84_cycle1_report.md) BEFORE starting batch 93 (AZ-622) or batch 94 (AZ-623) — both are still in the AZ-618 remediation cycle and the architecture surface around airborne_bootstrap.py deserves a cross-batch sweep before the umbrella's main() wiring (AZ-624) lands.

State

• Spec moved: _docs/02_tasks/todo/AZ-621_pre_constructed_phase_c_c7_inference.md → _docs/02_tasks/done/.
• Tracker: AZ-621 transitioned To Do → In Progress at batch start; will transition In Progress → In Testing after this commit (per implement skill Step 12).
• _docs/_autodev_state.md advanced to last_completed_batch: 92.

Next Batch

• Batch 93: AZ-622 (3 cp) — Phase D of AZ-618 umbrella. Adds c3_lightglue_runtime + c3_feature_extractor to build_pre_constructed. Depends on AZ-619 + AZ-620 + AZ-621 (all will be in done/ after this commit) + AZ-278 (already in done/).
• Alternative Batch 93: AZ-623 (3 cp) — Phase E. Independent of AZ-621; could batch alongside AZ-622 (combined 6 cp, well under the 20-cp cap) if next session prefers throughput over single-phase review focus.
• Recommended sequencing for next session: (1) run the deferred cumulative review for batches 85-92; (2) then batch 93 — single task (AZ-622) to maintain the AZ-618 single-phase-per-batch pattern, OR a two-task batch (AZ-622 + AZ-623) if cumulative review surfaces no architecture drift around the bootstrap surface.