---
phase: 18-verification-and-integration
plan: 02
subsystem: infra
tags: [abi-verification, binary-format, tech-debt, branch-cleanup, test-gate]

# Dependency graph
requires:
  - phase: 18-verification-and-integration
    plan: 01
    provides: "Integrated gsd/v0.5-milestone branch with 172 tests green"
provides:
  - "Registry-ready extension binary verified (C_STRUCT_UNSTABLE, correct symbols, no CMake)"
  - "TECH-DEBT.md with 4 new v0.5.0 decision entries (8-11)"
  - "Old branches deleted (gsd/v0.1-milestone, feat/cpp-entry-point)"
  - "Final test-all gate passed: 172 tests green"
affects: [milestone-closure, registry-submission]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "ABI footer verification via binary search (strings/xxd) not just metadata script output"

key-files:
  created: []
  modified:
    - "TECH-DEBT.md"

key-decisions:
  - "Keep C_STRUCT_UNSTABLE ABI: CPP entry failed under Python -fvisibility=hidden; C_STRUCT_UNSTABLE is functionally equivalent for version pinning and compatible with community extension registry"
  - "Statement rewrite approach for native DDL documented as accepted design decision"
  - "DDL connection isolation via file-scope static duckdb_connection documented"
  - "Amalgamation compilation via cc crate documented as accepted trade-off"

patterns-established:
  - "Binary verification: use python byte-search or xxd for footer metadata, not strings (null-separated fields may not appear)"

requirements-completed: [BUILD-05]

# Metrics
duration: 3min
completed: 2026-03-08
---

# Phase 18 Plan 02: Binary Verification, Tech Debt, and Final Gate Summary

**Extension binary verified with C_STRUCT_UNSTABLE ABI footer and correct symbol exports; TECH-DEBT.md updated with 4 v0.5.0 decisions; old branches deleted; 172 tests green**

## Performance

- **Duration:** 3 min
- **Started:** 2026-03-08T09:50:43Z
- **Completed:** 2026-03-08T09:54:03Z
- **Tasks:** 2
- **Files modified:** 1 (TECH-DEBT.md)

## Accomplishments
- Verified extension binary has correct C_STRUCT_UNSTABLE ABI footer in metadata
- Confirmed only FFI bridge symbols exported (entry point + C++ shim callbacks), no internal Rust symbols
- Confirmed no CMake dependency exists in the project
- Evaluated CPP vs C_STRUCT_UNSTABLE ABI and documented decision to keep C_STRUCT_UNSTABLE
- Added 4 new tech debt entries (sections 8-11) covering statement rewrite, DDL connection isolation, amalgamation compilation, and ABI evaluation
- Deleted old branches: gsd/v0.1-milestone and feat/cpp-entry-point
- Final test-all gate passed: 149 Rust + 4 SQL + 6 DuckLake CI + 13 vtab crash = 172 tests

## Task Commits

Each task was committed atomically:

1. **Task 1: Verify binary format and evaluate ABI** - No commit (verification-only task, no file changes)
2. **Task 2: Update TECH-DEBT.md, clean up branches, final gate** - `9cb4827` (docs)

## Files Created/Modified
- `TECH-DEBT.md` - Added decisions 8-11 for v0.5.0; updated title, intro, and footer to reflect v0.5.0 scope

## Decisions Made
- **Keep C_STRUCT_UNSTABLE ABI:** Evaluated CPP alternative. CPP entry point failed in Phase 15 because ExtensionLoader referenced non-inlined C++ symbols unavailable under Python DuckDB's -fvisibility=hidden. C_STRUCT_UNSTABLE pins to exact DuckDB version (same behavior as CPP in practice). Compatible with community extension registry (rusty_quack uses the same approach). Version-pinning cost mitigated by DuckDB Version Monitor CI.
- **Exported symbols are acceptable:** Beyond _semantic_views_init_c_api, the binary also exports _semantic_views_catalog_{delete,delete_if_exists,insert,upsert}, _sv_execute_ddl_rust, and _sv_parse_rust. These are #[no_mangle] pub extern "C" FFI bridge functions called by the C++ shim. They are namespaced with semantic_views_ or sv_ prefix and pose no ODR conflict risk.

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
- `strings` command did not find C_STRUCT_UNSTABLE in the extension binary due to null-separated metadata fields in the footer. Verified via python byte-search and xxd hex dump instead. Both confirmed the string is present at the expected offset.

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Phase 18 is complete. All success criteria met:
  - BUILD-05: Extension binary verified (ABI footer, symbols, no CMake)
  - TECH-DEBT.md documents all v0.5.0 decisions (sections 8-11)
  - Old branches deleted
  - just test-all passes as final gate (VERIFY-01 reconfirmed)
- v0.5.0 milestone is ready for closure
- Extension is registry-ready pending upstream PR to duckdb/community-extensions

## Self-Check: PASSED

- [x] TECH-DEBT.md exists with decisions 8-11
- [x] TECH-DEBT.md references v0.5.0 in header and footer
- [x] Commit 9cb4827 exists (Task 2: TECH-DEBT.md update)
- [x] Old branches deleted (gsd/v0.1-milestone, feat/cpp-entry-point)
- [x] Extension binary has C_STRUCT_UNSTABLE at offset 0x137a15e
- [x] No CMakeLists.txt in project root

---
*Phase: 18-verification-and-integration*
*Completed: 2026-03-08*
