---
phase: 56-yaml-export
plan: 01
subsystem: ddl
tags: [yaml, export, vscalar, serde, round-trip]

# Dependency graph
requires:
  - phase: 51-yaml-core
    provides: YAML parser core (from_yaml, yaml_serde dependency)
  - phase: 54-materialization-model
    provides: Materialization struct for YAML export inclusion
provides:
  - render_yaml_export() function for YAML serialization with field stripping
  - READ_YAML_FROM_SEMANTIC_VIEW scalar function for DuckDB SQL access
  - Fully qualified name resolution for scalar function
  - YAML export round-trip fidelity (export -> reimport produces identical definition)
affects: [57-introspection]

# Tech tracking
tech-stack:
  added: []
  patterns: [VScalar scalar function pattern for YAML export, field stripping via clone-and-clear]

key-files:
  created:
    - src/render_yaml.rs
    - src/ddl/read_yaml.rs
    - test/sql/phase56_yaml_export.test
  modified:
    - src/model.rs
    - src/lib.rs
    - src/ddl/mod.rs
    - tests/yaml_proptest.rs
    - test/sql/TEST_LIST

key-decisions:
  - "Field stripping via clone + clear + skip_serializing_if (not a separate export struct)"
  - "Bare name extraction via rsplit('.') for FQN support (consistent with catalog HashMap key lookup)"

patterns-established:
  - "render_yaml module pattern: always compiled (not feature-gated), unit-testable under cargo test"
  - "VScalar scalar function pattern for read-only catalog export (1 VARCHAR arg, VARCHAR return)"

requirements-completed: [YAML-04, YAML-08]

# Metrics
duration: 25min
completed: 2026-04-20
---

# Phase 56 Plan 01: YAML Export Summary

**READ_YAML_FROM_SEMANTIC_VIEW scalar function with field stripping, FQN resolution, and round-trip YAML export**

## Performance

- **Duration:** 25 min
- **Started:** 2026-04-20T00:54:43Z
- **Completed:** 2026-04-20T01:19:25Z
- **Tasks:** 2
- **Files modified:** 8

## Accomplishments
- YAML export function that strips 5 internal fields (column_type_names, column_types_inferred, created_on, database_name, schema_name) and serializes clean YAML
- VScalar function registered as read_yaml_from_semantic_view supporting bare names and fully qualified names (database.schema.view_name)
- Round-trip fidelity verified: exported YAML fed back through FROM YAML produces identical semantic view definitions
- 11 unit tests, 1 proptest (256 cases), 7 sqllogictest cases covering all requirements

## Task Commits

Each task was committed atomically:

1. **Task 1: YAML export function and model cleanup** - `5822060` (feat)
2. **Task 2: VScalar function and integration tests** - `f8c1f83` (feat)

## Files Created/Modified
- `src/render_yaml.rs` - YAML export function with field stripping and 11 unit tests
- `src/ddl/read_yaml.rs` - VScalar implementation with resolve_bare_name and 4 unit tests
- `test/sql/phase56_yaml_export.test` - 7 sqllogictest cases for integration testing
- `src/model.rs` - Added skip_serializing_if to 5 internal fields for clean serialization
- `src/lib.rs` - Registered render_yaml module and read_yaml_from_semantic_view scalar function
- `src/ddl/mod.rs` - Registered read_yaml module
- `tests/yaml_proptest.rs` - Added yaml_export_roundtrip proptest (256 cases)
- `test/sql/TEST_LIST` - Added phase56_yaml_export.test entry

## Decisions Made
- Field stripping via clone + clear + skip_serializing_if rather than a separate export struct -- simpler, leverages existing serde annotations, backward-compatible since all stripped fields already have `#[serde(default)]`
- Bare name extraction via `rsplit('.')` for FQN support -- safe string operation, used only as HashMap key lookup (no SQL interpolation), consistent with CatalogState design

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 3 - Blocking] Added phase56_yaml_export.test to TEST_LIST**
- **Found during:** Task 2 (sqllogictest integration)
- **Issue:** New test file not discovered by test runner because test/sql/TEST_LIST is an explicit file list
- **Fix:** Added `test/sql/phase56_yaml_export.test` entry to TEST_LIST
- **Files modified:** test/sql/TEST_LIST
- **Committed in:** f8c1f83 (Task 2 commit)

**2. [Rule 1 - Bug] Fixed clippy pedantic map_unwrap_or in model.rs**
- **Found during:** Task 1 (pre-commit hook)
- **Issue:** cargo fmt reformatted base_table() method to single line, triggering clippy::map_unwrap_or lint
- **Fix:** Changed `map(f).unwrap_or(default)` to `map_or(default, f)` per clippy suggestion
- **Files modified:** src/model.rs
- **Committed in:** 5822060 (Task 1 commit)

---

**Total deviations:** 2 auto-fixed (1 blocking, 1 bug)
**Impact on plan:** Both auto-fixes necessary for correctness. No scope creep.

## Issues Encountered
None

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

## Next Phase Readiness
- YAML export completes the YAML definition lifecycle (define from YAML + export to YAML)
- Ready for Phase 57 (Introspection) which will integrate YAML export into SHOW/DESCRIBE commands

## Self-Check: PASSED

---
*Phase: 56-yaml-export*
*Completed: 2026-04-20*
