---
phase: 41-describe-rewrite
verified: 2026-04-01T00:00:00Z
status: passed
score: 7/7 must-haves verified
re_verification: false
---

# Phase 41: DESCRIBE Rewrite Verification Report

**Phase Goal:** DESCRIBE SEMANTIC VIEW outputs a Snowflake-aligned property-per-row format where each row describes one property of one object, replacing the current single-row JSON-blob format
**Verified:** 2026-04-01
**Status:** passed
**Re-verification:** No — initial verification

## Goal Achievement

### Observable Truths

| # | Truth | Status | Evidence |
|---|-------|--------|----------|
| 1 | `DESCRIBE SEMANTIC VIEW` returns rows with 5 columns: object_kind, object_name, parent_entity, property, property_value | VERIFIED | `src/ddl/describe.rs` bind() declares exactly 5 VARCHAR columns; `query TTTTT` in all test assertions |
| 2 | TABLE objects emit BASE_TABLE_DATABASE_NAME, BASE_TABLE_SCHEMA_NAME, BASE_TABLE_NAME, and PRIMARY_KEY (when non-empty) properties | VERIFIED | `collect_table_rows()` emits 3 unconditional rows + conditional PRIMARY_KEY; confirmed in phase41_describe.test Tests 1 and 5 |
| 3 | RELATIONSHIP objects emit TABLE, REF_TABLE, FOREIGN_KEY, REF_KEY with JSON array format | VERIFIED | `collect_relationship_rows()` emits 4 rows; FOREIGN_KEY/REF_KEY use `format_json_array()`; confirmed in phase41_describe.test Test 2 |
| 4 | DIMENSION objects emit TABLE, EXPRESSION, DATA_TYPE with parent_entity set to source table alias | VERIFIED | `collect_dimension_rows()` sets parent_entity from `dim.source_table.unwrap_or(base_alias)`; confirmed in test assertions across all test files |
| 5 | FACT objects emit TABLE, EXPRESSION, DATA_TYPE with parent_entity set to source table alias | VERIFIED | `collect_fact_rows()` follows same pattern; FACT rows confirmed in phase29_facts.test, phase30_derived_metrics.test, phase41_describe.test Test 3 |
| 6 | METRIC objects (source_table Some) emit TABLE, EXPRESSION, DATA_TYPE | VERIFIED | `collect_metric_rows()` uses `is_derived` check; METRIC rows confirmed across all describe tests |
| 7 | DERIVED_METRIC objects (source_table None) emit EXPRESSION, DATA_TYPE only (no TABLE), with empty parent_entity | VERIFIED | `collect_metric_rows()` skips TABLE row when `is_derived`; parent set to empty string; confirmed in phase30_derived_metrics.test and phase41_describe.test Test 4 |

**Score:** 7/7 truths verified

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `src/ddl/describe.rs` | Property-per-row VTab with DescribeRow struct | VERIFIED | Complete rewrite present; struct DescribeRow at line 15; 5 collect_* helpers at lines 48-290; VTab at line 298 |
| `test/sql/phase41_describe.test` | Comprehensive DESCRIBE sqllogictest coverage | VERIFIED | 8 test groups; all 6 object kinds covered; `query TTTTT` assertions; 19 sqllogictests pass |

### Key Link Verification

| From | To | Via | Status | Details |
|------|----|-----|--------|---------|
| `src/ddl/describe.rs` | `crate::model::SemanticViewDefinition` | `SemanticViewDefinition::from_json` in bind() | VERIFIED | Line 336: `let def = SemanticViewDefinition::from_json(&name, json_str)?;` |
| `src/ddl/describe.rs` | `crate::catalog::CatalogState` | `get_extra_info::<CatalogState>` in bind() | VERIFIED | Line 328: `let state_ptr = bind.get_extra_info::<CatalogState>();` |
| `test/sql/phase20_extended_ddl.test` | `src/ddl/describe.rs` | `DESCRIBE SEMANTIC VIEW` invocation | VERIFIED | All 3 DESCRIBE assertions use `query TTTTT` with 5-column property-per-row output |
| `test/sql/phase33_cardinality_inference.test` | `src/ddl/describe.rs` | `describe_semantic_view()` table function | VERIFIED | Lines 420 and 676: COUNT(*) assertions updated to 18 rows each |

### Data-Flow Trace (Level 4)

The artifacts are VTab functions (Rust), not React components. The data flow is: CatalogState catalog (populated at CREATE SEMANTIC VIEW time) -> bind() reads JSON -> SemanticViewDefinition::from_json parses model -> collect_*_rows() build Vec<DescribeRow> -> func() emits rows.

| Artifact | Data Variable | Source | Produces Real Data | Status |
|----------|--------------|--------|-------------------|--------|
| `src/ddl/describe.rs` | `bind_data.rows` | CatalogState JSON via `SemanticViewDefinition::from_json` | Yes — reads persisted catalog state, not static | FLOWING |

### Behavioral Spot-Checks

| Behavior | Command | Result | Status |
|----------|---------|--------|--------|
| 19 sqllogictests pass including phase41_describe.test | `just test-sql` | `19 tests run, 0 failed` | PASS |
| 483 Rust unit + proptest tests pass | `cargo test` | 394+5+36+42+5+1 = 483 tests, 0 failed | PASS |
| No 6-column DESCRIBE patterns remain in DESCRIBE test assertions | `grep -r "query TTTTTT" test/sql/` | Only SHOW command tests (phase34) use TTTTTT, which is correct (SHOW has 6 columns) | PASS |
| format_json_array unit tests exist in describe.rs | Read source lines 399-418 | 3 unit tests: single, multiple, empty — present in `#[cfg(test)]` block | PASS (note: only run under `extension` feature, not `cargo test`; consistent with project design) |

### Requirements Coverage

| Requirement | Source Plan | Description | Status | Evidence |
|------------|------------|-------------|--------|----------|
| DESC-01 | 41-01, 41-02 | DESCRIBE returns property-per-row format with 5 columns | SATISFIED | bind() declares 5 columns; `query TTTTT` in all test files |
| DESC-02 | 41-01, 41-02 | TABLE objects emit BASE_TABLE_NAME, PRIMARY_KEY, database/schema name properties | SATISFIED | `collect_table_rows()` emits 3-4 rows; phase41 Test 1 and 5 confirm PK conditional |
| DESC-03 | 41-01, 41-02 | RELATIONSHIP objects emit TABLE, REF_TABLE, FOREIGN_KEY, REF_KEY | SATISFIED | `collect_relationship_rows()` emits 4 rows with JSON arrays; phase41 Test 2 confirms |
| DESC-04 | 41-01, 41-02 | DIMENSION objects emit TABLE, EXPRESSION, DATA_TYPE | SATISFIED | `collect_dimension_rows()` confirmed; coverage in all describe tests |
| DESC-05 | 41-01, 41-02 | FACT objects emit TABLE, EXPRESSION, DATA_TYPE | SATISFIED | `collect_fact_rows()` confirmed; phase29, phase30, phase41 Test 3 |
| DESC-06 | 41-01, 41-02 | METRIC objects emit TABLE, EXPRESSION, DATA_TYPE | SATISFIED | `collect_metric_rows()` with `!is_derived` path; confirmed across tests |
| DESC-07 | 41-01, 41-02 | DERIVED_METRIC objects emit EXPRESSION, DATA_TYPE (no TABLE) | SATISFIED | `collect_metric_rows()` with `is_derived` path skips TABLE row; phase30, phase41 Test 4 |

All 7 requirements marked Complete in REQUIREMENTS.md. No orphaned requirements found.

### Anti-Patterns Found

| File | Line | Pattern | Severity | Impact |
|------|------|---------|----------|--------|
| None | — | — | — | — |

Scanned `src/ddl/describe.rs`: no TODO/FIXME/placeholder comments, no `return null`/empty stub patterns. All 5 `collect_*_rows()` functions are substantive implementations that build property rows from real model data.

### Human Verification Required

None — all observable behaviors were verifiable programmatically.

The following item is confirmed by `just test-sql` output rather than requiring manual human inspection:
- The full sqllogictest suite (19 tests) passes, including `phase41_describe.test` which asserts all 6 object_kind values with exact row counts and property values.

### Gaps Summary

No gaps. All 7 must-haves are fully verified:

- `src/ddl/describe.rs` is a complete, substantive rewrite (397 lines) replacing the old single-row JSON blob VTab with a property-per-row implementation. All 6 object kinds are handled by dedicated `collect_*_rows()` helpers. The `format_json_array()` helper produces Snowflake-compatible JSON array format with no spaces after commas.
- `test/sql/phase41_describe.test` provides 8 comprehensive test groups covering all 6 object kinds, the no-PK edge case, case insensitivity, error handling for nonexistent views, and COUNT(*) verification for 4 different views.
- All 7 existing test files that previously contained 6-column `query TTTTTT` DESCRIBE assertions have been updated to the new 5-column `query TTTTT` property-per-row format. No old-format assertions remain.
- `src/query/error.rs` help message updated from `FROM describe_semantic_view('{view_name}')` to `DESCRIBE SEMANTIC VIEW {view_name}`.
- The quality gate (`just test-sql`: 19/19, `cargo test`: 483/483) is green.

---

_Verified: 2026-04-01_
_Verifier: Claude (gsd-verifier)_
