fix(indexing): prevent LanceDB metadata type coercion causing full re-index on restart

[barzhomi]

Fix: LanceDB metadata table type corruption causes full re-index on every restart

Summary

Fix a bug where the LanceDB metadata table's value column was inferred as number by LanceDB because the first row contained a numeric value (vector_size: 1024). All subsequent string values (embedding_provider, embedding_model_id) and boolean values (indexing_complete) were silently coerced to NaN/0/1, corrupting the stored metadata.

On every VS Code restart, _getStoredEmbeddingProfile() received NaN for the provider/model fields, failed the typeof !== "string" check, returned undefined, which set needsRecreation = true — causing the entire LanceDB database to be dropped and recreated, the file-hash cache to be cleared, and a full re-index to start from scratch.

Root Cause

In packages/kilo-indexing/src/indexing/vector-store/lancedb-vector-store.ts:

// BEFORE: mixed types cause LanceDB to infer value column as number
_createMetadataData() {
  return [
    { key: "vector_size",         value: 1024 },              // number — column type set here
    { key: "embedding_provider",  value: "ollama" },           // string → coerced to NaN
    { key: "embedding_model_id",  value: "qwen3-embed:0.6b" }, // string → coerced to NaN
    { key: "embedding_dimension", value: 1024 },                // number → OK
    { key: "indexing_complete",   value: false },               // boolean → coerced to 0/1
  ]
}

LanceDB infers the value column type from the first row's value (1024 = number). All subsequent rows with different types are silently coerced, losing their values.

Actual metadata stored on disk (confirmed via LanceDB query):

embedding_provider  = NaN     ← should be "ollama"
embedding_model_id  = NaN     ← should be "qwen3-embedding:0.6b"
indexing_complete   = 1       ← should be true/false

Fix

All metadata values are now explicitly converted to strings before being passed to LanceDB, ensuring a consistent string column type:

• _createMetadataData() — wrap numeric/boolean values with String()
• _upsertMetadata() — convert value to String(value) before storing
• markIndexingComplete() — store "true" instead of true
• markIndexingIncomplete() — store "false" instead of false
• hasIndexedData() — compare with "true" string instead of truthy check

The same issue was present in _persistEmbeddingProfile() which calls _upsertMetadata() with raw numeric values — now also uses String().

Verification

Tested end-to-end with the CLI binary on a small project:

Run	Message	Files	Mode
First (fresh DB)	"Starting workspace scan..."	7/7	Full scan
Second (restart)	"Checking for new or modified files..."	0/0	Incremental

Metadata after fix (all strings):

embedding_provider  = "ollama"                    ✓
embedding_model_id  = "qwen3-embedding:0.6b"      ✓
embedding_dimension = "1024"                      ✓
vector_size         = "1024"                      ✓
indexing_complete   = "true"                      ✓

File-hash cache persists across restarts (1123 bytes, not cleared).

Backward Compatibility

Existing databases with corrupted metadata (NaN values) will be auto-repaired on the first restart after this fix: the corrupted profile check triggers a one-time table recreation, which writes correct string values. Subsequent restarts use the persistent database normally.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Previously Reported Issues — All Resolved

Severity	Issue	Status
WARNING	Missing changeset file	✅ Fixed — .changeset/fix-lancedb-metadata-type-coercion.md added with user-facing description
SUGGESTION	Redundant double String() conversion at call sites	✅ Fixed — outer String() wrappers removed; _upsertMetadata handles conversion internally

Files Reviewed (2 files)

• .changeset/fix-lancedb-metadata-type-coercion.md — new file, correct patch bump and user-facing description
• packages/kilo-indexing/src/indexing/vector-store/lancedb-vector-store.ts — redundant String() calls removed at lines 601–602

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The fix is correct and complete. LanceDB metadata type coercion is resolved by storing all values as strings, the changeset is present with an appropriate user-facing message, and the minor style inconsistency has been cleaned up.

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_{Reviewed by claude-sonnet-4.6 · 109,926 tokens}

_{Review guidance: REVIEW.md from base branch main}

[marius-kilocode]

Verified this against the docs, this looks correct. Thanks @barzhomi