fix(store): escape interior double-quotes in sanitizeFTS to prevent FTS5 crash

[blak0p]

🔗 Linked Issue

Closes #574

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🏷️ PR Type

• type:bug — Bug fix

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📝 Summary

• Fixes FTS5 search crash on queries containing an interior double-quote (e.g. hello"world → SQL logic error: unterminated string (1)).
• Doubles interior " inside sanitizeFTS per the FTS5 string-literal escape rule ("""), so hello"world → "hello""world".
• Adds TestSanitizeFTS with 8 cases (written first, failing per TDD; all pass after the fix).

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🔧 Changes

File	Change
internal/store/store.go	Add strings.ReplaceAll(w, \"\", \"\"\"\") after Trim in sanitizeFTS to escape interior double-quotes for FTS5.
internal/store/store_test.go	Add TestSanitizeFTS covering plain words, multiple words, single/multiple interior quotes, already-quoted, just-quotes, mixed, and empty input.

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🧪 Test Plan

• New test TestSanitizeFTS fails on unpatched code (RED) and passes after the fix (GREEN): go test ./internal/store/ -run TestSanitizeFTS -v
• Full store package passes (no regressions): go test ./internal/store/
• Built binary no longer crashes: go build -o /tmp/engram-fix ./cmd/engram && /tmp/engram-fix search 'hello"world' → clean "No memories found" (exit 0).
• Normal search still works: /tmp/engram-fix search 'sanitizeFTS' → returns results.

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✅ Contributor Checklist

• Linked an approved issue ([Bug] FTS5 search returns HTTP 500 on queries containing an interior double-quote (e.g. foo"bar) #574)
• Added exactly one type:* label (type:bug)
• Tests included with the fix
• Conventional commit format
• No Co-Authored-By trailers

Summary by CodeRabbit

• Bug Fixes
  • Improved search query handling so text containing double quotes no longer produces malformed search expressions, resulting in more reliable search behavior.
• Tests
  • Added unit test coverage for search-term formatting across common scenarios, including plain terms, multi-word input, inputs with interior quotes, mixed quoted/unquoted sequences, and empty input.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 72e3028e-7143-46e8-98fa-796df51675e0

📥 Commits

Reviewing files that changed from the base of the PR and between 9190069 and 08fd805.

📒 Files selected for processing (2)

• internal/store/store.go
• internal/store/store_test.go

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📝 Walkthrough

Walkthrough

sanitizeFTS now escapes interior double quotes within tokens before wrapping them in FTS5-quoted literals. A table-driven test validates the updated formatting across quoted, unquoted, mixed, and empty inputs.

Changes

FTS Sanitization Fix

Layer / File(s)	Summary
Escape interior quotes in FTS sanitization internal/store/store.go, internal/store/store_test.go	sanitizeFTS doubles interior double quotes before FTS5 quoting, and TestSanitizeFTS validates the resulting query strings across multiple input cases.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Suggested reviewers: gentleman-programming, alan-thegentleman

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: escaping interior double quotes in sanitizeFTS to prevent FTS5 crashes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Alan-TheGentleman]

Correct fix, exemplary size. strings.ReplaceAll(w, "\"", "\"\"") after the Trim is the right FTS5 literal escape, and the 8-case table-driven test is exactly what this needed.

• Only blocker: rebase on main to resolve the conflict. It's positional, not semantic — you and #537 both edit the region right after sanitizeFTS.

Worth noting for whoever reviews #537: this fix is still required after that one lands. Its LIKE fallback uses searchTerms() and bypasses sanitizeFTS entirely, but foo"bar is 7 runes so it still takes the FTS path and still crashes without your escape.

One cosmetic thing, not blocking: Trim still strips an unbalanced trailing quote (a" → "a"), losing a character. Not a crash, just slightly lossy.

type:bug applied. Ping me after the rebase and I'll merge.

[Alan-TheGentleman]

Heads up: I rebased this on main for you and force-pushed to fix/fts5-interior-quote, since the conflict was purely mechanical and this is a crash fix worth landing quickly. Your commit and authorship are unchanged — only the parent moved (9190069 → 08fd805).

What the conflict actually was: both main and your branch appended new tests to the end of internal/store/store_test.go, so git interleaved them. I took main's version of the file and re-appended your TestSanitizeFTS intact. Your one-line production change in sanitizeFTS applied cleanly with no conflict at all.

Verified locally before pushing: go build ./... clean, gofmt clean, and the full internal/store suite passes including all 8 of your table cases.

If you have local work on this branch, git fetch && git reset --hard origin/fix/fts5-interior-quote before continuing.

Merging once CI goes green. Thanks for the fix — the escape is exactly right, and it stays necessary even after #537 lands, since that PR's LIKE fallback bypasses sanitizeFTS but foo"bar is 7 runes and still takes the FTS path.

[Alan-TheGentleman]

Rebase done and CI green across all gates. The escape is correct and the coverage is solid — merging.

[blak0p]

Thanks so much, Alan, really didn’t need to, but I appreciate it a lot. Thanks for the rebase and for the review too!