fix: defensive null guards on Memory.sessionIds

[rohitg00]

Bug-fix-triage pass: five callsites assumed Memory.sessionIds is always string[], which the type says — but JSONL imports + older on-disk records can deliver undefined. Touching memory.sessionIds[0] would then throw TypeError: Cannot read properties of undefined.

Read-side (now memory.sessionIds?.[0] ?? "memory"):

• src/index.ts:485 — BM25 rebuild loop
• src/state/memory-utils.ts:14 — memoryToObservation helper
• src/functions/remember.ts:145 — vectorIndexAddGuarded call
• src/functions/search.ts:264 — rebuild loop

Import side (src/functions/export-import.ts): normalise to [] before persisting, so downstream code never has to defend against the missing-field shape.

Full suite locally: 1227 pass, 1 pre-existing integration-test failure (needs running server, unrelated).

Summary by CodeRabbit

• Bug Fixes
  • Improved robustness of memory import so records with missing or malformed session info are handled safely.
  • Prevented index and search failures by defaulting missing session identifiers, ensuring memories remain indexed and retrievable.
  • Made memory-to-observation and backfill flows tolerant of absent session data to avoid runtime errors.

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No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between 029a7c6 and 5fde5cc.

📒 Files selected for processing (1)

• src/functions/export-import.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• src/functions/export-import.ts

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📝 Walkthrough

Walkthrough

This PR adds defensive handling for missing or non-array sessionIds in Memory objects. On import, invalid sessionIds are normalized to an empty array. Downstream functions in remember, search, index, and memory-utils now safely access sessionIds[0] using optional chaining with a fallback to "memory".

Changes

SessionIds resilience

Layer / File(s)	Summary
Import normalization of sessionIds src/functions/export-import.ts	The import loop defensively normalizes each imported Memory to ensure sessionIds is an array, replacing missing or non-array values with [] before persistence.
Safe sessionId access in consuming functions src/functions/remember.ts, src/functions/search.ts, src/index.ts, src/state/memory-utils.ts	Vector indexing in remember and search rebuild, BM25 legacy backfill, and memory-to-observation conversion now safely derive sessionId via optional chaining (sessionIds?.[0]) with fallback to "memory", preventing runtime errors when sessionIds is absent.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

A memory without a session?
No panic, just discretion!
We normalize imports with care,
Access safely everywhere,
With optionals and defaults fair. 🐇

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: adding defensive null guards to safely access Memory.sessionIds across multiple locations.
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.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/null-session-ids-defensive

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/functions/export-import.ts`:
- Around line 378-381: Remove the explanatory "WHAT" comment block above the
normalization of the sessionIds field (the three-line comment describing that
imported JSONL may carry malformed Memory entries and normalising to an empty
array); delete those lines and, if you feel a comment is still necessary,
replace them with a short WHY note (e.g., "preserve compatibility with
older/hand-edited exports") but do not restate what the code does—locate the
code that normalises the sessionIds field and remove the comment there.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: a6500ca8-2d88-4d36-905f-b752b5ad2f9d

📥 Commits

Reviewing files that changed from the base of the PR and between 4dd1dde and 029a7c6.

📒 Files selected for processing (5)

• src/functions/export-import.ts
• src/functions/remember.ts
• src/functions/search.ts
• src/index.ts
• src/state/memory-utils.ts