Fix BrainBar UI stats DB read-only mode

[EtanHey]

Summary

• Open the BrainBar UI stats database connection with SQLite READONLY flags and PRAGMA query_only = ON.
• Keep the daemon/server path as the sole read-write owner while preserving dashboard stats reads.
• Add regression coverage proving read-only dashboard stats can read existing rows and reject writes.

Test plan

• swift test --package-path brain-bar --filter DatabaseTests/testReadOnlyOpenConfigurationAllowsDashboardReadsButRejectsWrites
• pytest tests/test_brainbar_build_app_guards.py -q
• Live daemon/UI smoke: daemon opens temp DB READWRITE, UI opens same DB READONLY, killing UI leaves daemon MCP initialize healthy
• swift test --package-path brain-bar
• push hook: pytest unit suite, MCP registration, eval/hook routing, bun stale-index test, FTS5 regression shell

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Note

Medium Risk
Changes SQLite connection flags/PRAGMAs and schema-migration behavior, which could affect DB availability/locking if misconfigured, but is scoped to the UI stats reader path and covered by new tests.

Overview
Makes the BrainBar UI dashboard stats DB connection read-only so the daemon remains the sole read-write owner.

Adds readOnly to BrainDatabase.OpenConfiguration, opening connections with SQLITE_OPEN_READONLY + PRAGMA query_only=ON, and skipping migration/schema checks and write-oriented PRAGMAs when in read-only mode.

Threads the configuration through StatsCollector/makeStatsCollector, sets makeUIStatsCollector to readOnly: true, adds reopenIfNeeded() to self-heal when the DB appears later, and adds regression tests verifying read-only reads succeed, writes fail, and the collector can reopen after the daemon creates the DB.

^{Reviewed by Cursor Bugbot for commit 8a05bc0. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Fix BrainBar UI stats collector to open the database in read-only mode

• Adds readOnly support to BrainDatabase.OpenConfiguration, which sets SQLite query_only mode, adjusts cache size, and skips schema/migration checks on open.
• Updates BrainBarAppSupport.makeUIStatsCollector to pass OpenConfiguration(readOnly: true) so the UI process never attempts writes to the stats DB.
• Adds BrainDatabase.reopenIfNeeded() and calls it in StatsCollector.refresh so stats load once the DB becomes available after the daemon creates it.
• Adds tests covering read-only dashboard reads, write rejection, and deferred DB availability scenarios.

^{Macroscope summarized 8a05bc0.}

Summary by CodeRabbit

Release Notes

• New Features

  • Added read-only database access mode to enhance safety and prevent accidental data modifications
  • Dashboard statistics collector now uses read-only database configuration by default

• Improvements

  • Enhanced database configuration flexibility with parameterized open settings

• Tests

  • Added test coverage for read-only database operations and access patterns

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR extends BrainDatabase.OpenConfiguration to support read-only mode and threads this configuration through StatsCollector initialization. App helpers now explicitly wire read-only configuration for UI stats collection, while the core database layer applies SQLite read-only flags and pragmas during connection setup.

Changes

Read-only Database Configuration

Layer / File(s)	Summary
Read-only database configuration contract brain-bar/Sources/BrainBar/BrainDatabase.swift	OpenConfiguration stores readOnly: Bool flag. openAndConfigure() skips schema migration when read-only and returns early. openConnection and configureConnection apply SQLite read-only flags (SQLITE_OPEN_READONLY) and pragmas (query_only=ON) when enabled.
StatsCollector database configuration parameter brain-bar/Sources/BrainBar/Dashboard/StatsCollector.swift	StatsCollector initializer accepts databaseOpenConfiguration parameter and passes it to BrainDatabase constructor.
App helper read-only wiring brain-bar/Sources/BrainBar/BrainBarApp.swift	makeStatsCollector accepts databaseOpenConfiguration parameter and threads it to StatsCollector. makeUIStatsCollector explicitly passes BrainDatabase.OpenConfiguration(readOnly: true) when creating UI stats.
Read-only mode validation test brain-bar/Tests/BrainBarTests/DatabaseTests.swift	New test testReadOnlyOpenConfigurationAllowsDashboardReadsButRejectsWrites verifies that a read-only database instance can read dashboard stats but throws when attempting write operations.

Possibly related PRs

• EtanHey/brainlayer#273: Modifies BrainDatabase.OpenConfiguration initialization and wiring (adds configurable options like busyTimeoutMillis and open error tracking).
• EtanHey/brainlayer#136: Introduces the dashboard StatsCollector feature that this PR extends with read-only configuration support.
• EtanHey/brainlayer#145: Modifies StatsCollector.init(...) signature (removes observer wiring), which may conflict with this PR's databaseOpenConfiguration parameter addition.

Poem

🐰 Read-only reads are now blessed,
With pragmas set and flags compressed,
StatsCollector knows the way,
Through BrainDatabase's careful ballet—
No writes allowed on this fine day!

---

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% 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
Title check	✅ Passed	The title 'Fix BrainBar UI stats DB read-only mode' directly and clearly describes the main change across all modified files: adding read-only database mode support to the BrainBar UI's stats collector.
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.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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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/brainbar-ui-readonly-stats

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Reviewed commit: 29b74be701

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[chatgpt-codex-connector]

Reopen the UI stats DB after read-only startup misses

When the menu UI starts against a fresh install or a new BRAINBAR_DB_PATH before the daemon has created brainlayer.db, this read-only open cannot create the database, so BrainDatabase is left with no handle. StatsCollector.refresh() only catches notOpen and never retries openAndConfigure, so even after the daemon later creates the DB and emits bus events, the dashboard remains permanently degraded until the app is restarted. Either delay this read-only collector until the daemon DB exists or add a reopen path on refresh/events.

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[EtanHey]

Codex P2 follow-up fixed in 8a05bc0: added DashboardTests/testReadOnlyStatsCollectorReopensAfterDaemonCreatesDatabase for UI startup before daemon DB creation, added BrainDatabase.reopenIfNeeded(), reset partial DB handles/isOpen on failure/close, and call reopen before stats refresh reads. Verification: focused regression passed, full swift test --package-path brain-bar passed 369 tests, and push gate passed: Python 2020 passed/9 skipped/75 deselected/1 xfailed, MCP 3, eval/hook 32, Bun 1, FTS5 regression.

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Breezy!

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