fix(storage): scope ledger queries with bucket hint

[flemzord]

Summary

• scope ledger reads with a cached isAloneInBucket hint set at store open/create time
• add CountLedgersInBucket to system store and wire it in driver create/open flows
• document the cache invalidation constraint to prevent cross-ledger data exposure when caching stores

Validation

• go test ./internal/storage/ledger ./internal/storage/driver

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

Driver now queries the system store for the number of ledgers in a bucket when creating or opening a ledger and sets a shared per-bucket AloneInBucket flag on the ledger store; ledger query logic uses this flag to conditionally skip ledger-name filtering.

Changes

Cohort / File(s)	Summary
Driver changes internal/storage/driver/driver.go	Calls CountLedgersInBucket when creating/opening ledgers, wraps counting errors, and sets the store's AloneInBucket flag based on whether the bucket count equals 1.
System store API & impl internal/storage/system/store.go	Added CountLedgersInBucket(ctx context.Context, bucket string) (int, error) to the Store interface and implemented it in DefaultStore (SELECT COUNT on _system.ledgers).
Mocks / tests internal/storage/driver/system_generated_test.go	Extended mock SystemStore with CountLedgersInBucket and its recorder to support expectations in tests.
Ledger store optimization internal/storage/ledger/store.go	Added per-bucket shared aloneInBucket *atomic.Bool field and SetAloneInBucket(bool); modified scoped select logic to skip ledger-name filtering when the flag is true.
Factory bucket flags internal/storage/ledger/factory.go	Added mu sync.Mutex and bucketFlags map[string]*atomic.Bool to DefaultFactory; allocates/assigns per-bucket atomic flags to stores so flag is shared across a bucket.

Sequence Diagram(s)

sequenceDiagram
    participant Client
    participant Driver
    participant SystemStore
    participant LedgerStore

    Client->>Driver: CreateLedger/OpenLedger(bucket, name)
    Driver->>SystemStore: CountLedgersInBucket(ctx, bucket)
    SystemStore->>SystemStore: Execute COUNT query on _system.ledgers
    SystemStore-->>Driver: return count (n) or error
    Driver->>LedgerStore: SetAloneInBucket(n == 1)
    LedgerStore->>LedgerStore: update shared per-bucket atomic flag
    Driver-->>Client: return ledger store handle
    Note over LedgerStore: Subsequent queries use the flag to skip<br/>ledger-name filtering when true

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Poem

🐰 I counted buckets in the night,
One ledger stood alone in light.
A shared small flag I set with care,
Now queries breeze through thinner air.
Hop, skip, optimize — a rabbit's cheer! 🥕✨

🚥 Pre-merge checks | ✅ 2 | ❌ 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 (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: adding a bucket hint to scope ledger queries, which is the core optimization introduced across the modified files.
Description check	✅ Passed	The pull request description clearly relates to the changeset, explaining the addition of a cached isAloneInBucket hint and CountLedgersInBucket method across multiple files.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch flemzord/fresh-start

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[flemzord]

Superseded by a new PR targeting release/v2.2