fix(db): complete DeduplicatedLoadSubset follow-up coverage (#1352)

* fix(db): complete DeduplicatedLoadSubset follow-up fixes

Finish the DeduplicatedLoadSubset follow-up by deduping in-flight narrowed requests against the original request intent and cloning stored pagination options defensively. Add regressions covering repeated unfiltered loads, filtered-then-unfiltered coverage, in-flight load-all dedupe, and caller mutation of stored limited query options.

Made-with: Cursor

* ci: apply automated fixes

* chore: add changeset for subset dedupe follow-up

Add a short patch changeset for the DeduplicatedLoadSubset follow-up fixes so PR #1352 can version correctly.

Made-with: Cursor

* ci: apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: samwillis

.changeset/fuzzy-ties-dream.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/db': patch
+---
+
+Fix `loadSubset` dedupe follow-up edge cases and add regression coverage.

packages/db/src/query/subset-dedupe.ts

@@ -126,10 +126,8 @@ export class DeduplicatedLoadSubset {
       return prom
     }
 
-    // Not fully covered by existing data — load the missing subset.
-    // We need two clones: trackingOptions preserves the original predicate for
-    // accurate tracking (e.g., where=undefined means "all data"), while loadOptions
-    // may be narrowed with a difference expression for the actual backend request.
+    // Preserve the original request for tracking and in-flight dedupe, but allow
+    // the backend request to be narrowed to only the missing subset.
     const trackingOptions = cloneOptions(options)
     const loadOptions = cloneOptions(options)
     if (this.unlimitedWhere !== undefined && options.limit === undefined) {
@@ -147,7 +145,6 @@ export class DeduplicatedLoadSubset {
 
     // Handle both sync (true) and async (Promise<void>) return values
     if (resultPromise === true) {
-      // Sync return - update tracking with the original predicate
       this.updateTracking(trackingOptions)
       return true
     } else {
@@ -159,7 +156,7 @@ export class DeduplicatedLoadSubset {
 
       // We need to create a reference to the in-flight entry so we can remove it later
       const inflightEntry = {
-        options: loadOptions, // Store load options for subset matching of in-flight requests
+        options: trackingOptions,
         promise: resultPromise
           .then((result) => {
             // Only update tracking if this request is still from the current generation
@@ -238,5 +235,12 @@ export class DeduplicatedLoadSubset {
  * would reflect the mutated values rather than what was actually loaded.
  */
 export function cloneOptions(options: LoadSubsetOptions): LoadSubsetOptions {
-  return { ...options }
+  return {
+    ...options,
+    orderBy: options.orderBy?.map((clause) => ({
+      ...clause,
+      compareOptions: { ...clause.compareOptions },
+    })),
+    cursor: options.cursor ? { ...options.cursor } : undefined,
+  }
 }

packages/db/tests/query/subset-dedupe.test.ts

@@ -602,6 +602,194 @@ describe(`createDeduplicatedLoadSubset`, () => {
       expect(callCount).toBe(2)
     })
 
+    describe(`hasLoadedAllData after loading filtered + unfiltered data`, () => {
+      it(`should set hasLoadedAllData after a filtered load followed by an unfiltered load`, async () => {
+        let callCount = 0
+        const calls: Array<LoadSubsetOptions> = []
+        const mockLoadSubset = (options: LoadSubsetOptions) => {
+          callCount++
+          calls.push(cloneOptions(options))
+          return Promise.resolve()
+        }
+
+        const deduplicated = new DeduplicatedLoadSubset({
+          loadSubset: mockLoadSubset,
+        })
+
+        await deduplicated.loadSubset({
+          where: inOp(ref(`task_id`), [`id1`, `id2`, `id3`]),
+        })
+        expect(callCount).toBe(1)
+
+        await deduplicated.loadSubset({})
+        expect(callCount).toBe(2)
+        expect(calls[1]).toEqual({
+          where: not(inOp(ref(`task_id`), [`id1`, `id2`, `id3`])),
+        })
+
+        const result = await deduplicated.loadSubset({})
+        expect(result).toBe(true)
+        expect(callCount).toBe(2)
+      })
+
+      it(`should set hasLoadedAllData after a filtered load followed by an unfiltered load (with eq)`, async () => {
+        let callCount = 0
+        const mockLoadSubset = () => {
+          callCount++
+          return Promise.resolve()
+        }
+
+        const deduplicated = new DeduplicatedLoadSubset({
+          loadSubset: mockLoadSubset,
+        })
+
+        await deduplicated.loadSubset({
+          where: eq(ref(`task_id`), val(`single-id`)),
+        })
+        expect(callCount).toBe(1)
+
+        await deduplicated.loadSubset({})
+        expect(callCount).toBe(2)
+
+        const result1 = await deduplicated.loadSubset({})
+        expect(result1).toBe(true)
+        expect(callCount).toBe(2)
+
+        const result2 = await deduplicated.loadSubset({
+          where: eq(ref(`task_id`), val(`other-id`)),
+        })
+        expect(result2).toBe(true)
+        expect(callCount).toBe(2)
+      })
+
+      it(`should not produce exponentially growing predicates on repeated unfiltered loads`, async () => {
+        let callCount = 0
+        const calls: Array<LoadSubsetOptions> = []
+        const mockLoadSubset = (options: LoadSubsetOptions) => {
+          callCount++
+          calls.push(cloneOptions(options))
+          return Promise.resolve()
+        }
+
+        const deduplicated = new DeduplicatedLoadSubset({
+          loadSubset: mockLoadSubset,
+        })
+
+        await deduplicated.loadSubset({
+          where: inOp(ref(`task_id`), [`id1`, `id2`, `id3`]),
+        })
+        expect(callCount).toBe(1)
+
+        await deduplicated.loadSubset({})
+        expect(callCount).toBe(2)
+
+        const rounds: Array<{ round: number; whereSize: number }> = []
+        for (let i = 0; i < 10; i++) {
+          const result = await deduplicated.loadSubset({})
+          if (result !== true) {
+            const whereJson = JSON.stringify(calls[calls.length - 1]?.where)
+            rounds.push({ round: i + 1, whereSize: whereJson.length })
+          }
+        }
+
+        expect(callCount).toBe(2)
+        expect(rounds).toEqual([])
+      })
+    })
+
+    it(`should mark all data as loaded after a narrowed all-data request`, async () => {
+      const calls: Array<LoadSubsetOptions> = []
+      const mockLoadSubset = (options: LoadSubsetOptions) => {
+        calls.push(cloneOptions(options))
+        return Promise.resolve()
+      }
+
+      const deduplicated = new DeduplicatedLoadSubset({
+        loadSubset: mockLoadSubset,
+      })
+
+      await deduplicated.loadSubset({
+        where: eq(ref(`task_id`), val(`uuid-1`)),
+      })
+      await deduplicated.loadSubset({
+        where: eq(ref(`task_id`), val(`uuid-2`)),
+      })
+
+      await deduplicated.loadSubset({})
+
+      expect(calls[2]).toEqual({
+        where: not(inOp(ref(`task_id`), [`uuid-1`, `uuid-2`])),
+      })
+
+      expect((deduplicated as any).hasLoadedAllData).toBe(true)
+      expect((deduplicated as any).unlimitedWhere).toBeUndefined()
+    })
+
+    it(`should not keep issuing increasingly nested all-data predicates`, async () => {
+      const calls: Array<LoadSubsetOptions> = []
+      const mockLoadSubset = (options: LoadSubsetOptions) => {
+        calls.push(cloneOptions(options))
+        return Promise.resolve()
+      }
+
+      const deduplicated = new DeduplicatedLoadSubset({
+        loadSubset: mockLoadSubset,
+      })
+
+      await deduplicated.loadSubset({
+        where: eq(ref(`task_id`), val(`uuid-1`)),
+      })
+      await deduplicated.loadSubset({
+        where: eq(ref(`task_id`), val(`uuid-2`)),
+      })
+
+      await deduplicated.loadSubset({})
+      await deduplicated.loadSubset({})
+
+      expect(calls[3]).toBeUndefined()
+    })
+
+    it(`should deduplicate identical all-data requests while a narrowed all-data request is in flight`, async () => {
+      let resolveAllDataLoad: (() => void) | undefined
+      let callCount = 0
+      const calls: Array<LoadSubsetOptions> = []
+      const allDataLoadPromise = new Promise<void>((resolve) => {
+        resolveAllDataLoad = resolve
+      })
+
+      const mockLoadSubset = (options: LoadSubsetOptions) => {
+        callCount++
+        calls.push(cloneOptions(options))
+
+        if (callCount === 2) {
+          return allDataLoadPromise
+        }
+
+        return Promise.resolve()
+      }
+
+      const deduplicated = new DeduplicatedLoadSubset({
+        loadSubset: mockLoadSubset,
+      })
+
+      await deduplicated.loadSubset({
+        where: eq(ref(`task_id`), val(`uuid-1`)),
+      })
+
+      const firstAllDataLoad = deduplicated.loadSubset({})
+      const secondAllDataLoad = deduplicated.loadSubset({})
+
+      expect(callCount).toBe(2)
+      expect(calls[1]).toEqual({
+        where: not(eq(ref(`task_id`), val(`uuid-1`))),
+      })
+      expect(secondAllDataLoad).toBe(firstAllDataLoad)
+
+      resolveAllDataLoad?.()
+      await firstAllDataLoad
+      await secondAllDataLoad
+    })
+
     it(`should not produce unbounded WHERE expressions when loading all data after eq accumulation`, async () => {
       // This test reproduces the production bug where accumulating many eq predicates
       // and then loading all data (no WHERE clause) caused unboundedly growing
@@ -1005,5 +1193,57 @@ describe(`createDeduplicatedLoadSubset`, () => {
       expect(result).toBe(true)
       expect(callCount).toBe(1)
     })
+
+    it(`should not let caller mutations change stored limited call orderBy`, async () => {
+      let callCount = 0
+      const mockLoadSubset = () => {
+        callCount++
+        return Promise.resolve()
+      }
+
+      const deduplicated = new DeduplicatedLoadSubset({
+        loadSubset: mockLoadSubset,
+      })
+
+      const mutableOrderBy: OrderBy = [
+        {
+          expression: ref(`created_at`),
+          compareOptions: {
+            direction: `asc`,
+            nulls: `last`,
+            stringSort: `lexical`,
+          },
+        },
+      ]
+
+      await deduplicated.loadSubset({
+        where: eq(ref(`status`), val(`active`)),
+        orderBy: mutableOrderBy,
+        limit: 10,
+      })
+      expect(callCount).toBe(1)
+
+      mutableOrderBy[0]!.compareOptions.direction = `desc`
+
+      const originalOrderBy: OrderBy = [
+        {
+          expression: ref(`created_at`),
+          compareOptions: {
+            direction: `asc`,
+            nulls: `last`,
+            stringSort: `lexical`,
+          },
+        },
+      ]
+
+      const result = await deduplicated.loadSubset({
+        where: eq(ref(`status`), val(`active`)),
+        orderBy: originalOrderBy,
+        limit: 5,
+      })
+
+      expect(result).toBe(true)
+      expect(callCount).toBe(1)
+    })
   })
 })