Fix unhandled promise rejections during de/rehydration of pending queries by Ephem · Pull Request #9752 · TanStack/query

Ephem · 2025-10-13T18:03:41Z

🎯 Changes

This PR adds two .catch(noop) to handle previously unhandled promise rejection errors when dehydrating and hydrating promises, which happens when de/rehydrating pending queries.

The errors themselves are still propagated to the query client like before, this is just handling two extraneous promises we are not using the output of.

There are still other active bugs stemming from how we use query.fetch to set up a retryer. I took a stab at adding a new query.createRetryer method and use that instead, but turns out this was a bigger refactor so I wanted to get this quick fix out quickly before revisiting that.

✅ Checklist

I have followed the steps in the Contributing guide.
I have tested this code locally with pnpm run test:pr.

🚀 Release Impact

This change affects published code, and I have generated a changeset.
This change is docs/CI/dev-only (no release).

Summary by CodeRabbit

Bug Fixes
- Prevents unhandled promise rejections during de/rehydration of pending queries, improving app stability and clearer error handling in development.
Tests
- Simplified hydration tests by removing temporary unhandled rejection listeners, reflecting the new safe handling behavior.
Chores
- Patch release updates to reflect stability improvements and ensure consistent behavior across related query packages.

changeset-bot · 2025-10-13T18:03:45Z

🦋 Changeset detected

Latest commit: 6960735

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 19 packages

Name	Type
@tanstack/react-query	Patch
@tanstack/query-core	Patch
@tanstack/react-query-devtools	Patch
@tanstack/react-query-next-experimental	Patch
@tanstack/react-query-persist-client	Patch
@tanstack/angular-query-experimental	Patch
@tanstack/query-async-storage-persister	Patch
@tanstack/query-broadcast-client-experimental	Patch
@tanstack/query-persist-client-core	Patch
@tanstack/query-sync-storage-persister	Patch
@tanstack/solid-query	Patch
@tanstack/svelte-query	Patch
@tanstack/vue-query	Patch
@tanstack/angular-query-persist-client	Patch
@tanstack/solid-query-persist-client	Patch
@tanstack/svelte-query-persist-client	Patch
@tanstack/solid-query-devtools	Patch
@tanstack/svelte-query-devtools	Patch
@tanstack/vue-query-devtools	Patch

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nx-cloud · 2025-10-13T18:04:08Z

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☁️ Nx Cloud last updated this comment at 2025-10-13 18:08:34 UTC

coderabbitai · 2025-10-13T18:04:28Z

Walkthrough

Adds a shared dehydration promise with redaction and a no-op catch to prevent unhandled rejections for pending queries, applies a no-op catch during rehydration fetches, updates imports, removes test listeners for unhandledRejection, and adds a changeset for patch bumps to @tanstack/react-query and @tanstack/query-core.

Changes

Cohort / File(s)	Summary
De/rehydration promise handling `packages/query-core/src/hydration.ts`	Introduces a shared dehydration promise with error redaction, logging in non-production, and a no-op catch; rehydration now attaches a no-op catch to pending fetch promises; imports `noop`.
Test cleanup `packages/react-query/src/__tests__/HydrationBoundary.test.tsx`	Removes setup/teardown of temporary `unhandledRejection` listeners; tests no longer suppress unhandled rejections explicitly.
Release metadata `.changeset/tall-banks-drop.md`	Adds patch changeset for @tanstack/react-query and @tanstack/query-core with note on avoiding unhandled rejections during de/rehydration.

Sequence Diagram(s)

sequenceDiagram
autonumber
participant App
participant QueryClient
participant Serializer as Serializer/Dehydrate
participant Redactor as Error Redactor
participant Logger
rect rgba(230,245,255,0.5)
note over App,QueryClient: Dehydrate pending queries (changed)
App->>QueryClient: dehydrate()
QueryClient->>Serializer: serialize pending query
Serializer->>Redactor: redact non-permitted errors
Redactor-->>Serializer: redacted error/result
Serializer-->>QueryClient: shared promise (with catch(noop))
QueryClient-->>App: DehydratedState (refs shared promise)
end
Note right of Logger: In non-production, log redacted errors

sequenceDiagram
autonumber
participant App
participant Hydration as HydrationBoundary
participant QueryClient
participant Fetch as Pending Fetch
rect rgba(230,255,230,0.5)
note over App,Hydration: Rehydrate pending queries (changed)
App->>Hydration: useDehydratedState(DehydratedState)
Hydration->>QueryClient: rehydrate()
QueryClient->>Fetch: resume/trigger pending query fetch
Fetch-->>QueryClient: Promise
QueryClient->>Fetch: attach catch(noop) to avoid unhandled rejection
end

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Suggested reviewers

manudeli

Poem

I nibble bytes with whiskered care,
Catching promises mid-air.
No thumps of panic, no alarms—
Redacted errs in gentle arms.
Dehydrate, rehydrate—hop, no flop!
My queue is calm—hip, hop, hop. 🐇✨

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	You can run `@coderabbitai generate docstrings` to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The title clearly and concisely summarizes the primary change by referencing the fix for unhandled promise rejections during de/rehydration of pending queries, matching the core modifications in the pull request.
Description Check	✅ Passed	The pull request description follows the required template with all major sections present and clearly describes the changes, includes a completed checklist, and details the release impact including a generated changeset.

✨ Finishing touches

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📜 Recent review details

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Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between ee85d16 and 6960735.

📒 Files selected for processing (3)

.changeset/tall-banks-drop.md (1 hunks)
packages/query-core/src/hydration.ts (4 hunks)
packages/react-query/src/__tests__/HydrationBoundary.test.tsx (0 hunks)

💤 Files with no reviewable changes (1)

packages/react-query/src/tests/HydrationBoundary.test.tsx

🧰 Additional context used

🧬 Code graph analysis (1)

packages/query-core/src/hydration.ts (2)

packages/query-core/src/query.ts (1)
promise (198-200)
packages/query-core/src/utils.ts (1)
noop (82-82)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)

GitHub Check: Preview
GitHub Check: Test

🔇 Additional comments (6)

packages/query-core/src/hydration.ts (5)
2-2: LGTM: Import added for unhandled rejection handling.
The noop import is correctly added and will be used to prevent unhandled promise rejections while preserving error propagation to the query client.
82-94: LGTM: Error redaction logic correctly implemented.
The promise chain properly:
Uses optional chaining for query.promise (may be undefined)
Serializes successful results
Redacts errors when required while logging originals in non-production
Maintains rejection state by returning Promise.reject(...) in both branches
This preserves error propagation to the query client while enabling controlled error redaction.
96-100: LGTM: Unhandled rejection prevention correctly implemented.
The .catch(noop) pattern is the correct approach:
Consumes the rejection locally to prevent unhandled rejection warnings
Doesn't interfere with downstream error handling (promise still rejects)
Uses optional chaining since promise may be undefined
The explanatory comment clearly documents the intent.
113-113: LGTM: Shared promise correctly referenced.
Using the shared promise variable (with noop catch attached) in the return object is correct and ensures the dehydrated promise won't trigger unhandled rejections.
271-277: LGTM: Hydration side also protected from unhandled rejections.
The .catch(noop) on query.fetch() correctly prevents unhandled rejection warnings during rehydration while preserving error propagation through the query client's error handling.
This completes the fix for both dehydration and rehydration flows.
.changeset/tall-banks-drop.md (1)
1-6: LGTM: Changeset correctly documents the fix.
The changeset properly:
Marks both affected packages for patch bumps (appropriate for a bug fix)
Provides a clear description of the change
Follows standard changeset format

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pkg-pr-new · 2025-10-13T18:06:34Z

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commit: 6960735

codecov · 2025-10-13T18:08:49Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.78%. Comparing base (ee85d16) to head (6960735).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #9752 +/- ##
===========================================
+ Coverage 45.53% 59.78% +14.24% 
===========================================
Files 196 125 -71 Lines 8327 5555 -2772 Branches 1894 1516 -378 ===========================================
- Hits 3792 3321 -471 + Misses 4093 1935 -2158 + Partials 442 299 -143

Components	Coverage Δ
@tanstack/angular-query-experimental	`93.85% <ø> (ø)`
@tanstack/eslint-plugin-query	`∅ <ø> (∅)`
@tanstack/query-async-storage-persister	`43.85% <ø> (ø)`
@tanstack/query-broadcast-client-experimental	`24.39% <ø> (ø)`
@tanstack/query-codemods	`∅ <ø> (∅)`
@tanstack/query-core	`97.48% <100.00%> (+<0.01%)`	⬆️
@tanstack/query-devtools	`3.48% <ø> (ø)`
@tanstack/query-persist-client-core	`80.00% <ø> (ø)`
@tanstack/query-sync-storage-persister	`84.61% <ø> (ø)`
@tanstack/query-test-utils	`∅ <ø> (∅)`
@tanstack/react-query	`96.01% <ø> (ø)`
@tanstack/react-query-devtools	`10.00% <ø> (ø)`
@tanstack/react-query-next-experimental	`∅ <ø> (∅)`
@tanstack/react-query-persist-client	`100.00% <ø> (ø)`
@tanstack/solid-query	`78.06% <ø> (ø)`
@tanstack/solid-query-devtools	`∅ <ø> (∅)`
@tanstack/solid-query-persist-client	`100.00% <ø> (ø)`
@tanstack/svelte-query	`∅ <ø> (∅)`
@tanstack/svelte-query-devtools	`∅ <ø> (∅)`
@tanstack/svelte-query-persist-client	`∅ <ø> (∅)`
@tanstack/vue-query	`71.10% <ø> (ø)`
@tanstack/vue-query-devtools	`∅ <ø> (∅)`

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fix(hydration): fix unhandled promise rejections
6960735

github-actionsBot added package: react-query package: query-core labels Oct 13, 2025

TkDodo approved these changes Oct 13, 2025
View reviewed changes

Ephem merged commit 4e1c433 into TanStack:mainOct 13, 2025
9 checks passed

github-actionsBot mentioned this pull request Oct 13, 2025
ci: Version Packages #9753
Merged

Hellol77 pushed a commit to Hellol77/query that referenced this pull request Oct 14, 2025
fix(hydration): fix unhandled promise rejections (TanStack#9752)
868193d

coderabbitaiBot mentioned this pull request Nov 5, 2025
fix(core): only attach .then and .catch onto a promise if it gets dehydrated #9847
Merged
4 tasks

This was referenced Dec 14, 2025
test(react-query/HydrationBoundary): add tests for 'enabled: false' and 'staleTime: Infinity' #9969
Merged
experimental_prefetchInRender does not work with useQueryErrorResetBoundary#9978
Closed

coderabbitaiBot mentioned this pull request Dec 29, 2025
fix(react-query/HydrationBoundary): prevent unnecessary refetch during hydration #9968
Open
4 tasks

coderabbitaiBot mentioned this pull request Jan 27, 2026
Fix/infinite query hydration 8825 #10074
Merged
5 tasks

coderabbitaiBot mentioned this pull request Feb 21, 2026
Prevent useQuery from skipping hydration #10159
Open
4 tasks

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Fix unhandled promise rejections during de/rehydration of pending queries - #9752

Fix unhandled promise rejections during de/rehydration of pending queries#9752
Ephem merged 1 commit into
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Ephem:fredrik/fix-unhandled-rejection

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