fix: detect fixture that returns without calling `use` (#9831) by oilater · Pull Request #9861 · vitest-dev/vitest

oilater · 2026-03-13T17:07:57Z

Description

Resolves #9831

When a fixture function returns without calling use(), Vitest currently waits for a timeout and shows a generic Test timed out error, making it difficult to debug the root cause.

This PR detects the case immediately and rejects with a descriptive error:

Error: Fixture returned without calling "use". 
Make sure to call "use" in every code path of the fixture function.

Implementation

Added .then().catch() chain in resolveFixtureFunction — .then() detects when the fixture resolves without use() being called, .catch() handles errors thrown inside the fixture (existing behavior).

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If you introduce new functionality, document it. You can run documentation with pnpm run docs command. No documentation needed — this only improves an error message.

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Instead of waiting for a timeout, immediately reject with a descriptive error when a fixture function returns without calling `use()`.

AriPerkkio

Looks good to me, thanks for the fix! 💯

oilater · 2026-03-13T20:33:50Z

Looks good to me, thanks for the fix! 💯

Thank you so much! 😊

sheremet-va

This looks good to me, but the error doesn't have a proper stack trace. It would be nice to point to the fixture declaration, but I don't know how to calculate the error trace 🤔 Does Error.captureStackTrace on the fixture function works?

I would expect something like

Error: Fixture returned without calling "use". Make sure to call "use" in every code path of the fixture function.

    async ({ value }, use) => {
    ^

oilater · 2026-03-14T20:46:58Z

This looks good to me, but the error doesn't have a proper stack trace. It would be nice to point to the fixture declaration, but I don't know how to calculate the error trace 🤔 Does Error.captureStackTrace on the fixture function works?

I would expect something like
Error: Fixture returned without calling "use". Make sure to call "use" in every code path of the fixture function.

    async ({ value }, use) => {
    ^

Thanks for the feedback!
I implemented the stack trace using the same Symbol-based pattern as hooks.ts

Since the fixture function definition isn't a call frame, pointing to the exact line isn't possible at runtime 🤔
but it can point to the base.extend(...) call site like below.

How about also including the fixture name in the error message like this?

Error: Fixture "setup" returned without calling "use". Make sure to call "use" in every code path of the fixture function.

Let me know how you'd like to proceed, and I'll update this PR!

hi-ogawa · 2026-03-16T03:31:33Z

packages/runner/src/fixture.ts

+    if (!isUseFnArgResolved) {
+      useFnArgPromise.reject(
+        new Error(
+          'Fixture returned without calling "use". Make sure to call "use" in every code path of the fixture function.',


Can it surface fixture name? For the test case, it would be setup.

EDIT: ah sorry, you've already suggested that #9861 (comment).

Sure, Done in 09b3f1c!

hi-ogawa · 2026-03-16T03:36:42Z

test/cli/test/__snapshots__/fails.test.ts.snap


 exports[`should fail test-extend/fixture-without-destructuring.test.ts 1`] = `"FixtureParseError: The 1st argument inside a fixture must use object destructuring pattern, e.g. ({ task } => {}). Instead, received "context"."`;

+exports[`should fail test-extend/fixture-without-use.test.ts 1`] = `"Error: Fixture returned without calling "use". Make sure to call "use" in every code path of the fixture function."`;


I think we should favor runInlineTests + stderr snapshot pattern, so we can view full error output (even if we don't have stack right now, it might in the future). Probably we can put it somewhere around

vitest/test/cli/test/scoped-fixtures.test.ts

Lines 22 to 54 in 8fc9cff

test('test fixture cannot import from file fixture', async () => {

const { stderr } = await runInlineTests({

'basic.test.ts': () => {

const extendedTest = it.extend<{

file: string

local: string

}>({

local: ({}, use) => use('local'),

file: [({ local }, use) => use(local), { scope: 'file' }],

})

extendedTest('not working', ({ file: _file }) => {})

},

}, { globals: true })

expect(stderr).toMatchInlineSnapshot(`

"

⎯⎯⎯⎯⎯⎯ Failed Suites 1 ⎯⎯⎯⎯⎯⎯⎯

FAIL basic.test.ts [ basic.test.ts ]

FixtureDependencyError: The file "file" fixture cannot depend on a test fixture "local".

❯ basic.test.ts:2:27

1| await (() => {

2| const extendedTest = it.extend({

| ^

3| local: ({}, use) => use("local"),

4| file: [({ local }, use) => use(local), { scope: "file" }]

❯ basic.test.ts:8:1

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯

"

`)

})

- Capture registration-time stack trace using Symbol-based pattern from hooks.ts - Include fixture name in error message for easier identification - Move test to runInlineTests + stderr inline snapshot pattern

oilater · 2026-03-16T04:00:13Z

Updated in 09b3f1c !

Added stack trace pointing to base.extend(...) call site
Included fixture name in the error message
Moved test to runInlineTests + stderr inline snapshot pattern in scoped-fixtures.test.ts

hi-ogawa

lgtm!

sheremet-va · 2026-03-16T08:14:55Z

Thanks!

fix: detect fixture that returns without calling use (vitest-dev#9831)

81a7c8a

Instead of waiting for a timeout, immediately reject with a descriptive error when a fixture function returns without calling `use()`.

oilater force-pushed the fix/9831-fixture-use-error-message branch from 6d46e2a to 81a7c8a Compare March 13, 2026 17:38

AriPerkkio previously approved these changes Mar 13, 2026

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AriPerkkio requested a review from sheremet-va March 13, 2026 20:16

sheremet-va previously approved these changes Mar 14, 2026

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hi-ogawa requested changes Mar 16, 2026

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hi-ogawa reviewed Mar 16, 2026

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fix: add stack trace and fixture name to "use not called" error

09b3f1c

- Capture registration-time stack trace using Symbol-based pattern from hooks.ts - Include fixture name in error message for easier identification - Move test to runInlineTests + stderr inline snapshot pattern

oilater dismissed stale reviews from sheremet-va and AriPerkkio via 09b3f1c March 16, 2026 03:57

Merge branch 'main' into fix/9831-fixture-use-error-message

04ef793

hi-ogawa approved these changes Mar 16, 2026

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sheremet-va approved these changes Mar 16, 2026

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sheremet-va merged commit 633ae23 into vitest-dev:main Mar 16, 2026
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fix: detect fixture that returns without calling `use` (#9831)#9861

fix: detect fixture that returns without calling `use` (#9831)#9861
sheremet-va merged 3 commits intovitest-dev:mainfrom
hamsurang:fix/9831-fixture-use-error-message

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		exports[`should fail test-extend/fixture-without-destructuring.test.ts 1`] = `"FixtureParseError: The 1st argument inside a fixture must use object destructuring pattern, e.g. ({ task } => {}). Instead, received "context"."`;

		exports[`should fail test-extend/fixture-without-use.test.ts 1`] = `"Error: Fixture returned without calling "use". Make sure to call "use" in every code path of the fixture function."`;

	test('test fixture cannot import from file fixture', async () => {
	const { stderr } = await runInlineTests({
	'basic.test.ts': () => {
	const extendedTest = it.extend<{
	file: string
	local: string
	}>({
	local: ({}, use) => use('local'),
	file: [({ local }, use) => use(local), { scope: 'file' }],
	})

	extendedTest('not working', ({ file: _file }) => {})
	},
	}, { globals: true })
	expect(stderr).toMatchInlineSnapshot(`
	"
	⎯⎯⎯⎯⎯⎯ Failed Suites 1 ⎯⎯⎯⎯⎯⎯⎯

	FAIL basic.test.ts [ basic.test.ts ]
	FixtureDependencyError: The file "file" fixture cannot depend on a test fixture "local".
	❯ basic.test.ts:2:27
	1\| await (() => {
	2\| const extendedTest = it.extend({
	\| ^
	3\| local: ({}, use) => use("local"),
	4\| file: [({ local }, use) => use(local), { scope: "file" }]
	❯ basic.test.ts:8:1

	⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯

	"
	`)
	})

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Description

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