fix(expect): remove JestExtendError.context from verbose error reporting (#9983)

hi-ogawa · web-flow · commit 66751c9e8255 · 2026-03-27T07:29:41.000+01:00
diff --git a/packages/browser/src/client/tester/runner.ts b/packages/browser/src/client/tester/runner.ts
@@ -156,7 +156,8 @@ export function createBrowserRunner(
     }
 
     onTaskFinished = async (task: Task) => {
-      const lastErrorContext = task.result?.errors?.at(-1)?.context
+      // check custom matcher metadata in JestExtendError
+      const lastErrorContext = task.result?.errors?.at(-1)?.__vitest_error_context__
       if (
         this.config.browser.screenshotFailures
         && document.body.clientHeight > 0
diff --git a/packages/expect/src/jest-extend.ts b/packages/expect/src/jest-extend.ts
@@ -64,12 +64,18 @@ function getMatcherState(
   }
 }
 
+interface VitestErrorContext {
+  assertionName: string
+  meta?: object
+}
+
 class JestExtendError extends Error {
   constructor(
     message: string,
     public actual?: any,
     public expected?: any,
-    public context?: { assertionName: string; meta?: object },
+    /** @internal */
+    public __vitest_error_context__?: VitestErrorContext,
   ) {
     super(message)
   }
diff --git a/packages/vitest/src/node/printError.ts b/packages/vitest/src/node/printError.ts
@@ -283,6 +283,7 @@ const skipErrorProperties = new Set([
   'VITEST_TEST_NAME',
   'VITEST_TEST_PATH',
   '__vitest_rollup_error__',
+  '__vitest_error_context__',
   ...Object.getOwnPropertyNames(Error.prototype),
   ...Object.getOwnPropertyNames(Object.prototype),
 ])
diff --git a/test/cli/test/expect-extend.test.ts b/test/cli/test/expect-extend.test.ts
@@ -0,0 +1,56 @@
+import { expect, test } from 'vitest'
+import { runInlineTests } from '../../test-utils'
+
+// JestExtendError's internal context property shouldn't show up as "Serialized Error"
+test('expect.extend error message', async () => {
+  const result = await runInlineTests({
+    './basic.test.js': `
+import { expect, test } from 'vitest';
+
+expect.extend({
+  toMyEqual(actual, expected) {
+    const pass = actual === expected;
+    return { pass, message: () => 'my matcher failed', actual, expected };
+  },
+});
+
+test('fail', () => {
+  expect(123).toMyEqual(456);
+});
+`,
+  }, {
+    reporters: 'verbose',
+  })
+  expect(result.stderr).toMatchInlineSnapshot(`
+    "
+    ⎯⎯⎯⎯⎯⎯⎯ Failed Tests 1 ⎯⎯⎯⎯⎯⎯⎯
+
+     FAIL  basic.test.js > fail
+    Error: my matcher failed
+
+    - Expected
+    + Received
+
+    - 456
+    + 123
+
+     ❯ basic.test.js:12:15
+         10|
+         11| test('fail', () => {
+         12|   expect(123).toMyEqual(456);
+           |               ^
+         13| });
+         14|
+
+    ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯
+
+    "
+  `)
+  expect(result.testTree()).toMatchInlineSnapshot(`
+    {
+      "basic.test.js": {
+        "fail": "failed",
+      },
+    }
+  `)
+})

Original file line number	Diff line number	Diff line change
`@@ -156,7 +156,8 @@ export function createBrowserRunner(`
`156`	`156`	`}`
`157`	`157`
`158`	`158`	`onTaskFinished = async (task: Task) => {`
`159`		`- const lastErrorContext = task.result?.errors?.at(-1)?.context`
	`159`	`+ // check custom matcher metadata in JestExtendError`
	`160`	`+ const lastErrorContext = task.result?.errors?.at(-1)?.__vitest_error_context__`
`160`	`161`	`if (`
`161`	`162`	`this.config.browser.screenshotFailures`
`162`	`163`	`&& document.body.clientHeight > 0`
Original file line number	Diff line number	Diff line change
`@@ -64,12 +64,18 @@ function getMatcherState(`
`64`	`64`	`}`
`65`	`65`	`}`
`66`	`66`
	`67`	`+interface VitestErrorContext {`
	`68`	`+ assertionName: string`
	`69`	`+ meta?: object`
	`70`	`+}`
	`71`	`+`
`67`	`72`	`class JestExtendError extends Error {`
`68`	`73`	`constructor(`
`69`	`74`	`message: string,`
`70`	`75`	`public actual?: any,`
`71`	`76`	`public expected?: any,`
`72`		`- public context?: { assertionName: string; meta?: object },`
	`77`	`+ /** @internal */`
	`78`	`+ public __vitest_error_context__?: VitestErrorContext,`
`73`	`79`	`) {`
`74`	`80`	`super(message)`
`75`	`81`	`}`