vitest-dev
diff --git a/Collapse file
‎packages/vitest/src/node/core.ts‎
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+15Lines changed: 15 additions & 0 deletions b/Collapse file
‎packages/vitest/src/node/core.ts‎
Copy file name to clipboardExpand all lines: packages/vitest/src/node/core.ts
+15Lines changed: 15 additions & 0 deletions
diff --git a/Collapse file
‎packages/vitest/src/node/projects/resolveProjects.ts‎
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+4-3Lines changed: 4 additions & 3 deletions b/Collapse file
‎packages/vitest/src/node/projects/resolveProjects.ts‎
Copy file name to clipboardExpand all lines: packages/vitest/src/node/projects/resolveProjects.ts
+4-3Lines changed: 4 additions & 3 deletions
diff --git a/Collapse file
‎test/cli/test/config/browser-configs.test.ts‎
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+59Lines changed: 59 additions & 0 deletions b/Collapse file
‎test/cli/test/config/browser-configs.test.ts‎
Copy file name to clipboardExpand all lines: test/cli/test/config/browser-configs.test.ts
+59Lines changed: 59 additions & 0 deletions
@@ -1643,6 +1643,21 @@ export class Vitest {
       return regexp.test(name)
     })
   }
+
+  /** @internal */
+  isExcludedByProjectFilter(name: string): boolean {
+    const projects = this._config?.project || this._cliOptions?.project
+    if (!projects || !projects.length) {
+      return false
+    }
+    return toArray(projects).some((project) => {
+      if (!project.startsWith('!')) {
+        return false
+      }
+      const positivePattern = project.slice(1)
+      return wildcardPatternToRegExp(positivePattern).test(name)
+    })
+  }
 }
 
 function assert(condition: unknown, property: string, name: string = property): asserts condition {
 
@@ -211,13 +211,14 @@ export async function resolveBrowserProjects(
     if (!project.config.browser.enabled) {
       return
     }
+    const originalName = project.config.name
     const instances = project.config.browser.instances || []
-    if (instances.length === 0) {
+    if (instances.length === 0 || vitest.isExcludedByProjectFilter(originalName)) {
       removeProjects.add(project)
       return
     }
-    const originalName = project.config.name
-    // if original name is in the --project=name filter, keep all instances
+    // if original name matches a positive filter, keep all instances
+    // otherwise, filter instances individually (user may target a specific instance name)
     const filteredInstances = vitest.matchesProjectFilter(originalName)
       ? instances
       : instances.filter((instance) => {
 
@@ -317,6 +317,65 @@ test('browser instances with empty include array should get parent include patte
   expect(projects[1].config.include).toEqual(['**/*.test.{js,ts}'])
 })
 
+test('negation filter excludes all browser instances', async () => {
+  const { projects } = await vitest({ project: '!myproject' }, {
+    projects: [
+      {
+        test: {
+          name: 'myproject',
+          browser: {
+            enabled: true,
+            provider: playwright(),
+            headless: true,
+            instances: [
+              { browser: 'chromium' },
+              { browser: 'firefox' },
+              { browser: 'webkit' },
+            ],
+          },
+        },
+      },
+      {
+        test: {
+          name: 'other',
+        },
+      },
+    ],
+  })
+  expect(projects.map(p => p.name)).toEqual([
+    'other',
+  ])
+})
+
+test('negation wildcard filter excludes all matching browser instances', async () => {
+  const { projects } = await vitest({ project: '!my*' }, {
+    projects: [
+      {
+        test: {
+          name: 'myproject',
+          browser: {
+            enabled: true,
+            provider: playwright(),
+            headless: true,
+            instances: [
+              { browser: 'chromium' },
+              { browser: 'firefox' },
+            ],
+          },
+        },
+      },
+      {
+        test: {
+          name: 'other',
+        },
+      },
+    ],
+  })
+  expect(projects.map(p => p.name)).toEqual([
+    'other',
+  ])
+})
+
 test('filter for the global browser project includes all browser instances', async () => {
   const { projects } = await vitest({ project: 'myproject' }, {
     projects: [