Workspace API returns files from packages with their own configs, causing alias resolution failures

### Describe the bug

When using a Vitest workspace configuration (`vitest.workspace.ts`) without a root `vitest.config.ts` file, the workspace API's `getFiles()` method returns test files from all packages in the workspace, including packages that have their own `vitest.config.ts` files. This causes test files to be incorrectly associated with the workspace API instead of their respective package APIs.

**This leads to alias resolution failures** - when test files use path aliases (e.g., `import { something } from '#/somewhere'`), they fail to resolve because the files are being processed by the workspace API context instead of their package-specific API context, which has the correct path alias configuration.

The issue occurs because:
1. When there's no root `vitest.config.ts`, Vitest doesn't report any configs in `vitest.configs` for the workspace API
2. The `usedConfigs` set remains empty after workspace APIs are created
3. Package configs are correctly filtered out (they're in `usedConfigs`), but the workspace API still returns files from those packages
4. This leads to duplicate file associations and incorrect API routing

**Workaround**: Adding a root `vitest.config.ts` that excludes everything (`exclude: ['**']`) fixes the issue, but this shouldn't be necessary.

### Reproduction

1. Create a monorepo workspace with the following structure:
   ```
   workspace-root/
   ├── vitest.workspace.ts
   └── packages/
       ├── package-a/
       │   ├── vitest.config.ts
       │   └── test/
       │       └── test.spec.ts
       └── package-b/
           ├── vitest.config.ts
           └── test/
               └── test.spec.ts
   ```

2. Configure `vitest.workspace.ts` to include the package configs:
   ```typescript
   export default [
     './packages/package-a/vitest.config.ts',
     './packages/package-b/vitest.config.ts',
   ]
   ```

3. **Do NOT** create a root `vitest.config.ts` file

4. Open the workspace in VS Code with the Vitest extension installed

5. Observe that:
   - The workspace API's `getFiles()` returns files from both `package-a` and `package-b`
   - Package APIs also return their own files
   - Test files are incorrectly associated with the workspace API instead of their package APIs
   - **Path aliases fail to resolve** - imports like `import { something } from '#/somewhere'` fail with errors such as:
     ```
     Error: Failed to resolve import "#/somewhere" from "packages/package-a/test/test.spec.ts". Does the file exist?
     ```


### Output

```shell
With vitest.config.ts at workspace root that excludes all files (it works)


[INFO 10:33:48] [API] Collecting tests: packages/debug/test/unit/log/filePathResolvers.test.ts
[10:33:50] Disposing test runner
[10:33:50] Ending test run <none>
[10:33:50] Disposing test runner
[10:33:50] Ending test run <none>
[10:33:50] Disposing test runner
[10:33:50] Ending test run <none>
[10:33:50] Disposing test runner
[10:33:50] Ending test run <none>
[INFO 10:33:50] [API] Vitest process 89198 closed successfully
[INFO 10:33:50] [API] Vitest process 89238 closed successfully
[INFO 10:33:50] [API] Vitest process 89249 closed successfully
[INFO 10:33:50] [API] Vitest process 89252 closed successfully
[Error 10:33:50] Failed to close server
[10:33:50] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[Error 10:33:50] Failed to close server
[10:33:50] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[INFO 10:33:50] [API DEBUG] resolveVitestAPI called with:
[INFO 10:33:50] [API DEBUG]   1 workspace configs: [object Object]
[INFO 10:33:50] [API DEBUG]   4 package configs: [object Object],[object Object],[object Object],[object Object]
[INFO 10:33:50] [API] Resolving workspace configs: vitest.workspace.ts
[INFO 10:33:50] [API] Running Vitest v4.0.16 (ts-dk/vitest.workspace.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[Error 10:33:50] Failed to close server
[Error 10:33:50] Failed to close server
[10:33:50] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[10:33:50] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[INFO 10:33:51] [API DEBUG] Creating WORKSPACE API for: [object Object]
[INFO 10:33:51] [API DEBUG] WORKSPACE API added 1 configs to usedConfigs: /Users/sam/Development/am.ninja/ts-dk/vitest.config.ts
[INFO 10:33:51] [API DEBUG] Resolved 1 workspace APIs
[INFO 10:33:51] [API DEBUG] Workspace roots: 
[INFO 10:33:51] [API DEBUG] Used configs after workspace APIs: /Users/sam/Development/am.ninja/ts-dk/vitest.config.ts
[INFO 10:33:51] [API] Resolving configs: debug/vitest.config.ts, workflow/vitest.config.ts, utils/vitest.config.ts
[INFO 10:33:51] [API] Running Vitest v4.0.16 (debug/vitest.config.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[INFO 10:33:51] [API DEBUG] Creating PACKAGE API for: [object Object]
[INFO 10:33:51] [API DEBUG] PACKAGE API added 1 configs to usedConfigs: /Users/sam/Development/am.ninja/ts-dk/packages/debug/vitest.config.ts
[INFO 10:33:51] [API] Running Vitest v4.0.16 (workflow/vitest.config.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[INFO 10:33:51] [API DEBUG] Creating PACKAGE API for: [object Object]
[INFO 10:33:51] [API DEBUG] PACKAGE API added 1 configs to usedConfigs: /Users/sam/Development/am.ninja/ts-dk/packages/workflow/vitest.config.ts
[INFO 10:33:51] [API] Running Vitest v4.0.16 (utils/vitest.config.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[INFO 10:33:51] [API DEBUG] Creating PACKAGE API for: [object Object]
[INFO 10:33:51] [API DEBUG] PACKAGE API added 1 configs to usedConfigs: /Users/sam/Development/am.ninja/ts-dk/packages/utils/vitest.config.ts
[INFO 10:33:51] [API DEBUG] WORKSPACE API getFiles() returned 0 files. workspaceFile: /Users/sam/Development/am.ninja/ts-dk/vitest.workspace.ts
[INFO 10:33:51] [API DEBUG] discoverAllTestFiles called for WORKSPACE API with 0 files
[INFO 10:33:51] [API DEBUG] WORKSPACE API details: [object Object]
[INFO 10:33:51] [API] Watching vitest.workspace.ts
[INFO 10:33:51] [VSCODE] Watching ts-dk with pattern **/*
[INFO 10:33:51] [API DEBUG] PACKAGE API getFiles() returned 1 files. configFile: /Users/sam/Development/am.ninja/ts-dk/packages/debug/vitest.config.ts, cwd: /Users/sam/Development/am.ninja/ts-dk/packages/debug
[INFO 10:33:51] [API DEBUG] Files from PACKAGE API: /Users/sam/Development/am.ninja/ts-dk/packages/debug/test/unit/log/filePathResolvers.test.ts
[INFO 10:33:51] [API DEBUG] discoverAllTestFiles called for PACKAGE API with 1 files
[INFO 10:33:51] [API DEBUG] PACKAGE API details: [object Object]
[INFO 10:33:51] [API] Watching packages/debug/vitest.config.ts
[INFO 10:33:51] [API DEBUG] PACKAGE API getFiles() returned 1 files. configFile: /Users/sam/Development/am.ninja/ts-dk/packages/workflow/vitest.config.ts, cwd: /Users/sam/Development/am.ninja/ts-dk/packages/workflow
[INFO 10:33:51] [API DEBUG] Files from PACKAGE API: /Users/sam/Development/am.ninja/ts-dk/packages/workflow/test/unit/gitUtils.test.ts
[INFO 10:33:51] [API DEBUG] discoverAllTestFiles called for PACKAGE API with 1 files
[INFO 10:33:51] [API DEBUG] PACKAGE API details: [object Object]
[INFO 10:33:51] [API] Watching packages/workflow/vitest.config.ts
[INFO 10:33:51] [API DEBUG] PACKAGE API getFiles() returned 1 files. configFile: /Users/sam/Development/am.ninja/ts-dk/packages/utils/vitest.config.ts, cwd: /Users/sam/Development/am.ninja/ts-dk/packages/utils
[INFO 10:33:51] [API DEBUG] Files from PACKAGE API: /Users/sam/Development/am.ninja/ts-dk/packages/utils/test/unit/index.test.ts
[INFO 10:33:51] [API DEBUG] discoverAllTestFiles called for PACKAGE API with 1 files
[INFO 10:33:51] [API DEBUG] PACKAGE API details: [object Object]
[INFO 10:33:51] [API] Watching packages/utils/vitest.config.ts
[INFO 10:33:52] [API] Collecting tests: packages/debug/test/unit/log/filePathResolvers.test.ts

---

Without workspace root vitest.config.ts (it fails)


[10:32:29] Disposing test runner
[10:32:29] Ending test run <none>
[10:32:29] Disposing test runner
[10:32:29] Ending test run <none>
[10:32:29] Disposing test runner
[10:32:29] Ending test run <none>
[10:32:29] Disposing test runner
[10:32:29] Ending test run <none>
[INFO 10:32:29] [API] Vitest process 86213 closed successfully
[INFO 10:32:29] [API] Vitest process 86225 closed successfully
[INFO 10:32:29] [API] Vitest process 86243 closed successfully
[INFO 10:32:29] [API] Vitest process 86246 closed successfully
[Error 10:32:29] Failed to close server
[10:32:29] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[INFO 10:32:29] [API DEBUG] resolveVitestAPI called with:
[INFO 10:32:29] [API DEBUG]   1 workspace configs: [object Object]
[INFO 10:32:29] [API DEBUG]   3 package configs: [object Object],[object Object],[object Object]
[INFO 10:32:29] [API] Resolving workspace configs: vitest.workspace.ts
[INFO 10:32:29] [API] Running Vitest v4.0.16 (ts-dk/vitest.workspace.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[Error 10:32:29] Failed to close server
[Error 10:32:29] Failed to close server
[Error 10:32:29] Failed to close server
[10:32:29] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[10:32:29] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[10:32:29] [API] Vitest WebSocket connection closed, cannot call RPC anymore.
[INFO 10:32:29] [API DEBUG] Creating WORKSPACE API for: [object Object]
[INFO 10:32:29] [API DEBUG] WORKSPACE API added 0 configs to usedConfigs: 
[INFO 10:32:29] [API DEBUG] Resolved 1 workspace APIs
[INFO 10:32:29] [API DEBUG] Workspace roots: 
[INFO 10:32:29] [API DEBUG] Used configs after workspace APIs: 
[INFO 10:32:29] [API] Resolving configs: debug/vitest.config.ts, workflow/vitest.config.ts, utils/vitest.config.ts
[INFO 10:32:29] [API] Running Vitest v4.0.16 (debug/vitest.config.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[INFO 10:32:30] [API DEBUG] Creating PACKAGE API for: [object Object]
[INFO 10:32:30] [API DEBUG] PACKAGE API added 1 configs to usedConfigs: /Users/sam/Development/am.ninja/ts-dk/packages/debug/vitest.config.ts
[INFO 10:32:30] [API] Running Vitest v4.0.16 (workflow/vitest.config.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[INFO 10:32:30] [API DEBUG] Creating PACKAGE API for: [object Object]
[INFO 10:32:30] [API DEBUG] PACKAGE API added 1 configs to usedConfigs: /Users/sam/Development/am.ninja/ts-dk/packages/workflow/vitest.config.ts
[INFO 10:32:30] [API] Running Vitest v4.0.16 (utils/vitest.config.ts) with "/Users/sam/.nvm/versions/node/v24.12.0/bin/node /Users/sam/Development/vscode/dist/worker.js"
[INFO 10:32:30] [API DEBUG] Creating PACKAGE API for: [object Object]
[INFO 10:32:30] [API DEBUG] PACKAGE API added 1 configs to usedConfigs: /Users/sam/Development/am.ninja/ts-dk/packages/utils/vitest.config.ts
[INFO 10:32:30] [API DEBUG] WORKSPACE API getFiles() returned 3 files. workspaceFile: /Users/sam/Development/am.ninja/ts-dk/vitest.workspace.ts
[INFO 10:32:30] [API DEBUG] Files from WORKSPACE API: /Users/sam/Development/am.ninja/ts-dk/packages/utils/test/unit/index.test.ts,/Users/sam/Development/am.ninja/ts-dk/packages/workflow/test/unit/gitUtils.test.ts,/Users/sam/Development/am.ninja/ts-dk/packages/debug/test/unit/log/filePathResolvers.test.ts
[INFO 10:32:30] [API DEBUG] discoverAllTestFiles called for WORKSPACE API with 3 files
[INFO 10:32:30] [API DEBUG] WORKSPACE API details: [object Object]
[INFO 10:32:30] [API] Watching vitest.workspace.ts
[INFO 10:32:30] [VSCODE] Watching ts-dk with pattern **/*
[INFO 10:32:30] [API DEBUG] PACKAGE API getFiles() returned 1 files. configFile: /Users/sam/Development/am.ninja/ts-dk/packages/debug/vitest.config.ts, cwd: /Users/sam/Development/am.ninja/ts-dk/packages/debug
[INFO 10:32:30] [API DEBUG] Files from PACKAGE API: /Users/sam/Development/am.ninja/ts-dk/packages/debug/test/unit/log/filePathResolvers.test.ts
[INFO 10:32:30] [API DEBUG] discoverAllTestFiles called for PACKAGE API with 1 files
[INFO 10:32:30] [API DEBUG] PACKAGE API details: [object Object]
[INFO 10:32:30] [API] Watching packages/debug/vitest.config.ts
[INFO 10:32:30] [API DEBUG] PACKAGE API getFiles() returned 1 files. configFile: /Users/sam/Development/am.ninja/ts-dk/packages/workflow/vitest.config.ts, cwd: /Users/sam/Development/am.ninja/ts-dk/packages/workflow
[INFO 10:32:30] [API DEBUG] Files from PACKAGE API: /Users/sam/Development/am.ninja/ts-dk/packages/workflow/test/unit/gitUtils.test.ts
[INFO 10:32:30] [API DEBUG] discoverAllTestFiles called for PACKAGE API with 1 files
[INFO 10:32:30] [API DEBUG] PACKAGE API details: [object Object]
[INFO 10:32:30] [API] Watching packages/workflow/vitest.config.ts
[INFO 10:32:30] [API DEBUG] PACKAGE API getFiles() returned 1 files. configFile: /Users/sam/Development/am.ninja/ts-dk/packages/utils/vitest.config.ts, cwd: /Users/sam/Development/am.ninja/ts-dk/packages/utils
[INFO 10:32:30] [API DEBUG] Files from PACKAGE API: /Users/sam/Development/am.ninja/ts-dk/packages/utils/test/unit/index.test.ts
[INFO 10:32:30] [API DEBUG] discoverAllTestFiles called for PACKAGE API with 1 files
[INFO 10:32:30] [API DEBUG] PACKAGE API details: [object Object]
[INFO 10:32:30] [API] Watching packages/utils/vitest.config.ts
[INFO 10:32:30] [API] Collecting tests: packages/debug/test/unit/log/filePathResolvers.test.ts
[Error 10:32:30] Error in /Users/sam/Development/am.ninja/ts-dk/packages/debug/test/unit/log/filePathResolvers.test.ts Error: Failed to resolve import "#/log/filePathResolvers" from "packages/debug/test/unit/log/filePathResolvers.test.ts". Does the file exist?
    at TransformPluginContext._formatLog (file:///Users/sam/Development/am.ninja/ts-dk/node_modules/.pnpm/vite@7.3.0_@types+node@24.10.4_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/vite/dist/node/chunks/config.js:28998:43)
    at TransformPluginContext.error (file:///Users/sam/Development/am.ninja/ts-dk/node_modules/.pnpm/vite@7.3.0_@types+node@24.10.4_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/vite/dist/node/chunks/config.js:28995:14)
    at normalizeUrl (file:///Users/sam/Development/am.ninja/ts-dk/node_modules/.pnpm/vite@7.3.0_@types+node@24.10.4_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/vite/dist/node/chunks/config.js:27118:18)
    at processTicksAndRejections (node:internal/process/task_queues:103:5)
    at file:///Users/sam/Development/am.ninja/ts-dk/node_modules/.pnpm/vite@7.3.0_@types+node@24.10.4_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/vite/dist/node/chunks/config.js:27176:32
    at async Promise.all (index 4)
    at TransformPluginContext.transform (file:///Users/sam/Development/am.ninja/ts-dk/node_modules/.pnpm/vite@7.3.0_@types+node@24.10.4_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/vite/dist/node/chunks/config.js:27144:4)
    at EnvironmentPluginContainer.transform (file:///Users/sam/Development/am.ninja/ts-dk/node_modules/.pnpm/vite@7.3.0_@types+node@24.10.4_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/vite/dist/node/chunks/config.js:28796:14)
    at loadAndTransform (file:///Users/sam/Development/am.ninja/ts-dk/node_modules/.pnpm/vite@7.3.0_@types+node@24.10.4_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/vite/dist/node/chunks/config.js:22669:26)
```

### Extension Version

1.36.0 commit: ff6e44d4841f59662c15ea67f69435edfb185e67

### Vitest Version

4.0.16

### Validations

- [x] Check that you are using the latest version of the extension
- [x] Check that there isn't [already an issue](https://github.com/vitest-dev/vscode/issues) that reports the same bug to avoid creating a duplicate.
- [x] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/vitest-dev/vscode/discussions) or join our [Discord Chat Server](https://chat.vitest.dev).
- [x] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.

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Uh oh!

Uh oh!

Workspace API returns files from packages with their own configs, causing alias resolution failures #705

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Uh oh!

Workspace API returns files from packages with their own configs, causing alias resolution failures #705

Description

Describe the bug

Reproduction

Output

Extension Version

Vitest Version

Validations

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions