fix: respect explicit tsconfig files for alias resolution

src/resolver.ts

@@ -419,11 +419,17 @@ function createResolver(
   }
 
   const isIncludedRelative = getIncluder(
-    config.include?.map((p) => ensureRelative(configDir, p)),
+    config.include?.map((p) => ensureRelative(configDir, p)) ??
+      (config.files ? [] : undefined),
     config.exclude?.map((p) => ensureRelative(configDir, p)),
     outDir
   )
 
+  // Explicit files are included independently of include/exclude globs.
+  const includedFiles = new Set(
+    config.files?.map((file) => path.resolve(configDir, path.normalize(file)))
+  )
+
   const isImporterSupported = opts.loose
     ? () => true
     : (opts.importerFilter ??
@@ -456,7 +462,10 @@ function createResolver(
 
     // Respect the include/exclude properties.
     const relativeImporterFile = path.relative(configDir, importerFile)
-    if (!isIncludedRelative(relativeImporterFile)) {
+    if (
+      !includedFiles.has(importerFile) &&
+      !isIncludedRelative(relativeImporterFile)
+    ) {
       logFile?.write('configMismatch', { importer, id, configPath })
       return notApplicable
     }
@@ -600,7 +609,7 @@ function getIncluder(
       return includers.some(test) && !excluders.some(test)
     }
   }
-  return () => true
+  return () => false
 }
 
 function addCompiledGlob(this: RegExp[], glob: string) {

test/resolver.test.ts

@@ -432,3 +432,47 @@ async function expectResolution(
     true,
   ])
 }
+
+test('resolves aliases from explicit files even when include is empty and exclude matches', async () => {
+  const root = createProject(
+    {},
+    {
+      files: ['src/index.ts'],
+      include: [],
+      exclude: ['src'],
+    }
+  )
+  const resolvers = createTsconfigResolvers({
+    projects: ['tsconfig.json'],
+    projectRoot: root,
+    workspaceRoot: root,
+    logger: { error() {}, hasErrorLogged: () => false },
+  })
+  resolvers.reset()
+  const importer = join(root, 'src/index.ts')
+  const [resolveId] = await collect(resolvers.get(importer))
+  await expect(resolveId('@/value', importer)).resolves.toEqual([
+    normalize(realpathSync(join(root, 'src/value.ts'))),
+    true,
+  ])
+})
+
+test('files-only configs do not include unlisted importers', async () => {
+  const root = createProject({}, { files: ['src/index.ts'], exclude: [] })
+  const resolvers = createTsconfigResolvers({
+    projects: ['tsconfig.json'],
+    projectRoot: root,
+    workspaceRoot: root,
+    logger: { error() {}, hasErrorLogged: () => false },
+  })
+  resolvers.reset()
+  const importer = join(root, 'src/index.ts')
+  const [resolveId] = await collect(resolvers.get(importer))
+  await expect(resolveId('@/value', importer)).resolves.toEqual([
+    normalize(realpathSync(join(root, 'src/value.ts'))),
+    true,
+  ])
+  await expect(
+    resolveId('@/value', join(root, 'src/unlisted.ts'))
+  ).resolves.toEqual([undefined, false])
+})

test/typescript-parity.test.ts

@@ -476,3 +476,33 @@ function startServer(
     optimizeDeps: { noDiscovery: true, include: [] },
   })
 }
+
+test('explicit files override exclude and empty include like TypeScript', async () => {
+  const root = makeRoot()
+  let server: Awaited<ReturnType<typeof createServer>> | undefined
+  try {
+    writeConfig(
+      root,
+      'tsconfig.json',
+      {},
+      {
+        files: ['src/index.ts'],
+        include: [],
+        exclude: ['src'],
+      }
+    )
+    write(root, 'src/index.ts', 'export { value } from "@/value"')
+    write(root, 'src/value.ts', 'export const value = true')
+    const importer = join(root, 'src/index.ts')
+    const config = parseConfig(join(root, 'tsconfig.json'))
+    expect(config.fileNames.map(normalize)).toContain(normalize(importer))
+    const expected = normalize(realpathSync(join(root, 'src/value.ts')))
+    expect(resolveTypescript('@/value', importer, config)).toBe(expected)
+    server = await startServer(root)
+    const result = await server.pluginContainer.resolveId('@/value', importer)
+    expect(result?.id).toBe(expected)
+  } finally {
+    await server?.close()
+    rmSync(root, { recursive: true, force: true })
+  }
+})