fix(emit): normalize extra-extension declaration paths (issue #63)

patches/typescript/overlay/src/compiler/tsgoChecker.ts

@@ -5925,6 +5925,22 @@ function extensionFromPathOrTs(fileName: string): any {
     }
     return ts.Extension.Ts;
 }
+/**
+ * Issue #63: tsgo emits `{name}.d.{ext}.ts` for allowArbitraryExtensions
+ * source files (e.g. Button.vue → Button.vue.d.vue.ts), but the host
+ * convention (stock TypeScript + Volar) is `{name}.d.ts` (Button.vue.d.ts).
+ * Strip the redundant extra-extension segment from declaration output paths.
+ */
+function fixExtraExtDeclarationPath(fileName: string, extraExts: { extension: string }[] | undefined): string {
+    if (!extraExts?.length) return fileName;
+    for (const { extension } of extraExts) {
+        const suffix = `.d${extension}.ts`;
+        if (fileName.endsWith(suffix)) {
+            return fileName.slice(0, -suffix.length) + ".d.ts";
+        }
+    }
+    return fileName;
+}
 /**
  * Builds the `extraFileExtensions` field sent with tsgo snapshots.
  *
@@ -8501,7 +8517,9 @@ export function createTsgoProgram(
             for (const o of outputs) {
                 // Go-computed output path — crosses the wire boundary before
                 // reaching writeFile/emittedFiles consumers.
-                const outFileName = wireFileNameToHost(o.fileName);
+                // Issue #63: strip the redundant extra-extension segment from
+                // declaration paths (e.g. Button.vue.d.vue.ts → Button.vue.d.ts).
+                const outFileName = fixExtraExtDeclarationPath(wireFileNameToHost(o.fileName), programCtx.pendingExtraFileExtensions);
                 // Builder wrappers mutate data (data.skippedDtsWrite on the
                 // dts-unchanged skip path in builder.ts), so a data object
                 // must always ride along — stock emitter threads one too.

tools/ci-witness-groups.mjs

@@ -40,7 +40,7 @@ import * as fs from 'node:fs';
 import * as path from 'node:path';
 import { fileURLToPath } from 'node:url';
 
-const TOTAL = 72;
+const TOTAL = 73;
 
 // Witnesses intentionally NOT in the matrix — run on demand (reasons above).
 const LOCAL_ONLY = [
@@ -158,6 +158,7 @@ const groups = [
 			'triage-completion-span-i55', // ~6s (npm install @types/node best-effort + tsserver session)
 			'triage-prototype-refresh', // ~1s
 			'triage-declared-type-hostonly', // ~1s
+			'triage-vue-tsc-decl-emit', // ~0s
 		],
 	},
 	{

tools/triage-vue-tsc-decl-emit.mjs

@@ -0,0 +1,84 @@
+#!/usr/bin/env node
+/**
+ * Witness for issue #63: declaration emit for `.vue` source files must produce
+ * `Button.vue.d.ts`, not `Button.vue.d.vue.ts`.
+ *
+ * tsgo emits `{name}.d.{ext}.ts` for allowArbitraryExtensions source files
+ * (e.g. Button.vue → Button.vue.d.vue.ts); the bridge must normalize this to
+ * `{name}.d.ts` (Button.vue.d.ts) before handing the path to the host's
+ * writeFile, matching stock TypeScript + Volar convention.
+ *
+ * The fixture mirrors the minimal reproduction from the issue: a .vue SFC
+ * with plain-TS content (Volar's virtual TS injection role) and an index.ts
+ * that re-exports it, compiled with declaration + emitDeclarationOnly.
+ *
+ * Exit 0 = PASS, exit 1 = FAIL.
+ */
+import { createRequire } from 'node:module';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+
+const require = createRequire(import.meta.url);
+const repoRoot = path.resolve(import.meta.dirname, '..');
+const ts = require(path.join(repoRoot, 'lib', 'typescript.js'));
+
+const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'tnb-vue-tsc-decl-emit-'));
+fs.mkdirSync(path.join(dir, 'src', 'components'), { recursive: true });
+
+// .vue file with plain-TS content — mirrors what Volar injects as virtual TS
+// for an SFC with a <script setup lang="ts"> block.
+fs.writeFileSync(path.join(dir, 'src', 'components', 'Button.vue'), 'export default {};\n');
+fs.writeFileSync(path.join(dir, 'src', 'index.ts'), 'export { default as Button } from "./components/Button.vue";\n');
+fs.writeFileSync(path.join(dir, 'tsconfig.json'), JSON.stringify({
+	compilerOptions: {
+		module: 'ESNext',
+		moduleResolution: 'Bundler',
+		target: 'ESNext',
+		strict: true,
+		skipLibCheck: true,
+		declaration: true,
+		emitDeclarationOnly: true,
+		rootDir: 'src',
+		outDir: 'dist',
+		types: [],
+	},
+	include: ['src/**/*.ts', 'src/**/*.vue'],
+}));
+
+// Register .vue as an extra script extension so collectExtraFileExtensions
+// picks it up and tsgo treats the file as allowArbitraryExtensions, matching
+// what vue-tsc / Volar do at program-creation time.
+ts.supportedTSExtensionsFlat.push('.vue');
+
+const configPath = path.join(dir, 'tsconfig.json');
+const parsed = ts.getParsedCommandLineOfConfigFile(configPath, {}, {
+	...ts.sys,
+	onUnRecoverableConfigFileDiagnostic: (d) => { throw new Error(ts.flattenDiagnosticMessageText(d.messageText, '\n')); },
+});
+if (!parsed) {
+	console.error('FAIL: could not parse fixture tsconfig');
+	process.exit(1);
+}
+
+const program = ts.createProgram(parsed.fileNames, parsed.options);
+
+// Capture all writeFile calls to inspect the emitted declaration paths.
+const written = [];
+program.emit(undefined, (fileName) => written.push(fileName));
+
+const correct = written.filter(f => /Button\.vue\.d\.ts$/.test(f));
+const broken  = written.filter(f => /Button\.vue\.d\.vue\.ts$/.test(f));
+const indexDts = written.some(f => /index\.d\.ts$/.test(f));
+
+console.log('Emitted files:');
+for (const f of written) console.log(' ', path.relative(dir, f));
+
+if (broken.length || !correct.length || !indexDts) {
+	console.error('FAIL: wrong declaration emit for .vue source file (issue #63)');
+	if (broken.length)   console.error('  spurious Button.vue.d.vue.ts output');
+	if (!correct.length) console.error('  missing  Button.vue.d.ts output');
+	if (!indexDts)       console.error('  missing  index.d.ts output');
+	process.exit(1);
+}
+console.log('PASS: .vue declaration emitted as Button.vue.d.ts (not Button.vue.d.vue.ts)');