Handle --isolatedModules and d.ts emit in the builder

src/compiler/builder.ts

@@ -173,8 +173,7 @@ namespace ts {
         const compilerOptions = newProgram.getCompilerOptions();
         state.compilerOptions = compilerOptions;
         // With --out or --outFile, any change affects all semantic diagnostics so no need to cache them
-        // With --isolatedModules, emitting changed file doesnt emit dependent files so we cant know of dependent files to retrieve errors so dont cache the errors
-        if (!compilerOptions.outFile && !compilerOptions.out && !compilerOptions.isolatedModules) {
+        if (!compilerOptions.outFile && !compilerOptions.out) {
             state.semanticDiagnosticsPerFile = createMap<readonly Diagnostic[]>();
         }
         state.changedFilesSet = createMap<true>();
@@ -483,16 +482,43 @@ namespace ts {
         return !state.semanticDiagnosticsFromOldState.size;
     }
 
+    function isChangedSignagure(state: BuilderProgramState, path: Path) {
+        const newSignature = Debug.assertDefined(state.currentAffectedFilesSignatures).get(path);
+        const oldSignagure = Debug.assertDefined(state.fileInfos.get(path)).signature;
+        return newSignature !== oldSignagure;
+    }
+
     /**
      * Iterate on referencing modules that export entities from affected file
      */
     function forEachReferencingModulesOfExportOfAffectedFile(state: BuilderProgramState, affectedFile: SourceFile, fn: (state: BuilderProgramState, filePath: Path) => boolean) {
         // If there was change in signature (dts output) for the changed file,
         // then only we need to handle pending file emit
-        if (!state.exportedModulesMap || state.affectedFiles!.length === 1 || !state.changedFilesSet.has(affectedFile.path)) {
+        if (!state.exportedModulesMap || !state.changedFilesSet.has(affectedFile.path)) {
             return;
         }
 
+        if (!isChangedSignagure(state, affectedFile.path)) return;
+
+        // Since isolated modules dont change js files, files affected by change in signature is itself
+        // But we need to cleanup semantic diagnostics and queue dts emit for affected files
+        if (state.compilerOptions.isolatedModules) {
+            const seenFileNamesMap = createMap<true>();
+            seenFileNamesMap.set(affectedFile.path, true);
+            const queue = BuilderState.getReferencedByPaths(state, affectedFile.resolvedPath);
+            while (queue.length > 0) {
+                const currentPath = queue.pop()!;
+                if (!seenFileNamesMap.has(currentPath)) {
+                    seenFileNamesMap.set(currentPath, true);
+                    const result = fn(state, currentPath);
+                    if (result && isChangedSignagure(state, currentPath)) {
+                        const currentSourceFile = Debug.assertDefined(state.program).getSourceFileByPath(currentPath)!;
+                        queue.push(...BuilderState.getReferencedByPaths(state, currentSourceFile.resolvedPath));
+                    }
+                }
+            }
+        }
+
         Debug.assert(!!state.currentAffectedFilesExportedModulesMap);
         const seenFileAndExportsOfFile = createMap<true>();
         // Go through exported modules from cache first

src/compiler/builderState.ts

@@ -466,7 +466,7 @@ namespace ts.BuilderState {
     /**
      * Gets the files referenced by the the file path
      */
-    function getReferencedByPaths(state: Readonly<BuilderState>, referencedFilePath: Path) {
+    export function getReferencedByPaths(state: Readonly<BuilderState>, referencedFilePath: Path) {
         return arrayFrom(mapDefinedIterator(state.referencedMap!.entries(), ([filePath, referencesInFile]) =>
             referencesInFile.has(referencedFilePath) ? filePath as Path : undefined
         ));

tests/baselines/reference/tsbuild/inferredTypeFromTransitiveModule/incremental-declaration-changes/inferred-type-from-transitive-module-with-isolatedModules.js

@@ -21,6 +21,12 @@ exports.default = foo()(function foobar() {
 });
 
 
+//// [/src/obj/index.d.ts]
+import { LazyAction } from './bundling';
+export declare const lazyBar: LazyAction<() => void, typeof import("./lazyIndex")>;
+
+
+//// [/src/obj/lazyIndex.d.ts] file written with same contents
 //// [/src/obj/tsconfig.tsbuildinfo]
 {
   "program": {
@@ -47,7 +53,7 @@ exports.default = foo()(function foobar() {
       },
       "../index.ts": {
         "version": "-11602502901-import { LazyAction, LazyModule } from './bundling';\r\nconst lazyModule = new LazyModule(() =>\r\n    import('./lazyIndex')\r\n);\r\nexport const lazyBar = new LazyAction(lazyModule, m => m.bar);",
-        "signature": "18468008756-import { LazyAction } from './bundling';\r\nexport declare const lazyBar: LazyAction<(param: string) => void, typeof import(\"./lazyIndex\")>;\r\n"
+        "signature": "6256067474-import { LazyAction } from './bundling';\r\nexport declare const lazyBar: LazyAction<() => void, typeof import(\"./lazyIndex\")>;\r\n"
       }
     },
     "options": {
@@ -75,7 +81,15 @@ exports.default = foo()(function foobar() {
       "../lazyindex.ts": [
         "../bar.ts"
       ]
-    }
+    },
+    "semanticDiagnosticsPerFile": [
+      "../../lib/lib.d.ts",
+      "../bar.ts",
+      "../bundling.ts",
+      "../global.d.ts",
+      "../index.ts",
+      "../lazyindex.ts"
+    ]
   },
   "version": "FakeTSVersion"
 }

tests/baselines/reference/tsbuild/inferredTypeFromTransitiveModule/initial-Build/inferred-type-from-transitive-module-with-isolatedModules.js

@@ -118,7 +118,15 @@ exports.bar = bar_1.default;
       "../lazyindex.ts": [
         "../bar.ts"
       ]
-    }
+    },
+    "semanticDiagnosticsPerFile": [
+      "../../lib/lib.d.ts",
+      "../bar.ts",
+      "../bundling.ts",
+      "../global.d.ts",
+      "../index.ts",
+      "../lazyindex.ts"
+    ]
   },
   "version": "FakeTSVersion"
 }