fixup! fix(@angular/build): improve library compilation diagnostics and skip redundant d.ts rebundling

Author: alan-agius4

packages/angular/build/src/builders/library/pipeline/compilation.ts

@@ -260,11 +260,7 @@ function updateEmittedFileCaches(
 
     if (targetFiles.get(normalized) !== contents) {
       targetFiles.set(normalized, contents);
-      if (!isDts) {
-        changedEsmFiles.add(isMap ? normalized.slice(0, -4) : normalized);
-      } else if (!isMap) {
-        changedDtsFiles.add(normalized);
-      }
+      (isDts ? changedDtsFiles : changedEsmFiles).add(isMap ? normalized.slice(0, -4) : normalized);
     }
   }
 

packages/angular/build/src/builders/library/pipeline/compilation_spec.ts

@@ -340,7 +340,7 @@ describe('compileLibrary pipeline', () => {
     expect(state.getAffectedFiles([partialNew])).toEqual(new Set([partialNew, compScss]));
   });
 
-  it('should not mark .d.ts as changed in changedDtsFiles when only .d.ts.map changed', async () => {
+  it('should mark .d.ts as changed in changedDtsFiles when .d.ts.map changes', async () => {
     const dtsPath = '/workspace/projects/my-lib/src/lib/lib.component.d.ts';
     const dtsMapPath = '/workspace/projects/my-lib/src/lib/lib.component.d.ts.map';
     const jsPath = '/workspace/projects/my-lib/src/lib/lib.component.js';
@@ -379,22 +379,17 @@ describe('compileLibrary pipeline', () => {
     await output1.diagnosePromise;
 
     expect(output1.changedEsmFiles).toEqual(new Set([jsPath]));
-    expect(output1.changedDtsFiles.size).toBe(0);
-    // The updated .d.ts.map content should still be stored in dtsFiles
+    expect(output1.changedDtsFiles).toEqual(new Set([dtsPath]));
     expect(output1.dtsFiles.get(dtsMapPath)).toBe('{"version":3,"mappings":"AACA"}');
 
-    // Case 2: .d.ts content itself changes
+    // Case 2: neither .d.ts nor .d.ts.map changed
     emitted = [
-      { filename: dtsPath, contents: 'export declare class LibComponent { id: string; }\n' },
-      { filename: dtsMapPath, contents: '{"version":3,"mappings":"AADA"}' },
+      { filename: dtsPath, contents: 'export declare class LibComponent {}\n' },
+      { filename: dtsMapPath, contents: '{"version":3,"mappings":"AACA"}' },
     ];
     const output2 = await compileLibrary(createOptions(), bundler, state);
     await output2.diagnosePromise;
 
-    expect(output2.changedDtsFiles).toEqual(new Set([dtsPath]));
-    expect(output2.dtsFiles.get(dtsPath)).toBe(
-      'export declare class LibComponent { id: string; }\n',
-    );
-    expect(output2.dtsFiles.get(dtsMapPath)).toBe('{"version":3,"mappings":"AADA"}');
+    expect(output2.changedDtsFiles.size).toBe(0);
   });
 });