fix(@angular/build): avoid internal karma request cache for assets

The internal karma common middleware that handles requests converts
the to be cached data into a string when stored. This can lead to invalid data
when the cached string is then sent in a followup request if the original content
was not intended to be a string. To avoid this  problem, asset files are now
explicitly not cached by karma's middleware.
Ref: https://github.com/karma-runner/karma/blob/84f85e7016efc2266fa6b3465f494a3fa151c85c/lib/middleware/common.js#L72

Author: clydin

packages/angular/build/src/builders/karma/application_builder.ts

@@ -86,7 +86,7 @@ class AngularAssetsMiddleware {
 
     switch (file.origin) {
       case 'disk':
-        this.serveFile(file.inputPath, undefined, res);
+        this.serveFile(file.inputPath, undefined, res, undefined, undefined, /* doNotCache */ true);
         break;
       case 'memory':
         // Include pathname to help with Content-Type headers.

packages/angular/build/src/builders/karma/tests/behavior/rebuilds_spec.ts

@@ -10,6 +10,7 @@ import { concatMap, count, debounceTime, distinctUntilChanged, take, timeout } f
 import { execute } from '../../index';
 import { BASE_OPTIONS, KARMA_BUILDER_INFO, describeKarmaBuilder } from '../setup';
 import { BuilderOutput } from '@angular-devkit/architect';
+import { randomBytes } from 'node:crypto';
 
 describeKarmaBuilder(execute, KARMA_BUILDER_INFO, (harness, setupTarget) => {
   describe('Behavior: "Rebuilds"', () => {
@@ -68,5 +69,59 @@ describeKarmaBuilder(execute, KARMA_BUILDER_INFO, (harness, setupTarget) => {
 
       expect(buildCount).toBe(expectedSequence.length);
     });
+
+    it('correctly serves binary assets on rebuilds', async () => {
+      await harness.writeFiles({
+        './src/random.bin': randomBytes(1024),
+        './src/app/app.component.spec.ts': `
+            describe('AppComponent', () => {
+              it('should fetch binary file with correct size', async () => {
+                const resp = await fetch('/random.bin');
+                const data = await resp.arrayBuffer();
+                expect(data.byteLength).toBe(1024);
+              });
+            });`,
+      });
+
+      harness.useTarget('test', {
+        ...BASE_OPTIONS,
+        watch: true,
+        assets: ['src/random.bin'],
+      });
+
+      interface OutputCheck {
+        (result: BuilderOutput | undefined): Promise<void>;
+      }
+
+      const expectedSequence: OutputCheck[] = [
+        async (result) => {
+          // Karma run should succeed.
+          expect(result?.success).withContext('Initial test run should succeed').toBeTrue();
+          // Modify test file to trigger a rebuild
+          await harness.appendToFile(
+            'src/app/app.component.spec.ts',
+            `\n;console.log('modified');`,
+          );
+        },
+        async (result) => {
+          expect(result?.success).withContext('Test should succeed again').toBeTrue();
+        },
+      ];
+
+      const buildCount = await harness
+        .execute({ outputLogsOnFailure: true })
+        .pipe(
+          timeout(60000),
+          debounceTime(500),
+          concatMap(async ({ result }, index) => {
+            await expectedSequence[index](result);
+          }),
+          take(expectedSequence.length),
+          count(),
+        )
+        .toPromise();
+
+      expect(buildCount).toBe(expectedSequence.length);
+    });
   });
 });