fix(@angular/build): inherit preserveSymlinks option from build target in unit-test builder

clydin · alan-agius4 · commit dc27e17fc2cb · 2026-06-25T08:37:23.000+02:00
The unit-test builder did not pass the preserveSymlinks configuration to Vitest's custom configuration plugin and resolved it directly from buildTargetOptions in Karma executor without considering process arguments. This caused module resolution failures in unit tests for symlinked packages.

This change inherits preserveSymlinks from the referenced buildTarget options, falling back to process.execArgv if not defined. The resolved value is then successfully forwarded to the underlying bundlers and executors (Karma and Vitest).
diff --git a/packages/angular/build/src/builders/unit-test/builder.ts b/packages/angular/build/src/builders/unit-test/builder.ts
@@ -286,6 +286,10 @@ export async function* execute(
     return;
   }
 
+  // Resolve final preserveSymlinks option
+  normalizedOptions.preserveSymlinks =
+    buildTargetOptions.preserveSymlinks ?? process.execArgv.includes('--preserve-symlinks');
+
   // Get runner-specific build options
   let runnerBuildOptions;
   let virtualFiles;
@@ -327,6 +331,7 @@ export async function* execute(
       progress: normalizedOptions.buildProgress ?? buildTargetOptions.progress,
       quiet: normalizedOptions.quiet,
       ...(normalizedOptions.tsConfig ? { tsConfig: normalizedOptions.tsConfig } : {}),
+      preserveSymlinks: normalizedOptions.preserveSymlinks,
     } satisfies ApplicationBuilderInternalOptions;
 
     const dumpDirectory = normalizedOptions.dumpVirtualFiles
diff --git a/packages/angular/build/src/builders/unit-test/options.ts b/packages/angular/build/src/builders/unit-test/options.ts
@@ -134,6 +134,7 @@ export async function normalizeOptions(
       : [],
     dumpVirtualFiles: options.dumpVirtualFiles,
     listTests: options.listTests,
+    preserveSymlinks: undefined as boolean | undefined,
     runnerConfig:
       typeof runnerConfig === 'string'
         ? runnerConfig.length === 0
diff --git a/packages/angular/build/src/builders/unit-test/runners/karma/executor.ts b/packages/angular/build/src/builders/unit-test/runners/karma/executor.ts
@@ -91,7 +91,7 @@ export class KarmaExecutor implements TestExecutor {
       progress: unitTestOptions.buildProgress ?? buildTargetOptions.progress,
       watch: unitTestOptions.watch,
       poll: buildTargetOptions.poll,
-      preserveSymlinks: buildTargetOptions.preserveSymlinks,
+      preserveSymlinks: unitTestOptions.preserveSymlinks,
       browsers: unitTestOptions.browsers?.join(','),
       codeCoverage: unitTestOptions.coverage.enabled,
       codeCoverageExclude: unitTestOptions.coverage.exclude,
diff --git a/packages/angular/build/src/builders/unit-test/runners/vitest/executor.ts b/packages/angular/build/src/builders/unit-test/runners/vitest/executor.ts
@@ -382,6 +382,7 @@ export class VitestExecutor implements TestExecutor {
           include,
           watch,
           isolate: this.options.isolate,
+          preserveSymlinks: this.options.preserveSymlinks,
         }),
       ],
     };
diff --git a/packages/angular/build/src/builders/unit-test/runners/vitest/plugins.ts b/packages/angular/build/src/builders/unit-test/runners/vitest/plugins.ts
@@ -56,6 +56,7 @@ interface VitestConfigPluginOptions {
   optimizeDepsInclude: string[];
   watch: boolean;
   isolate: boolean | undefined;
+  preserveSymlinks?: boolean;
 }
 
 async function findTestEnvironment(
@@ -259,6 +260,7 @@ export async function createVitestConfigPlugin(
         resolve: {
           mainFields: ['es2020', 'module', 'main'],
           conditions: ['es2015', 'es2020', 'module', ...(browser ? ['browser'] : [])],
+          preserveSymlinks: options.preserveSymlinks,
         },
       };
 
