fix(manager/copier): process update templates outside repository root (#30708)

lib/modules/manager/copier/artifacts.spec.ts

@@ -118,6 +118,29 @@ describe('modules/manager/copier/artifacts', () => {
       expect(execSnapshots).toMatchObject([
         {
           cmd: 'copier update --skip-answered --defaults --answers-file .copier-answers.yml --vcs-ref 1.1.0',
+          options: {
+            cwd: '/tmp/github/some/repo',
+          },
+        },
+      ]);
+    });
+
+    it('invokes copier update with nested destination and answer file', async () => {
+      const execSnapshots = mockExecAll();
+
+      await updateArtifacts({
+        packageFileName: 'apps/my-app/.copier-answers.yml',
+        updatedDeps: upgrades,
+        newPackageFileContent: '',
+        config: {},
+      });
+
+      expect(execSnapshots).toMatchObject([
+        {
+          cmd: 'copier update --skip-answered --defaults --answers-file .copier-answers.yml --vcs-ref 1.1.0',
+          options: {
+            cwd: '/tmp/github/some/repo/apps/my-app',
+          },
         },
       ]);
     });

lib/modules/manager/copier/artifacts.ts

 import { quote } from 'shlex';
+import upath from 'upath';
 import { GlobalConfig } from '../../../config/global';
 import { logger } from '../../../logger';
 import { exec } from '../../../util/exec';
@@ -28,7 +29,7 @@ function buildCommand(
   }
   command.push(
     '--answers-file',
-    quote(packageFileName),
+    quote(upath.basename(packageFileName)),
     '--vcs-ref',
     quote(newVersion),
   );
@@ -72,6 +73,7 @@ export async function updateArtifacts({
 
   const command = buildCommand(config, packageFileName, newVersion);
   const execOptions: ExecOptions = {
+    cwdFile: packageFileName,
     docker: {},
     userConfiguredEnv: config.env,
     toolConstraints: [