fix: sysroot filter should not drop workspace custom mounts

src/compose-generator.test.ts

@@ -1,4 +1,5 @@
 import { generateDockerCompose } from './compose-generator';
+import { getRealUserHome } from './host-identity';
 import { ACT_PRESET_BASE_IMAGE } from './host-identity';
 import { logger } from './logger';
 import { WrapperConfig } from './types';
@@ -496,24 +497,42 @@ describe('generateDockerCompose', () => {
         expect(result.volumes).toEqual({ sysroot: {} });
       });
 
-      it('filters out workDir-based and home-based bind mounts on split-fs', () => {
+      it('filters out workDir and home dot-directory bind mounts on split-fs', () => {
         const config = {
           ...mockConfig,
           runnerTopology: 'arc-dind' as const,
           workDir: '/tmp/awf-12345',
         };
         const result = generateDockerCompose(config, mockNetworkConfig);
         const volumes = result.services.agent.volumes as string[];
+        const workspaceDir = process.env.GITHUB_WORKSPACE || process.cwd();
 
         // workDir-based mounts should be dropped
         expect(volumes.some(v => v.startsWith('/tmp/awf-12345'))).toBe(false);
 
-        // Home-based mounts targeting /host/home should be dropped
-        const homeTargets = volumes.filter(v => {
+        // Home dot-directory mounts should be dropped, but workspace mounts under home should remain.
+        const homeTargets = volumes
+          .filter(v => {
+            const target = v.split(':')[1];
+            return target.startsWith('/host/home') && !v.startsWith('/dev/null');
+          })
+          .map(v => v.split(':')[1]);
+
+        expect(homeTargets).toContain(`/host${workspaceDir}`);
+        expect(homeTargets.some(target => target.startsWith('/host/home/runner/.'))).toBe(false);
+
+        // Home root mounts (including trailing slash source) should be dropped.
+        const effectiveHome = getRealUserHome();
+        const configWithHomeRootMount = {
+          ...config,
+          volumeMounts: [`${effectiveHome}/:/host${effectiveHome}:rw`],
+        };
+        const resultWithHomeRootMount = generateDockerCompose(configWithHomeRootMount, mockNetworkConfig);
+        const homeRootMounts = (resultWithHomeRootMount.services.agent.volumes as string[]).filter(v => {
           const target = v.split(':')[1];
-          return target.startsWith('/host/home') && !v.startsWith('/dev/null');
+          return target === `/host${effectiveHome}` || target === `/host${effectiveHome}/`;
         });
-        expect(homeTargets).toHaveLength(0);
+        expect(homeRootMounts).toHaveLength(0);
 
         // Should still have /tmp:/tmp, /sys, /dev, sysroot volume
         expect(volumes).toContain('/tmp:/tmp:rw');

src/compose-generator.ts

@@ -149,8 +149,14 @@ export function generateDockerCompose(
       // Drop mounts sourced from AWF workDir (runner's unshared /tmp/awf-*)
       if (source.startsWith(workDirPrefix)) return false;
 
-      // Drop home directory mounts targeting /host/home/... — sysroot provides them
-      if (source.startsWith(effectiveHome) && target.startsWith(hostHomeMountPrefix)) return false;
+      // Drop home dot-directory mounts (e.g. .cache, .config) — sysroot provides them.
+      // Keep workspace/work paths (e.g. _work/_temp/gh-aw) since those are user-supplied
+      // custom mounts or tool-cache mounts that the sysroot doesn't provide.
+      if (source.startsWith(effectiveHome) && target.startsWith(hostHomeMountPrefix)) {
+        const normalizedSource = source.replace(/\/+$/, '') || '/';
+        const relPath = normalizedSource.slice(effectiveHome.length);
+        if (relPath.startsWith('/.') || relPath === '') return false;
+      }
 
       return true;
     });