libs/template: don't create directories that a later {{skip}} names

.nextchanges/cli/template-skip-dir-not-created.md

@@ -0,0 +1 @@
+`bundle init` no longer creates an empty directory when a template's `{{skip}}` directive names a directory that the template walk had already visited.

libs/template/renderer.go

@@ -372,8 +372,24 @@ func (r *renderer) persistToDisk(ctx context.Context, out filer.Filer) error {
 			continue
 		}
 
+		// A {{skip}} directive can name a directory the walk has already
+		// visited, because the directive lives in a file processed later.
+		// walk() only tests the patterns known when it reaches a directory, so
+		// re-test the accumulated set here; otherwise the directory is created
+		// even though it was explicitly skipped. This leaves directories whose
+		// files merely happened to be skipped untouched, since those patterns
+		// match the files rather than the directory itself.
+		match, err := isSkipped(dir, r.skipPatterns)
+		if err != nil {
+			return err
+		}
+		if match {
+			log.Infof(r.ctx, "skipping directory: %s", dir)
+			continue
+		}
+
 		// Check if directory already exists (may have been created during file writes)
-		_, err := out.Stat(ctx, dir)
+		_, err = out.Stat(ctx, dir)
 		if err == nil {
 			// Directory already exists, nothing to do
 			continue

libs/template/renderer_test.go

@@ -631,3 +631,29 @@ func TestRendererSubTemplateInPath(t *testing.T) {
 		assert.Equal(t, "my_directory/my_file", f.RelPath())
 	}
 }
+
+// A {{skip}} directive can name a directory that the BFS walk has already
+// visited, because the directive lives in a file processed later. The
+// directory must still not be created: the walk records visited directories
+// before any later file can skip them, so the skip patterns have to be applied
+// again when directories are materialized.
+func TestRendererSkipDirectoryVisitedBeforeSkipDirective(t *testing.T) {
+	ctx := t.Context()
+	ctx = cmdctx.SetWorkspaceClient(ctx, nil)
+	tmpDir := t.TempDir()
+
+	helpers := loadHelpers(ctx)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/skip-dir-after-visit/template", "./testdata/skip-dir-after-visit/library")
+	require.NoError(t, err)
+
+	err = r.walk()
+	require.NoError(t, err)
+
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
+	require.NoError(t, err)
+
+	assert.NoDirExists(t, filepath.Join(tmpDir, "dir1"))
+	assert.FileExists(t, filepath.Join(tmpDir, "dir2", "file2"))
+}

libs/template/testdata/skip-dir-after-visit/template/dir1/file1.tmpl

@@ -0,0 +1 @@
+This file is skipped by dir2, so dir1 must not be created

libs/template/testdata/skip-dir-after-visit/template/dir2/file2.tmpl

@@ -0,0 +1,3 @@
+I should be the only file created
+
+{{skip "../dir1"}}{{skip "../dir1/*"}}