fix: allow media downloads to shared output dirs

CHANGELOG.md

@@ -51,6 +51,7 @@
 - Messages: store forwarded-message metadata and add `--forwarded` filters for list/search. (#24 — thanks @bnvyas)
 - Doctor: report lock owner PID and distinguish paired stores locked by another process. (#105 — thanks @artemgetmann)
 - Media: recover panics per download job so one bad payload no longer drains the worker pool. (#179 — thanks @shaun0927)
+- Media: allow explicit download outputs in shared directories like `/tmp` without trying to chmod the parent directory.
 - Messages: attribute history messages from LID-addressed groups to the top-level participant sender. (#19 — thanks @entropyy0)
 - Messages: show display text for replies, reactions, and media in `messages context`. (#183 — thanks @fuleinist)
 - Send: strip a leading `+` from phone-number recipients before building WhatsApp JIDs. (#74 — thanks @FrederickStempfle)

internal/fsutil/permissions.go

@@ -21,3 +21,17 @@ func EnsurePrivateDir(path string) error {
 	}
 	return nil
 }
+
+func EnsureWritableDir(path string) error {
+	if err := os.MkdirAll(path, 0o700); err != nil {
+		return fmt.Errorf("create dir: %w", err)
+	}
+	info, err := os.Stat(path)
+	if err != nil {
+		return fmt.Errorf("stat dir: %w", err)
+	}
+	if !info.IsDir() {
+		return fmt.Errorf("%s is not a directory", path)
+	}
+	return nil
+}

internal/fsutil/permissions_test.go

@@ -52,3 +52,37 @@ func TestEnsurePrivateDirRejectsFiles(t *testing.T) {
 		t.Fatalf("expected error for file path")
 	}
 }
+
+func TestEnsureWritableDirDoesNotChmodExistingDir(t *testing.T) {
+	dir := filepath.Join(t.TempDir(), "shared")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		t.Fatalf("MkdirAll: %v", err)
+	}
+	if err := os.Chmod(dir, 0o755); err != nil {
+		t.Fatalf("Chmod setup: %v", err)
+	}
+	if err := EnsureWritableDir(dir); err != nil {
+		t.Fatalf("EnsureWritableDir: %v", err)
+	}
+	info, err := os.Stat(dir)
+	if err != nil {
+		t.Fatalf("Stat: %v", err)
+	}
+	if got := info.Mode().Perm(); got != 0o755 {
+		t.Fatalf("mode = %04o, want 0755", got)
+	}
+}
+
+func TestEnsureWritableDirCreatesPrivateDir(t *testing.T) {
+	dir := filepath.Join(t.TempDir(), "new")
+	if err := EnsureWritableDir(dir); err != nil {
+		t.Fatalf("EnsureWritableDir: %v", err)
+	}
+	info, err := os.Stat(dir)
+	if err != nil {
+		t.Fatalf("Stat: %v", err)
+	}
+	if got := info.Mode().Perm(); got != 0o700 {
+		t.Fatalf("mode = %04o, want 0700", got)
+	}
+}

internal/wa/media.go

@@ -45,7 +45,7 @@ func (c *Client) DownloadMediaToFile(ctx context.Context, directPath string, enc
 		return 0, err
 	}
 
-	if err := fsutil.EnsurePrivateDir(filepath.Dir(targetPath)); err != nil {
+	if err := fsutil.EnsureWritableDir(filepath.Dir(targetPath)); err != nil {
 		return 0, fmt.Errorf("create output dir: %w", err)
 	}