1 files changed, 76 insertions, 1 deletions
diff --git a/internal/image/download_test.go b/internal/image/download_test.go
index 84e8f5f..073e0d8 100644
--- a/internal/image/download_test.go
+++ b/internal/image/download_test.go
@@ -216,10 +216,85 @@ func TestDownloadImageRejectsSymlinkAncestor(t *testing.T) {
 	if err == nil {
 		t.Fatal("expected error for symlink ancestor")
 	}
-	if !strings.Contains(err.Error(), "symlink") {
+	if !strings.Contains(err.Error(), "symlink") && !strings.Contains(err.Error(), "not a directory") {
 		t.Fatalf("DownloadImage() error = %v, want symlink rejection", err)
 	}
 	if _, statErr := os.Stat(filepath.Join(outsideDir, "escape.png")); !os.IsNotExist(statErr) {
 		t.Fatalf("unexpected file write outside output dir: %v", statErr)
 	}
 }
+
+func TestDownloadImageRejectsSymlinkSwapDuringDownload(t *testing.T) {
+	t.Parallel()
+
+	baseDir := t.TempDir()
+	outsideDir := t.TempDir()
+	nestedDir := filepath.Join(baseDir, "nested")
+	if err := os.Mkdir(nestedDir, 0o755); err != nil {
+		t.Fatalf("Mkdir() error = %v", err)
+	}
+
+	downloadReady := make(chan struct{})
+	releaseDownload := make(chan struct{})
+	provider := &swapBlockingProvider{
+		payload:         "image-bytes",
+		downloadReady:   downloadReady,
+		releaseDownload: releaseDownload,
+	}
+	d := NewDownloader(provider, &DownloadOptions{
+		OutputDir:         baseDir,
+		CreateDir:         true,
+		OverwriteExisting: true,
+	})
+
+	result := &SearchResult{
+		URL:         "https://example.com/image.png",
+		Source:      Gemini,
+		Attribution: "safe attribution",
+	}
+	outputPath := filepath.Join(nestedDir, "escape.png")
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- d.DownloadImage(context.Background(), result, outputPath)
+	}()
+
+	<-downloadReady
+	if err := os.RemoveAll(nestedDir); err != nil {
+		t.Fatalf("RemoveAll() error = %v", err)
+	}
+	if err := os.Symlink(outsideDir, nestedDir); err != nil {
+		t.Fatalf("Symlink() error = %v", err)
+	}
+	close(releaseDownload)
+
+	err := <-errCh
+	if err == nil {
+		t.Fatal("expected error for symlink swap during download")
+	}
+	if !strings.Contains(err.Error(), "symlink") && !strings.Contains(err.Error(), "open dir") {
+		t.Fatalf("DownloadImage() error = %v, want symlink rejection", err)
+	}
+	if _, statErr := os.Stat(filepath.Join(outsideDir, "escape.png")); !os.IsNotExist(statErr) {
+		t.Fatalf("unexpected file write outside output dir: %v", statErr)
+	}
+}
+
+type swapBlockingProvider struct {
+	payload         string
+	downloadReady   chan struct{}
+	releaseDownload chan struct{}
+}
+
+func (p *swapBlockingProvider) Name() string { return "swap-blocking" }
+
+func (p *swapBlockingProvider) Search(context.Context, *SearchOptions) ([]SearchResult, error) {
+	return nil, nil
+}
+
+func (p *swapBlockingProvider) Download(_ context.Context, _ string) (io.ReadCloser, error) {
+	close(p.downloadReady)
+	<-p.releaseDownload
+	return io.NopCloser(strings.NewReader(p.payload)), nil
+}
+
+func (p *swapBlockingProvider) GetAttribution(*SearchResult) string { return "" }