fix: Ignore irregular files during copy

Irregular files do not contain data and should not be copied.
They are typically used for inter-process communication or other special purposes.

Fixes: #31139

Signed-off-by: Evans Mungai <mbuevans@gmail.com>

internal/third_party/dep/fs/fs.go

@@ -36,6 +36,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
+	"log/slog"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -173,6 +174,13 @@ func CopyFile(src, dst string) (err error) {
 		} else {
 			return nil
 		}
+	} else {
+		if fi, err := os.Lstat(src); err != nil {
+			return fmt.Errorf("stat failed: %w", err)
+		} else if !fi.Mode().IsRegular() {
+			slog.Debug("skipping non-regular file", "path", src, "mode", fi.Mode())
+			return nil
+		}
 	}
 
 	in, err := os.Open(src)

internal/third_party/dep/fs/fs_test.go

@@ -35,6 +35,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"syscall"
 	"testing"
 )
 
@@ -542,6 +543,48 @@ func TestIsDir(t *testing.T) {
 	}
 }
 
+func TestCopyFileSkipIrregularFiles(t *testing.T) {
+	dir := t.TempDir()
+
+	// Create a regular file first
+	regularFile := filepath.Join(dir, "regular.txt")
+	if err := os.WriteFile(regularFile, []byte("regular file content"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	// Test copying a regular file - should succeed
+	dstRegular := filepath.Join(dir, "regular_copy.txt")
+	if err := CopyFile(regularFile, dstRegular); err != nil {
+		t.Fatalf("expected CopyFile to succeed for regular file, got error: %v", err)
+	}
+
+	// Verify the regular file was copied
+	if _, err := os.Stat(dstRegular); err != nil {
+		t.Fatalf("expected regular file to be copied, but destination doesn't exist: %v", err)
+	}
+
+	// Create a named pipe (FIFO) - this is an irregular file
+	// Note: syscall.Mkfifo is not available on Windows, so we skip this test there
+	pipeFile := filepath.Join(dir, "pipe")
+	if err := syscall.Mkfifo(pipeFile, 0644); err != nil {
+		if runtime.GOOS == "windows" {
+			t.Skip("skipping on windows - syscall.Mkfifo not available")
+		}
+		t.Fatal(err)
+	}
+
+	// Test copying the named pipe - should skip without error
+	dstPipe := filepath.Join(dir, "pipe_copy")
+	if err := CopyFile(pipeFile, dstPipe); err != nil {
+		t.Fatalf("expected CopyFile to skip irregular file without error, got error: %v", err)
+	}
+
+	// Verify the irregular file was NOT copied (destination should not exist)
+	if _, err := os.Stat(dstPipe); err == nil {
+		t.Fatalf("expected irregular file to be skipped, but destination exists")
+	}
+}
+
 func TestIsSymlink(t *testing.T) {
 
 	var currentUID = os.Getuid()