remove use of github.com/docker/docker/pkg/longpath

cli/command/image/build/context_windows.go

@@ -2,14 +2,35 @@ package build
 
 import (
 	"path/filepath"
-
-	"github.com/docker/docker/pkg/longpath"
+	"strings"
 )
 
 func getContextRoot(srcPath string) (string, error) {
 	cr, err := filepath.Abs(srcPath)
 	if err != nil {
 		return "", err
 	}
-	return longpath.AddPrefix(cr), nil
+	return addPrefix(cr), nil
+}
+
+// longPathPrefix is the longpath prefix for Windows file paths.
+const longPathPrefix = `\\?\`
+
+// addPrefix adds the Windows long path prefix to the path provided if
+// it does not already have it.
+//
+// See https://github.com/moby/moby/pull/15898
+//
+// This is a copy of [longpath.AddPrefix].
+//
+// [longpath.AddPrefix]:https://pkg.go.dev/github.com/docker/[email protected]+incompatible/pkg/longpath#AddPrefix
+func addPrefix(path string) string {
+	if strings.HasPrefix(path, longPathPrefix) {
+		return path
+	}
+	if strings.HasPrefix(path, `\\`) {
+		// This is a UNC path, so we need to add 'UNC' to the path as well.
+		return longPathPrefix + `UNC` + path[1:]
+	}
+	return longPathPrefix + path
 }

cli/command/image/build/context_windows_test.go

@@ -0,0 +1,22 @@
+package build
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestStandardLongPath(t *testing.T) {
+	c := `C:\simple\path`
+	longC := addPrefix(c)
+	if !strings.EqualFold(longC, `\\?\C:\simple\path`) {
+		t.Errorf("Wrong long path returned. Original = %s ; Long = %s", c, longC)
+	}
+}
+
+func TestUNCLongPath(t *testing.T) {
+	c := `\\server\share\path`
+	longC := addPrefix(c)
+	if !strings.EqualFold(longC, `\\?\UNC\server\share\path`) {
+		t.Errorf("Wrong UNC long path returned. Original = %s ; Long = %s", c, longC)
+	}
+}

vendor/modules.txt

@@ -97,7 +97,6 @@ github.com/docker/docker/internal/multierror
 github.com/docker/docker/pkg/homedir
 github.com/docker/docker/pkg/ioutils
 github.com/docker/docker/pkg/jsonmessage
-github.com/docker/docker/pkg/longpath
 github.com/docker/docker/pkg/process
 github.com/docker/docker/pkg/progress
 github.com/docker/docker/pkg/stdcopy