fix: enable paths with junction inside windows (#5245)

Co-authored-by: Simon Sawert <[email protected]>
Co-authored-by: Fernandez Ludovic <[email protected]>

Author: 3 people

pkg/fsutils/fsutils.go

@@ -61,7 +61,7 @@ func EvalSymlinks(path string) (string, error) {
 	}
 
 	var er evalSymlinkRes
-	er.path, er.err = filepath.EvalSymlinks(path)
+	er.path, er.err = evalSymlinks(path)
 	evalSymlinkCache.Store(path, er)
 
 	return er.path, er.err

pkg/fsutils/fsutils_unix.go

@@ -0,0 +1,9 @@
+//go:build !windows
+
+package fsutils
+
+import "path/filepath"
+
+func evalSymlinks(path string) (string, error) {
+	return filepath.EvalSymlinks(path)
+}

pkg/fsutils/fsutils_windows.go

@@ -0,0 +1,39 @@
+//go:build windows
+
+package fsutils
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// This is a workaround for the behavior of [filepath.EvalSymlinks],
+// which fails with [syscall.ENOTDIR] if the specified path contains a junction on Windows.
+// Junctions can occur, for example, when a volume is mounted as a subdirectory inside another drive.
+// This can usually happen when using the Dev Drives feature and replacing existing directories.
+// See: https://github.com/golang/go/issues/40180
+//
+// Since [syscall.ENOTDIR] is only returned when calling [filepath.EvalSymlinks] on Windows
+// if part of the presented path is a junction and nothing before was a symlink,
+// we simply treat this as NOT symlink,
+// because a symlink over the junction makes no sense at all.
+func evalSymlinks(path string) (string, error) {
+	resolved, err := filepath.EvalSymlinks(path)
+	if err == nil {
+		return resolved, nil
+	}
+
+	if !errors.Is(err, syscall.ENOTDIR) {
+		return "", err
+	}
+
+	_, err = os.Stat(path)
+	if err != nil {
+		return "", err
+	}
+
+	// If exists, we make the path absolute, to be sure...
+	return filepath.Abs(path)
+}