[#2519] replace os.Rename with manually moving the dir children

tools/osutils/dir.go

@@ -0,0 +1,80 @@
+package osutils
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+
+	"github.com/pocketbase/pocketbase/tools/list"
+)
+
+// MoveDirContent moves the src dir content, that is not listed in the exclide list,
+// to dest dir (it will be created if missing).
+//
+// The rootExclude argument is used to specify a list of src root entries to exclude.
+//
+// Note that this method doesn't delete the old src dir.
+//
+// It is an alternative to os.Rename() for the cases where we can't
+// rename/delete the src dir (see https://github.com/pocketbase/pocketbase/issues/2519).
+func MoveDirContent(src string, dest string, rootExclude ...string) error {
+	entries, err := os.ReadDir(src)
+	if err != nil {
+		return err
+	}
+
+	// make sure that the dest dir exist
+	manuallyCreatedDestDir := false
+	if _, err := os.Stat(dest); err != nil {
+		if err := os.Mkdir(dest, os.ModePerm); err != nil {
+			return err
+		}
+		manuallyCreatedDestDir = true
+	}
+
+	moved := map[string]string{}
+
+	tryRollback := func() ([]error) {
+		errs := []error{}
+
+		for old, new := range moved {
+			if err := os.Rename(new, old); err != nil{
+				errs = append(errs, err)
+			}
+		}
+
+		// try to delete manually the created dest dir if all moved files were restored
+		if manuallyCreatedDestDir && len(errs) == 0 {
+			if err := os.Remove(dest); err != nil {
+				errs = append(errs, err)
+			}
+		}
+
+		return errs
+	}
+
+	for _, entry := range entries {
+		basename := entry.Name()
+
+		if list.ExistInSlice(basename, rootExclude) {
+			continue
+		}
+
+		old := filepath.Join(src, basename)
+		new := filepath.Join(dest, basename)
+
+		if err := os.Rename(old, new); err != nil {
+			if errs := tryRollback(); len(errs) > 0  {
+				// currently just log the rollback errors
+				// in the future we may require go 1.20+ to use errors.Join()
+				log.Println(errs)
+			}
+
+			return err
+		}
+
+		moved[old] = new
+	}
+
+	return nil
+}