project: Rename if deletion fails

If a project contains files not owned by the current user, remove will
fail. In order to ensure repo sync continues to work, rename the
affected project instead, and let user know about it.

Bug: 321273512
Change-Id: I0779d61fc67042308a0226adea7d98167252a5d3
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/404372
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>
diff --git a/project.py b/project.py
index db74c65..1821c35 100644
--- a/project.py
+++ b/project.py
@@ -1848,7 +1848,7 @@
                     platform_utils.remove(path)
                 except OSError as e:
                     if e.errno != errno.ENOENT:
-                        logger.error("error: %s: Failed to remove: %s", path, e)
+                        logger.warning("%s: Failed to remove: %s", path, e)
                         failed = True
                         errors.append(e)
             dirs[:] = [
@@ -1867,7 +1867,7 @@
                     platform_utils.remove(d)
                 except OSError as e:
                     if e.errno != errno.ENOENT:
-                        logger.error("error: %s: Failed to remove: %s", d, e)
+                        logger.warning("%s: Failed to remove: %s", d, e)
                         failed = True
                         errors.append(e)
             elif not platform_utils.listdir(d):
@@ -1875,18 +1875,30 @@
                     platform_utils.rmdir(d)
                 except OSError as e:
                     if e.errno != errno.ENOENT:
-                        logger.error("error: %s: Failed to remove: %s", d, e)
+                        logger.warning("%s: Failed to remove: %s", d, e)
                         failed = True
                         errors.append(e)
         if failed:
-            logger.error(
-                "error: %s: Failed to delete obsolete checkout.",
-                self.RelPath(local=False),
+            rename_path = (
+                f"{self.worktree}_repo_to_be_deleted_{int(time.time())}"
             )
-            logger.error(
-                "       Remove manually, then run `repo sync -l`.",
-            )
-            raise DeleteWorktreeError(aggregate_errors=errors)
+            try:
+                platform_utils.rename(self.worktree, rename_path)
+                logger.warning(
+                    "warning: renamed %s to %s. You can delete it, but you "
+                    "might need elevated permissions (e.g. root)",
+                    self.worktree,
+                    rename_path,
+                )
+                # Rename successful! Clear the errors.
+                errors = []
+            except OSError:
+                logger.error(
+                    "%s: Failed to delete obsolete checkout.\n",
+                    "       Remove manually, then run `repo sync -l`.",
+                    self.RelPath(local=False),
+                )
+                raise DeleteWorktreeError(aggregate_errors=errors)
 
         # Try deleting parent dirs if they are empty.
         path = self.worktree