fix: handle paths outside repository

aider/repo.py

@@ -571,7 +571,10 @@ def path_in_repo(self, path):
             return
 
         tracked_files = set(self.get_tracked_files())
-        normalized = self.normalize_path(path)
+        try:
+            normalized = self.normalize_path(path)
+        except ValueError:
+            return False
         return normalized in tracked_files
 
     def abs_root_path(self, path):

tests/basic/test_issue_5620_add_route.py

@@ -0,0 +1,42 @@
+"""Regression for Aider-AI/aider#5620, second entry route (/read-only + /add).
+
+An image outside the repo is allowed as read-only from anywhere. Promoting it
+with /add reaches GitRepo.path_in_repo() with an out-of-root absolute path,
+which must answer "not tracked" rather than raise ValueError.
+"""
+
+import os
+import tempfile
+from pathlib import Path
+from unittest import TestCase
+
+from aider.coders import Coder
+from aider.commands import Commands
+from aider.io import InputOutput
+from aider.models import Model
+from aider.utils import GitTemporaryDirectory
+
+
+class TestIssue5620AddRoute(TestCase):
+    def test_add_promotes_outside_readonly_image_without_crash(self):
+        with tempfile.TemporaryDirectory() as outside_dir:
+            outside_image = Path(outside_dir) / "outside.png"
+            outside_image.write_bytes(b"not really a png")
+            with GitTemporaryDirectory():
+                io = InputOutput(pretty=False, fancy_input=False, yes=True)
+                coder = Coder.create(Model("gpt-4o"), None, io)
+                commands = Commands(io, coder)
+
+                commands.cmd_read_only(str(outside_image))
+                self.assertEqual(len(coder.abs_read_only_fnames), 1)
+
+                # Must not raise; the file is not part of the repository.
+                commands.cmd_add(str(outside_image))
+
+                self.assertEqual(len(coder.abs_fnames), 0)
+                self.assertTrue(
+                    any(
+                        os.path.samefile(str(outside_image), fname)
+                        for fname in coder.abs_read_only_fnames
+                    )
+                )

tests/basic/test_repo.py

@@ -584,6 +584,14 @@ def test_get_tracked_files_from_subdir(self):
             fnames = git_repo.get_tracked_files()
             self.assertIn(str(fname), fnames)
 
+    def test_path_outside_repo_is_not_tracked(self):
+        with GitTemporaryDirectory():
+            outside_path = Path.cwd().parent / "outside.txt"
+            git_repo = GitRepo(InputOutput(), None, None)
+
+            self.assertFalse(git_repo.path_in_repo(outside_path))
+            self.assertTrue(git_repo.is_dirty(outside_path))
+
     def test_subtree_only(self):
         with GitTemporaryDirectory():
             # Create a new repo