From 91f48dfdf1f9836ea522d41799432b3ed1d5757e Mon Sep 17 00:00:00 2001
From: Paul Gauthier <aider@paulg.org>
Date: Sun, 4 Jun 2023 06:43:30 -0700
Subject: [PATCH] aider: Added a check for an empty `tags` list in `to_tree`
 function.

# Context:
USER:  File "/Users/gauthier/Projects/aider/aider/repomap.py", line 107, in choose_files_listing
    files_listing = self.get_ranked_tags_map(chat_files, other_files)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/gauthier/Projects/aider/aider/repomap.py", line 318, in get_ranked_tags_map
    tree = to_tree(ranked_tags[:middle])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/gauthier/Projects/aider/aider/repomap.py", line 26, in to_tree
    last = [None] * len(tags[0])
                        ~~~~^^^
ASSISTANT: I see the code snippets from the `aider/repomap.py` file. Please let me know what changes you would like to make, and make sure to provide me with the *read-write* access to the file.
USER: I added these *read-write* files: aider/repomap.py
ASSISTANT: Great! Now, please let me know what changes you would like to make in the `aider/repomap.py` file.
USER:   File "/Users/gauthier/Projects/aider/aider/repomap.py", line 318, in get_ranked_tags_map
    tree = to_tree(ranked_tags[:middle])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/gauthier/Projects/aider/aider/repomap.py", line 26, in to_tree
    last = [None] * len(tags[0])
                        ~~~~^^^
IndexError: list index out of range
ASSISTANT: It seems like you are encountering an IndexError due to an empty `tags` list. To fix this issue, you can add a check to ensure that the `tags` list is not empty before accessing its elements. Here's the change you need to make in the `aider/repomap.py` file:

```python
aider/repomap.py
<<<<<<< ORIGINAL
def to_tree(tags):
    tags = sorted(tags)

    output = ""
    last = [None] * len(tags[0])
=======
def to_tree(tags):
    if not tags:
        return ""

    tags = sorted(tags)

    output = ""
    last = [None] * len(tags[0])
>>>>>>> UPDATED
```

This change adds a check for an empty `tags` list and returns an empty string if the list is empty, preventing the IndexError.
---
 aider/repomap.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/aider/repomap.py b/aider/repomap.py
index 9b6342eae..e7d70df82 100644
--- a/aider/repomap.py
+++ b/aider/repomap.py
@@ -20,6 +20,9 @@ from .dump import dump  # noqa: F402
 
 
 def to_tree(tags):
+    if not tags:
+        return ""
+
     tags = sorted(tags)
 
     output = ""