100% cpu freezing does not respond to ctrl c on latest release

[trashhalo]

Issue

Process hangs at 100% CPU while rendering markdown/syntax highlighting. The process becomes unresponsive and requires force termination. This appears to be due to a pathological case in Pygments' lexer pattern matching.

Stack trace indicates issue is triggered during syntax highlighting in Rich/Pygments pipeline:

• Entry point: aider markdown rendering
• Through Rich markdown -> syntax highlighting
• Finally stuck in Pygments lexer processing

Steps to reproduce

1. Running standard aider chat interface
2. Process hangs during markdown/code rendering
3. CPU usage spikes to 100%
4. Process becomes unresponsive
5. Requires force termination via kill -6 (SIGABRT)

Stack trace
Most relevant section showing where process got stuck:

pythonCopyFile "/Users/stephensolka/.local/pipx/venvs/aider-chat/lib/python3.12/site-packages/pygments/lexer.py", line 712 in get_tokens_unprocessed
File "/Users/stephensolka/.local/pipx/venvs/aider-chat/lib/python3.12/site-packages/pygments/lexers/scripting.py", line 169 in get_tokens_unprocessed
File "/Users/stephensolka/.local/pipx/venvs/aider-chat/lib/python3.12/site-packages/pygments/lexer.py", line 270 in streamer

Full stack trace attached below for reference.
aider_abort.txt

Version and model info

Python Version: 3.12.9
OS: macOS
Installed via: pipx
❯ aider --version
aider 0.74.1

[trashhalo]

Confirmed that running aider --no-pretty it no longer happens. So much be tied to syntax highlighting.

[trashhalo]

My best guess is it's something related to the litellm upgrade from two days ago. There were code changes that landed in the stream processor which shows up in the stack.

[trashhalo]

I dont know if this makes sense but I think its tied to lua syntax parsing? its happening on a lua repo, but not on an elixir repo?

[UnrealPk]

Same issue is happening to me.

[MrOrz]

I also encounter this "Process hangs at 100% CPU" issue. In my case I have these symptoms:

• CPU 100%
• ctrl-c does not work, aider is not responding.

However in my case:

• --no-pretty doesn't help
• Just saying "hi" also triggers this issue

Using verbose mode (aider --verbose) it's stuck at a certain file in my repository. So in my case it's probably related to #1587 instead.