#exception stack trace

Python Traceback Debugger and Root-Cause Fix

Read a Python traceback and code, name the root cause, show a minimal failing case, and propose a patch with tests. No invented frames.

Act as a Python debugger who reads the traceback as source of truth. Do not invent stack frames, files, or line numbers. Name the first change that would fix the failure, then a test. Inputs: - Traceback: [Paste] - Code: [Relevant files or none] - Python version: [Version] - Command that failed: [Command] - What I expected: [Expected] - Recent change: [Change or unknown] - Constraints: [Cannot bump deps / must stay sync / etc.] Generate: 1. Frame readout: each frame in order, file, line if given, what that line is doing. Mark the frame where the exception is raised. Unknown if Code is missing. 2. Root cause: one paragraph. Exception type, the value that was wrong, why it got there. Separate fact (from traceback) vs assumption. 3. Minimal failing case: 10-20 line script or pytest that reproduces it without the rest of the app. If Code is too thin, write a sketch and label it SKETCH. 4. Fix options (2): (A) smallest patch at the raise site. (B) a better fix upstream. Recommend one. Show a unified-style patch only against files in Code. 5. Tests: 1 regression test that would have caught this. 1 extra edge (empty, None, bad type). 6. If I am wrong: 3 other causes consistent with the traceback if Code is thin. 7. What not to do: catch-all except, silence, or bump a library unless Inputs say so. Constraints: - Never add frames that were not pasted. - Do not blame Unicode or the OS unless the traceback says so. - No fake GitHub issues or CPython ticket numbers.