jgorbe added a comment.

I found the actual reason for the crash I was talking about. This patch only 
addressed the incorrect `OverflowError`, but the crash comes from a double free 
(as @rupprecht mentioned) in the error handling logic. The error path here 
<https://github.com/llvm/llvm-project/blob/main/lldb/bindings/python/python-typemaps.swig#L298>
 does both `free($1);` and `SWIG_fail;`. The same goes for another error check 
a few lines below that. In the generated code, the `SWIG_fail` macro is 
expanded to `goto fail` and the `fail` label also frees the same memory buffer.

I believe (but I don't have any experience with SWIG typemaps so this is an 
educated guess) that the call to `free` in the error path comes from the 
`%typemap(freearg)` immediately after that one. So if freearg already takes 
care of it, the error handling logic in `%typemap(in)` should just call 
`SWIG_fail`. Does that sound correct?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D146590/new/

https://reviews.llvm.org/D146590

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