[llvm] [lit] Don't crash in _write_message when getsourcefile() returns None (PR #206957)

[James Henderson via llvm-commits]

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@@ -222,7 +222,13 @@ def _write_message(self, kind, message):
         f = inspect.currentframe()
         # Step out of _write_message, and then out of wrapper.
         f = f.f_back.f_back
-        file = os.path.abspath(inspect.getsourcefile(f))
+        # getsourcefile() returns None when the calling frame's source is not on
+        # disk and not in linecache (e.g. lit packaged into a zip/par, or code
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jh7370 wrote:

What's a "par"?

https://github.com/llvm/llvm-project/pull/206957