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jbevain / cecil

Cecil is a library to inspect, modify and create .NET programs and libraries.
MIT License
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Harden debug scope update logic #824

Closed vitek-karas closed 2 years ago

vitek-karas commented 2 years ago

Based on bug reports like #816 it seems there are still cases where the IL and scope offsets are out of sync in weird ways. This change modifies the logic to have no potential to cause the IndexOutOfRangeException. While I was not able to determine what combination could cause this, it's better this way.

The corner case comes when there's potential problem with the first/second instruction in the method body. The change in this case will potentially make the debug scopes slightly wrong by not pointing to the previous instruction (as there's none). Without having a real repro it's hard to tell what would be a better solution, this way it won't crash and the scopes still make sense.

vitek-karas commented 2 years ago

/cc @SteveGilham

jbevain commented 2 years ago

Thank you!