[release/6.0] Fix Crossgen2 bug #61104 and add regression test #64027
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The issue tracks the runtime regression failure where Crossgen2-compiled app is unable to locate a type with non-ASCII characters in its name. The failure was caused by the fact that Crossgen2 was incorrectly zero-extended the individual characters when calculating the hash whereas runtime is sign-extending them. Thanks Tomas
mangod9
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Jan 20, 2022
jeffschwMSFT
approved these changes
Jan 20, 2022
jeffschwMSFT
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Eek, it is not the right time to merge (quite yet). We need to wait for a checkin window and request approval. @mmitche to help stop this from flowing. |
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Hmm, sorry about that, I was under the impression that the actual move to the servicing release will happen as a subsequent step. Thanks Jeff for letting me know, I'll remember it the next time. |
leecow
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Are there builds with this fix available yet? |
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@Tragetaschen not yet, these builds will start to show up on https://github.com/dotnet/installer in the coming week. |
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Backport of #63956 to release/6.0
/cc @mangod9 @trylek
Customer Impact
Fixes issue reported by multiple customers where Crossgen2-compiled apps fail runtime reflection lookup for types with non-ASCII characters in their names, in particular:
#61104
#63193
#63481
Testing
As part of fixing the bug I locally reproed the failure in 61104 and I used comparative debugging to observe the native runtime vs. Crossgen2 code path that revealed the subtle difference in type hash code calculation. After fixing the discrepancy I locally observed the hash codes getting in sync between the CoreCLR runtime and Crossgen2 even for types with names containing non-ASCII characters. As part of the fix I created a regression test based on the bug report 61104 and I ran a successful [modulo minor infra hiccups] outerloop run.
Risk
Extremely low - the fix only affects a corner case of type names containing non-ASCII characters; the two algorithms, their previous divergence and its fix in the PR proposed for porting are well understood and quite trivial to reason about; the fix is well localized and literally involves about 20 characters in a single method.