Assembly loader cache is case-insensitive even on cache-sensitive file systems

[jkotas]

FEATURE_CASE_SENSITIVE_FILESYSTEM is never defined. It means that the assembly loader ends up doing case-insensitive caching even on OSes that are naturally case-insensitive. It leads to odd behaviors like #57237 (comment) .

Repro:

1. Create a dummy TestAssembly.dll somewhere
2. Run on Linux:

Assembly.LoadFrom(@"/path_to_test_assembly/TestAssembly.dll");

// This will succeed by using cached copy of TestAssembly.dll even though testassembly.dll does not actually exist on the case-sensitive filesystem
Assembly.LoadFrom(@"/path_to_test_assembly/testassembly.dll");

Note that calling Assembly.LoadFrom(@"/path_to_test_assembly/testassembly.dll"); without the previous LoadFrom call that populates the cache is going to fail.

We need to:

• Decide whether whether to fix the current behavior. (Note that Mono does not have this bug, and that fixing it in CoreCLR would be a minor breaking change.)
• Add tests for this scenario.

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Issue Details

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FEATURE_CASE_SENSITIVE_FILESYSTEM is never defined. It means that the assembly loader ends up doing case-insensitive caching even on OSes that are naturally case-insensitive. It leads to odd behaviors like #57237 (comment) .

Repro:

1. Create a dummy TestAssembly.dll somewhere
2. Run on Linux:

Assembly.LoadFrom(@"/path_to_test_assembly/TestAssembly.dll");

// This will succeed by using cached copy of TestAssembly.dll even though it does not actually exist on the case-sensitive filesystem
Assembly.LoadFrom(@"/path_to_test_assembly/testassembly.dll");

Note that calling Assembly.LoadFrom(@"/path_to_test_assembly/testassembly.dll"); without the previous LoadFrom call that populates the cache is going to fail.

We need to:

• Decide whether whether to fix the current behavior. (Note that Mono does not have this bug, and that fixing it in CoreCLR would be a minor breaking change.)
• Add tests for this scenario.

Author:	jkotas
Assignees:	-
Labels:	area-AssemblyLoader-coreclr, untriaged
Milestone:	-