Test Failure: System.IO.Compression.Tests.ZipFile_*

[JulieLeeMSFT]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574201
Build error leg or test failing: System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToDirectory_EncryptedWithOverwrite_Success

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorPattern": "System\\.IO\\.Compression\\.Tests\\.ZipFile_.+\\[FAIL\\]",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Failed tests:

    System.IO.Compression.Tests.ZipFile_Create.CreateFromDirectory_IncludeBaseDirectory(async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_Create.CreateFromDirectoryNormal(async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_Create.CreateSetsExternalAttributesCorrectly(async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.Encryption_LargeFile_RoundTrip(async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToDirectory_EncryptedWithOverwrite_Success(encryptionMethod: Aes192, async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToDirectory_EncryptedWithOverwrite_Success(encryptionMethod: Aes256, async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_Create_Stream.CreateFromDirectoryNormal_Unreadable_Unseekable(async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.UpdateMode_LargeEncryptedEntry_Modify(async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToFile_EncryptedEntry_Success(encryptionMethod: ZipCrypto, async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToFile_EncryptedEntry_Overwrite_Success(encryptionMethod: ZipCrypto, async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToFile_EncryptedEntry_Overwrite_Success(encryptionMethod: Aes192, async: True) [FAIL]
    System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToFile_EncryptedEntry_Overwrite_Success(encryptionMethod: Aes256, async: True) [FAIL]

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574201
Error message validated: [System\.IO\.Compression\.Tests\.ZipFile_.+\[FAIL\]]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 9/2/2026 9:06:57 PM UTC

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574201
Error message validated: [System\.IO\.Compression\.Tests\.ZipFile_.+\[FAIL\]]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 9/2/2026 9:07:06 PM UTC

Report

Build	Repository	Test	Pull Request
1584906	dotnet/runtime	System.IO.Compression.Tests.ZipFile_EncryptionTests.Encryption_LargeFile_RoundTrip
1584422	dotnet/runtime	System.IO.Compression.Tests.ZipFile_EncryptionTests.Encryption_LargeFile_RoundTrip
1579855	dotnet/runtime	System.IO.Compression.Tests.ZipFile_EncryptionTests.Encryption_LargeFile_RoundTrip
1574201	dotnet/runtime	System.IO.Compression.Tests.ZipFile_EncryptionTests.Encryption_LargeFile_RoundTrip

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	1	4

[dotnet-policy-service]

Tagging subscribers to this area: @karelz, @dotnet/area-system-io-compression
See info in area-owners.md if you want to be subscribed.

[JulieLeeMSFT]

@karelz, this test failed in 23 test cases in libraries-pgo pipeline. PTAL.

[alinpahontu2912]

Hey @JulieLeeMSFT, I will take a look

[JulieLeeMSFT]

Thanks, @alinpahontu2912. Here is some more information.

Failed in (1):

• runtime-coreclr libraries-pgo 20260902.1

Console Log: Console Log

Failed tests:

- net11.0-linux-Release-x64-jitosr_stress_random-AzureLinux.3.Amd64.Open
- net11.0-windows-Release-x64-jitosr_stress_random-Windows.Amd64.Open.rt
  - System.IO.Compression.Tests.ZipFile_Create.CreateFromDirectoryNormal
  - System.IO.Compression.Tests.ZipFile_Create.CreateFromDirectory_IncludeBaseDirectory
  - System.IO.Compression.Tests.ZipFile_Create.CreateSetsExternalAttributesCorrectly
  - System.IO.Compression.Tests.ZipFile_Create_Stream.CreateFromDirectoryNormal_Unreadable_Unseekable
  - System.IO.Compression.Tests.ZipFile_EncryptionTests.Encryption_LargeFile_RoundTrip
  - System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToDirectory_EncryptedWithOverwrite_Success
  - ... and 1 more
  - System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToDirectory_MultipleEncryptedEntries_SamePassword_Success
  - System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToFile_EncryptedEntry_Overwrite_Success
  - System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToFile_EncryptedEntry_Success
  - System.IO.Compression.Tests.ZipFile_EncryptionTests.ExtractToFile_EncryptedEntry_WrongPassword_Throws
  - ... and 1 more

[alinpahontu2912]

Hey @JulieLeeMSFT, I believe this is not a System.IO.Compression bug.
All failures are NullReferenceExceptions from trivial code ( ZipArchiveEntry.get_IsEncrypted() : a bitmask read on a constructor-initialized field; DirectToArchiveWriterStream.ThrowIfDisposed() : a bool check). Neither can legitimately throw NRE. These pieces of code are also unchanged by recent commits. Another finding was that failures only occurr on async tests, which is odd.

[rzikm]

Another finding was that failures only occurr on async tests, which is odd.

Can this be related to the new runtime-async feature? Cc. @jakobbotsch