Preserve invalid friend assembly error by Copilot · Pull Request #127180 · dotnet/runtime

Copilot · 2026-04-20T20:51:47Z

When an assembly declares an invalid friend reference via InternalsVisibleTo (for example, specifying both PublicKey and PublicKeyToken), the runtime swallows the assembly name parse failure and throws a generic file load error. This change propagates the invalid assembly name error as an inner exception for the assembly load.

cc @dotnet/appmodel @AaronRobinsonMSFT

Before:

System.IO.FileLoadException: Unable to load file 'C:\...\InvalidFriendAssemblyName.dll'.

After:

System.IO.FileLoadException: Could not load file or assembly
   'InvalidFriendAssemblyName, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'. ... (0x80131621)
File name: 'InvalidFriendAssemblyName, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'
 ---> System.IO.FileLoadException: The given assembly name was invalid.
      FileName = 'Broken,PublicKey=…,PublicKeyToken=282361b99ded7e8e'

dotnet-policy-service · 2026-04-20T21:06:36Z

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…T roundtrip Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/406c2ee2-d0ea-4ba1-a45b-52ac7d68918e Co-authored-by: elinor-fung <47805090+elinor-fung@users.noreply.github.com>

Wrap the friend-assembly name parse failure so the underlying reason (the invalid assembly identity) is kept as the inner exception, while the outer FileLoadException reports which assembly declared the invalid InternalsVisibleTo/friend reference. Update the regression test to assert the outer exception identifies the declaring assembly and the inner exception carries the invalid name and message. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR changes the CoreCLR friend-assembly parsing error path so that failures while parsing InternalsVisibleTo / IgnoresAccessChecksTo assembly identities preserve the original parsing exception as an inner exception, rather than converting through a lossy HRESULT-only rethrow. It also adds a new loader regression test intended to validate the improved FileLoadException diagnostics for invalid friend assembly names.

Changes:

Wrap FriendAssemblyName_t::Init(displayName) in an exception-preserving EX_TRY/EX_CATCH, rethrowing as EEFileLoadException with the original exception as the inner exception.
Add a new loader regression test project InvalidFriendAssemblyName with an intentionally invalid InternalsVisibleTo string and assertions about the resulting FileLoadException chain.

Show a summary per file

File	Description
src/coreclr/vm/assembly.cpp	Preserve underlying assembly-name parse exceptions by wrapping `Init` failures as inner exceptions when building friend descriptors.
src/tests/Loader/classloader/regressions/InvalidFriendAssemblyName/InvalidFriendAssemblyName.csproj	Adds a new regression test project to the loader/classloader regressions suite.
src/tests/Loader/classloader/regressions/InvalidFriendAssemblyName/InvalidFriendAssemblyName.cs	Adds a test intended to validate diagnostics for invalid `InternalsVisibleTo` friend assembly identities.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Address review feedback: clarify that invoking the protected Object.MemberwiseClone drives the accessibility check that parses the invalid InternalsVisibleTo metadata. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Mono silently ignores invalid InternalsVisibleTo/friend assembly names rather than throwing, so this diagnostic behavior is CoreCLR-only. Gate the test with CLRTestTargetUnsupported to avoid failing Mono test legs. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 0 new

The test asserts the CoreCLR-specific FileLoadException thrown when parsing an invalid InternalsVisibleTo friend name. The previous CLRTestTargetUnsupported (RuntimeFlavor != coreclr) gate only excluded Mono; NativeAOT test legs run with RuntimeFlavor=coreclr, so the test still ran there and failed because NativeAOT resolves accessibility at compile time and never throws. Use a ConditionalFact that runs only on CoreCLR JIT (not Mono, not NativeAOT). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: c29dbe26-1e58-4183-a5f0-28a9fa5fd3ff

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

EEFileLoadException::Throw asserts its inner exception is not transient. The friend-name parse can fail with a transient exception (e.g. OutOfMemoryException), which would trip that assertion or incorrectly report a transient failure as a load failure. Switch the catch to EX_HOOK and only wrap non-transient exceptions; transient exceptions are rethrown unchanged, matching the pattern in PEAssembly::OpenSystem. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: c29dbe26-1e58-4183-a5f0-28a9fa5fd3ff

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 2

Initial plan

80302f4

Copilot AI assigned Copilot and elinor-fung Apr 20, 2026

Copilot AI requested review from Copilot and removed request for Copilot April 20, 2026 20:51

github-project-automation Bot added this to AppModel Apr 20, 2026

Copilot started work on behalf of elinor-fung April 20, 2026 20:51 View session

Copilot AI linked an issue Apr 20, 2026 that may be closed by this pull request

Weird FileLoadException when using old library and .NET 10 #126126

Closed

github-actions Bot added the area-VM-coreclr label Apr 20, 2026

Preserve invalid friend assembly diagnostics by removing lossy HRESUL…

6e589e5

…T roundtrip Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/406c2ee2-d0ea-4ba1-a45b-52ac7d68918e Co-authored-by: elinor-fung <47805090+elinor-fung@users.noreply.github.com>

Copilot AI requested review from Copilot and removed request for Copilot April 20, 2026 21:49

Copilot AI changed the title ~~[WIP] Fix FileLoadException when using old library with .NET 10~~ Preserve invalid friend assembly diagnostics by removing lossy HRESULT roundtrip Apr 20, 2026

Copilot AI requested a review from elinor-fung April 20, 2026 21:49

Copilot finished work on behalf of elinor-fung April 20, 2026 21:49

build-analysis Bot mentioned this pull request Apr 21, 2026

System.Net.NameResolution.Tests DNS failures: Name or service not known #126641

Open

Copilot AI review requested due to automatic review settings July 8, 2026 22:32

elinor-fung had a problem deploying to copilot-pat-pool July 8, 2026 22:32 — with GitHub Actions Failure

Copilot started reviewing on behalf of elinor-fung July 8, 2026 22:33 View session

Copilot AI reviewed Jul 8, 2026

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Comment thread src/tests/Loader/classloader/regressions/InvalidFriendAssemblyName/InvalidFriendAssemblyName.cs

elinor-fung changed the title ~~Preserve invalid friend assembly diagnostics by removing lossy HRESULT roundtrip~~ Preserve invalid friend assembly error Jul 8, 2026

Copilot AI review requested due to automatic review settings July 8, 2026 22:55

elinor-fung had a problem deploying to copilot-pat-pool July 8, 2026 22:56 — with GitHub Actions Failure

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Copilot AI reviewed Jul 8, 2026

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Comment thread src/tests/Loader/classloader/regressions/InvalidFriendAssemblyName/InvalidFriendAssemblyName.cs

elinor-fung marked this pull request as ready for review July 8, 2026 23:53

Copilot AI review requested due to automatic review settings July 8, 2026 23:57

elinor-fung had a problem deploying to copilot-pat-pool July 8, 2026 23:57 — with GitHub Actions Failure

Copilot started reviewing on behalf of elinor-fung July 8, 2026 23:58 View session

Copilot AI reviewed Jul 9, 2026

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build-analysis Bot mentioned this pull request Jul 9, 2026

The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008

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3 tasks

AaronRobinsonMSFT reviewed Jul 9, 2026

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Comment thread src/coreclr/vm/assembly.cpp

Copilot AI review requested due to automatic review settings July 9, 2026 19:29

elinor-fung had a problem deploying to copilot-pat-pool July 9, 2026 19:30 — with GitHub Actions Failure

Copilot started reviewing on behalf of elinor-fung July 9, 2026 19:30 View session

Copilot AI reviewed Jul 9, 2026

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Comment thread src/coreclr/vm/assembly.cpp Outdated

AaronRobinsonMSFT approved these changes Jul 9, 2026

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Copilot AI review requested due to automatic review settings July 10, 2026 00:30

elinor-fung had a problem deploying to copilot-pat-pool July 10, 2026 00:30 — with GitHub Actions Failure

Copilot started reviewing on behalf of elinor-fung July 10, 2026 00:31 View session

Copilot AI reviewed Jul 10, 2026

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Comment thread src/tests/Loader/classloader/regressions/InvalidFriendAssemblyName/InvalidFriendAssemblyName.cs Outdated

Potential fix for pull request finding

33bf728

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings July 10, 2026 01:04

elinor-fung had a problem deploying to copilot-pat-pool July 10, 2026 01:04 — with GitHub Actions Failure

Copilot started reviewing on behalf of elinor-fung July 10, 2026 01:04 View session

Copilot AI reviewed Jul 10, 2026

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Comment thread src/coreclr/vm/assembly.cpp

Comment thread src/tests/Loader/classloader/regressions/InvalidFriendAssemblyName/InvalidFriendAssemblyName.cs

AaronRobinsonMSFT approved these changes Jul 10, 2026

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build-analysis Bot mentioned this pull request Jul 10, 2026

[ci-scan] Test failure: System.Globalization.Tests.IdnMappingGetUnicodeTests DllNotFoundException 'libSystem.Globalization.Native' on browser-wasm CoreCLR #130479

Open

elinor-fung merged commit 9d70f01 into main Jul 10, 2026
115 of 118 checks passed

elinor-fung deleted the copilot/fix-fileloadexception-net10 branch July 10, 2026 21:13

github-project-automation Bot moved this to Done in AppModel Jul 10, 2026

dotnet-maestro Bot mentioned this pull request Jul 11, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#7672

Merged

dotnet-milestone-bot Bot added this to the 11.0-preview7 milestone Jul 11, 2026

github-actions Bot mentioned this pull request Jul 12, 2026

[ci-scan] Test failure: Loader/classloader/regressions/InvalidFriendAssemblyName under R2R/crossgen2 #130569

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Preserve invalid friend assembly error#127180

Preserve invalid friend assembly error#127180
elinor-fung merged 8 commits into
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Copilot AI commented Apr 20, 2026 •

edited by elinor-fung

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Copilot AI commented Apr 20, 2026 •

edited by elinor-fung

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