Skip to content

[release/10.0] Fix hash collision in TypeMapLazyDictionary causing non-deterministic ArgumentException #123517

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
github-actions wants to merge 5 commits into
base: release/10.0
Choose a base branch
from
+4 −8
Open

[release/10.0] Fix hash collision in TypeMapLazyDictionary causing non-deterministic ArgumentException #123517

Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
ee818c2
Initial plan
Copilot Jan 22, 2026
03fab19
Fix TypeMapLazyDictionary hash collision issue by using string keys i…
Copilot Jan 22, 2026
072555e
Tests built successfully - code changes and tests complete
Copilot Jan 22, 2026
3e69b59
Remove generated XunitStub.cs build artifact
Copilot Jan 22, 2026
5fd4ae6
Revert test changes - remove added TypeMap tests per feedback
Copilot Jan 22, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 4 additions & 8 deletions ...raries/System.Private.CoreLib/src/System/Runtime/InteropServices/TypeMapLazyDictionary.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -308,14 +308,11 @@ public unsafe Type GetOrLoadType()
[RequiresUnreferencedCode("Lazy TypeMap isn't supported for Trimmer scenarios")]
private sealed class LazyExternalTypeDictionary : LazyTypeLoadDictionary<string>
{
private static int ComputeHashCode(string key) => key.GetHashCode();

private readonly Dictionary<int, DelayedType> _lazyData = new();
private readonly Dictionary<string, DelayedType> _lazyData = new();

protected override bool TryGetOrLoadType(string key, [NotNullWhen(true)] out Type? type)
{
int hash = ComputeHashCode(key);
if (!_lazyData.TryGetValue(hash, out DelayedType? value))
if (!_lazyData.TryGetValue(key, out DelayedType? value))
{
type = null;
return false;
Expand All @@ -327,13 +324,12 @@ protected override bool TryGetOrLoadType(string key, [NotNullWhen(true)] out Typ

public void Add(string key, TypeNameUtf8 targetType, RuntimeAssembly fallbackAssembly)
{
int hash = ComputeHashCode(key);
if (_lazyData.ContainsKey(hash))
if (_lazyData.ContainsKey(key))
{
ThrowHelper.ThrowAddingDuplicateWithKeyArgumentException(key);
}

_lazyData.Add(hash, new DelayedType(targetType, fallbackAssembly));
_lazyData.Add(key, new DelayedType(targetType, fallbackAssembly));
}
}

Expand Down
Loading