Skip to content

Fix TarReader_SparseFileTests reflection breaking under Native AOT by replacing with [UnsafeAccessor] #126854

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

Merged
rzikm merged 2 commits into from
Apr 14, 2026
+12 −8
Merged

Fix TarReader_SparseFileTests reflection breaking under Native AOT by replacing with [UnsafeAccessor] #126854

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
d954d3f
Initial plan
Copilot Apr 13, 2026
dff0ee0
Replace reflection with UnsafeAccessor in TarReader.SparseFile.Tests.cs
Copilot Apr 13, 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
20 changes: 12 additions & 8 deletions src/libraries/System.Formats.Tar/tests/TarReader/TarReader.SparseFile.Tests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,9 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
Expand Down Expand Up @@ -34,13 +35,10 @@ private static void WriteSparseEntry(TarWriter writer, string realName, long rea
["GNU.sparse.name"] = realName,
};
var entry = new PaxTarEntry(TarEntryType.RegularFile, "GNUSparseFile.0/" + realName, gnuSparseAttributes);
// Inject GNU.sparse.realsize into the internal _header.ExtendedAttributes dictionary via
// reflection, bypassing the public ReadOnlyDictionary façade and constructor validation.
// This allows intentionally-invalid archives (negative realsize) to be constructed for tests.
var headerField = typeof(TarEntry).GetField("_header", BindingFlags.NonPublic | BindingFlags.Instance)!;
var header = headerField.GetValue(entry)!;
var eaProp = header.GetType().GetProperty("ExtendedAttributes", BindingFlags.NonPublic | BindingFlags.Instance)!;
var ea = (Dictionary<string, string>)eaProp.GetValue(header)!;
// Inject GNU.sparse.realsize into the internal EA dictionary via UnsafeAccessor, bypassing
// the public ReadOnlyDictionary façade and constructor validation. This allows
// intentionally-invalid archives (negative realsize) to be constructed for tests.
var ea = (Dictionary<string, string>)ReadOnlyDictionaryAccessors<string, string>.GetInnerDictionary((ReadOnlyDictionary<string, string>)entry.ExtendedAttributes);
Comment thread
rzikm marked this conversation as resolved.
ea["GNU.sparse.realsize"] = realSize.ToString();
entry.DataStream = new MemoryStream(rawSparseData);
writer.WriteEntry(entry);
Expand Down Expand Up @@ -546,6 +544,12 @@ private static void VerifyExpandedContent(byte[] buf, long realSize, (long Offse
Assert.Equal(0, buf[i]);
}
}

private static class ReadOnlyDictionaryAccessors<TKey, TValue> where TKey : notnull
{
[UnsafeAccessor(UnsafeAccessorKind.Field, Name = "m_dictionary")]
public static extern ref IDictionary<TKey, TValue> GetInnerDictionary(ReadOnlyDictionary<TKey, TValue> d);
}
}

// Minimal non-seekable stream wrapper for testing.
Expand Down
Loading