From eb7e55ac7d20970589006f68f118d71576d06af9 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 14 Feb 2026 10:08:28 +0000
Subject: [PATCH 1/4] Initial plan


From 31c6eb3b5c300fc80cb27f7685a80f7fa222f973 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 14 Feb 2026 10:14:01 +0000
Subject: [PATCH 2/4] Fix NullReferenceException for 7z empty-stream entries

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>
---
 .../Archives/SevenZip/SevenZipArchive.cs      |   6 +++
 src/SharpCompress/packages.lock.json          |  12 +++---
 .../SevenZip/SevenZipArchiveTests.cs          |  35 ++++++++++++++++++
 .../TestArchives/Archives/7Zip.EmptyStream.7z | Bin 0 -> 182 bytes
 4 files changed, 47 insertions(+), 6 deletions(-)
 create mode 100644 tests/TestArchives/Archives/7Zip.EmptyStream.7z

diff --git a/src/SharpCompress/Archives/SevenZip/SevenZipArchive.cs b/src/SharpCompress/Archives/SevenZip/SevenZipArchive.cs
index de0adc98..710e490c 100644
--- a/src/SharpCompress/Archives/SevenZip/SevenZipArchive.cs
+++ b/src/SharpCompress/Archives/SevenZip/SevenZipArchive.cs
@@ -164,6 +164,12 @@ public partial class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, Sev
 
             var folder = entry.FilePart.Folder;
 
+            // If folder is null (empty stream entry), return empty stream
+            if (folder is null)
+            {
+                return CreateEntryStream(Stream.Null);
+            }
+
             // Check if we're starting a new folder - dispose old folder stream if needed
             if (folder != _currentFolder)
             {
diff --git a/src/SharpCompress/packages.lock.json b/src/SharpCompress/packages.lock.json
index 29e7a1bd..27e9e496 100644
--- a/src/SharpCompress/packages.lock.json
+++ b/src/SharpCompress/packages.lock.json
@@ -216,9 +216,9 @@
     "net10.0": {
       "Microsoft.NET.ILLink.Tasks": {
         "type": "Direct",
-        "requested": "[10.0.0, )",
-        "resolved": "10.0.0",
-        "contentHash": "kICGrGYEzCNI3wPzfEXcwNHgTvlvVn9yJDhSdRK+oZQy4jvYH529u7O0xf5ocQKzOMjfS07+3z9PKRIjrFMJDA=="
+        "requested": "[10.0.2, )",
+        "resolved": "10.0.2",
+        "contentHash": "sXdDtMf2qcnbygw9OdE535c2lxSxrZP8gO4UhDJ0xiJbl1wIqXS1OTcTDFTIJPOFd6Mhcm8gPEthqWGUxBsTqw=="
       },
       "Microsoft.NETFramework.ReferenceAssemblies": {
         "type": "Direct",
@@ -264,9 +264,9 @@
     "net8.0": {
       "Microsoft.NET.ILLink.Tasks": {
         "type": "Direct",
-        "requested": "[8.0.22, )",
-        "resolved": "8.0.22",
-        "contentHash": "MhcMithKEiyyNkD2ZfbDZPmcOdi0GheGfg8saEIIEfD/fol3iHmcV8TsZkD4ZYz5gdUuoX4YtlVySUU7Sxl9SQ=="
+        "requested": "[8.0.23, )",
+        "resolved": "8.0.23",
+        "contentHash": "GqHiB1HbbODWPbY/lc5xLQH8siEEhNA0ptpJCC6X6adtAYNEzu5ZlqV3YHA3Gh7fuEwgA8XqVwMtH2KNtuQM1Q=="
       },
       "Microsoft.NETFramework.ReferenceAssemblies": {
         "type": "Direct",
diff --git a/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs b/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
index ea9316e5..9947168e 100644
--- a/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
+++ b/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
@@ -344,4 +344,39 @@ public class SevenZipArchiveTests : ArchiveTests
         // The critical check: within a single folder, the stream should NEVER be recreated
         Assert.Equal(0, streamRecreationsWithinFolder); // Folder stream should remain the same for all entries in the same folder
     }
+
+    [Fact]
+    public void SevenZipArchive_EmptyStream_WriteToDirectory()
+    {
+        // This test specifically verifies that archives with empty-stream entries
+        // (files with size 0 and no compressed data) can be extracted without throwing
+        // NullReferenceException. This was previously failing because the folder was null
+        // for empty-stream entries.
+        var testArchive = Path.Combine(TEST_ARCHIVES_PATH, "7Zip.EmptyStream.7z");
+        using var archive = SevenZipArchive.OpenArchive(testArchive);
+
+        foreach (var entry in archive.Entries)
+        {
+            if (!entry.IsDirectory)
+            {
+                // This should not throw NullReferenceException
+                entry.WriteToDirectory(SCRATCH_FILES_PATH);
+            }
+        }
+
+        // Verify that empty files were created
+        var extractedFiles = Directory.GetFiles(
+            SCRATCH_FILES_PATH,
+            "*",
+            SearchOption.AllDirectories
+        );
+        Assert.NotEmpty(extractedFiles);
+
+        // All extracted files should be empty (0 bytes)
+        foreach (var file in extractedFiles)
+        {
+            var fileInfo = new FileInfo(file);
+            Assert.Equal(0, fileInfo.Length);
+        }
+    }
 }
diff --git a/tests/TestArchives/Archives/7Zip.EmptyStream.7z b/tests/TestArchives/Archives/7Zip.EmptyStream.7z
new file mode 100644
index 0000000000000000000000000000000000000000..c2d9bfa43031f2047e153e162376e0c073e0ee92
GIT binary patch
literal 182
zcmXr7+Ou9=hJi(`KF_<90Rj{u6vNZH2YVP88aH&b<T+(*6^M4zdTbdmv&_ah<aW2A
z=qy|J%&P}BhKEl4AN@c4s{1$bMfz*`^<1<bT=>6hN#I(`FTQF&0_{XUN6Ij?Z(QdX
zWc2P`W7owAJ3LISzu%dx-?f2LyTFp;hI0EGDbpai6EiJe2KZ^pM>R7sh_f*;a+Wf%
eb2Bn9Dl;=Ovc@t9Ffi~ma&a-LKCO7czyJW@x<AtZ

literal 0
HcmV?d00001


From fb70f06fd47768699f0a8229e6b5f5a50468475e Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 14 Feb 2026 10:15:55 +0000
Subject: [PATCH 3/4] Improve empty-stream test to verify HasStream == false
 entries

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>
---
 .../SevenZip/SevenZipArchiveTests.cs              | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs b/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
index 9947168e..0b77c040 100644
--- a/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
+++ b/tests/SharpCompress.Test/SevenZip/SevenZipArchiveTests.cs
@@ -4,6 +4,7 @@ using System.Linq;
 using SharpCompress.Archives;
 using SharpCompress.Archives.SevenZip;
 using SharpCompress.Common;
+using SharpCompress.Common.SevenZip;
 using SharpCompress.Factories;
 using SharpCompress.Readers;
 using Xunit;
@@ -355,15 +356,29 @@ public class SevenZipArchiveTests : ArchiveTests
         var testArchive = Path.Combine(TEST_ARCHIVES_PATH, "7Zip.EmptyStream.7z");
         using var archive = SevenZipArchive.OpenArchive(testArchive);
 
+        var emptyStreamFileCount = 0;
         foreach (var entry in archive.Entries)
         {
             if (!entry.IsDirectory)
             {
+                // Verify this is actually an empty-stream entry (HasStream == false)
+                var sevenZipEntry = entry as SevenZipEntry;
+                if (sevenZipEntry?.FilePart.Header.HasStream == false)
+                {
+                    emptyStreamFileCount++;
+                }
+
                 // This should not throw NullReferenceException
                 entry.WriteToDirectory(SCRATCH_FILES_PATH);
             }
         }
 
+        // Ensure we actually tested empty-stream entries
+        Assert.True(
+            emptyStreamFileCount > 0,
+            "Test archive should contain at least one empty-stream entry"
+        );
+
         // Verify that empty files were created
         var extractedFiles = Directory.GetFiles(
             SCRATCH_FILES_PATH,

From 13fdb4d7ca31d3d5d954cf6f39eef9d5b5989c51 Mon Sep 17 00:00:00 2001
From: Adam Hathcock <adam@hathcock.uk>
Date: Sat, 14 Feb 2026 10:34:12 +0000
Subject: [PATCH 4/4] add better length from master

---
 src/SharpCompress/IO/SharpCompressStream.cs | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/SharpCompress/IO/SharpCompressStream.cs b/src/SharpCompress/IO/SharpCompressStream.cs
index b47b7031..a7c09072 100644
--- a/src/SharpCompress/IO/SharpCompressStream.cs
+++ b/src/SharpCompress/IO/SharpCompressStream.cs
@@ -206,8 +206,22 @@ internal partial class SharpCompressStream : Stream, IStreamStack
         throw new NotSupportedException();
     }
 
-    public override long Length =>
-        _isPassthrough ? stream.Length : throw new NotSupportedException();
+    public override long Length
+    {
+        get
+        {
+            if (_isPassthrough)
+            {
+                return stream.Length;
+            }
+
+            if (_ringBuffer is not null)
+            {
+                return _ringBuffer.Length;
+            }
+            throw new NotSupportedException();
+        }
+    }
 
     public override long Position
     {