From c783a83a9c8a8c174e09faf8a220cb901b4d156f Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 29 Nov 2025 13:32:01 +0000
Subject: [PATCH] Address code review feedback for ACE archive support

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>
---
 src/SharpCompress/Common/Ace/AceFilePart.cs | 40 ++++++++++-----------
 src/SharpCompress/Readers/Ace/AceReader.cs  | 13 +++----
 2 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/src/SharpCompress/Common/Ace/AceFilePart.cs b/src/SharpCompress/Common/Ace/AceFilePart.cs
index 962d173d..21506be5 100644
--- a/src/SharpCompress/Common/Ace/AceFilePart.cs
+++ b/src/SharpCompress/Common/Ace/AceFilePart.cs
@@ -24,29 +24,27 @@ public class AceFilePart : FilePart
 
     internal override Stream GetCompressedStream()
     {
-        if (_stream != null)
+        if (_stream is null)
         {
-            Stream compressedStream;
-            switch (Header.CompressionMethod)
-            {
-                case CompressionType.None:
-                    // Stored - no compression
-                    compressedStream = new ReadOnlySubStream(
-                        _stream,
-                        Header.DataStartPosition,
-                        Header.CompressedSize
-                    );
-                    break;
-                default:
-                    // ACE uses proprietary compression methods that are not publicly documented
-                    // For now, we throw an exception for compressed entries
-                    throw new NotSupportedException(
-                        $"ACE compression method '{Header.CompressionMethod}' is not supported. Only stored (uncompressed) entries can be extracted."
-                    );
-            }
-            return compressedStream;
+            throw new InvalidOperationException("Stream is not available.");
+        }
+
+        switch (Header.CompressionMethod)
+        {
+            case CompressionType.None:
+                // Stored - no compression
+                return new ReadOnlySubStream(
+                    _stream,
+                    Header.DataStartPosition,
+                    Header.CompressedSize
+                );
+            default:
+                // ACE uses proprietary compression methods that are not publicly documented
+                // For now, we throw an exception for compressed entries
+                throw new NotSupportedException(
+                    $"ACE compression method '{Header.CompressionMethod}' is not supported. Only stored (uncompressed) entries can be extracted."
+                );
         }
-        return _stream.NotNull();
     }
 
     internal override Stream? GetRawStream() => _stream;
diff --git a/src/SharpCompress/Readers/Ace/AceReader.cs b/src/SharpCompress/Readers/Ace/AceReader.cs
index 3105902b..f64480e8 100644
--- a/src/SharpCompress/Readers/Ace/AceReader.cs
+++ b/src/SharpCompress/Readers/Ace/AceReader.cs
@@ -13,14 +13,14 @@ namespace SharpCompress.Readers.Ace;
 /// </summary>
 public class AceReader : AbstractReader<AceEntry, AceVolume>
 {
-    private readonly AceEntryHeader _headerReader;
+    private readonly AceEntryHeader _mainHeaderReader;
     private bool _mainHeaderRead;
 
     private AceReader(Stream stream, ReaderOptions options)
         : base(options, ArchiveType.Ace)
     {
         Volume = new AceVolume(stream, options, 0);
-        _headerReader = new AceEntryHeader(Options.ArchiveEncoding);
+        _mainHeaderReader = new AceEntryHeader(Options.ArchiveEncoding);
     }
 
     public override AceVolume Volume { get; }
@@ -42,17 +42,18 @@ public class AceReader : AbstractReader<AceEntry, AceVolume>
         // First, skip past the main header if we haven't already
         if (!_mainHeaderRead)
         {
-            if (!_headerReader.ReadMainHeader(stream))
+            if (!_mainHeaderReader.ReadMainHeader(stream))
             {
                 yield break;
             }
             _mainHeaderRead = true;
         }
 
-        // Read file entries
-        AceEntryHeader headerReader = new AceEntryHeader(Options.ArchiveEncoding);
+        // Read file entries - create new header reader for each entry
+        // since ReadHeader modifies the object state
+        AceEntryHeader entryHeaderReader = new AceEntryHeader(Options.ArchiveEncoding);
         AceEntryHeader? header;
-        while ((header = headerReader.ReadHeader(stream)) != null)
+        while ((header = entryHeaderReader.ReadHeader(stream)) != null)
         {
             yield return new AceEntry(new AceFilePart(header, stream));
         }