Open file via FileStream with ReadWrite sharing (#743)

* Open file via FileStream with ReadWrite sharing

Replace File.OpenText(path) with a FileStream using FileMode.Open, FileAccess.Read and FileShare.ReadWrite, then wrap it in a StreamReader. This allows reading files that may be concurrently written to by other processes while preserving the existing Read(...) behavior.

* Update Directory.Build.props

Author: SimonCropp

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
   <PropertyGroup>
     <NoWarn>CS1591;NU1608;NU1109</NoWarn>
-    <Version>28.0.1</Version>
+    <Version>28.0.2</Version>
     <LangVersion>preview</LangVersion>
     <AssemblyVersion>1.0.0</AssemblyVersion>
     <PackageTags>Markdown, Snippets, mdsnippets, documentation, MarkdownSnippets</PackageTags>
@@ -16,4 +16,4 @@
   <ItemGroup>
     <Using Include="System.ReadOnlySpan&lt;System.Char&gt;" Alias="CharSpan" />
   </ItemGroup>
-</Project>
+</Project>

src/MarkdownSnippets/Reading/FileSnippetExtractor.cs

@@ -101,7 +101,8 @@ public static IEnumerable<Snippet> Read(string path, int maxWidth = int.MaxValue
             return [];
         }
 
-        using var reader = File.OpenText(path);
+        using var stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+        using var reader = new StreamReader(stream);
         return Read(reader, path, maxWidth, newLine).ToList();
     }
 

src/Tests/SnippetExtractor/SnippetExtractorTests.CanReadFileWhileLockedByAnotherProcess.verified.txt

@@ -0,0 +1,10 @@
+[
+  {
+    Key: CodeKey,
+    Language: cs,
+    Value: The Code,
+    Error: ,
+    FileLocation: LockedFile.cs(1-3),
+    IsInError: false
+  }
+]

src/Tests/SnippetExtractor/SnippetExtractorTests.cs

@@ -39,6 +39,29 @@ await Verify(snippets)
         }
     }
 
+    [Fact]
+    public Task CanReadFileWhileLockedByAnotherProcess()
+    {
+        var temp = Path.Combine(Path.GetTempPath(), "LockedSnippetFile.cs");
+        try
+        {
+            File.WriteAllText(temp,
+                """
+                #region CodeKey
+                The Code
+                #endregion
+                """);
+            using var lockingStream = new FileStream(temp, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
+            var snippets = FileSnippetExtractor.Read(temp);
+            return Verify(snippets)
+                .AddScrubber(_ => _.Replace(temp, "LockedFile.cs"));
+        }
+        finally
+        {
+            File.Delete(temp);
+        }
+    }
+
     [Fact]
     public Task CanExtractWithInnerWhiteSpace()
     {