Ignore .addins files in XML format

Author: CharliePoole

GitVersion.yml

@@ -1,3 +1,4 @@
+next-version: 3.21.0
 mode: ContinuousDelivery
 branches:
   main:

src/NUnitEngine/nunit.engine.core.tests/Internal/AddinsFileTests.cs

@@ -48,6 +48,25 @@ public void Read_Stream()
             }
         }
 
+        [Test]
+        public void Read_AddinsFileIsNotOurs()
+        {
+            var content = new[]
+            {
+                "Anything",
+                "<SomeXml>",
+                "  We don't understand this",
+                "</SomeXml>",
+                "More stuff"
+            };
+
+            using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(string.Join(Environment.NewLine, content))))
+            {
+                var result = AddinsFile.Read(stream);
+                Assert.That(result.Count, Is.Zero);
+            }
+        }
+
         [Test]
         public void Read_InvalidEntry()
         {

src/NUnitEngine/nunit.engine.core/DotNetHelper.cs

@@ -34,13 +34,6 @@ public static class DotNet
         private static Lazy<List<RuntimeInfo>> _x64Runtimes = new Lazy<List<RuntimeInfo>>(() => [.. GetAllRuntimes(x86: false)]);
         private static Lazy<List<RuntimeInfo>> _x86Runtimes = new Lazy<List<RuntimeInfo>>(() => [.. GetAllRuntimes(x86: true)]);
 
-        public enum Architecture
-        {
-            Unspecified,
-            X64,
-            X86
-        }
-
         public class RuntimeInfo
         {
             public string Name;

src/NUnitEngine/nunit.engine.core/Internal/AddinsFile.cs

@@ -13,6 +13,8 @@ namespace NUnit.Engine.Internal
 {
     internal class AddinsFile : List<AddinsFileEntry>
     {
+        static readonly Logger log = InternalTrace.GetLogger(typeof(AddinsFile));
+
         public static AddinsFile Read(IFile file)
         {
             if (file == null)
@@ -33,29 +35,55 @@ public static AddinsFile Read(IFile file)
         /// <remarks>If the executing system uses backslashes ('\') to separate directories, these will be substituted with slashes ('/').</remarks>
         internal static AddinsFile Read(Stream stream, string fullName = null)
         {
+            // Read the whole file first
+            var content = new List<string>();
             using (var reader = new StreamReader(stream))
+            { 
+                while (!reader.EndOfStream)
+                    content.Add(reader.ReadLine().Trim());
+            }
+
+            // Create an empty AddinsFile, with no entries
+            var addinsFile = new AddinsFile();
+
+            // Ensure that this is actually an NUnit .addins file, since
+            // the extension is used by others. See, for example,
+            // https://github.com/nunit/nunit-console/issues/1761
+            // TODO: Consider using an extension specific to NUnit for V4
+            if (!IsNUnitAddinsFile(content))
             {
-                var addinsFile = new AddinsFile();
+                log.Warning($"Ignoring file {fullName} because it's not an NUnit .addins file");
+                return addinsFile;
+            }
 
-                int lineNumber = 0;
-                while (!reader.EndOfStream)
+            // It's our file, so process it
+            int lineNumber = 0;
+            foreach (var line in content)
+            {
+                var entry = new AddinsFileEntry(++lineNumber, line);
+                if (entry.Text != "" && !entry.IsValid)
                 {
-                    var entry = new AddinsFileEntry(++lineNumber, reader.ReadLine());
-                    if (entry.Text != "" && !entry.IsValid)
-                    {
-                        string msg = $"Invalid Entry in {fullName ?? "addins file"}:\r\n  {entry}";
-                        throw new InvalidOperationException(msg);
-                    }
-
-                    addinsFile.Add(entry);
+                    string msg = $"Invalid Entry in {fullName ?? "addins file"}:\r\n  {entry}";
+                    throw new InvalidOperationException(msg);
                 }
 
-                return addinsFile;
+                addinsFile.Add(entry);
             }
+
+            return addinsFile;
         }
 
         private AddinsFile() { }
 
+        private static bool IsNUnitAddinsFile(List<string> content)
+        {
+            foreach (var line in content)
+                if (line.Length > 0 && line[0] == '<')
+                    return false;
+
+            return true;
+        }
+
         public override string ToString()
         {
             var sb = new StringBuilder("AddinsFile:");