mark log4net.Ext.Mail as CLS compliant (#307)

.github/workflows/build.yaml

@@ -45,7 +45,7 @@ jobs:
         uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332   # 4.1.7
 
       - name: Set up dotnet
-        uses: actions/setup-dotnet@6bd8b7f7774af54e05809fcc5431931b3eb1ddee   # 4.0.1
+        uses: actions/setup-dotnet@a98b56852c35b8e3190ac28c8c2271da59106c68   # 6.0.0
         with:
           dotnet-version: 10
           dotnet-quality: ga

src/Directory.Build.props

@@ -31,4 +31,11 @@
   <ItemGroup>
     <GlobalAnalyzerConfigFiles Include="$(MSBuildThisFileDirectory)log4net.globalconfig" />
   </ItemGroup>
+  <ItemGroup>
+    <!-- Emitted into every project that generates its assembly info, which is the shipping
+         libraries but not the test projects, as those set GenerateAssemblyInfo to false. -->
+    <AssemblyAttribute Include="System.CLSCompliantAttribute">
+      <_Parameter1>true</_Parameter1>
+    </AssemblyAttribute>
+  </ItemGroup>
 </Project>

src/log4net.Ext.Mail/Appender/SmtpAppender.cs

@@ -356,6 +356,13 @@ protected virtual void SendEmail(string messageBody)
   /// </summary>
   /// <param name="messageBody">the body text to include in the mail</param>
   /// <returns>the message to send</returns>
+  /// <remarks>
+  /// <para>
+  /// Not CLS compliant, because <see cref="MimeMessage"/> comes from MimeKit, which does not
+  /// declare itself CLS compliant.
+  /// </para>
+  /// </remarks>
+  [CLSCompliant(false)]
   protected virtual MimeMessage CreateMessage(string messageBody)
   {
     MimeMessage message = new();

src/log4net/AssemblyInfo.cs

@@ -19,7 +19,6 @@
 
 // log4net makes use of static methods which cannot be made com visible
 [assembly: System.Runtime.InteropServices.ComVisible(false)]
-[assembly: System.CLSCompliant(true)]
 // If log4net is strongly named it still allows partially trusted callers
 [assembly: System.Security.AllowPartiallyTrustedCallers]