Introduce ICustomDiagnosticMessage to allow for custom string formatting

This fixes issue #933, effectively.

1 files changed, 45 insertions, 0 deletions

diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/ForeignMessagePartial.cs b/csharp/src/Google.Protobuf.Test/TestProtos/ForeignMessagePartial.cs
new file mode 100644
index 00000000..5663a699
--- /dev/null
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/ForeignMessagePartial.cs
@@ -0,0 +1,45 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2016 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+namespace Google.Protobuf.TestProtos
+{
+    /// <summary>
+    /// A message with custom diagnostics (to test that they work).
+    /// </summary>
+    public partial class ForeignMessage : ICustomDiagnosticMessage
+    {
+        public string ToDiagnosticString()
+        {
+            return $"{{ \"c\": {C}, \"@cInHex\": \"{C:x}\" }}";
+        }
+    }
+}