Fixed explicitly applied maxstack being ignored.

Author: kekyo

Mono.Cecil.Cil/CodeWriter.cs

@@ -341,7 +341,9 @@ void ComputeHeader ()
 			}
 
 			body.code_size = offset;
-			body.max_stack_size = max_stack;
+			if (body.max_stack_size == 0) {
+				body.max_stack_size = max_stack;
+			}
 		}
 
 		void ComputeExceptionHandlerStackSize (ref Dictionary<Instruction, int> stack_sizes)

Test/Mono.Cecil.Tests/MethodBodyTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.IO;
 using System.Linq;
 
 using Mono.Cecil;
@@ -449,5 +450,31 @@ public void RemoveInstruction ()
 			Assert.AreEqual (first, third.Previous);
 			Assert.IsNull (third.Next);
 		}
+
+		[Test]
+		public void ApplyExplicitMaxStack ()
+		{
+			var path = Path.GetTempFileName ();
+			var module = ModuleDefinition.CreateModule ("FooFoo", ModuleKind.Dll);
+
+			var method = new MethodDefinition ("foo", MethodAttributes.Static, module.TypeSystem.Void);
+			var body = method.Body;
+
+			body.MaxStackSize = 100;
+
+			var il = body.GetILProcessor ();
+
+			var ret = il.Create (OpCodes.Ret);
+			body.Instructions.Add (ret);
+
+			var type = new TypeDefinition ("foo", "foo", TypeAttributes.Public | TypeAttributes.Class, module.TypeSystem.Object);
+			type.Methods.Add (method);
+			module.Types.Add (type);
+
+			module.Write (path);
+
+			using (var read_module = ModuleDefinition.ReadModule (path))
+				Assert.AreEqual (100, read_module.Types [1].Methods[0].Body.MaxStackSize);
+		}
 	}
 }