Improve the error output that occurs when saving the module

[wwh1004]

Fixes #238

Test code:

using System;
using System.IO;
using dnlib.DotNet;
using dnlib.DotNet.Emit;
using dnlib.DotNet.Writer;

class Program {
	static void Main() {
		Test1();
		Console.ReadKey(true);
	}

	static void Test1() {
		using var module = ModuleDefMD.Load(typeof(Program).Module);
		var type = module.FindNormal("Program");
		var method = type.FindMethod("Test1");

		module.Resources.Add(null);
		// null resource

		type.CustomAttributes.Add(null);
		// null custom attribute

		method.ParamDefs.Add(new ParamDefUser { Constant = new ConstantUser() });
		// null constant

		var body = method.Body;
		for (int i = 0; i < ushort.MaxValue + 10; i++)
			body.Variables.Add(new Local(module.CorLibTypes.Int32));
		// too many locals

		body.Instructions[0] = new Instruction(OpCodes.Ldstr, 123);
		// mismatching operand type

		body.Instructions[1] = new Instruction(OpCodes.Pop);
		body.Instructions[2] = new Instruction(OpCodes.Pop);
		// evaluation stack overflow

		Test2();
		type.Remove(type.FindMethod("Test2"));
		// removed method but still referenced

		using var output = new MemoryStream();
		var writerOptions = new ModuleWriterOptions(module) { Logger = new Logger() };
		module.Write(output, writerOptions);
	}

	static void Test2() {
	}

	class Logger : ILogger {
		int count = 0;

		public bool IgnoresEvent(LoggerEvent loggerEvent) {
			return loggerEvent != LoggerEvent.Error && loggerEvent != LoggerEvent.Warning;
		}

		public void Log(object sender, LoggerEvent loggerEvent, string format, params object[] args) {
			Console.WriteLine($"{++count}. {string.Format(format, args)}");
			Console.WriteLine();
		}
	}
}

Before:

1. Constant is null

2. Custom attribute is null

3. Resource is null

4. Error calculating max stack value. If the method's obfuscated, set CilBody.KeepOldMaxStack or MetadataOptions.Flags (KeepOldMaxStack, global option) to ignore this error. Otherwise fix your generated CIL code so it conforms to the ECMA standard. At method System.Void Program::Test1() (06000002).

5. Too many locals, max number of locals is 65535 (0xFFFF)

6. Invalid instruction operand

7. Method System.Void Test2() (06000003) is not defined in this module (dnlib-test.dll). A method was removed that is still referenced by this module.

After:

1. Constant is null. Error occurred after metadata event MemberDefRidsAllocated during writing method 'System.Void Program::Test1()' (0x06000002).

2. Custom attribute is null. Error occurred after metadata event MostTablesSorted during writing type 'Program' (0x02000002).

3. Resource is null. Error occurred after metadata event BeginAddResources.

4. Error calculating max stack value. If the method's obfuscated, set CilBody.KeepOldMaxStack or MetadataOptions.Flags (KeepOldMaxStack, global option) to ignore this error. Otherwise fix your generated CIL code so it conforms to the ECMA standard. Error occurred after metadata event BeginWriteMethodBodies during writing method 'System.Void Program::Test1()' (0x06000002).

5. Too many locals, max number of locals is 65535 (0xFFFF). Error occurred after metadata event BeginWriteMethodBodies during writing method 'System.Void Program::Test1()' (0x06000002).

6. Invalid instruction operand. Error occurred after metadata event BeginWriteMethodBodies during writing method 'System.Void Program::Test1()' (0x06000002).

7. Method 'System.Void Test2()' (0x06000003) is not defined in this module 'dnlib-test.dll'. A method was removed that is still referenced by this module. Error occurred after metadata event BeginWriteMethodBodies during writing method 'System.Void Program::Test1()' (0x06000002).

If allows break changes in new major version, is it possible to merge IWriterError2 into IWriterError and delete Extensions.Error2? I think code can be more clear in that case.
https://github.com/wwh1004/dnlib/blob/a9bb8f9e7514504e22b9d98d2ac625d5b4d975bb/src/DotNet/Writer/IWriterError.cs#L39

[wtfsck]

I'll check this later when I have more time. I just had a very quick check.

• I think this fixes Show more information. #238 , and if so add Fixes #238 to your first post.
• I think the responsibility of adding the . is in the other code, not the callers of Error(). There will be less changes and we won't forget to add a period in the future if we add another error.

[wtfsck]

Looks good, just a few problems, including the extra ".".

[wtfsck]

See also my comments here: #447 (comment)

[CreateAndInject]

@wtfsck Could you complete this PR yourself or bump version without this PR? We need other updates. This PR is sended more than 2 months, maybe @wwh1004 has stopped working on it.

[wtfsck]

@wwh1004 are you still working on this PR?

[wwh1004]

@wwh1004 are you still working on this PR?
I will update it these days.

[wwh1004]

Updated

[wwh1004]

Updated

[wtfsck]

Thanks!