[Feature Request] Add support for `AllowUnsafeBlocks` in `properties`

[andywiecko]

Hi,
I would like to request a feature enhancement to add support for the "AllowUnsafeBlocks" within the "properties" section of docfx.json.

According to the documentation, the "properties" section:

Specifies an optional set of MSBuild properties used when interpreting project files. These are the same properties that are passed to MSBuild via the /property:name=value command line argument.

However, it seems that "AllowUnsafeBlocks" is currently not supported. From my understanding, adding support for this would require a small modification in the following file:

docfx/src/Docfx.Dotnet/CompilationHelper.cs

Lines 205 to 212 in 73d8279

	private static CS.CSharpParseOptions GetCSharpParseOptions(IDictionary<string, string> msbuildProperties)
	{
	var preprocessorSymbols = (msbuildProperties.TryGetValue("DefineConstants", out var defineConstants))
	? defineConstants.Split(';', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
	: null;
	return new CS.CSharpParseOptions(preprocessorSymbols: preprocessorSymbols);
	}

Here’s a minimal working example that demonstrates the issue:

• Program.cs

namespace Test
{
    public static class Program
    {
        public static unsafe void Main() { }
    }
}

• docfx.json

{
  "metadata": [
    {
      "src": [{"src": "./", "files": ["Program.cs"]}],
      "dest": "api",
      "properties": { "AllowUnsafeBlocks": true }
    }
  ]
}

Expected behavior:

The api documentation should generate correctly without any errors or warnings.

Current behavior:

The build fails with errors/warnings, (unless one set "allowCompilationErrors": true).

---

Thank you for considering this request. I believe it would be a valuable addition.

Best,
Andrzej