[generator] generator --lang-features=do-not-fix-obsolete-overrides (#1143)

Fixes: #1142
Context: d0231c5
In d0231c5, we added a feature to automatically mark a method as
"deprecated" if it overrides a "deprecated" method.
However, there can be instances where this is undesirable for a user,
and there is currently no way to opt out of this change on a global
or `metadata` level.
Add a global opt-out for this feature, usable via
`generator --lang-features=do-not-fix-obsolete-overrides …`.
This will eventually be made available to users via an MSBuild
property in a separate xamarin/xamarin-android PR.

Author: jpobst

tests/generator-Tests/Unit-Tests/CodeGeneratorTests.cs

@@ -1138,6 +1138,12 @@ public void FixupDeprecatedBaseMethods ()
 
 vargens=ParseApiDefinition(xml);
 
+// Override method should not be marked deprecated because it's: deprecated='not deprecated'
+Assert.IsNull(gens.Single(g =>g.Name=="MyClass").Methods.Single(m =>m.Name=="DoStuff").Deprecated);
+
+options.FixObsoleteOverrides=true;
+gens=ParseApiDefinition(xml);
+
 // Override method should be marked deprecated because base method is
 Assert.AreEqual("deprecated",gens.Single(g =>g.Name=="MyClass").Methods.Single(m =>m.Name=="DoStuff").Deprecated);
 }
@@ -1158,6 +1164,7 @@ public void FixupDeprecatedSinceBaseMethods ()
  </package>
  </api>";
 
+options.FixObsoleteOverrides=true;
 vargens=ParseApiDefinition(xml);
 
 // Override method should match base method's 'deprecated-since'

tools/generator/CodeGenerationOptions.cs

@@ -65,6 +65,7 @@ public SymbolTable SymbolTable {
 publicboolUseShallowReferencedTypes{get;set;}
 publicboolUseObsoletedOSPlatformAttributes{get;set;}
 publicboolUseRestrictToAttributes{get;set;}
+publicboolFixObsoleteOverrides{get;set;}
 publicboolRemoveConstSugar=>BuildingCoreAssembly;
 
 bool?buildingCoreAssembly;

tools/generator/CodeGenerator.cs

@@ -85,6 +85,7 @@ static void Run (CodeGeneratorOptions options, DirectoryAssemblyResolver resolve
 SupportNullableReferenceTypes=options.SupportNullableReferenceTypes,
 UseObsoletedOSPlatformAttributes=options.UseObsoletedOSPlatformAttributes,
 UseRestrictToAttributes=options.UseRestrictToAttributes,
+FixObsoleteOverrides=options.FixObsoleteOverrides,
 };
 varresolverCache=newTypeDefinitionCache();
 

tools/generator/CodeGeneratorOptions.cs

@@ -53,6 +53,7 @@ public CodeGeneratorOptions ()
 publicboolSupportNestedInterfaceTypes{get;set;}
 publicboolSupportNullableReferenceTypes{get;set;}
 publicboolUseRestrictToAttributes{get;set;}
+publicboolFixObsoleteOverrides{get;set;}=true;
 publicboolUseLegacyJavaResolver{get;set;}
 publicboolUseObsoletedOSPlatformAttributes{get;set;}
 
@@ -104,14 +105,15 @@ public static CodeGeneratorOptions Parse (string[] args)
 "SDK Platform {VERSION}/API level.",
  v =>opts.ApiLevel=v},
 {"lang-features=",
-"For internal use. (Flags: interface-constants,default-interface-methods,nested-interface-types,nullable-reference-types,obsoleted-platform-attributes,restrict-to-attributes)",
+"For internal use. (Flags: interface-constants,default-interface-methods,nested-interface-types,nullable-reference-types,obsoleted-platform-attributes,restrict-to-attributes,do-not-fix-obsolete-overrides)",
  v =>{
 opts.SupportInterfaceConstants=v?.Contains("interface-constants")==true;
 opts.SupportDefaultInterfaceMethods=v?.Contains("default-interface-methods")==true;
 opts.SupportNestedInterfaceTypes=v?.Contains("nested-interface-types")==true;
 opts.SupportNullableReferenceTypes=v?.Contains("nullable-reference-types")==true;
 opts.UseObsoletedOSPlatformAttributes=v?.Contains("obsoleted-platform-attributes")==true;
 opts.UseRestrictToAttributes=v?.Contains("restrict-to-attributes")==true;
+opts.FixObsoleteOverrides=v?.Contains("do-not-fix-obsolete-overrides")==false;
 }},
 {"preserve-enums",
 "For internal use.",

tools/generator/Java.Interop.Tools.Generator.ObjectModel/GenBase.cs

@@ -311,13 +311,15 @@ public void FixupMethodOverrides (CodeGenerationOptions opt)
 if(bm!=null&&bm.RetVal.FullName==m.RetVal.FullName){// if return type is different, it could be still "new", not "override".
 m.IsOverride=true;
 
-// If method overrides a deprecated method, it also needs to be marked as deprecated
-if(bm.Deprecated.HasValue()&&!m.Deprecated.HasValue())
-m.Deprecated=bm.Deprecated;
-
-// Fix issue when base method was deprecated before the overriding method, set both both to base method value
-if(bm.DeprecatedSince.GetValueOrDefault(0)<m.DeprecatedSince.GetValueOrDefault(0))
-m.DeprecatedSince=bm.DeprecatedSince;
+if(opt.FixObsoleteOverrides){
+// If method overrides a deprecated method, it also needs to be marked as deprecated
+if(bm.Deprecated.HasValue()&&!m.Deprecated.HasValue())
+m.Deprecated=bm.Deprecated;
+
+// Fix issue when base method was deprecated before the overriding method, set both both to base method value
+if(bm.DeprecatedSince.GetValueOrDefault(0)<m.DeprecatedSince.GetValueOrDefault(0))
+m.DeprecatedSince=bm.DeprecatedSince;
+}
 
 break;
 }