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[generator] Fix NRE when interfaces appear to implement classes. #798

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Merged
jonpryor merged 1 commit into from
Feb 12, 2021
Merged

[generator] Fix NRE when interfaces appear to implement classes. #798

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38 changes: 38 additions & 0 deletions tests/generator-Tests/Unit-Tests/CodeGeneratorTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -229,6 +229,44 @@ public void SupportedOSPlatform ()

StringAssert.DoesNotContain ("[global::System.Runtime.Versioning.SupportedOSPlatformAttribute (\"android30.0\")]", builder.ToString (), "Should contain SupportedOSPlatform!");
}

[Test]
public void InheritedInterfaceAsClass ()
{
// This is a somewhat cheating way to repro a real issue.
// The real issue is:
// - Binding an interface which implements 'android.provider.BaseColumns'
// - android.provider.BaseColumns is an interface in android.jar
// - Mono.Android.dll has both:
// - [Register ("android.provider.BaseColumns")] public abstract class BaseColumns
// - [Register ("android.provider.BaseColumns")] public interface IBaseColumns
// Our Java type resolution is "last one wins" and happens to pick the class instead of
// the interface. So our code is trying to bind an interface that implements a class.
var xml = @"<api>
<package name='java.lang' jni-name='java/lang'>
<class abstract='false' deprecated='not deprecated' final='false' name='Object' static='false' visibility='public' jni-signature='Ljava/lang/Object;' />
</package>
<package name='com.xamarin.android' jni-name='com/xamarin/android'>
<class abstract='false' deprecated='not deprecated' extends='java.lang.Object' extends-generic-aware='java.lang.Object' final='false' name='MyConsts' static='false' visibility='public' jni-signature='Ljava/lang/Object;' />
<interface abstract='false' deprecated='not deprecated' extends='java.lang.Object' extends-generic-aware='java.lang.Object' jni-extends='Ljava/lang/Object;' final='false' name='MyClass' static='false' visibility='public' jni-signature='Lcom/xamarin/android/MyClass;'>
<implements name='com.xamarin.android.MyConsts' name-generic-aware='com.xamarin.android.MyConsts' jni-type='Lcom/xamarin/android/MyConsts;'></implements>
</interface>
</package>
</api>";

var gens = ParseApiDefinition (xml);

// Disable "BuildingCoreAssembly"
(gens.Single (g => g.Name == "Object") as ClassGen).FromXml = false;

var klass = gens.Single (g => g.Name == "IMyClass");

generator.Context.ContextTypes.Push (klass);
generator.WriteType (klass, string.Empty, new GenerationInfo ("", "", "MyAssembly"));
generator.Context.ContextTypes.Pop ();

Assert.Pass ("WriteType did not NRE");
}
}

[TestFixture]
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6 changes: 5 additions & 1 deletion tools/generator/SourceWriters/BoundInterface.cs
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Expand Up @@ -137,7 +137,11 @@ void AddInheritedInterfaces (InterfaceGen iface, CodeGenerationOptions opt)
foreach (var isym in iface.Interfaces) {
var igen = (isym is GenericSymbol ? (isym as GenericSymbol).Gen : isym) as InterfaceGen;

if (igen.IsConstSugar (opt) || igen.RawVisibility != "public")
// igen *should not* be null here because we *should* only be inheriting interfaces, but
// in the case of constants on that interface we create a C# *class* that is registered for the
// Java *interface*. Thus when we do type resolution, we are actually pointed to the
// Foo abstract class instead of the IFoo interface.
if (igen is null || igen.IsConstSugar (opt) || igen.RawVisibility != "public")
continue;

Implements.Add (opt.GetOutputName (isym.FullName));
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