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jonpryorjonpryor
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[Xamarin.Android.Tools.Bytecode] Support @jvmoverloads (#651)
@moljac ran into an interesting warning from `class-parse` when binding [OfficeUIFrabric][0]: warning : class-parse: warning: method com/microsoft/officeuifabric/widget/BottomNavigationView.<init>(Landroid/content/Context;)V: Local variables array has 0 entries ('LocalVariableTableAttribute(LocalVariableTableEntry(Name='context', Descriptor='Landroid/content/Context;'))'); descriptor has 1 entries! For starters, this shouldn't be a warning; it's not actionable. There is nothing a user can do to fix this warning; it's only meaningful to the Java.Interop team. Update `Xamarin.Android.Tools.Bytecode.MethodInfo.GetParameters()` so that these messages are *debug* messages, not warnings. `class-parse` knows how many parameters are present based on the JNI method descriptor, in this case `(Landroid/content/Context;)V`, which specifies one parameter type. The JNI descriptor *doesn't* contain parameter name information; where do parameter names come from? If the `.class` file was built via `javac -parameters`, then the `MethodParametersAttribute` blob can be used; see 4273e5c. However, before checking for `MethodParametersAttribute`, `class-parse` will attempt to use the `LocalVariableTableAttribute` and `LocalVariableTableEntry` values to infer parameter names. As part of this inference, method parameters are assumed to be variables with `LocalVariableTableEntry.StartPC` is 0; from `class-parse --dump BottomNavigationView.class`: LocalVariableTableAttribute( LocalVariableTableEntry(Name='context', Descriptor='Landroid/content/Context;', StartPC=0, Index=1)) Next, `class-parse` will "skip" the first variable for instance methods. This results in "skipping" the `context` variable, resulting in the message: Local variables array has 0 entries …; descriptor has 1 entries! To fix this, `class-parse` needs a stricter "skip the `this` parameter" check: the first parameter should *only* be skipped when: 1. The method is an instance method, not a `static` method, *and* 2. The JNI descriptor of the first parameter is the same as the descriptor of the declaring type. Additionally, update the code style to use `enumValue.HasFlag(V)` instead of `(enumValue & V) == V` for readability. Finally, why was this failing in the first place? In some circumstances, when the Kotlin [`@JvmOverloads`][2] annotation is used on a `constructor`, Kotlin will emit all possible overloads for the constructor, and in many of those overloads the `this` parameter *won't* be present in the `LocalVariableTableAttribute` data, as seen above with `BottomNavigationView`. [0]: https://jcenter.bintray.com/com/microsoft/uifabric/OfficeUIFabric/ [1]: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.jvm/-jvm-overloads/
1 parent b00e644 commit 4b266fa

8 files changed

Lines changed: 284 additions & 7 deletions

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‎src/Xamarin.Android.Tools.Bytecode/AttributeInfo.cs‎

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@@ -429,7 +429,7 @@ public string Descriptor {
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publicoverridestringToString()
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{
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returnstring.Format("LocalVariableTableEntry(Name='{0}', Descriptor='{1}')",Name,Descriptor);
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return$"LocalVariableTableEntry(Name='{Name}', Descriptor='{Descriptor}', StartPC={StartPC}, Index={Index})";
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}
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}
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‎src/Xamarin.Android.Tools.Bytecode/ClassFile.cs‎

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@@ -98,6 +98,8 @@ public string PackageName {
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}
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}
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publicstringFullJniName=>"L"+ThisClass.Name.Value+";";
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publicstringSourceFileName{
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get{
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varsourceFile=Attributes.Get<SourceFileAttribute>();

‎src/Xamarin.Android.Tools.Bytecode/Methods.cs‎

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@@ -90,17 +90,21 @@ public ParameterInfo[] GetParameters ()
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if(locals!=null){
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varnames=locals.LocalVariables.Where(p =>p.StartPC==0).ToList();
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intstart=0;
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if((AccessFlags&MethodAccessFlags.Static)==0)
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if(names.Count!=parameters.Length&&
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!AccessFlags.HasFlag(MethodAccessFlags.Static)&&
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names.Count>start&&
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names[start].Descriptor==DeclaringType.FullJniName){
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start++;// skip `this` parameter
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}
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if(!DeclaringType.IsStatic&&
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names.Count>start&&
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(parameters.Length==0||parameters[0].Type.BinaryName!=names[start].Descriptor)){
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start++;// JDK 8?
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}
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if(((AccessFlags&MethodAccessFlags.Synthetic)!=MethodAccessFlags.Synthetic)&&
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if(!AccessFlags.HasFlag(MethodAccessFlags.Synthetic)&&
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((names.Count-start)!=parameters.Length)&&
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!enumCtor){
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Log.Warning(1,"class-parse: warning: method {0}.{1}{2}: "+
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Log.Debug("class-parse: method {0}.{1}{2}: "+
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"Local variables array has {3} entries ('{4}'); descriptor has {5} entries!",
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DeclaringType.ThisClass.Name.Value,Name,Descriptor,
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names.Count-start,
@@ -111,7 +115,7 @@ public ParameterInfo[] GetParameters ()
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for(inti=0;i<max;++i){
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parameters[i].Name=names[start+i].Name;
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if(parameters[i].Type.BinaryName!=names[start+i].Descriptor){
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Log.Warning(1,"class-parse: warning: method {0}.{1}{2}: "+
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Log.Debug("class-parse: method {0}.{1}{2}: "+
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"Local variable type descriptor mismatch! Got '{3}'; expected '{4}'.",
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DeclaringType.ThisClass.Name.Value,Name,Descriptor,
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parameters[i].Type.BinaryName,
@@ -122,7 +126,7 @@ public ParameterInfo[] GetParameters ()
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varsig=GetSignature();
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if(sig!=null){
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if((sig.Parameters.Count!=parameters.Length)&&!enumCtor){
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Log.Warning(1,"class-parse: warning: method {0}.{1}{2}: "+
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Log.Debug("class-parse: method {0}.{1}{2}: "+
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"Signature ('{3}') has {4} entries; Descriptor '{5}' has {6} entries!",
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DeclaringType.ThisClass.Name.Value,Name,Descriptor,
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Attributes.Get<SignatureAttribute>(),

‎src/Xamarin.Android.Tools.Bytecode/XmlClassDeclarationBuilder.cs‎

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@@ -39,7 +39,7 @@ public XElement ToXElement ()
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GetExtendsGenericAware(),
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newXAttribute("final",(classFile.AccessFlags&ClassAccessFlags.Final)!=0),
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newXAttribute("name",GetThisClassName()),
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newXAttribute("jni-signature","L"+classFile.ThisClass.Name.Value+";"),
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newXAttribute("jni-signature",classFile.FullJniName),
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GetSourceFile(),
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newXAttribute("static",classFile.IsStatic),
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newXAttribute("visibility",GetVisibility(classFile.Visibility)),

‎tests/Xamarin.Android.Tools.Bytecode-Tests/JvmOverloadsConstructorTests.cs‎

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usingSystem;
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usingSystem.Collections.Generic;
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usingSystem.Linq;
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usingXamarin.Android.Tools.Bytecode;
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usingNUnit.Framework;
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usingAssembly=System.Reflection.Assembly;
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namespaceXamarin.Android.Tools.BytecodeTests{
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[TestFixture]
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publicclassJvmOverloadsConstructorTests:ClassFileFixture{
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conststringClassFile="JvmOverloadsConstructor.class";
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conststringXmlFile="JvmOverloadsConstructor.xml";
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[Test]
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publicvoidClassFile_WithJavaType_class()
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{
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varc=LoadClassFile(ClassFile);
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newExpectedTypeDeclaration{
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MajorVersion=0x32,
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MinorVersion=0,
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ConstantPoolCount=59,
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AccessFlags=ClassAccessFlags.Public|ClassAccessFlags.Final|ClassAccessFlags.Super,
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FullName="JvmOverloadsConstructor",
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Superclass=newTypeInfo("java/lang/Object","Ljava/lang/Object;"),
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Methods={
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newExpectedMethodDeclaration{
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Name="<init>",
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AccessFlags=MethodAccessFlags.Public,
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ReturnDescriptor="V",
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Parameters={
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newParameterInfo("something","LJvmOverloadsConstructor;","LJvmOverloadsConstructor;"),
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newParameterInfo("id","I","I"),
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newParameterInfo("imageId","I","I"),
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newParameterInfo("title","Ljava/lang/String;","Ljava/lang/String;"),
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newParameterInfo("useDivider","Z","Z"),
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},
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},
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newExpectedMethodDeclaration{
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Name="<init>",
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AccessFlags=MethodAccessFlags.Public|MethodAccessFlags.Synthetic,
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ReturnDescriptor="V",
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Parameters={
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newParameterInfo("p0","LJvmOverloadsConstructor;","LJvmOverloadsConstructor;"),
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newParameterInfo("p1","I","I"),
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newParameterInfo("p2","I","I"),
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newParameterInfo("p3","Ljava/lang/String;","Ljava/lang/String;"),
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newParameterInfo("p4","Z","Z"),
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newParameterInfo("p5","I","I"),
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newParameterInfo("p6","Lkotlin/jvm/internal/DefaultConstructorMarker;","Lkotlin/jvm/internal/DefaultConstructorMarker;"),
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},
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},
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newExpectedMethodDeclaration{
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Name="<init>",
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AccessFlags=MethodAccessFlags.Public,
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ReturnDescriptor="V",
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Parameters={
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newParameterInfo("something","LJvmOverloadsConstructor;","LJvmOverloadsConstructor;"),
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newParameterInfo("id","I","I"),
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newParameterInfo("imageId","I","I"),
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newParameterInfo("title","Ljava/lang/String;","Ljava/lang/String;"),
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},
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},
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newExpectedMethodDeclaration{
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Name="<init>",
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AccessFlags=MethodAccessFlags.Public,
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ReturnDescriptor="V",
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Parameters={
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newParameterInfo("something","LJvmOverloadsConstructor;","LJvmOverloadsConstructor;"),
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newParameterInfo("id","I","I"),
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newParameterInfo("title","Ljava/lang/String;","Ljava/lang/String;"),
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},
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},
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newExpectedMethodDeclaration{
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Name="<init>",
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AccessFlags=MethodAccessFlags.Public,
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ReturnDescriptor="V",
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Parameters={
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newParameterInfo("something","LJvmOverloadsConstructor;","LJvmOverloadsConstructor;"),
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newParameterInfo("title","Ljava/lang/String;","Ljava/lang/String;"),
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},
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},
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},
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}.Assert(c);
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}
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[Test]
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publicvoidXmlDeclaration_WithJavaType_class()
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{
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AssertXmlDeclaration(ClassFile,XmlFile);
95+
}
96+
}
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}
98+

‎tests/Xamarin.Android.Tools.Bytecode-Tests/Resources/JvmOverloadsConstructor.xml‎

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<api
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api-source="class-parse">
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<package
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name=""
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jni-name="">
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<class
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abstract="false"
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deprecated="not deprecated"
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jni-extends="Ljava/lang/Object;"
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extends="java.lang.Object"
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extends-generic-aware="java.lang.Object"
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final="true"
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name="JvmOverloadsConstructor"
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jni-signature="LJvmOverloadsConstructor;"
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source-file-name="JvmOverloadsConstructor.kt"
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static="false"
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visibility="public">
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<constructor
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deprecated="not deprecated"
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final="false"
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name="JvmOverloadsConstructor"
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static="false"
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visibility="public"
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bridge="false"
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synthetic="false"
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jni-signature="(LJvmOverloadsConstructor;IILjava/lang/String;)V">
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<parameter
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name="something"
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type="JvmOverloadsConstructor"
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jni-type="LJvmOverloadsConstructor;"
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not-null="true" />
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<parameter
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name="id"
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type="int"
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jni-type="I" />
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<parameter
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name="imageId"
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type="int"
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jni-type="I" />
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<parameter
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name="title"
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type="java.lang.String"
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jni-type="Ljava/lang/String;"
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not-null="true" />
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</constructor>
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<constructor
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deprecated="not deprecated"
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final="false"
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name="JvmOverloadsConstructor"
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static="false"
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visibility="public"
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bridge="false"
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synthetic="false"
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jni-signature="(LJvmOverloadsConstructor;IILjava/lang/String;Z)V">
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<parameter
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name="something"
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type="JvmOverloadsConstructor"
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jni-type="LJvmOverloadsConstructor;"
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not-null="true" />
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<parameter
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name="id"
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type="int"
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jni-type="I" />
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<parameter
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name="imageId"
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type="int"
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jni-type="I" />
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<parameter
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name="title"
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type="java.lang.String"
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jni-type="Ljava/lang/String;"
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not-null="true" />
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<parameter
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name="useDivider"
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type="boolean"
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jni-type="Z" />
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</constructor>
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<constructor
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deprecated="not deprecated"
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final="false"
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name="JvmOverloadsConstructor"
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static="false"
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visibility="public"
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bridge="false"
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synthetic="true"
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jni-signature="(LJvmOverloadsConstructor;IILjava/lang/String;ZILkotlin/jvm/internal/DefaultConstructorMarker;)V">
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<parameter
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name="p0"
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type="JvmOverloadsConstructor"
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jni-type="LJvmOverloadsConstructor;" />
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<parameter
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name="p1"
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type="int"
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jni-type="I" />
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<parameter
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name="p2"
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type="int"
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jni-type="I" />
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<parameter
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name="p3"
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type="java.lang.String"
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jni-type="Ljava/lang/String;" />
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<parameter
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name="p4"
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type="boolean"
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jni-type="Z" />
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<parameter
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name="p5"
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type="int"
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jni-type="I" />
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<parameter
112+
name="p6"
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type="kotlin.jvm.internal.DefaultConstructorMarker"
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jni-type="Lkotlin/jvm/internal/DefaultConstructorMarker;" />
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</constructor>
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<constructor
117+
deprecated="not deprecated"
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final="false"
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name="JvmOverloadsConstructor"
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static="false"
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visibility="public"
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bridge="false"
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synthetic="false"
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jni-signature="(LJvmOverloadsConstructor;ILjava/lang/String;)V">
125+
<parameter
126+
name="something"
127+
type="JvmOverloadsConstructor"
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jni-type="LJvmOverloadsConstructor;"
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not-null="true" />
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<parameter
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name="id"
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type="int"
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jni-type="I" />
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<parameter
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name="title"
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type="java.lang.String"
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jni-type="Ljava/lang/String;"
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not-null="true" />
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</constructor>
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<constructor
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deprecated="not deprecated"
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final="false"
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name="JvmOverloadsConstructor"
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static="false"
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visibility="public"
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bridge="false"
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synthetic="false"
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jni-signature="(LJvmOverloadsConstructor;Ljava/lang/String;)V">
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<parameter
150+
name="something"
151+
type="JvmOverloadsConstructor"
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jni-type="LJvmOverloadsConstructor;"
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not-null="true" />
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<parameter
155+
name="title"
156+
type="java.lang.String"
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jni-type="Ljava/lang/String;"
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not-null="true" />
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</constructor>
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</class>
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</package>
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</api>

‎tests/Xamarin.Android.Tools.Bytecode-Tests/kotlin/JvmOverloadsConstructor.class‎

1.74 KB
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‎tests/Xamarin.Android.Tools.Bytecode-Tests/kotlin/JvmOverloadsConstructor.kt‎

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classJvmOverloadsConstructor {
2+
@JvmOverloads
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constructor(
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something :JvmOverloadsConstructor,
5+
id:Int=1,
6+
imageId:Int=2,
7+
title:String,
8+
useDivider:Boolean=false
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) {
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}
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}

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