[Bug]: Can't parse inner classes located in methods

[hunterpayne]

Describe the bug

Java allows inner classes inside of methods now. It appears that Spoon won't parse this construct correctly yet. Is this supported yet? Is this on the roadmap?

Source code you are trying to analyze/transform

public class Foo {
   private static final Stats$1 extractStats$1(final String line, final Regex apacheLogRegex$1) {
      Option var3 = apacheLogRegex$1.findFirstIn(line);

      class Stats$1 implements Serializable {
         private final int count;
         private final int numBytes;

         public int count() {
            return this.count;
         }

         public int numBytes() {
            return this.numBytes;
         }

         public Stats$1 merge(final Stats$1 other) {
            return new Stats$1(this.count() + other.count(), this.numBytes() + other.numBytes());
         }

         public String toString() {
            return StringOps$.MODULE$.format$extension(Predef$.MODULE$.augmentString("bytes=%s\tn=%s"), ScalaRunTime$.MODULE$.genericWrapArray(new Object[]{BoxesRunTime.boxToInteger(this.numBytes()), BoxesRunTime.boxToInteger(this.count())}));
         }

         public Stats$1(final int count, final int numBytes) {
            this.count = count;
            this.numBytes = numBytes;
         }
      }

      if (var3 instanceof Some) {
         Some var4 = (Some)var3;
         String var5 = (String)var4.value();
         if (var5 != null) {
            Option var6 = apacheLogRegex$1.unapplySeq(var5);
            if (!var6.isEmpty() && var6.get() != null && ((List)var6.get()).lengthCompare(9) == 0) {
               String bytes = (String)((LinearSeqOps)var6.get()).apply(6);
               return new Stats$1(1, StringOps$.MODULE$.toInt$extension(Predef$.MODULE$.augmentString(bytes)));
            }
         }
      }

      return new Stats$1(1, 0);
   }
}

Source code for your Spoon processing

// load the provided LogQuery$.java file
String logQuerySourceText = ...
CtClass cls = Launcher.parseClass(logQuerySourceText);
System.out.println(cls.getMethodsByName("extractStats$1").get(0).toString);

Actual output

    private static final org.apache.spark.examples.Stats$1 extractStats$1(final java.lang.String line, final scala.util.matching.Regex apacheLogRegex$1) {
        scala.Option var3 = apacheLogRegex$1.findFirstIn(line);
         {
            private final int count;

            private final int numBytes;

            public int count() {
                return this.count;
            }

            public int numBytes() {
                return this.numBytes;
            }

            public org.apache.spark.examples.LogQuery$$1 merge(final org.apache.spark.examples.LogQuery$$1 other) {
                return new org.apache.spark.examples.LogQuery$$1(this.count() + other.count(), this.numBytes() + other.numBytes());
            }

            public java.lang.String toString() {
                return scala.collection.StringOps$.MODULE$.format$extension(scala.Predef$.MODULE$.augmentString("bytes=%s\tn=%s"), scala.runtime.ScalaRunTime$.MODULE$.genericWrapArray(new java.lang.Object[]{ scala.runtime.BoxesRunTime.boxToInteger(this.numBytes()), scala.runtime.BoxesRunTime.boxToInteger(this.count()) }));
            }

            public 1(final int count, final int numBytes) {
                this.count = count;
                this.numBytes = numBytes;
            }
        }
        if (var3 instanceof scala.Some) {
            scala.Some var4 = ((scala.Some) (var3));
            java.lang.String var5 = ((java.lang.String) (var4.value()));
            if (var5 != null) {
                scala.Option var6 = apacheLogRegex$1.unapplySeq(var5);
                if (((!var6.isEmpty()) && (var6.get() != null)) && (((scala.collection.immutable.List) (var6.get())).lengthCompare(9) == 0)) {
                    java.lang.String bytes = ((java.lang.String) (((scala.collection.LinearSeqOps) (var6.get())).apply(6)));
                    return new org.apache.spark.examples.LogQuery$$1(1, scala.collection.StringOps$.MODULE$.toInt$extension(scala.Predef$.MODULE$.augmentString(bytes)));
                }
            }
        }
        return new org.apache.spark.examples.LogQuery$$1(1, 0);
    }

Expected output

   private static final Stats$1 extractStats$1(final String line, final Regex apacheLogRegex$1) {
      Option var3 = apacheLogRegex$1.findFirstIn(line);

      class Stats$1 implements Serializable {
         private final int count;
         private final int numBytes;

         public int count() {
            return this.count;
         }

         public int numBytes() {
            return this.numBytes;
         }

         public Stats$1 merge(final Stats$1 other) {
            return new Stats$1(this.count() + other.count(), this.numBytes() + other.numBytes());
         }

         public String toString() {
            return StringOps$.MODULE$.format$extension(Predef$.MODULE$.augmentString("bytes=%s\tn=%s"), ScalaRunTime$.MODULE$.genericWrapArray(new Object[]{BoxesRunTime.boxToInteger(this.numBytes()), BoxesRunTime.boxToInteger(this.count())}));
         }

         public Stats$1(final int count, final int numBytes) {
            this.count = count;
            this.numBytes = numBytes;
         }
      }

      if (var3 instanceof Some) {
         Some var4 = (Some)var3;
         String var5 = (String)var4.value();
         if (var5 != null) {
            Option var6 = apacheLogRegex$1.unapplySeq(var5);
            if (!var6.isEmpty() && var6.get() != null && ((List)var6.get()).lengthCompare(9) == 0) {
               String bytes = (String)((LinearSeqOps)var6.get()).apply(6);
               return new Stats$1(1, StringOps$.MODULE$.toInt$extension(Predef$.MODULE$.augmentString(bytes)));
            }
         }
      }

      return new Stats$1(1, 0);
   }

Spoon Version

11.2.1

JVM Version

JDK 17

What operating system are you using?

Ubuntu

[monperrus]

Yes, this is supported. Maybe the dollar in the name is the problem. Could you provide an executable failing test case?

[SirYwell]

Note that your code snippet is incorrect as long as the return type is a type declared inside the method.

Assuming this is decompiled Scala code, I guess this is a shortcoming of the decompiler used.

[hunterpayne]

It is a decompiled snippet from here:

LogQuery.scala

Here is the fully decompiled class:

LogQuery$.java

[hunterpayne]

Yes, the code is wrong...but for what I'm doing, that doesn't matter. I need it to parse anyway. It probably should print out a warning too though.

[SirYwell]

Can you complete the original issue template? It would be great to know how you're processing the input and what happens instead of what you expect to happen.

[hunterpayne]

I'm using FernFlower to decompile a classfile compiled by the Scala compiler. That gives me the provided .java files. Then I parse them with Spoon. It would be nice if this terrible code could be parsed so that the identified inner CtClass somehow can be accessed programmatically.

[SirYwell]

The printer output might be a bit confusing here. It looks like it omits the class X implements Y because it assumes the class to be anonymous, but the class also doesn't have the new class part printed.

So I would expect the class to be still part of the model, just the printing is odd. Can you verify that?

[hunterpayne]

I can confirm that a CtType can't be found in the descendantIterator, nor though any sort of search of the nested classes. I think it is in the AST as a CtBlock. Give me a day to confirm this though.

[I-Al-Istannen]

Judging by the spoon visualizer it is a class node, but its simple name is 1. i.e. it is treated as an anoynmous class, which is why the name and surrounding context is omitted from the printing.

[hunterpayne]

Why does it get parsed into that form? It clearly isn't an anonymous class.

[I-Al-Istannen]

See this

spoon/src/main/java/spoon/support/compiler/jdt/JDTTreeBuilderHelper.java

Lines 863 to 866 in 55251cd

	if ((type instanceof CtClass || type instanceof CtInterface)
	&& typeDeclaration.binding != null
	&& (typeDeclaration.binding.isAnonymousType() || typeDeclaration.binding instanceof LocalTypeBinding && typeDeclaration.binding.enclosingMethod() != null)) {
	type.setSimpleName(computeAnonymousName(typeDeclaration.binding.constantPoolName()));

This behaviour was introduced in 9e0de75.
I am not sure if it is desirable, but I also haven't thought deeply about it

[hunterpayne]

Which takes presidence, the 'or' on the left or the 'and' on the right? Seems like some parenthesis might help? It also seems to wrongly be treating classes in methods like anonymous classes?

[hunterpayne]

Ok, so it was a CtClass. Turns out, I had a processor which removed classes whose names are numbers to work around this specific issue.

It would be nice if Spoon didn't drop the class line though. I do believe this is related to the fact that there is a $ in the classname. I do think the correct behavior is to issue a warning and treat CtClass objects inside of methods like normal classes instead of anonymous classes. I also think correct behavior is to ignore '$' in classnames and don't assume inner classnames need additional processing but I could be wrong. Perhaps a config to control this if there is some issue with another decompiler's output requiring handling of inner classnames.