'queuePendingMember' causes NPE

[fxshlein]

There is this bit of code here, which constructs FieldEntry and MethodEntry objects with the source name set to null:

mapping-io/src/main/java/net/fabricmc/mappingio/tree/MemoryMappingTree.java

Lines 479 to 483 in a301899

	if (isField) {
	member = new FieldEntry(currentClass, null, desc);
	} else {
	member = new MethodEntry(currentClass, null, desc);
	}

I think this always causes a null pointer exception, because the parent constructor uses it to construct a key:

mapping-io/src/main/java/net/fabricmc/mappingio/tree/MemoryMappingTree.java

Line 1122 in a301899

this.key = new MemberKey(srcName, srcDesc);

And the constructor of the key in turn calls .hashCode() on the name without checking for null:

mapping-io/src/main/java/net/fabricmc/mappingio/tree/MemoryMappingTree.java

Lines 1680 to 1684 in a301899

	if (desc == null) {
	hash = name.hashCode();
	} else {
	hash = name.hashCode() * 257 + desc.hashCode();
	}

I suppose, since a key without the name being present probably makes little sense, it would make sense to lazily compute the key as soon as the entry is no longer pending?

Stack trace of the exception:

Caused by: java.lang.NullPointerException: Cannot invoke "String.hashCode()" because "name" is null
	at net.fabricmc.mappingio.tree.MemoryMappingTree$MemberKey.<init>(MemoryMappingTree.java:1683)
	at net.fabricmc.mappingio.tree.MemoryMappingTree$MemberEntry.<init>(MemoryMappingTree.java:1122)
	at net.fabricmc.mappingio.tree.MemoryMappingTree$MethodEntry.<init>(MemoryMappingTree.java:1217)
	at net.fabricmc.mappingio.tree.MemoryMappingTree.queuePendingMember(MemoryMappingTree.java:482)
	at net.fabricmc.mappingio.tree.MemoryMappingTree.visitMethod(MemoryMappingTree.java:459)
	at net.fabricmc.mappingio.adapter.ForwardingMappingVisitor.visitMethod(ForwardingMappingVisitor.java:77)
	at net.fabricmc.mappingio.format.tiny.Tiny2FileReader.readClass(Tiny2FileReader.java:149)
	at net.fabricmc.mappingio.format.tiny.Tiny2FileReader.read(Tiny2FileReader.java:116)
	at net.fabricmc.mappingio.format.tiny.Tiny2FileReader.read(Tiny2FileReader.java:55)
	at net.fabricmc.mappingio.MappingReader.read(MappingReader.java:186)

[NebelNidas]

It's not a particularly urgent issue, since the use case this was designed to cover wasn't supported previously either and would've crashed anyway.

[fxshlein]

Yeah I thought as much haha, just wanted to mentioned it. I ran into it because I was trying to hook up mappings wrongly, which "triggered" this feature, after I did it right it worked perfectly.