Fix nested annotation element encoding in StubGenerator (#724) - #725
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wasabii wants to merge 1 commit into
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Fix nested annotation element encoding in StubGenerator (#724)#725wasabii wants to merge 1 commit into
wasabii wants to merge 1 commit into
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The object-overload of EncodeElementValue iterated a nested annotation's name/value pairs with i++ instead of i += 2. After the first pair, i lands on a value slot, so (string)v[i] throws InvalidCastException when the value is an array (nested annotation, enum, or array member). This was a porting typo introduced in 3dad0f9 when StubGen was rewritten on top of IKVM.ByteCode; the pre-rewrite loop and the two sibling loops (EncodeAnnotation and the CustomAttributeTypedArgument overload) all use i += 2 correctly. Fixes #724
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Fixes #724.
The bug
StubGenerator.EncodeElementValue(theobjectoverload) encodes a nested annotation (TAG_ANNOTATION) whose payload is laid out as name/value pairs:[tag, typeName, name0, value0, name1, value1, …]. The loop advanced by one instead of two:After the first pair,
ilands on a value slot, and(string)v[i]throwsInvalidCastException: Unable to cast object of type 'System.Object[]' to type 'System.String'whenever that value is itself an array (a nested annotation, enum, or array member). It only fires for nested annotations with more than one element, which is why it went unnoticed for so long.The fix
One character —
i++→i += 2— restoring parity with the two sibling loops that were ported correctly (EncodeAnnotationand theCustomAttributeTypedArgumentoverload) and with the pre-rewrite implementation.History
Regression introduced in 3dad0f9 (Aug 18 2024), the rewrite of StubGen onto IKVM.ByteCode. The old
WriteAnnotationElementValueusedi += 2; the rewrite produced three copies of the pattern and two of the three kept the increment. This one didn't.