Fix GCC 16 incompatible-pointer return in IoFile_readUArrayOfLength_#499
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GCC 16 promotes -Wincompatible-pointer-types to an error by default, which broke the native build (discussion #498). IoFile_readUArrayOfLength_ returns UArray *, but its error path returned IONIL(self) — an IoObject *. Besides the type mismatch this was also a latent logic/leak bug: both callers (readBufferOfLength_, readStringOfLength_) test the result for NULL to mean "return Nil", so the non-NULL ioNil pointer made a failed read look successful, and the freshly allocated UArray was leaked. Free the buffer and return NULL, matching the existing end-of-file path. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Problem
Reported in #498: the native VM fails to build with GCC 16, which promotes
-Wincompatible-pointer-typesto a hard error by default. The reporter worked around it withCFLAGS=-Wno-error=incompatible-pointer-types, but there's a genuine bug underneath.IoFile_readUArrayOfLength_(libs/iovm/source/IoFile.c) returnsUArray *, but its error path did:IONIL(self)expands toIOSTATE->ioNil, anIoObject *. SinceUArrayis a distinct basekit struct (not atypedefofIoObject), this is a real incompatible-pointer return.It was also a latent logic + leak bug: both callers (
readBufferOfLength_,readStringOfLength_) test the result forNULLto mean "return Nil". The non-NULLioNilpointer would make a failed read look successful and then get passed toIoSeq_newWithUArray_copy_, and the freshly allocatedUArraywas leaked.Fix
Free the buffer and return
NULL, matching the existing end-of-file path a few lines below.I swept the rest of the tree for the same class of incompatible-pointer return; this was the only genuine one (other apparent hits return
IoObject-typedef'd types likeIoMessage/IoNumber, which are fine).🤖 Generated with Claude Code