fix: guard stringbuilder size overflows#1672
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Reject stringbuilder append and reserve requests whose size arithmetic would wrap. This prevents skipped buffer growth on 32-bit targets and avoids wrapping the allocation growth loop for huge reservations. Co-Authored-By: OpenAI Codex <noreply@openai.com>
JoshuaMoelans
approved these changes
Apr 27, 2026
mujacica
approved these changes
Apr 27, 2026
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Reject
stringbuilder_appendandstringbuilder_reserverequests whose size arithmetic would wrap before comparing the requested size with the current allocation. On 32-bit targets, wrappedsize_tarithmetic could make an oversized append look small enough to fit and skip buffer growth before copying the payload.This also prevents the reserve growth loop from wrapping while doubling the allocation size for very large reservations. The added unit coverage exercises the append and reserve overflow paths without allocating large buffers.