gh-150449: Fix sqlite3.Blob crash with negative-step slices#150450
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ever0de wants to merge 1 commit into
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gh-150449: Fix sqlite3.Blob crash with negative-step slices#150450ever0de wants to merge 1 commit into
ever0de wants to merge 1 commit into
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Reading or writing a sqlite3.Blob with a negative-step slice such as blob[9:0:-2] caused a crash (SystemError on older versions, ValueError on current main) because the C code computed stop - start as the read length, which is negative for negative steps. Fix subscript_slice() and ass_subscript_slice() in Modules/_sqlite/blob.c to handle both positive and negative steps correctly: - For step > 1: keep reading [start, stop) and indexing forward as before. - For step < -1: read the contiguous range [start+(len-1)*step, start] and index backward with stride -step.
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Reading or writing a sqlite3.Blob with a negative-step slice such as blob[9:0:-2] caused a crash (SystemError on older versions, ValueError on current main) because the C code computed stop - start as the read length, which is negative for negative steps.
Fix subscript_slice() and ass_subscript_slice() in Modules/_sqlite/blob.c to handle both positive and negative steps correctly: