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[3.15] gh-160324: Keep io.StringIO state after MemoryError (GH-160325) - #161041
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…GH-160325) Allocate before consuming the accumulated writes in realize() and make_intermediate(), and reset the size when the contents are lost, so that later calls do not index outside the internal buffer. Shrink the buffer of the accumulating writer before finishing it, so that getvalue(), read() and the other methods leave the contents unchanged when they fail with MemoryError instead of dropping them. ANT-2026-MPHGX2FL (cherry picked from commit 83b047ef80836c24672cf3e2e807e68efed7d495) Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>
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@gpshead Same thing for the 3.14 backport: #161042. |
gpshead
disabled auto-merge
November 9, 2026 00:28
Update the writer fields directly instead.
In 3.15, writing a string to a new PyUnicodeWriter copies it, so a MemoryError there lost the contents of the StringIO. Disable overallocation for this write so the writer shares the string (copy-on-write) instead, as it does in main.
gpshead
approved these changes
Nov 9, 2026
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Allocate before consuming the accumulated writes in realize() and
make_intermediate(), and reset the size when the contents are lost,
so that later calls do not index outside the internal buffer.
Shrink the buffer of the accumulating writer before finishing it, so
that getvalue(), read() and the other methods leave the contents
unchanged when they fail with MemoryError instead of dropping them.
ANT-2026-MPHGX2FL
(cherry picked from commit 83b047e)
Co-authored-by: Gregory P. Smith 68491+gpshead@users.noreply.github.com
io.StringIOcrashes or returns garbage when used after aMemoryError#160324