gh-143008: Safer TextIOWrapper underlying stream access#145957
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cmaloney wants to merge 2 commits intopython:mainfrom
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gh-143008: Safer TextIOWrapper underlying stream access#145957cmaloney wants to merge 2 commits intopython:mainfrom
cmaloney wants to merge 2 commits intopython:mainfrom
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TextIOWrapper keeps its underlying stream in a member called `self->buffer`. That stream can be detached by user code, such as custom `.flush` implementations resulting in `self->buffer` being set to NULL. The implementation often checked at the start of functions if `self->buffer` is in a good state, but did not always recheck after other Python code was called which could modify `self->buffer`. The cases which need to be re-checked are hard to spot so rather than rely on reviewer effort create better safety by making all self->buffer access go through helper functions. Thank you yihong0618 for the test, NEWS and initial implementation in pythongh-143041. Co-authored-by: yihong0618 <zouzou0208@gmail.com>
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wow that is cool thanks |
cmaloney
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needs backport to 3.13
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TextIOWrapper keeps its underlying stream in a member called
self->buffer. That stream can be detached by user code, such as custom.flush()implementations, resulting inself->bufferbeing set to NULL. The implementation often checked at the start of functions ifself->bufferis in a good state but did not always recheck after other Python code which could modifyself->buffer.The cases which need to be re-checked are hard to spot so rather than rely on reviewer effort make a better safety net by changing all
self->bufferaccess to go through helper functions.Thank you @yihong0618 for the test, NEWS and an initial implementation in gh-143041.
TextIOWrapper.truncatevia re-entrantflush#143008