gh-115398: Increment PyExpat_CAPI_MAGIC for SetReparseDeferralEnabled addition #116301
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This is a followup to git commit 6a95676 from Github PR python#115623.
This was referenced Mar 4, 2024
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woodruffw
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Mar 4, 2024
…nabled addition (pythonGH-116301) * Increment PyExpat_CAPI_MAGIC due to SetReparseDeferralEnabled addition. This is a followup to git commit 6a95676 from Github PR python#115623. * RESTify news API list.
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This looks unnecessary: There's an extra size field that's also checked. See #115623 (comment) . |
hartwork
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Mar 6, 2024
…eferralEnabled addition (pythonGH-116301)" This reverts part of commit eda2963.
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It's also hurting, so I have created pull request #116411 now to revert the bump. |
gpshead
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Mar 6, 2024
Revert "gh-115398: Increment PyExpat_CAPI_MAGIC for SetReparseDeferralEnabled addition (GH-116301)" This reverts part of commit eda2963. Why? this comment buried in an earlier code review explains: I checked again how that value is used in practice, it's here: https://github.com/python/cpython/blob/0c80da4c14d904a367968955544dd6ae58c8101c/Modules/_elementtree.c#L4363-L4372 Based on that code my understanding is that loading bigger structs from the future is considered okay unless `PyExpat_CAPI_MAGIC` differs, which implies that (1) magic needs to stay the same to support loading the future from the past and (2) that `PyExpat_CAPI_MAGIC` should only ever change for changes that do not increase size (but keep it constant). To summarize, that supports your argument. I checked branches 3.8, 3.9, 3.10, 3.11, 3.12 now and they all have the same comparison code there so reverting that magic string bump will support seamless backporting.
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I hadn't seen the earlier review comment, I just looked at the history of the magic and saw it was bumped up to 1.1 during a bugfix release 6+ years ago. I trust y'all's analysis. revert merged. |
adorilson
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Mar 25, 2024
…nabled addition (pythonGH-116301) * Increment PyExpat_CAPI_MAGIC due to SetReparseDeferralEnabled addition. This is a followup to git commit 6a95676 from Github PR python#115623. * RESTify news API list.
adorilson
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Mar 25, 2024
…16411) Revert "pythongh-115398: Increment PyExpat_CAPI_MAGIC for SetReparseDeferralEnabled addition (pythonGH-116301)" This reverts part of commit eda2963. Why? this comment buried in an earlier code review explains: I checked again how that value is used in practice, it's here: https://github.com/python/cpython/blob/0c80da4c14d904a367968955544dd6ae58c8101c/Modules/_elementtree.c#L4363-L4372 Based on that code my understanding is that loading bigger structs from the future is considered okay unless `PyExpat_CAPI_MAGIC` differs, which implies that (1) magic needs to stay the same to support loading the future from the past and (2) that `PyExpat_CAPI_MAGIC` should only ever change for changes that do not increase size (but keep it constant). To summarize, that supports your argument. I checked branches 3.8, 3.9, 3.10, 3.11, 3.12 now and they all have the same comparison code there so reverting that magic string bump will support seamless backporting.
diegorusso
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Apr 17, 2024
…nabled addition (pythonGH-116301) * Increment PyExpat_CAPI_MAGIC due to SetReparseDeferralEnabled addition. This is a followup to git commit 6a95676 from Github PR python#115623. * RESTify news API list.
diegorusso
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Apr 17, 2024
…16411) Revert "pythongh-115398: Increment PyExpat_CAPI_MAGIC for SetReparseDeferralEnabled addition (pythonGH-116301)" This reverts part of commit eda2963. Why? this comment buried in an earlier code review explains: I checked again how that value is used in practice, it's here: https://github.com/python/cpython/blob/0c80da4c14d904a367968955544dd6ae58c8101c/Modules/_elementtree.c#L4363-L4372 Based on that code my understanding is that loading bigger structs from the future is considered okay unless `PyExpat_CAPI_MAGIC` differs, which implies that (1) magic needs to stay the same to support loading the future from the past and (2) that `PyExpat_CAPI_MAGIC` should only ever change for changes that do not increase size (but keep it constant). To summarize, that supports your argument. I checked branches 3.8, 3.9, 3.10, 3.11, 3.12 now and they all have the same comparison code there so reverting that magic string bump will support seamless backporting.
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Increment PyExpat_CAPI_MAGIC due to SetReparseDeferralEnabled addition.
This is a followup to git commit 6a95676 from Github PR #115623.
Also ReSTify's the NEWS entry.
XML_SetReparseDeferralEnabled#115398