| msg366064 - (view) |
Author: STINNER Victor (vstinner) *  |
Date: 2020-04-09 15:19 |
| Similarly to bpo-39573 (PyObject) and bpo-40170 (PyTypeObject), I propose to make the PyGC_Head structure opaque in the C API. See https://bugs.python.org/issue39573#msg361513 for the rationale. In short, my plan is to hide all implementation details from the C API. The PyGC_Head structure caused ABI issues recently: bpo-39599 "ABI breakage between Python 3.7.4 and 3.7.5: change in PyGC_Head structure". Making the structure opaque would reduce the risk of such ABI issue. In fact, the reporter of bpo-39599 really require to access PyGC_Head structure to write a profiler, so this issue doesn't fix all use cases, but it should benefit to most people ;-) PyGC_Head structure will remain accessible via the internal C API which doesn't provide any backward compatibility warranty. |
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| msg366067 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-09 15:20 |
| See also bpo-40240: "Expose public spelling of _PyGC_FINALIZED and _PyGC_SET_FINALIZED?". |
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| msg366092 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-10 00:06 |
| The following macros rely on PyGC_Head: * _PyGCHead_FINALIZED() * _PyGCHead_NEXT() * _PyGCHead_PREV() * _PyGCHead_SET_FINALIZED() * _PyGCHead_SET_NEXT() * _PyGCHead_SET_PREV() * _PyGC_FINALIZED() * _PyGC_PREV_MASK * _PyGC_PREV_MASK_COLLECTING * _PyGC_PREV_MASK_FINALIZED * _PyGC_PREV_SHIFT * _PyGC_SET_FINALIZED() * _PyObject_GC_IS_TRACKED() * _PyObject_GC_MAY_BE_TRACKED() * _Py_AS_GC() _testcapi uses _PyObject_GC_IS_TRACKED() and sizeof(PyGC_Head). |
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| msg366094 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-10 00:18 |
| > The following macros rely on PyGC_Head: (...) I already moved them to the internal C API in commit 1a6be91e6fd65ce9cb88cbbbb193db7e92ec6076 of bpo-35081. But Stefan Behnel reported that it breaks Cython: "Making _PyGC_FINALIZED() internal broke Cython (https://github.com/cython/cython/issues/2721). It's used in the finaliser implementation (https://github.com/cython/cython/blob/da657c8e326a419cde8ae6ea91be9661b9622504/Cython/Compiler/ModuleNode.py#L1442-L1456), to determine if an object for which tp_dealloc() is called has already been finalised or whether we have to do it. I'm not sure how to deal with this on our side now. Any clue?" https://bugs.python.org/issue35081#msg330045 So I simply reverted (partially) this change: commit 3e21ad1a254cc33e8d4920ad7f026254ec728bee. |
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| msg366095 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-10 00:23 |
| _testcapi uses _PyObject_GC_IS_TRACKED(). This macro is exposed in Python as gc.is_tracked(). IMO the function should be available in the public C API. For example, PyObject_GC_IsTracked(obj). Cython uses _PyGC_FINALIZED(). This macro is exposed in Python as gc.is_finalized(). So again, I consider that it should be exposed in a public C function as well, like PyObject_GC_IsFinalized(obj). |
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| msg366170 - (view) |
Author: Pablo Galindo Salgado (pablogsal) * |
Date: 2020-04-11 00:22 |
| New changeset f13072b8a89a922285737988b086beb4b06c6648 by Pablo Galindo in branch 'master': bpo-40241: Add PyObject_GC_IsTracked and PyObject_GC_IsFinalized to the public C-API (GH-19461) https://github.com/python/cpython/commit/f13072b8a89a922285737988b086beb4b06c6648 |
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| msg366291 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-13 09:38 |
| New changeset 0135598d729d01f35ce08d47160adaa095a6149f by Victor Stinner in branch 'master': bpo-40241: Add pycore_gc.h header file (GH-19494) https://github.com/python/cpython/commit/0135598d729d01f35ce08d47160adaa095a6149f |
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| msg366296 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-13 10:20 |
| Ok, this issue should now be closed. It was easier than expected ;-) |
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| msg366300 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-13 10:47 |
| New changeset 0c13e1f96a9487e0efe63c3d3a05ff9738bd7dac by Victor Stinner in branch 'master': bpo-40241: Add pycore_interp.h header (GH-19499) https://github.com/python/cpython/commit/0c13e1f96a9487e0efe63c3d3a05ff9738bd7dac |
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| msg366353 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-04-13 23:59 |
| > bpo-40241: Add pycore_interp.h header (GH-19499) Oops, this change was for bpo-40268. |
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| msg370600 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2020-06-02 10:03 |
| New changeset 337d3103a2344e1fec75985e85fabcbdedac7d26 by Victor Stinner in branch 'master': bpo-40241: What's New in Python 3.9: opaque PyGC_Head (GH-20586) https://github.com/python/cpython/commit/337d3103a2344e1fec75985e85fabcbdedac7d26 |
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| msg370601 - (view) |
Author: miss-islington (miss-islington) |
Date: 2020-06-02 10:09 |
| New changeset ff442f36b91810c8b8a6346e39f1dbf2c6d85764 by Miss Islington (bot) in branch '3.9': bpo-40241: What's New in Python 3.9: opaque PyGC_Head (GH-20586) https://github.com/python/cpython/commit/ff442f36b91810c8b8a6346e39f1dbf2c6d85764 |
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