patch 9.0.1776: No support for stable Python 3 ABI Commit: https://github.com/vim/vim/commit/c13b3d1350b60b94fe87f0761ea31c0e7fb6ebf3 Author: Yee Cheng Chin <ychin.git@gmail.com> Date: Sun Aug 20 21:18:38 2023 +0200 patch 9.0.1776: No support for stable Python 3 ABI Problem: No support for stable Python 3 ABI Solution: Support Python 3 stable ABI Commits: 1) Support Python 3 stable ABI to allow mixed version interoperatbility Vim currently supports embedding Python for use with plugins, and the "dynamic" linking option allows the user to specify a locally installed version of Python by setting `pythonthreedll`. However, one caveat is that the Python 3 libs are not binary compatible across minor versions, and mixing versions can potentially be dangerous (e.g. let's say Vim was linked against the Python 3.10 SDK, but the user sets `pythonthreedll` to a 3.11 lib). Usually, nothing bad happens, but in theory this could lead to crashes, memory corruption, and other unpredictable behaviors. It's also difficult for the user to tell something is wrong because Vim has no way of reporting what Python 3 version Vim was linked with. For Vim installed via a package manager, this usually isn't an issue because all the dependencies would already be figured out. For prebuilt Vim binaries like MacVim (my motivation for working on this), AppImage, and Win32 installer this could potentially be an issue as usually a single binary is distributed. This is more tricky when a new Python version is released, as there's a chicken-and-egg issue with deciding what Python version to build against and hard to keep in sync when a new Python version just drops and we have a mix of users of different Python versions, and a user just blindly upgrading to a new Python could lead to bad interactions with Vim. Python 3 does have a solution for this problem: stable ABI / limited API (see https://docs.python.org/3/c-api/stable.html). The C SDK limits the API to a set of functions that are promised to be stable across versions. This pull request adds an ifdef config that allows us to turn it on when building Vim. Vim binaries built with this option should be safe to freely link with any Python 3 libraies without having the constraint of having to use the same minor version. Note: Python 2 has no such concept and this doesn't change how Python 2 integration works (not that there is going to be a new version of Python 2 that would cause compatibility issues in the future anyway). --- Technical details: ====== The stable ABI can be accessed when we compile with the Python 3 limited API (by defining `Py_LIMITED_API`). The Python 3 code (in `if_python3.c` and `if_py_both.h`) would now handle this and switch to limited API mode. Without it set, Vim will still use the full API as before so this is an opt-in change. The main difference is that `PyType_Object` is now an opaque struct that we can't directly create "static types" out of, and we have to create type objects as "heap types" instead. This is because the struct is not stable and changes from version to version (e.g. 3.8 added a `tp_vectorcall` field to it). I had to change all the types to be allocated on the heap instead with just a pointer to them. Other functions are also simply missing in limited API, or they are introduced too late (e.g. `PyUnicode_AsUTF8AndSize` in 3.10) to it that we need some other ways to do the same thing, so I had to abstract a few things into macros, and sometimes re-implement functions like `PyObject_NEW`. One caveat is that in limited API, `OutputType` (used for replacing `sys.stdout`) no longer inherits from `PyStdPrinter_Type` which I don't think has any real issue other than minor differences in how they convert to a string and missing a couple functions like `mode()` and `fileno()`. Also fixed an existing bug where `tp_basicsize` was set incorrectly for `BufferObject`, `TabListObject, `WinListObject`. Technically, there could be a small performance drop, there is a little more indirection with accessing type objects, and some APIs like `PyUnicode_AsUTF8AndSize` are missing, but in practice I didn't see any difference, and any well-written Python plugin should try to avoid excessing callbacks to the `vim` module in Python anyway. I only tested limited API mode down to Python 3.7, which seemes to compile and work fine. I haven't tried earlier Python versions. 2) Fix PyIter_Check on older Python vers / type##Ptr unused warning For PyIter_Check, older versions exposed them as either macros (used in full API), or a function (for use in limited API). A previous change exposed PyIter_Check to the dynamic build because Python just moved it to function-only in 3.10 anyway. Because of that, just make sure we always grab the function in dynamic builds in earlier versions since that's what Python eventually did anyway. 3) Move Py_LIMITED_API define to configure script Can now use --with-python-stable-abi flag to customize what stable ABI version to target. Can also use an env var to do so as well. 4) Show +python/dyn-stable in :version, and allow has() feature query Not sure if the "/dyn-stable" suffix would break things, or whether we should do it another way. Or just don't show it in version and rely on has() feature checking. 5) Documentation first draft. Still need to implement v:python3_version 6) Fix PyIter_Check build breaks when compiling against Python 3.8 7) Add CI coverage stable ABI on Linux/Windows / make configurable on Windows This adds configurable options for Windows make files (both MinGW and MSVC). CI will also now exercise both traditional full API and stable ABI for Linux and Windows in the matrix for coverage. Also added a "dynamic" option to Linux matrix as a drive-by change to make other scripting languages like Ruby / Perl testable under both static and dynamic builds. 8) Fix inaccuracy in Windows docs Python's own docs are confusing but you don't actually want to use `python3.dll` for the dynamic linkage. 9) Add generated autoconf file 10) Add v:python3_version support This variable indicates the version of Python3 that Vim was built against (PY_VERSION_HEX), and will be useful to check whether the Python library you are loading in dynamically actually fits it. When built with stable ABI, it will be the limited ABI version instead (`Py_LIMITED_API`), which indicates the minimum version of Python 3 the user should have, rather than the exact match. When stable ABI is used, we won't be exposing PY_VERSION_HEX in this var because it just doesn't seem necessary to do so (the whole point of stable ABI is the promise that it will work across versions), and I don't want to confuse the user with too many variables. Also, cleaned up some documentation, and added help tags. 11) Fix Python 3.7 compat issues Fix a couple issues when using limited API < 3.8 - Crash on exit: In Python 3.7, if a heap-allocated type is destroyed before all instances are, it would cause a crash later. This happens when we destroyed `OptionsType` before calling `Py_Finalize` when using the limited API. To make it worse, later versions changed the semantics and now each instance has a strong reference to its own type and the recommendation has changed to have each instance de-ref its own type and have its type in GC traversal. To avoid dealing with these cross-version variations, we just don't free the heap type. They are static types in non-limited-API anyway and are designed to last through the entirety of the app, and we also don't restart the Python runtime and therefore do not need it to have absolutely 0 leaks. See: - https://docs.python.org/3/whatsnew/3.8.html#changes-in-the-c-api - https://docs.python.org/3/whatsnew/3.9.html#changes-in-the-c-api - PyIter_Check: This function is not provided in limited APIs older than 3.8. Previously I was trying to mock it out using manual PyType_GetSlot() but it was brittle and also does not actually work properly for static types (it will generate a Python error). Just return false. It does mean using limited API < 3.8 is not recommended as you lose the functionality to handle iterators, but from playing with plugins I couldn't find it to be an issue. - Fix loading of PyIter_Check so it will be done when limited API < 3.8. Otherwise loading a 3.7 Python lib will fail even if limited API was specified to use it. 12) Make sure to only load `PyUnicode_AsUTF8AndSize` in needed in limited API We don't use this function unless limited API >= 3.10, but we were loading it regardless. Usually it's ok in Unix-like systems where Python just has a single lib that we load from, but in Windows where there is a separate python3.dll this would not work as the symbol would not have been exposed in this more limited DLL file. This makes it much clearer under what condition is this function needed. closes: #12032 Signed-off-by: Christian Brabandt <cb@256bit.org> Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>

*pi_spec.txt*   For Vim version 9.0.  Last change: 2006 Apr 24

by Gustavo Niemeyer ~

This is a filetype plugin to work with rpm spec files.

Currently, this Vim plugin allows you to easily update the %changelog
section in RPM spec files.  It will even create a section for you if it
doesn't exist yet.  If you've already inserted an entry today, it will
give you the opportunity to just add a new item in today's entry.  If you
don't provide a format string (|spec_chglog_format|), it'll ask you an
email address and build a format string by itself.

1. How to use it	|spec-how-to-use-it|
2. Customizing		|spec-customizing|

==============================================================================
1. How to use it				*spec-how-to-use-it*

The spec_chglog plugin provides a map like the following:

	:map <buffer> <LocalLeader>c <Plug>SpecChangelog

It means that you may run the plugin inside a spec file by pressing
your maplocalleader key (default is '\') plus 'c'.  If you do not have
|spec_chglog_format| set, the plugin will ask you for an email address
to use in this edit session.

Every time you run the plugin, it will check to see if the last entry in the
changelog has been written today and by you.  If the entry matches, it will
just insert a new changelog item, otherwise it will create a new changelog
entry.  If you are running with |spec_chglog_release_info| enabled, it will
also check if the name, version and release matches.  The plugin is smart
enough to ask you if it should update the package release, if you have not
done so.

Setting a map					*spec-setting-a-map*
-------------

As you should know, you can easily set a map to access any Vim command (or
anything, for that matter).  If you don't like the default map of
<LocalLeader>c, you may just set up your own key.  The following line
shows you how you could do this in your .vimrc file, mapping the plugin to
the <F5> key:

	au FileType spec map <buffer> <F5> <Plug>SpecChangelog

Note: the plugin will respect your desire to change the default mapping
      and won't set it.

This command will add a map only in the spec file buffers.


==============================================================================
2. Customizing					*spec-customizing*

The format string				*spec_chglog_format*
-----------------

You can easily customize how your spec file entry will look like.  To do
this just set the variable "spec_chglog_format" in your .vimrc file like
this: >

	let spec_chglog_format = "%a %b %d %Y My Name <my@email.com>"

Note that "%a %b %d %Y" is the most used time format.  If you don't provide
a format string, when you run the SpecChangelog command for the first
time, it will ask you an email address and build the |spec_chglog_format|
variable for you.  This way, you will only need to provide your email
address once.

To discover which format options you can use, take a look at the strftime()
function man page.

Where to insert new items			*spec_chglog_prepend*
-------------------------

The plugin will usually insert new %changelog entry items (note that it's
not the entry itself) after the existing ones.  If you set the
spec_chglog_prepend variable >

	let spec_chglog_prepend = 1

it will insert new items before the existing ones.

Inserting release info				*spec_chglog_release_info*
----------------------

If you want, the plugin may automatically insert release information
on each changelog entry.  One advantage of turning this feature on is
that it may control if the release has been updated after the last
change in the package or not.  If you have not updated the package
version or release, it will ask you if it should update the package
release for you.  To turn this feature on, just insert the following
code in your .vimrc: >

	let spec_chglog_release_info = 1

Then, the first item in your changelog entry will be something like: >

	+ name-1.0-1cl

If you don't like the release updating feature and don't want to answer
"No" each time it detects an old release, you may disable it with >

	let spec_chglog_never_increase_release = 1


Good luck!!

vim:tw=78:ts=8:noet:ft=help:norl: