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>

*help.txt*	For Vim version 9.0.  Last change: 2022 Dec 03

			VIM - main help file
									 k
      Move around:  Use the cursor keys, or "h" to go left,	       h   l
		    "j" to go down, "k" to go up, "l" to go right.	 j
Close this window:  Use ":q<Enter>".
   Get out of Vim:  Use ":qa!<Enter>" (careful, all changes are lost!).

Jump to a subject:  Position the cursor on a tag (e.g. |bars|) and hit CTRL-].
   With the mouse:  ":set mouse=a" to enable the mouse (in xterm or GUI).
		    Double-click the left mouse button on a tag, e.g. |bars|.
	Jump back:  Type CTRL-O.  Repeat to go further back.

Get specific help:  It is possible to go directly to whatever you want help
		    on, by giving an argument to the |:help| command.
		    Prepend something to specify the context:  *help-context*

			  WHAT			PREPEND    EXAMPLE	~
		      Normal mode command		   :help x
		      Visual mode command	  v_	   :help v_u
		      Insert mode command	  i_	   :help i_<Esc>
		      Command-line command	  :	   :help :quit
		      Command-line editing	  c_	   :help c_<Del>
		      Vim command argument	  -	   :help -r
		      Option			  '	   :help 'textwidth'
		      Regular expression	  /	   :help /[
		    See |help-summary| for more contexts and an explanation.
		    See |notation| for an explanation of the help syntax.

  Search for help:  Type ":help word", then hit CTRL-D to see matching
		    help entries for "word".
		    Or use ":helpgrep word". |:helpgrep|

  Getting started:  Do the Vim tutor, a 30-minute interactive course for the
		    basic commands, see |vimtutor|.
		    Read the user manual from start to end: |usr_01.txt|

Vim stands for Vi IMproved.  Most of Vim was made by Bram Moolenaar, but only
through the help of many others.  See |credits|.
------------------------------------------------------------------------------
						*doc-file-list* *Q_ct*
BASIC:
|quickref|	Overview of the most common commands you will use
|tutor|		30-minute interactive course for beginners
|copying|	About copyrights
|iccf|		Helping poor children in Uganda
|sponsor|	Sponsor Vim development, become a registered Vim user
|www|		Vim on the World Wide Web
|bugs|		Where to send bug reports

USER MANUAL: These files explain how to accomplish an editing task.

|usr_toc.txt|	Table Of Contents

Getting Started ~
|usr_01.txt|  About the manuals
|usr_02.txt|  The first steps in Vim
|usr_03.txt|  Moving around
|usr_04.txt|  Making small changes
|usr_05.txt|  Set your settings
|usr_06.txt|  Using syntax highlighting
|usr_07.txt|  Editing more than one file
|usr_08.txt|  Splitting windows
|usr_09.txt|  Using the GUI
|usr_10.txt|  Making big changes
|usr_11.txt|  Recovering from a crash
|usr_12.txt|  Clever tricks

Editing Effectively ~
|usr_20.txt|  Typing command-line commands quickly
|usr_21.txt|  Go away and come back
|usr_22.txt|  Finding the file to edit
|usr_23.txt|  Editing other files
|usr_24.txt|  Inserting quickly
|usr_25.txt|  Editing formatted text
|usr_26.txt|  Repeating
|usr_27.txt|  Search commands and patterns
|usr_28.txt|  Folding
|usr_29.txt|  Moving through programs
|usr_30.txt|  Editing programs
|usr_31.txt|  Exploiting the GUI
|usr_32.txt|  The undo tree

Tuning Vim ~
|usr_40.txt|  Make new commands
|usr_41.txt|  Write a Vim script
|usr_42.txt|  Add new menus
|usr_43.txt|  Using filetypes
|usr_44.txt|  Your own syntax highlighted
|usr_45.txt|  Select your language

Writing Vim scripts ~
|usr_50.txt|  Advanced Vim script writing
|usr_51.txt|  Create a plugin
|usr_52.txt|  Write plugins using Vim9 script

Making Vim Run ~
|usr_90.txt|  Installing Vim

REFERENCE MANUAL: These files explain every detail of Vim.	*reference_toc*

General subjects ~
|intro.txt|	general introduction to Vim; notation used in help files
|help.txt|	overview and quick reference (this file)
|helphelp.txt|	about using the help files
|index.txt|	alphabetical index of all commands
|help-tags|	all the tags you can jump to (index of tags)
|howto.txt|	how to do the most common editing tasks
|tips.txt|	various tips on using Vim
|message.txt|	(error) messages and explanations
|quotes.txt|	remarks from users of Vim
|todo.txt|	known problems and desired extensions
|develop.txt|	development of Vim
|debug.txt|	debugging Vim itself
|uganda.txt|	Vim distribution conditions and what to do with your money

Basic editing ~
|starting.txt|	starting Vim, Vim command arguments, initialisation
|editing.txt|	editing and writing files
|motion.txt|	commands for moving around
|scroll.txt|	scrolling the text in the window
|insert.txt|	Insert and Replace mode
|change.txt|	deleting and replacing text
|undo.txt|	Undo and Redo
|repeat.txt|	repeating commands, Vim scripts and debugging
|visual.txt|	using the Visual mode (selecting a text area)
|various.txt|	various remaining commands
|recover.txt|	recovering from a crash

Advanced editing ~
|cmdline.txt|	Command-line editing
|options.txt|	description of all options
|pattern.txt|	regexp patterns and search commands
|map.txt|	key mapping and abbreviations
|tagsrch.txt|	tags and special searches
|windows.txt|	commands for using multiple windows and buffers
|tabpage.txt|	commands for using multiple tab pages
|spell.txt|	spell checking
|diff.txt|	working with two to eight versions of the same file
|autocmd.txt|	automatically executing commands on an event
|eval.txt|	expression evaluation, conditional commands
|builtin.txt|	builtin functions
|userfunc.txt|	defining user functions
|channel.txt|	Jobs, Channels, inter-process communication
|fold.txt|	hide (fold) ranges of lines

Special issues ~
|testing.txt|	testing Vim and Vim scripts
|print.txt|	printing
|remote.txt|	using Vim as a server or client
|term.txt|	using different terminals and mice
|terminal.txt|	Terminal window support
|popup.txt|	popup window support
|vim9.txt|	using Vim9 script
|vim9class.txt|	using Vim9 script classes

Programming language support ~
|indent.txt|	automatic indenting for C and other languages
|syntax.txt|	syntax highlighting
|textprop.txt|	Attaching properties to text for highlighting or other
|filetype.txt|	settings done specifically for a type of file
|quickfix.txt|	commands for a quick edit-compile-fix cycle
|ft_ada.txt|	Ada (the programming language) support
|ft_context.txt|	Filetype plugin for ConTeXt
|ft_mp.txt|	Filetype plugin for METAFONT and MetaPost
|ft_ps1.txt|	Filetype plugin for Windows PowerShell
|ft_raku.txt|	Filetype plugin for Raku
|ft_rust.txt|	Filetype plugin for Rust
|ft_sql.txt|	about the SQL filetype plugin

Language support ~
|digraph.txt|	list of available digraphs
|mbyte.txt|	multibyte text support
|mlang.txt|	non-English language support
|rileft.txt|	right-to-left editing mode
|arabic.txt|	Arabic language support and editing
|farsi.txt|	Farsi (Persian) editing
|hebrew.txt|	Hebrew language support and editing
|russian.txt|	Russian language support and editing
|hangulin.txt|	Hangul (Korean) input mode

GUI ~
|gui.txt|	Graphical User Interface (GUI)
|gui_w32.txt|	Win32 GUI
|gui_x11.txt|	X11 GUI

Interfaces ~
|if_cscop.txt|	using Cscope with Vim
|if_lua.txt|	Lua interface
|if_mzsch.txt|	MzScheme interface
|if_perl.txt|	Perl interface
|if_pyth.txt|	Python interface
|if_tcl.txt|	Tcl interface
|if_ole.txt|	OLE automation interface for Win32
|if_ruby.txt|	Ruby interface
|debugger.txt|	Interface with a debugger
|netbeans.txt|	NetBeans External Editor interface
|sign.txt|	debugging signs

Versions ~
|vi_diff.txt|	Main differences between Vim and Vi
|version4.txt|	Differences between Vim version 3.0 and 4.x
|version5.txt|	Differences between Vim version 4.6 and 5.x
|version6.txt|	Differences between Vim version 5.7 and 6.x
|version7.txt|	Differences between Vim version 6.4 and 7.x
|version8.txt|	Differences between Vim version 7.4 and 8.x
|version9.txt|	Differences between Vim version 8.2 and 9.0
						*sys-file-list*
Remarks about specific systems ~
|os_390.txt|	OS/390 Unix
|os_amiga.txt|	Amiga
|os_beos.txt|	BeOS and BeBox
|os_dos.txt|	MS-DOS and MS-Windows common items
|os_haiku.txt|	Haiku
|os_mac.txt|	Macintosh
|os_mint.txt|	Atari MiNT
|os_msdos.txt|	MS-DOS (plain DOS and DOS box under Windows)
|os_os2.txt|	OS/2
|os_qnx.txt|	QNX
|os_risc.txt|	RISC-OS
|os_unix.txt|	Unix
|os_vms.txt|	VMS
|os_win32.txt|	MS-Windows
						*standard-plugin-list*
Standard plugins ~
|pi_getscript.txt| Downloading latest version of Vim scripts
|pi_gzip.txt|      Reading and writing compressed files
|pi_logipat.txt|   Logical operators on patterns
|pi_netrw.txt|     Reading and writing files over a network
|pi_paren.txt|     Highlight matching parens
|pi_spec.txt|      Filetype plugin to work with rpm spec files
|pi_tar.txt|       Tar file explorer
|pi_vimball.txt|   Create a self-installing Vim script
|pi_zip.txt|       Zip archive explorer

LOCAL ADDITIONS:				*local-additions*

------------------------------------------------------------------------------
*bars*		Bars example

Now that you've jumped here with CTRL-] or a double mouse click, you can use
CTRL-T, CTRL-O, g<RightMouse>, or <C-RightMouse> to go back to where you were.

Note that tags are within | characters, but when highlighting is enabled these
characters are hidden.  That makes it easier to read a command.

Anyway, you can use CTRL-] on any word, also when it is not within |, and Vim
will try to find help for it.  Especially for options in single quotes, e.g.
'compatible'.

------------------------------------------------------------------------------
 vim:tw=78:isk=!-~,^*,^\|,^\":ts=8:noet:ft=help:norl: