feat(provider)!: remove support for python2 and python3.[3-5]

These versions of python has reached End-of-life. getting rid
of python2 support removes a lot of logic to support two
incompatible python versions in the same version.

runtime/autoload/health/nvim.vim

@@ -104,8 +104,8 @@ function! s:check_rplugin_manifest() abort
         if !has_key(existing_rplugins, script)
           let msg = printf('"%s" is not registered.', fnamemodify(path, ':t'))
           if python_version ==# 'pythonx'
-            if !has('python2') && !has('python3')
+            if !has('python3')
-              let msg .= ' (python2 and python3 not available)'
+              let msg .= ' (python3 not available)'
             endif
           elseif !has(python_version)
             let msg .= printf(' (%s not available)', python_version)

runtime/autoload/health/provider.vim

@@ -282,10 +282,10 @@ function! s:disabled_via_loaded_var(provider) abort
   return 0
 endfunction
 
-function! s:check_python(version) abort
+function! s:check_python() abort
-  call health#report_start('Python ' . a:version . ' provider (optional)')
+  call health#report_start('Python 3 provider (optional)')
 
-  let pyname = 'python'.(a:version == 2 ? '' : '3')
+  let pyname = 'python3'
   let python_exe = ''
   let venv = exists('$VIRTUAL_ENV') ? resolve($VIRTUAL_ENV) : ''
   let host_prog_var = pyname.'_host_prog'
@@ -301,7 +301,7 @@ function! s:check_python(version) abort
     call health#report_info(printf('Using: g:%s = "%s"', host_prog_var, get(g:, host_prog_var)))
   endif
 
-  let [pyname, pythonx_errors] = provider#pythonx#Detect(a:version)
+  let [pyname, pythonx_errors] = provider#pythonx#Detect(3)
 
   if empty(pyname)
     call health#report_warn('No Python executable found that can `import neovim`. '
@@ -405,7 +405,7 @@ function! s:check_python(version) abort
     " can import 'pynvim'. If so, that Python failed to import 'neovim' as
     " well, which is most probably due to a failed pip upgrade:
     " https://github.com/neovim/neovim/wiki/Following-HEAD#20181118
-    let [pynvim_exe, errors] = provider#pythonx#DetectByModule('pynvim', a:version)
+    let [pynvim_exe, errors] = provider#pythonx#DetectByModule('pynvim', 3)
     if !empty(pynvim_exe)
       call health#report_error(
             \ 'Detected pip upgrade failure: Python executable can import "pynvim" but '
@@ -416,14 +416,14 @@ function! s:check_python(version) abort
             \ . pynvim_exe ." -m pip install neovim  # only if needed by third-party software")
     endif
   else
-    let [pyversion, current, latest, status] = s:version_info(python_exe)
+    let [majorpyversion, current, latest, status] = s:version_info(python_exe)
 
-    if a:version != str2nr(pyversion)
+    if 3 != str2nr(majorpyversion)
       call health#report_warn('Unexpected Python version.' .
                   \ ' This could lead to confusing error messages.')
     endif
 
-    call health#report_info('Python version: ' . pyversion)
+    call health#report_info('Python version: ' . majorpyversion)
 
     if s:is_bad_response(status)
       call health#report_info(printf('pynvim version: %s (%s)', current, status))
@@ -751,8 +751,7 @@ endfunction
 
 function! health#provider#check() abort
   call s:check_clipboard()
-  call s:check_python(2)
+  call s:check_python()
-  call s:check_python(3)
   call s:check_virtualenv()
   call s:check_ruby()
   call s:check_node()

runtime/autoload/provider/python.vim

@@ -1,45 +0,0 @@
-" The Python provider uses a Python host to emulate an environment for running
-" python-vim plugins. :help provider
-"
-" Associating the plugin with the Python host is the first step because plugins
-" will be passed as command-line arguments
-
-if exists('g:loaded_python_provider')
-  finish
-endif
-let [s:prog, s:err] = provider#pythonx#Detect(2)
-let g:loaded_python_provider = empty(s:prog) ? 1 : 2
-
-function! provider#python#Prog() abort
-  return s:prog
-endfunction
-
-function! provider#python#Error() abort
-  return s:err
-endfunction
-
-" The Python provider plugin will run in a separate instance of the Python
-" host.
-call remote#host#RegisterClone('legacy-python-provider', 'python')
-call remote#host#RegisterPlugin('legacy-python-provider', 'script_host.py', [])
-
-function! provider#python#Call(method, args) abort
-  if s:err != ''
-    return
-  endif
-  if !exists('s:host')
-    let s:rpcrequest = function('rpcrequest')
-
-    " Ensure that we can load the Python host before bootstrapping
-    try
-      let s:host = remote#host#Require('legacy-python-provider')
-    catch
-      let s:err = v:exception
-      echohl WarningMsg
-      echomsg v:exception
-      echohl None
-      return
-    endtry
-  endif
-  return call(s:rpcrequest, insert(insert(a:args, 'python_'.a:method), s:host))
-endfunction

runtime/autoload/provider/pythonx.vim

@@ -6,10 +6,8 @@ endif
 let s:loaded_pythonx_provider = 1
 
 function! provider#pythonx#Require(host) abort
-  let ver = (a:host.orig_name ==# 'python') ? 2 : 3
-
   " Python host arguments
-  let prog = (ver == '2' ?  provider#python#Prog() : provider#python3#Prog())
+  let prog = provider#python3#Prog()
   let args = [prog, '-c', 'import sys; sys.path = list(filter(lambda x: x != "", sys.path)); import neovim; neovim.start_host()']
 
 
@@ -23,14 +21,12 @@ function! provider#pythonx#Require(host) abort
 endfunction
 
 function! s:get_python_executable_from_host_var(major_version) abort
-  return expand(get(g:, 'python'.(a:major_version == 3 ? '3' : '').'_host_prog', ''), v:true)
+  return expand(get(g:, 'python'.(a:major_version == 3 ? '3' : execute("throw 'unsupported'")).'_host_prog', ''), v:true)
 endfunction
 
 function! s:get_python_candidates(major_version) abort
   return {
-        \ 2: ['python2', 'python2.7', 'python2.6', 'python'],
+        \ 3: ['python3', 'python3.10', 'python3.9', 'python3.8', 'python3.7', 'python']
-        \ 3: ['python3', 'python3.10', 'python3.9', 'python3.8', 'python3.7',
-        \     'python3.6', 'python']
         \ }[a:major_version]
 endfunction
 
@@ -82,7 +78,7 @@ function! provider#pythonx#CheckForModule(prog, module, major_version) abort
     return [0, a:prog . ' not found in search path or not executable.']
   endif
 
-  let min_version = (a:major_version == 2) ? '2.6' : '3.3'
+  let min_version = '3.7'
 
   " Try to load module, and output Python version.
   " Exit codes:

runtime/doc/eval.txt

@@ -5806,7 +5806,6 @@ has({feature})	Returns 1 if {feature} is supported, 0 otherwise.  The
 					this is not present).
 			mac		MacOS system.
 			nvim		This is Nvim.
-			python2		Legacy Vim |python2| interface. |has-python|
 			python3		Legacy Vim |python3| interface. |has-python|
 			pythonx		Legacy Vim |python_x| interface. |has-pythonx|
 			ttyin		input is a terminal (tty)

runtime/doc/if_pyth.txt

@@ -1,10 +1,10 @@
 *if_pyth.txt*   Nvim
 
 
-		  VIM REFERENCE MANUAL    by Paul Moore
+		  NVIM REFERENCE MANUAL
 
 
-The Python Interface to Vim				*if_pyth* *python* *Python*
+The Python Interface to NVim				*if_pyth* *python* *Python*
 
 See |provider-python| for more information.
 
@@ -134,7 +134,7 @@ Instead, put the Python command in a function and call that function:
 Note that "EOF" must be at the start of the line.
 
 ==============================================================================
-The vim module						*python-vim* *python2*
+The vim module							*python-vim*
 
 Python code gets all of its access to vim (with one exception - see
 |python-output| below) via the "vim" module.  The vim module implements two
@@ -322,14 +322,13 @@ Output from Python					*python-output*
 	supported, and may cause the program to crash.  This should probably be
 	fixed.
 
-		    *python2-directory* *python3-directory* *pythonx-directory*
+				  *python3-directory* *pythonx-directory*
 Python 'runtimepath' handling				*python-special-path*
 
 In python vim.VIM_SPECIAL_PATH special directory is used as a replacement for
 the list of paths found in 'runtimepath': with this directory in sys.path and
 vim.path_hooks in sys.path_hooks python will try to load module from
-{rtp}/python2 (or python3) and {rtp}/pythonx (for both python versions) for
+{rtp}/python3 and {rtp}/pythonx for each {rtp} found in 'runtimepath'.
-each {rtp} found in 'runtimepath'.
 
 Implementation is similar to the following, but written in C: >
 
@@ -401,8 +400,8 @@ vim._get_paths						*python-_get_paths*
 	hook. You should not rely on this method being present in future
 	versions, but can use it for debugging.
 
-	It returns a list of {rtp}/python2 (or {rtp}/python3) and
+	It returns a list of {rtp}/python3 and {rtp}/pythonx
-	{rtp}/pythonx directories for each {rtp} in 'runtimepath'.
+	directories for each {rtp} in 'runtimepath'.
 
 ==============================================================================
 Buffer objects						*python-buffer*
@@ -590,6 +589,11 @@ functions to evaluate Python expressions and pass their values to Vim script.
 ==============================================================================
 Python 3						*python3*
 
+As Python 3 is the only supported version in Nvim, "python" is synonymous
+with "python3" in the current version. However, code that aims to support older
+versions of Neovim, as well as Vim, should prefer to use "python3"
+variants explicitly if Python 3 is required.
+
 							*:py3* *:python3*
 :[range]py3 {stmt}
 :[range]py3 << [endmarker]
@@ -619,31 +623,26 @@ Raising SystemExit exception in python isn't endorsed way to quit vim, use: >
 	:py vim.command("qall!")
 <
 							*has-python*
-You can test what Python version is available with: >
+You can test if Python is available with: >
-	if has('python')
+	if has('pythonx')
-	  echo 'there is Python 2.x'
+	  echo 'there is Python'
 	endif
   	if has('python3')
 	  echo 'there is Python 3.x'
 	endif
 
+Python 2 is no longer supported. Thus `has('python')` always returns
+zero for backwards compatibility reasons.
+
 ==============================================================================
 Python X						*python_x* *pythonx*
 
-Because most python code can be written so that it works with Python 2.6+ and
+The "pythonx" and "pyx" prefixes were introduced for python code which
-Python 3, the pyx* functions and commands have been written.  They work the
+works with Python 2.6+ and Python 3. As Nvim only supports Python 3,
-same as the Python 2 and 3 variants, but select the Python version using the
+all these commands are now synonymous to their "python3" equivalents.
-'pyxversion' setting.
-
-Set 'pyxversion' in your |vimrc| to prefer Python 2 or Python 3 for Python
-commands. Changing this setting at runtime risks losing the state of plugins
-(such as initialization).
-
-If you want to use a module, you can put it in the {rtp}/pythonx directory.
-See |pythonx-directory|.
 
 							*:pyx* *:pythonx*
-`:pyx` and `:pythonx` work similar to `:python`.  To check if `:pyx` works: >
+`:pyx` and `:pythonx` work the same as `:python3`.  To check if `:pyx` works: >
 	:pyx print("Hello")
 
 To see what version of Python is being used: >
@@ -651,34 +650,16 @@ To see what version of Python is being used: >
 	:pyx print(sys.version)
 <
 					*:pyxfile* *python_x-special-comments*
-`:pyxfile` works similar to `:pyfile`.  But you can add a "shebang" comment to
+`:pyxfile` works the same as `:py3file`. 
-force Vim to use `:pyfile` or `:py3file`: >
-  #!/any string/python2		" Shebang. Must be the first line of the file.
-  #!/any string/python3		" Shebang. Must be the first line of the file.
-  # requires python 2.x		" Maximum lines depend on 'modelines'.
-  # requires python 3.x		" Maximum lines depend on 'modelines'.
-Unlike normal modelines, the bottom of the file is not checked.
-If none of them are found, the 'pyxversion' option is used.
-							*W20* *W21*
-If Vim does not support the selected Python version a silent message will be
-printed.  Use `:messages` to read them.
 
 							*:pyxdo*
-`:pyxdo` works similar to `:pydo`.
+`:pyxdo` works the same as `:py3do`.
 
 							*has-pythonx*
-To check if pyx* functions and commands are available: >
+To check if `pyx*` functions and commands are available: >
 	if has('pythonx')
 	  echo 'pyx* commands are available. (Python ' . &pyx . ')'
 	endif
 
-If you prefer Python 2 and want to fallback to Python 3, set 'pyxversion'
-explicitly in your |.vimrc|.  Example: >
-	if has('python')
-	  set pyx=2
-	elseif has('python3')
-	  set pyx=3
-	endif
-
 ==============================================================================
  vim:tw=78:ts=8:noet:ft=help:norl:

runtime/doc/options.txt

@@ -4637,26 +4637,11 @@ A jump table for the options with a short description can be found at |Q_op|.
 	nudged to fit on the screen.
 
 						*'pyxversion'* *'pyx'*
-'pyxversion' 'pyx'	number	(default depends on the build)
+'pyxversion' 'pyx'	number	(default 3)
 			global
 	Specifies the python version used for pyx* functions and commands
-	|python_x|.  The default value is as follows:
+	|python_x|.  As only Python 3 is supported, this always has the value
-
+	`3`. Setting any other value is an error.
-		|provider| installed	    Default ~
-		|+python| and |+python3|	0
-		only |+python|			2
-		only |+python3|			3
-
-	Available values are 0, 2 and 3.
-	If 'pyxversion' is 0, it is set to 2 or 3 after the first execution of
-	any python2/3 commands or functions.  E.g. `:py` sets to 2, and `:py3`
-	sets to 3. `:pyx` sets it to 3 if Python 3 is available, otherwise sets
-	to 2 if Python 2 is available.
-	See also: |has-pythonx|
-
-	If only |+python| or |+python3| are available,
-	'pyxversion' has no effect. The pyx* functions and commands are
-	always the same as the installed version.
 
 	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.

runtime/doc/provider.txt

@@ -20,11 +20,12 @@ Run the |:checkhealth| command, and review the sections below.
 ==============================================================================
 Python integration				*provider-python*
 
-Nvim supports Python |remote-plugin|s and the Vim legacy |python2| and
+Nvim supports Python |remote-plugin|s and the Vim legacy |python3| and
-|python3| interfaces (which are implemented as remote-plugins).
+|pythonx| interfaces (which are implemented as remote-plugins).
 
 Note: Only the Vim 7.3 legacy interface is supported, not later features such
-as |python-bindeval| (Vim 7.4); use the Nvim API instead.
+as |python-bindeval| (Vim 7.4); use the Nvim API instead. Python 2 is not
+supported.
 
 
 PYTHON QUICKSTART ~
@@ -38,11 +39,6 @@ For Python 3 plugins:
 2. Install the module (try "python" if "python3" is missing): >
    python3 -m pip install --user --upgrade pynvim
 
-For Python 2 plugins:
-1. Make sure Python 2.7 is available in your $PATH.
-2. Install the module (try "python" if "python2" is missing): >
-   python2 -m pip install --user --upgrade pynvim
-
 The pip `--upgrade` flag ensures that you get the latest version even if
 a previous version was already installed.
 
@@ -56,21 +52,11 @@ If you run into problems, uninstall _both_ then install "pynvim" again: >
 
 
 PYTHON PROVIDER CONFIGURATION ~
-						*g:python_host_prog*
-Command to start Python 2 (executable, not directory). Setting this makes
-startup faster. Useful for working with virtualenvs. Must be set before any
-check for has("python2").  >
-    let g:python_host_prog  = '/path/to/python'
-<
 						*g:python3_host_prog*
 Command to start Python 3 (executable, not directory). Setting this makes
 startup faster. Useful for working with virtualenvs. Must be set before any
 check for has("python3").  >
     let g:python3_host_prog = '/path/to/python3'
-<
-						*g:loaded_python_provider*
-To disable Python 2 support: >
-    let g:loaded_python_provider = 0
 <
 						*g:loaded_python3_provider*
 To disable Python 3 support: >
@@ -81,8 +67,8 @@ PYTHON VIRTUALENVS ~
 						*python-virtualenv*
 If you plan to use per-project virtualenvs often, you should assign one
 virtualenv for Neovim and hard-code the interpreter path via
-|g:python3_host_prog| (or |g:python_host_prog|) so that the "pynvim" package
+|g:python3_host_prog| so that the "pynvim" package is not required
-is not required for each virtualenv.
+for each virtualenv.
 
 Example using pyenv: >
     pyenv install 3.4.4

runtime/doc/quickfix.txt

@@ -1446,7 +1446,7 @@ error message (line numbers are not part of the actual output):
      4	Traceback (most recent call last):
      5	  File "unittests/dbfacadeTest.py", line 89, in testFoo
      6	    self.assertEquals(34, dtid)
-     7	  File "/usr/lib/python2.2/unittest.py", line 286, in
+     7	  File "/usr/lib/python3.8/unittest.py", line 286, in
      8	 failUnlessEqual
      9	    raise self.failureException, \
     10	AssertionError: 34 != 33

src/nvim/eval.lua

@@ -270,8 +270,8 @@ return {
     pum_getpos={},
     pumvisible={},
     py3eval={args=1, base=1},
-    pyeval={args=1, base=1},
+    pyeval={args=1, base=1, func="f_py3eval"},
-    pyxeval={args=1, base=1},
+    pyxeval={args=1, base=1, func="f_py3eval"},
     perleval={args=1, base=1},
     range={args={1, 3}, base=1},
     readdir={args={1, 2}, base=1},

src/nvim/eval/funcs.c

@@ -6982,36 +6982,13 @@ static void f_pumvisible(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 }
 
-/*
+/// "py3eval()" and "pyxeval()" functions (always python3)
- * "pyeval()" function
- */
-static void f_pyeval(typval_T *argvars, typval_T *rettv, FunPtr fptr)
-{
-  script_host_eval("python", argvars, rettv);
-}
-
-/*
- * "py3eval()" function
- */
 static void f_py3eval(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
   script_host_eval("python3", argvars, rettv);
 }
 
-// "pyxeval()" function
-static void f_pyxeval(typval_T *argvars, typval_T *rettv, FunPtr fptr)
-{
-  init_pyxversion();
-  if (p_pyx == 2) {
-    f_pyeval(argvars, rettv, NULL);
-  } else {
-    f_py3eval(argvars, rettv, NULL);
-  }
-}
-
-///
 /// "perleval()" function
-///
 static void f_perleval(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
   script_host_eval("perl", argvars, rettv);

src/nvim/ex_cmds.lua

@@ -2097,19 +2097,19 @@ module.cmds = {
     command='python',
     flags=bit.bor(RANGE, EXTRA, NEEDARG, CMDWIN),
     addr_type='ADDR_LINES',
-    func='ex_python',
+    func='ex_python3',
   },
   {
     command='pydo',
     flags=bit.bor(RANGE, DFLALL, EXTRA, NEEDARG, CMDWIN),
     addr_type='ADDR_LINES',
-    func='ex_pydo',
+    func='ex_pydo3',
   },
   {
     command='pyfile',
     flags=bit.bor(RANGE, FILE1, NEEDARG, CMDWIN),
     addr_type='ADDR_LINES',
-    func='ex_pyfile',
+    func='ex_py3file',
   },
   {
     command='py3',
@@ -2139,25 +2139,25 @@ module.cmds = {
     command='pyx',
     flags=bit.bor(RANGE, EXTRA, NEEDARG, CMDWIN),
     addr_type='ADDR_LINES',
-    func='ex_pyx',
+    func='ex_python3',
   },
   {
     command='pyxdo',
     flags=bit.bor(RANGE, DFLALL, EXTRA, NEEDARG, CMDWIN),
     addr_type='ADDR_LINES',
-    func='ex_pyxdo',
+    func='ex_pydo3',
   },
   {
     command='pythonx',
     flags=bit.bor(RANGE, EXTRA, NEEDARG, CMDWIN),
     addr_type='ADDR_LINES',
-    func='ex_pyx',
+    func='ex_python3',
   },
   {
     command='pyxfile',
     flags=bit.bor(RANGE, FILE1, NEEDARG, CMDWIN),
     addr_type='ADDR_LINES',
-    func='ex_pyxfile',
+    func='ex_py3file',
   },
   {
     command='quit',

src/nvim/ex_cmds2.c

@@ -135,21 +135,6 @@ void ex_profile(exarg_T *eap)
   }
 }
 
-void ex_python(exarg_T *eap)
-{
-  script_host_execute("python", eap);
-}
-
-void ex_pyfile(exarg_T *eap)
-{
-  script_host_execute_file("python", eap);
-}
-
-void ex_pydo(exarg_T *eap)
-{
-  script_host_do_range("python", eap);
-}
-
 void ex_ruby(exarg_T *eap)
 {
   script_host_execute("ruby", eap);
@@ -1660,126 +1645,6 @@ void ex_options(exarg_T *eap)
   cmd_source((char_u *)SYS_OPTWIN_FILE, NULL);
 }
 
-// Detect Python 3 or 2, and initialize 'pyxversion'.
-void init_pyxversion(void)
-{
-  if (p_pyx == 0) {
-    if (eval_has_provider("python3")) {
-      p_pyx = 3;
-    } else if (eval_has_provider("python")) {
-      p_pyx = 2;
-    }
-  }
-}
-
-// Does a file contain one of the following strings at the beginning of any
-// line?
-// "#!(any string)python2"  => returns 2
-// "#!(any string)python3"  => returns 3
-// "# requires python 2.x"  => returns 2
-// "# requires python 3.x"  => returns 3
-// otherwise return 0.
-static int requires_py_version(char_u *filename)
-{
-  FILE *file;
-  int requires_py_version = 0;
-  int i, lines;
-
-  lines = (int)p_mls;
-  if (lines < 0) {
-    lines = 5;
-  }
-
-  file = os_fopen((char *)filename, "r");
-  if (file != NULL) {
-    for (i = 0; i < lines; i++) {
-      if (vim_fgets(IObuff, IOSIZE, file)) {
-        break;
-      }
-      if (i == 0 && IObuff[0] == '#' && IObuff[1] == '!') {
-        // Check shebang.
-        if (strstr((char *)IObuff + 2, "python2") != NULL) {
-          requires_py_version = 2;
-          break;
-        }
-        if (strstr((char *)IObuff + 2, "python3") != NULL) {
-          requires_py_version = 3;
-          break;
-        }
-      }
-      IObuff[21] = '\0';
-      if (STRCMP("# requires python 2.x", IObuff) == 0) {
-        requires_py_version = 2;
-        break;
-      }
-      if (STRCMP("# requires python 3.x", IObuff) == 0) {
-        requires_py_version = 3;
-        break;
-      }
-    }
-    fclose(file);
-  }
-  return requires_py_version;
-}
-
-
-// Source a python file using the requested python version.
-static void source_pyx_file(exarg_T *eap, char_u *fname)
-{
-  exarg_T ex;
-  long int v = requires_py_version(fname);
-
-  init_pyxversion();
-  if (v == 0) {
-    // user didn't choose a preference, 'pyx' is used
-    v = p_pyx;
-  }
-
-  // now source, if required python version is not supported show
-  // unobtrusive message.
-  if (eap == NULL) {
-    memset(&ex, 0, sizeof(ex));
-  } else {
-    ex = *eap;
-  }
-  ex.arg = fname;
-  ex.cmd = (char_u *)(v == 2 ? "pyfile" : "pyfile3");
-
-  if (v == 2) {
-    ex_pyfile(&ex);
-  } else {
-    ex_py3file(&ex);
-  }
-}
-
-// ":pyxfile {fname}"
-void ex_pyxfile(exarg_T *eap)
-{
-  source_pyx_file(eap, eap->arg);
-}
-
-// ":pyx"
-void ex_pyx(exarg_T *eap)
-{
-  init_pyxversion();
-  if (p_pyx == 2) {
-    ex_python(eap);
-  } else {
-    ex_python3(eap);
-  }
-}
-
-// ":pyxdo"
-void ex_pyxdo(exarg_T *eap)
-{
-  init_pyxversion();
-  if (p_pyx == 2) {
-    ex_pydo(eap);
-  } else {
-    ex_pydo3(eap);
-  }
-}
-
 /// ":source [{fname}]"
 void ex_source(exarg_T *eap)
 {

src/nvim/option.c

@@ -4349,6 +4349,12 @@ static char *set_num_option(int opt_idx, char_u *varp, long value, char *errbuf,
     } else if (value > 10000) {
       errmsg = e_invarg;
     }
+  } else if (pp == &p_pyx) {
+    if (value == 0) {
+      value = 3;
+    } else if (value != 3) {
+      errmsg = e_invarg;
+    }
   } else if (pp == &p_re) {
     if (value < 0 || value > 2) {
       errmsg = e_invarg;
@@ -4523,10 +4529,6 @@ static char *set_num_option(int opt_idx, char_u *varp, long value, char *errbuf,
     if (pum_drawn()) {
       pum_redraw();
     }
-  } else if (pp == &p_pyx) {
-    if (p_pyx != 0 && p_pyx != 2 && p_pyx != 3) {
-      errmsg = e_invarg;
-    }
   } else if (pp == &p_ul || pp == &curbuf->b_p_ul) {
     // sync undo before 'undolevels' changes
     // use the old value, otherwise u_sync() may not work properly

src/nvim/options.lua

@@ -1846,7 +1846,7 @@ return {
       type='number', scope={'global'},
       secure=true,
       varname='p_pyx',
-      defaults={if_true=0}
+      defaults={if_true=3}
     },
     {
       full_name='quickfixtextfunc', abbreviation='qftf',

src/nvim/testdir/test_python3.vim

@@ -69,6 +69,7 @@ func Test_vim_function()
 endfunc
 
 func Test_skipped_python3_command_does_not_affect_pyxversion()
+  throw 'skipped: Nvim hardcodes pyxversion=3'
   set pyxversion=0
   if 0
     python3 import vim

src/nvim/testdir/test_pyx2.vim

@@ -1,9 +1,9 @@
 " Test for pyx* commands and functions with Python 2.
 
-set pyx=2
 if !has('python')
   finish
 endif
+set pyx=2
 
 let s:py2pattern = '^2\.[0-7]\.\d\+'
 let s:py3pattern = '^3\.\d\+\.\d\+'

test/functional/ex_cmds/script_spec.lua

@@ -62,10 +62,10 @@ describe('script_get-based command', function()
 
   -- Provider-based scripts
   test_garbage_exec('ruby', not missing_provider('ruby'))
-  test_garbage_exec('python', not missing_provider('python'))
   test_garbage_exec('python3', not missing_provider('python3'))
 
   -- Missing scripts
+  test_garbage_exec('python', false)
   test_garbage_exec('tcl', false)
   test_garbage_exec('mzscheme', false)
   test_garbage_exec('perl', false)

test/functional/provider/python3_spec.lua

@@ -8,6 +8,7 @@ local source = helpers.source
 local missing_provider = helpers.missing_provider
 local matches = helpers.matches
 local pcall_err = helpers.pcall_err
+local funcs = helpers.funcs
 
 do
   clear()
@@ -93,16 +94,40 @@ describe('python3 provider', function()
       ghi]])
   end)
 
-  it('py3eval', function()
+  describe('py3eval()', function()
-    eq({1, 2, {['key'] = 'val'}}, eval([[py3eval('[1, 2, {"key": "val"}]')]]))
+    it('works', function()
+      eq({1, 2, {['key'] = 'val'}}, funcs.py3eval('[1, 2, {"key": "val"}]'))
+    end)
+
+    it('errors out when given non-string', function()
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(10)'))
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(v:_null_dict)'))
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(v:_null_list)'))
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(0.0)'))
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(function("tr"))'))
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(v:true)'))
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(v:false)'))
+      eq('Vim:E474: Invalid argument', pcall_err(eval, 'py3eval(v:null)'))
+    end)
+
+    it('accepts NULL string', function()
+      matches('.*SyntaxError.*', pcall_err(eval, 'py3eval($XXX_NONEXISTENT_VAR_XXX)'))
+    end)
   end)
 
   it('pyxeval #10758', function()
-    eq(0, eval([[&pyxversion]]))
+    eq(3, eval([[&pyxversion]]))
     eq(3, eval([[pyxeval('sys.version_info[:3][0]')]]))
     eq(3, eval([[&pyxversion]]))
   end)
 
+  it("setting 'pyxversion'", function()
+    command 'set pyxversion=3' -- no error
+    eq('Vim(set):E474: Invalid argument: pyxversion=2', pcall_err(command, 'set pyxversion=2'))
+    command 'set pyxversion=0' -- allowed, but equivalent to pyxversion=3
+    eq(3, eval'&pyxversion')
+  end)
+
   it('RPC call to expand("<afile>") during BufDelete #5245 #5617', function()
     helpers.add_builddir_to_rtp()
     source([=[
@@ -120,3 +145,15 @@ describe('python3 provider', function()
     assert_alive()
   end)
 end)
+
+describe('python2 feature test', function()
+  -- python2 is not supported, so correct behaviour is to return 0
+  it('works', function()
+    eq(0, funcs.has('python2'))
+    eq(0, funcs.has('python'))
+    eq(0, funcs.has('python_compiled'))
+    eq(0, funcs.has('python_dynamic'))
+    eq(0, funcs.has('python_dynamic_'))
+    eq(0, funcs.has('python_'))
+  end)
+end)

test/functional/provider/python_spec.lua

@@ -1,123 +0,0 @@
-local helpers = require('test.functional.helpers')(after_each)
-
-local eq = helpers.eq
-local neq = helpers.neq
-local feed = helpers.feed
-local clear = helpers.clear
-local funcs = helpers.funcs
-local meths = helpers.meths
-local insert = helpers.insert
-local expect = helpers.expect
-local command = helpers.command
-local exc_exec = helpers.exc_exec
-local write_file = helpers.write_file
-local curbufmeths = helpers.curbufmeths
-local missing_provider = helpers.missing_provider
-local matches = helpers.matches
-local pcall_err = helpers.pcall_err
-
-do
-  clear()
-  local reason = missing_provider('python')
-  if reason then
-    it(':python reports E319 if provider is missing', function()
-      local expected = [[Vim%(py.*%):E319: No "python" provider found.*]]
-      matches(expected, pcall_err(command, 'py print("foo")'))
-      matches(expected, pcall_err(command, 'pyfile foo'))
-    end)
-    pending(string.format('Python 2 (or the pynvim module) is broken/missing (%s)', reason), function() end)
-    return
-  end
-end
-
-before_each(function()
-  clear()
-  command('python import vim')
-end)
-
-describe('python feature test', function()
-  it('works', function()
-    eq(1, funcs.has('python'))
-    eq(1, funcs.has('python_compiled'))
-    eq(1, funcs.has('python_dynamic'))
-    eq(0, funcs.has('python_dynamic_'))
-    eq(0, funcs.has('python_'))
-  end)
-end)
-
-describe(':python command', function()
-  it('works with a line', function()
-    command('python vim.vars["set_by_python"] = [100, 0]')
-    eq({100, 0}, meths.get_var('set_by_python'))
-  end)
-
-  -- TODO(ZyX-I): works with << EOF
-  -- TODO(ZyX-I): works with execute 'python' line1."\n".line2."\n"…
-
-  it('supports nesting', function()
-    command([[python vim.command('python vim.command("python vim.command(\'let set_by_nested_python = 555\')")')]])
-    eq(555, meths.get_var('set_by_nested_python'))
-  end)
-
-  it('supports range', function()
-    insert([[
-      line1
-      line2
-      line3
-      line4]])
-    feed('ggjvj:python vim.vars["range"] = vim.current.range[:]<CR>')
-    eq({'line2', 'line3'}, meths.get_var('range'))
-  end)
-end)
-
-describe(':pyfile command', function()
-  it('works', function()
-    local fname = 'pyfile.py'
-    write_file(fname, 'vim.command("let set_by_pyfile = 123")')
-    command('pyfile pyfile.py')
-    eq(123, meths.get_var('set_by_pyfile'))
-    os.remove(fname)
-  end)
-end)
-
-describe(':pydo command', function()
-  it('works', function()
-    -- :pydo 42 returns None for all lines,
-    -- the buffer should not be changed
-    command('normal :pydo 42')
-    eq(false, curbufmeths.get_option('modified'))
-    -- insert some text
-    insert('abc\ndef\nghi')
-    expect([[
-      abc
-      def
-      ghi]])
-    -- go to top and select and replace the first two lines
-    feed('ggvj:pydo return str(linenr)<CR>')
-    expect([[
-      1
-      2
-      ghi]])
-  end)
-end)
-
-describe('pyeval()', function()
-  it('works', function()
-    eq({1, 2, {['key'] = 'val'}}, funcs.pyeval('[1, 2, {"key": "val"}]'))
-  end)
-
-  it('errors out when given non-string', function()
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(10)'))
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(v:_null_dict)'))
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(v:_null_list)'))
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(0.0)'))
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(function("tr"))'))
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(v:true)'))
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(v:false)'))
-    eq('Vim(call):E474: Invalid argument', exc_exec('call pyeval(v:null)'))
-  end)
-
-  it('accepts NULL string', function()
-    neq(0, exc_exec('call pyeval($XXX_NONEXISTENT_VAR_XXX)'))
-  end)
-end)