health/pythonx: refactor #Detect()

2 files changed, 55 insertions, 50 deletions

diff --git a/runtime/autoload/health/provider.vim b/runtime/autoload/health/provider.vim
index 97498bc42e..526623c86f 100644
--- a/runtime/autoload/health/provider.vim
+++ b/runtime/autoload/health/provider.vim
@@ -258,10 +258,10 @@ function! s:check_python(version) abort
   call health#report_start('Python ' . a:version . ' provider (optional)')
 
   let pyname = 'python'.(a:version == 2 ? '' : '3')
+  let python_exe = ''
   let venv = exists('$VIRTUAL_ENV') ? resolve($VIRTUAL_ENV) : ''
   let host_prog_var = pyname.'_host_prog'
   let loaded_var = 'g:loaded_'.pyname.'_provider'
-  let python_bin = ''
   let python_multiple = []
 
   if exists(loaded_var) && !exists('*provider#'.pyname.'#Call')
@@ -274,38 +274,40 @@ 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_errs] = provider#pythonx#Detect(a:version)
+  let [pyname, pythonx_errors] = provider#pythonx#Detect(a:version)
+
   if empty(pyname)
-    call health#report_warn('No Python interpreter was found with the pynvim '
-            \ . 'module.  Using the first available for diagnostics.')
+    call health#report_warn('No Python executable found that could `import neovim`. '
+            \ . 'Using the first available executable for diagnostics.')
   elseif exists('g:'.host_prog_var)
-    let python_bin = pyname
+    let python_exe = pyname
   endif
 
-  if !empty(pythonx_errs)
-    call health#report_error('Python provider error', pythonx_errs)
+  " No Python executable could `import neovim`.
+  if !empty(pythonx_errors)
+    call health#report_error('Python provider error:', pythonx_errors)
 
-  elseif !empty(pyname) && empty(python_bin)
+  elseif !empty(pyname) && empty(python_exe)
     if !exists('g:'.host_prog_var)
       call health#report_info(printf('`g:%s` is not set.  Searching for '
             \ . '%s in the environment.', host_prog_var, pyname))
     endif
 
     if !empty(pyenv)
-      let python_bin = s:trim(s:system([pyenv, 'which', pyname], '', 1))
+      let python_exe = s:trim(s:system([pyenv, 'which', pyname], '', 1))
 
-      if empty(python_bin)
+      if empty(python_exe)
         call health#report_warn(printf('pyenv could not find %s.', pyname))
       endif
     endif
 
-    if empty(python_bin)
-      let python_bin = exepath(pyname)
+    if empty(python_exe)
+      let python_exe = exepath(pyname)
 
       if exists('$PATH')
         for path in split($PATH, has('win32') ? ';' : ':')
           let path_bin = s:normalize_path(path.'/'.pyname)
-          if path_bin != s:normalize_path(python_bin)
+          if path_bin != s:normalize_path(python_exe)
                 \ && index(python_multiple, path_bin) == -1
                 \ && executable(path_bin)
             call add(python_multiple, path_bin)
@@ -319,8 +321,8 @@ function! s:check_python(version) abort
                 \ . 'Set `g:%s` to avoid surprises.', pyname, host_prog_var))
         endif
 
-        if python_bin =~# '\<shims\>'
-          call health#report_warn(printf('`%s` appears to be a pyenv shim.', python_bin), [
+        if python_exe =~# '\<shims\>'
+          call health#report_warn(printf('`%s` appears to be a pyenv shim.', python_exe), [
                       \ '`pyenv` is not in $PATH, your pyenv installation is broken. '
                       \ .'Set `g:'.host_prog_var.'` to avoid surprises.',
                       \ ])
@@ -329,9 +331,9 @@ function! s:check_python(version) abort
     endif
   endif
 
-  if !empty(python_bin) && !exists('g:'.host_prog_var)
+  if !empty(python_exe) && !exists('g:'.host_prog_var)
     if empty(venv) && !empty(pyenv)
-          \ && !empty(pyenv_root) && resolve(python_bin) !~# '^'.pyenv_root.'/'
+          \ && !empty(pyenv_root) && resolve(python_exe) !~# '^'.pyenv_root.'/'
       call health#report_warn('pyenv is not set up optimally.', [
             \ printf('Create a virtualenv specifically '
             \ . 'for Neovim using pyenv, and set `g:%s`.  This will avoid '
@@ -345,7 +347,7 @@ function! s:check_python(version) abort
         let venv_root = fnamemodify(venv, ':h')
       endif
 
-      if resolve(python_bin) !~# '^'.venv_root.'/'
+      if resolve(python_exe) !~# '^'.venv_root.'/'
         call health#report_warn('Your virtualenv is not set up optimally.', [
               \ printf('Create a virtualenv specifically '
               \ . 'for Neovim and use `g:%s`.  This will avoid '
@@ -356,16 +358,16 @@ function! s:check_python(version) abort
     endif
   endif
 
-  if empty(python_bin) && !empty(pyname)
+  if empty(python_exe) && !empty(pyname)
     " An error message should have already printed.
     call health#report_error(printf('`%s` was not found.', pyname))
-  elseif !empty(python_bin) && !s:check_bin(python_bin)
-    let python_bin = ''
+  elseif !empty(python_exe) && !s:check_bin(python_exe)
+    let python_exe = ''
   endif
 
   " Check if $VIRTUAL_ENV is valid.
-  if exists('$VIRTUAL_ENV') && !empty(python_bin)
-    if $VIRTUAL_ENV ==# matchstr(python_bin, '^\V'.$VIRTUAL_ENV)
+  if exists('$VIRTUAL_ENV') && !empty(python_exe)
+    if $VIRTUAL_ENV ==# matchstr(python_exe, '^\V'.$VIRTUAL_ENV)
       call health#report_info('$VIRTUAL_ENV matches executable')
     else
       call health#report_warn(
@@ -376,7 +378,7 @@ function! s:check_python(version) abort
   endif
 
   " Diagnostic output
-  call health#report_info('Executable: ' . (empty(python_bin) ? 'Not found' : python_bin))
+  call health#report_info('Executable: ' . (empty(python_exe) ? 'Not found' : python_exe))
   if len(python_multiple)
     for path_bin in python_multiple
       call health#report_info('Other python executable: ' . path_bin)
@@ -385,8 +387,8 @@ function! s:check_python(version) abort
 
   let pip = 'pip' . (a:version == 2 ? '' : '3')
 
-  if !empty(python_bin)
-    let [pyversion, current, latest, status] = s:version_info(python_bin)
+  if !empty(python_exe)
+    let [pyversion, current, latest, status] = s:version_info(python_exe)
     if a:version != str2nr(pyversion)
       call health#report_warn('Unexpected Python version.' .
                   \ ' This could lead to confusing error messages.')
@@ -398,7 +400,7 @@ function! s:check_python(version) abort
     call health#report_info('Python version: ' . pyversion)
     if s:is_bad_response(status)
       call health#report_info(printf('pynvim version: %s (%s)', current, status))
-      let [module_found, _msg] = provider#pythonx#CheckForModule(python_bin,
+      let [module_found, _msg] = provider#pythonx#CheckForModule(python_exe,
             \ 'pynvim', a:version)
       if status !=? '^outdated' && module_found
         " neovim module was not found, but pynvim was
diff --git a/runtime/autoload/provider/pythonx.vim b/runtime/autoload/provider/pythonx.vim
index 05b04e7e2c..06611377b1 100644
--- a/runtime/autoload/provider/pythonx.vim
+++ b/runtime/autoload/provider/pythonx.vim
@@ -21,37 +21,40 @@ function! provider#pythonx#Require(host) abort
   return provider#Poll(args, a:host.orig_name, '$NVIM_PYTHON_LOG_FILE')
 endfunction
 
-function! provider#pythonx#Detect(major_ver) abort
-  if a:major_ver == 2
-    if exists('g:python_host_prog')
-      return [expand(g:python_host_prog), '']
-    else
-      let progs = ['python2', 'python2.7', 'python2.6', 'python']
-    endif
-  else
-    if exists('g:python3_host_prog')
-      return [expand(g:python3_host_prog), '']
-    else
-      let progs = ['python3', 'python3.7', 'python3.6', 'python3.5',
-            \ 'python3.4', 'python3.3', 'python']
-    endif
+function! s:get_python_executable_from_host_var(major_version) abort
+  return expand(get(g:, 'python'.(a:major_version == 3 ? '3' : '').'_host_prog', ''))
+endfunction
+
+function! s:get_python_candidates(major_version) abort
+  return {
+        \ 2: ['python2', 'python2.7', 'python2.6', 'python'],
+        \ 3: ['python3', 'python3.7', 'python3.6', 'python3.5', 'python3.4', 'python3.3',
+        \     'python']
+        \ }[a:major_version]
+endfunction
+
+" Returns [path_to_python_executable, error_message]
+function! provider#pythonx#Detect(major_version) abort
+  let python_exe = s:get_python_executable_from_host_var(a:major_version)
+
+  if !empty(python_exe)
+    return [python_exe, '']
   endif
 
+  let candidates = s:get_python_candidates(a:major_version)
   let errors = []
 
-  for prog in progs
-    let [result, err] = provider#pythonx#CheckForModule(prog, 'neovim', a:major_ver)
+  for exe in candidates
+    let [result, error] = provider#pythonx#CheckForModule(exe, 'neovim', a:major_version)
     if result
-      return [prog, err]
+      return [exe, error]
     endif
-    " Accumulate errors in case we don't find
-    " any suitable Python interpreter.
-    call add(errors, err)
+    " Accumulate errors in case we don't find any suitable Python executable.
+    call add(errors, error)
   endfor
 
-  " No suitable Python interpreter found.
-  return ['', 'provider/pythonx: Could not load Python ' . a:major_ver
-        \ . ":\n" .  join(errors, "\n")]
+  " No suitable Python executable found.
+  return ['', 'provider/pythonx: Could not load Python '.a:major_version.":\n".join(errors, "\n")]
 endfunction
 
 " Returns array: [prog_exitcode, prog_version]