Merge #10161 from equalsraf/tb-clipboard-reload

Support "reload" of providers

8 files changed, 46 insertions, 52 deletions

diff --git a/runtime/autoload/health/nvim.vim b/runtime/autoload/health/nvim.vim
index a2227e3b29..c25f5ee64f 100644
--- a/runtime/autoload/health/nvim.vim
+++ b/runtime/autoload/health/nvim.vim
@@ -123,7 +123,7 @@ function! s:check_performance() abort
   else
     call health#report_info(buildtype)
     call health#report_warn(
-          \ 'Non-optimized build-type. Nvim will be slower.',
+          \ 'Non-optimized '.(has('debug')?'(DEBUG) ':'').'build. Nvim will be slower.',
           \ ['Install a different Nvim package, or rebuild with `CMAKE_BUILD_TYPE=RelWithDebInfo`.',
           \  s:suggest_faq])
   endif
diff --git a/runtime/autoload/provider/clipboard.vim b/runtime/autoload/provider/clipboard.vim
index 2b06ee8c48..ce140b0948 100644
--- a/runtime/autoload/provider/clipboard.vim
+++ b/runtime/autoload/provider/clipboard.vim
@@ -1,6 +1,16 @@
 " The clipboard provider uses shell commands to communicate with the clipboard.
 " The provider function will only be registered if a supported command is
 " available.
+
+if exists('g:loaded_clipboard_provider')
+  finish
+endif
+" Default to 1.  provider#clipboard#Executable() may set 2.
+" To force a reload:
+"   :unlet g:loaded_clipboard_provider
+"   :runtime autoload/provider/clipboard.vim
+let g:loaded_clipboard_provider = 1
+
 let s:copy = {}
 let s:paste = {}
 let s:clipboard = {}
@@ -120,13 +130,6 @@ function! provider#clipboard#Executable() abort
   return ''
 endfunction
 
-if empty(provider#clipboard#Executable())
-  " provider#clipboard#Call() *must not* be defined if the provider is broken.
-  " Otherwise eval_has_provider() thinks the clipboard provider is
-  " functioning, and eval_call_provider() will happily call it.
-  finish
-endif
-
 function! s:clipboard.get(reg) abort
   if type(s:paste[a:reg]) == v:t_func
     return s:paste[a:reg]()
@@ -192,3 +195,6 @@ function! provider#clipboard#Call(method, args) abort
     let s:here = v:false
   endtry
 endfunction
+
+" eval_has_provider() decides based on this variable.
+let g:loaded_clipboard_provider = empty(provider#clipboard#Executable()) ? 1 : 2
diff --git a/runtime/autoload/provider/node.vim b/runtime/autoload/provider/node.vim
index 35882849bd..b2a3b3ee08 100644
--- a/runtime/autoload/provider/node.vim
+++ b/runtime/autoload/provider/node.vim
@@ -140,8 +140,9 @@ endfunction
 
 let s:err = ''
 let s:prog = provider#node#Detect()
+let g:loaded_node_provider = empty(s:prog) ? 1 : 2
 
-if empty(s:prog)
+if g:loaded_node_provider != 2
   let s:err = 'Cannot find the "neovim" node package. Try :checkhealth'
 endif
 
diff --git a/runtime/autoload/provider/python.vim b/runtime/autoload/provider/python.vim
index a06cbe4814..8a1d162784 100644
--- a/runtime/autoload/provider/python.vim
+++ b/runtime/autoload/provider/python.vim
@@ -7,9 +7,8 @@
 if exists('g:loaded_python_provider')
   finish
 endif
-let g:loaded_python_provider = 1
-
 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
@@ -19,11 +18,6 @@ function! provider#python#Error() abort
   return s:err
 endfunction
 
-if s:prog == ''
-  " Detection failed
-  finish
-endif
-
 " The Python provider plugin will run in a separate instance of the Python
 " host.
 call remote#host#RegisterClone('legacy-python-provider', 'python')
diff --git a/runtime/autoload/provider/python3.vim b/runtime/autoload/provider/python3.vim
index 242a224cb3..38ef0cccfc 100644
--- a/runtime/autoload/provider/python3.vim
+++ b/runtime/autoload/provider/python3.vim
@@ -7,9 +7,8 @@
 if exists('g:loaded_python3_provider')
   finish
 endif
-let g:loaded_python3_provider = 1
-
 let [s:prog, s:err] = provider#pythonx#Detect(3)
+let g:loaded_python3_provider = empty(s:prog) ? 1 : 2
 
 function! provider#python3#Prog() abort
   return s:prog
@@ -19,11 +18,6 @@ function! provider#python3#Error() abort
   return s:err
 endfunction
 
-if s:prog == ''
-  " Detection failed
-  finish
-endif
-
 " The Python3 provider plugin will run in a separate instance of the Python3
 " host.
 call remote#host#RegisterClone('legacy-python3-provider', 'python3')
diff --git a/runtime/autoload/provider/ruby.vim b/runtime/autoload/provider/ruby.vim
index 3b4c6c4839..f843050df9 100644
--- a/runtime/autoload/provider/ruby.vim
+++ b/runtime/autoload/provider/ruby.vim
@@ -62,8 +62,9 @@ endfunction
 let s:err = ''
 let s:prog = s:detect()
 let s:plugin_path = expand('<sfile>:p:h') . '/script_host.rb'
+let g:loaded_ruby_provider = empty(s:prog) ? 1 : 2
 
-if empty(s:prog)
+if g:loaded_ruby_provider != 2
   let s:err = 'Cannot find the neovim RubyGem. Try :checkhealth'
 endif
 
diff --git a/runtime/doc/develop.txt b/runtime/doc/develop.txt
index 843e23ee54..3262d9dec7 100644
--- a/runtime/doc/develop.txt
+++ b/runtime/doc/develop.txt
@@ -84,12 +84,11 @@ Developer guidelines				        *dev-guidelines*
 
 PROVIDERS 						*dev-provider*
 
-A goal of Nvim is to allow extension of the editor without special knowledge
-in the core. But some Vim components are too tightly coupled; in those cases
-a "provider" hook is exposed.
+A primary goal of Nvim is to allow extension of the editor without special
+knowledge in the core.  Some core functions are delegated to "providers"
+implemented as external scripts.
 
-Consider two examples of integration with external systems that are
-implemented in Vim and are now decoupled from Nvim core as providers:
+Examples:
 
 1. In the Vim source code, clipboard logic accounts for more than 1k lines of
    C source code (ui.c), to perform two tasks that are now accomplished with
@@ -101,29 +100,28 @@ implemented in Vim and are now decoupled from Nvim core as providers:
    scripting is performed by an external host process implemented in ~2k lines
    of Python.
 
-Ideally we could implement Python and clipboard integration in pure vimscript
-and without touching the C code. But this is infeasible without compromising
-backwards compatibility with Vim; that's where providers help.
+The provider framework invokes VimL from C.  It is composed of two functions
+in eval.c:
 
-The provider framework helps call vimscript from C. It is composed of two
-functions in eval.c:
-
-- eval_call_provider(name, method, arguments): calls provider#(name)#Call
+- eval_call_provider(name, method, arguments): calls provider#{name}#Call
   with the method and arguments.
-- eval_has_provider(name): Checks if a provider is implemented. Returns true
-  if the provider#(name)#Call function is implemented. Called by |has()|
-  (vimscript) to check if features are available.
-
-The provider#(name)#Call function implements integration with an external
-system, because shell commands and |RPC| clients are easier to work with in
-vimscript.
+- eval_has_provider(name): Checks the `g:loaded_{name}_provider` variable
+  which must be set to 2 by the provider script to indicate that it is
+  "enabled and working". Called by |has()| to check if features are available.
 
 For example, the Python provider is implemented by the
-autoload/provider/python.vim script; the provider#python#Call function is only
-defined if a valid external Python host is found. That works well with the
-`has('python')` expression (normally used by Python plugins) because if the
-Python host isn't installed then the plugin will "think" it is running in
-a Vim compiled without the "+python" feature.
+"autoload/provider/python.vim" script, which sets `g:loaded_python_provider`
+to 2 only if a valid external Python host is found.  Then `has("python")`
+reflects whether Python support is working.
+
+							*provider-reload*
+Sometimes a GUI or other application may want to force a provider to
+"reload".  To reload a provider, undefine its "loaded" flag, then use
+|:runtime| to reload it: >
+
+    :unlet g:loaded_clipboard_provider
+    :runtime autoload/provider/clipboard.vim
+
 
 DOCUMENTATION						*dev-doc*
 
diff --git a/runtime/doc/provider.txt b/runtime/doc/provider.txt
index 594c9602f4..dc045c360a 100644
--- a/runtime/doc/provider.txt
+++ b/runtime/doc/provider.txt
@@ -68,11 +68,11 @@ startup faster. Useful for working with virtualenvs.  >
 <
 						*g:loaded_python_provider*
 To disable Python 2 support: >
-    let g:loaded_python_provider = 1
+    let g:loaded_python_provider = 0
 <
 						*g:loaded_python3_provider*
 To disable Python 3 support: >
-    let g:loaded_python3_provider = 1
+    let g:loaded_python3_provider = 0
 
 
 PYTHON VIRTUALENVS ~
@@ -111,7 +111,7 @@ Run |:checkhealth| to see if your system is up-to-date.
 RUBY PROVIDER CONFIGURATION ~
 						*g:loaded_ruby_provider*
 To disable Ruby support: >
-    let g:loaded_ruby_provider = 1
+    let g:loaded_ruby_provider = 0
 <
 						*g:ruby_host_prog*
 Command to start the Ruby host. By default this is "neovim-ruby-host". With
@@ -142,7 +142,7 @@ Run |:checkhealth| to see if your system is up-to-date.
 NODEJS PROVIDER CONFIGURATION~
 						*g:loaded_node_provider*
 To disable Node.js support: >
-    :let g:loaded_node_provider = 1
+    :let g:loaded_node_provider = 0
 <
 						*g:node_host_prog*
 Command to start the Node.js host. Setting this makes startup faster.