Merge #10161 from equalsraf/tb-clipboard-reload

Support "reload" of providers

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

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

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
 

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')

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')

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
 

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*
 

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.

src/nvim/eval.c

@@ -23968,52 +23968,57 @@ typval_T eval_call_provider(char *provider, char *method, list_T *arguments)
   return rettv;
 }
 
+/// Checks if a named provider is enabled.
 bool eval_has_provider(const char *name)
 {
-#define CHECK_PROVIDER(name) \
-  if (has_##name == -1) { \
-    has_##name = !!find_func((char_u *)"provider#" #name "#Call"); \
-    if (!has_##name) { \
-      script_autoload("provider#" #name "#Call", \
-                      sizeof("provider#" #name "#Call") - 1, \
-                      false); \
-      has_##name = !!find_func((char_u *)"provider#" #name "#Call"); \
-    } \
-  }
-
-  static int has_clipboard = -1;
-  static int has_python = -1;
-  static int has_python3 = -1;
-  static int has_ruby = -1;
-  typval_T args[1];
-  args[0].v_type = VAR_UNKNOWN;
-
-  if (strequal(name, "clipboard")) {
-    CHECK_PROVIDER(clipboard);
-    return has_clipboard;
-  } else if (strequal(name, "python3")) {
-    CHECK_PROVIDER(python3);
-    return has_python3;
-  } else if (strequal(name, "python")) {
-    CHECK_PROVIDER(python);
-    return has_python;
-  } else if (strequal(name, "ruby")) {
-    bool need_check_ruby = (has_ruby == -1);
-    CHECK_PROVIDER(ruby);
-    if (need_check_ruby && has_ruby == 1) {
-      char *rubyhost = call_func_retstr("provider#ruby#Detect", 0, args, true);
-      if (rubyhost) {
-        if (*rubyhost == NUL) {
-          // Invalid rubyhost executable. Gem is probably not installed.
-          has_ruby = 0;
-        }
-        xfree(rubyhost);
-      }
-    }
-    return has_ruby;
-  }
-
+  if (!strequal(name, "clipboard")
+      && !strequal(name, "python")
+      && !strequal(name, "python3")
+      && !strequal(name, "ruby")
+      && !strequal(name, "node")) {
+    // Avoid autoload for non-provider has() features.
     return false;
+  }
+
+  char buf[256];
+  int len;
+  typval_T tv;
+
+  // Get the g:loaded_xx_provider variable.
+  len = snprintf(buf, sizeof(buf), "g:loaded_%s_provider", name);
+  if (get_var_tv(buf, len, &tv, NULL, false, true) == FAIL) {
+    // Trigger autoload once.
+    len = snprintf(buf, sizeof(buf), "provider#%s#bogus", name);
+    script_autoload(buf, len, false);
+
+    // Retry the (non-autoload-style) variable.
+    len = snprintf(buf, sizeof(buf), "g:loaded_%s_provider", name);
+    if (get_var_tv(buf, len, &tv, NULL, false, true) == FAIL) {
+      // Show a hint if Call() is defined but g:loaded_xx_provider is missing.
+      snprintf(buf, sizeof(buf), "provider#%s#Call", name);
+      if (!!find_func((char_u *)buf) && p_lpl) {
+        emsgf("provider: %s: missing required variable g:loaded_%s_provider",
+              name, name);
+      }
+      return false;
+    }
+  }
+
+  bool ok = (tv.v_type == VAR_NUMBER)
+    ? 2 == tv.vval.v_number  // Value of 2 means "loaded and working".
+    : false;
+
+  if (ok) {
+    // Call() must be defined if provider claims to be working.
+    snprintf(buf, sizeof(buf), "provider#%s#Call", name);
+    if (!find_func((char_u *)buf)) {
+      emsgf("provider: %s: g:loaded_%s_provider=2 but %s is not defined",
+            name, name, buf);
+      ok = false;
+    }
+  }
+
+  return ok;
 }
 
 /// Writes "<sourcing_name>:<sourcing_lnum>" to `buf[bufsize]`.

test/functional/fixtures/autoload/provider/clipboard.vim

@@ -1,3 +1,5 @@
+let g:loaded_clipboard_provider = 2
+
 let g:test_clip = { '+': [''], '*': [''], }
 
 let s:methods = {}
@@ -35,7 +37,6 @@ function! s:methods.set(lines, regtype, reg)
   let g:test_clip[a:reg] = [a:lines, a:regtype]
 endfunction
 
-
 function! provider#clipboard#Call(method, args)
   return call(s:methods[a:method],a:args,s:methods)
 endfunction

test/functional/fixtures/autoload/provider/python.vim

@@ -0,0 +1,6 @@
+" Dummy test provider, missing this required variable:
+"   let g:loaded_brokenenabled_provider = 0
+
+function! provider#python#Call(method, args)
+  return 42
+endfunction

test/functional/fixtures/autoload/provider/ruby.vim

@@ -0,0 +1,2 @@
+" A dummy test provider
+let g:loaded_ruby_provider = 2

test/functional/provider/provider_spec.lua

@@ -0,0 +1,26 @@
+
+local helpers = require('test.functional.helpers')(after_each)
+local clear, eval = helpers.clear, helpers.eval
+local command = helpers.command
+local expect_err = helpers.expect_err
+
+describe('providers', function()
+  before_each(function()
+    clear('--cmd', 'let &rtp = "test/functional/fixtures,".&rtp')
+  end)
+
+  it('with #Call(), missing g:loaded_xx_provider', function()
+    command('set loadplugins')
+    -- Using test-fixture with broken impl:
+    -- test/functional/fixtures/autoload/provider/python.vim
+    expect_err('Vim:provider: python: missing required variable g:loaded_python_provider',
+      eval, "has('python')")
+  end)
+
+  it('with g:loaded_xx_provider, missing #Call()', function()
+    -- Using test-fixture with broken impl:
+    -- test/functional/fixtures/autoload/provider/ruby.vim
+    expect_err('Vim:provider: ruby: g:loaded_ruby_provider=2 but provider#ruby#Call is not defined',
+      eval, "has('ruby')")
+  end)
+end)