fix(checkhealth): mitigate issues with duplicate healthchecks #15919

* fix(runtime/health): mitigate issues with duplicate healthchecks
  Previously if a healthcheck was found as Lua and Vim it was executed
  both times.
  This new implementations prefers Lua, therefore if two are found It only
  runs the Lua one, this way a plugin can mantain both implementations the
  Lua one with the method `check()` and the autoload function `#check()`
  (for none HEAD nvim versions).
  **Note: This will require plugins to use `check()` as the function name,
  since the autoload function that wraps the lua implementation won't be
  called**
* docs(health): use spaces and don't overuse backtics

followup to #15259

runtime/autoload/health.vim

@@ -41,8 +41,8 @@ function! health#check(plugin_names) abort
     call setline(1, 'ERROR: No healthchecks found.')
   else
     redraw|echo 'Running healthchecks...'
-    for c in healthchecks
-      let [name, func, type] = c
+    for name in sort(keys(healthchecks))
+      let [func, type] = healthchecks[name]
       let s:output = []
       try
         if func == ''
@@ -176,8 +176,30 @@ function! s:discover_healthchecks() abort
   return s:get_healthcheck('*')
 endfunction
 
-" Returns list of lists [ [{name}, {func}, {type}] ] representing healthchecks
+" Returns Dictionary {name: [func, type], ..} representing healthchecks
 function! s:get_healthcheck(plugin_names) abort
+  let health_list = s:get_healthcheck_list(a:plugin_names)
+  let healthchecks = {}
+  for c in health_list
+    let name = c[0]
+    let existent = get(healthchecks, name, [])
+    " If an entry with the same name exists and is from vim, prefer Lua so
+    " overwrite it.
+    if existent != []
+      if existent[1] == "v"
+        let healthchecks[name] = c[1:] 
+      else
+        continue
+      endif
+    else
+      let healthchecks[name] = c[1:]
+    endif
+  endfor
+  return healthchecks
+endfunction
+
+" Returns list of lists [ [{name}, {func}, {type}] ] representing healthchecks
+function! s:get_healthcheck_list(plugin_names) abort
   let healthchecks = []
   let plugin_names = type('') == type(a:plugin_names)
         \ ? split(a:plugin_names, ' ', v:false)

runtime/doc/pi_health.txt

@@ -83,14 +83,14 @@ will automatically find and invoke this function.
 
 If your plugin is named "foo", then its healthcheck module should be a file in
 one of these locations on 'runtimepath' or 'packpath':
-	- `lua/foo/health/init.lua`
-	- `lua/foo/health.lua`
+        - lua/foo/health/init.lua
+        - lua/foo/health.lua
 
 If your plugin provides a submodule named "bar" for which you want a separate
 healthcheck, define the healthcheck at one of these locations on 'runtimepath'
 or 'packpath':
-	- `lua/foo/bar/health/init.lua`
-	- `lua/foo/bar/health.lua`
+        - lua/foo/bar/health/init.lua
+        - lua/foo/bar/health.lua
 
 All submodules should return a Lua table containing the method `check()`.
 
@@ -159,8 +159,8 @@ health#{plugin}#check() function in autoload/health/{plugin}.vim.
 If your plugin is named "foo", then its healthcheck function must be >
         health#foo#check()
 
-defined in this file on 'runtimepath' or 'packpath': >
-	autoload/health/foo.vim
+defined in this file on 'runtimepath' or 'packpath':
+        - autoload/health/foo.vim
 
 Copy this sample code into autoload/health/foo.vim and replace "foo" with your
 plugin name: >
@@ -177,4 +177,4 @@ plugin name: >
           endif
         endfunction
 
-vim:noet tw=78:ts=8:ft=help:fdm=marker
+vim:et:tw=78:ts=8:ft=help:fdm=marker

test/functional/fixtures/lua/test_plug/autoload/health/test_plug.vim

@@ -0,0 +1,3 @@
+function! health#success1#check()
+  call health#report_start("If you see this I'm broken")
+endfunction

test/functional/plugin/health_spec.lua

@@ -100,8 +100,10 @@ describe('health.vim', function()
         ]])
     end)
 
-    it("lua plugins", function()
+    it("lua plugins, skips vimscript healthchecks with the same name", function()
       command("checkhealth test_plug")
+      -- Existing file in test/functional/fixtures/lua/test_plug/autoload/health/test_plug.vim
+      -- and the Lua healthcheck is used instead.
       helpers.expect([[
 
         test_plug: require("test_plug.health").check()