provide option to disable runtimepath extension loading. resolves #483

autoload/airline/extensions.vim

@@ -207,22 +207,24 @@ function! airline#extensions#load()
     call airline#extensions#promptline#init(s:ext)
   endif
 
-  " Load all other extensions, which are not part of the default distribution.
-  " (autoload/airline/extensions/*.vim outside of our s:script_path).
-  for file in split(globpath(&rtp, "autoload/airline/extensions/*.vim"), "\n")
-    " we have to check both resolved and unresolved paths, since it's possible
-    " that they might not get resolved properly (see #187)
-    if stridx(tolower(resolve(fnamemodify(file, ':p'))), s:script_path) < 0
-          \ && stridx(tolower(fnamemodify(file, ':p')), s:script_path) < 0
-      let name = fnamemodify(file, ':t:r')
-      if !get(g:, 'airline#extensions#'.name.'#enabled', 1)
-        continue
+  if !get(g:, 'airline#extensions#disable_rtp_load', 0)
+    " load all other extensions, which are not part of the default distribution.
+    " (autoload/airline/extensions/*.vim outside of our s:script_path).
+    for file in split(globpath(&rtp, "autoload/airline/extensions/*.vim"), "\n")
+      " we have to check both resolved and unresolved paths, since it's possible
+      " that they might not get resolved properly (see #187)
+      if stridx(tolower(resolve(fnamemodify(file, ':p'))), s:script_path) < 0
+            \ && stridx(tolower(fnamemodify(file, ':p')), s:script_path) < 0
+        let name = fnamemodify(file, ':t:r')
+        if !get(g:, 'airline#extensions#'.name.'#enabled', 1)
+          continue
+        endif
+        try
+          call airline#extensions#{name}#init(s:ext)
+        catch
+        endtry
       endif
-      try
-        call airline#extensions#{name}#init(s:ext)
-      catch
-      endtry
-    endif
-  endfor
+    endfor
+  endif
 endfunction
 

doc/airline.txt

@@ -217,6 +217,14 @@ EXTENSIONS                                              *airline-extensions*
 Most extensions are enabled by default and lazily loaded when the
 corresponding plugin (if any) is detected.
 
+By default, airline will attempt to load any extension it can find in the
+'runtimepath'.  On some systems this can result in an undersirable startup
+cost.  You can disable the check with the following flag. >
+  let g:airline#extensions#disable_rtp_load = 1
+<
+  Note: Third party plugins that rely on this behavior will be affected. You
+  will need to manually load them.
+
 -------------------------------------                      *airline-default*
 The default extension understands all of the `g:` variables in the
 |airline-configuration| section, however it also has some more fine-tuned
@@ -240,7 +248,6 @@ configuration values that you can use.
       \ [ 'x', 'y', 'z', 'warning' ]
       \ ])
 <
-
 -------------------------------------                     *airline-quickfix*
 The quickfix extension is a simple built-in extension which determines
 whether the buffer is a quickfix or location list buffer, and adjusts the