From ec795366da28ba1348878c8861a7decaa353794b Mon Sep 17 00:00:00 2001
From: Fatih Arslan <ftharsln@gmail.com>
Date: Wed, 20 Jul 2016 22:02:57 -0400
Subject: [PATCH] util: add go#util#env function

Add new function to return cached version of Go environment variables.
With that set GOROOT everytime we execute gocode. This will prevent
gocode using the internal embedded GOROOT and will use the GOROOT from
the latest installed Go version.

Fixes #901
---
 autoload/go/complete.vim |  4 ++++
 autoload/go/util.vim     | 25 +++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/autoload/go/complete.vim b/autoload/go/complete.vim
index 178345366a..4bdafb638a 100644
--- a/autoload/go/complete.vim
+++ b/autoload/go/complete.vim
@@ -32,7 +32,9 @@ function! s:gocodeCommand(cmd, preargs, args)
   " we might hit cache problems, as gocode doesn't handle well different
   " GOPATHS: https://github.com/nsf/gocode/issues/239
   let old_gopath = $GOPATH
+  let old_goroot = $GOROOT
   let $GOPATH = go#path#Detect()
+  let $GOROOT = go#util#env("goroot")
 
   let socket_type = get(g:, 'go_gocode_socket_type', s:sock_type)
   let cmd = printf('%s -sock %s %s %s %s', 
@@ -45,6 +47,8 @@ function! s:gocodeCommand(cmd, preargs, args)
 
   let result = go#util#System(cmd)
   let $GOPATH = old_gopath
+  let $GOROOT = old_goroot
+
   if go#util#ShellError() != 0
     return "[\"0\", []]"
   else
diff --git a/autoload/go/util.vim b/autoload/go/util.vim
index 0251b14a43..8792e2304c 100644
--- a/autoload/go/util.vim
+++ b/autoload/go/util.vim
@@ -43,6 +43,31 @@ function! go#util#IsWin()
   return 0
 endfunction
 
+let s:env_cache = {}
+
+" env returns the go environment variable for the given key. Where key can be
+" GOARCH, GOOS, GOROOT, etc... It caches the result and returns the cached
+" version. 
+function! go#util#env(key)
+  let l:key = tolower(a:key)
+  if has_key(s:env_cache, l:key)
+    return s:env_cache[l:key]
+  endif
+
+  if executable('go')
+    let l:var = call('go#util#'.l:key, [])
+    if go#util#ShellError() != 0
+      call go#util#EchoError(printf("'go env %s' failed", toupper(l:key)))
+      return ''
+    endif
+  else
+    let l:var = eval("$".toupper(a:key))
+  endif
+
+  let s:env_cache[l:key] = l:var
+  return l:var
+endfunction
+
 function! go#util#goarch()
   return substitute(go#util#System('go env GOARCH'), '\n', '', 'g')
 endfunction