config: remove support for g:go_autodetect_gopath

Remove support for g:go_autodetect_gopath; it was only necessary for
tools like gb and godep. Both of those were long ago archived and
there's no need for them now with Go modules and vendoring.

Fixes fatih#3065

autoload/go/config.vim

@@ -2,10 +2,6 @@
 let s:cpo_save = &cpo
 set cpo&vim
 
-function! go#config#AutodetectGopath() abort
-	return get(g:, 'go_autodetect_gopath', 0)
-endfunction
-
 function! go#config#ListTypeCommands() abort
   return get(g:, 'go_list_type_commands', {})
 endfunction

autoload/go/path.vim

@@ -69,60 +69,6 @@ function! s:HasPath(path) abort
   return hasA || hasB
 endfunction
 
-" Detect returns the current GOPATH. If a package manager is used, such as
-" Godeps, GB, it will modify the GOPATH so those directories take precedence
-" over the current GOPATH. It also detects diretories whose are outside
-" GOPATH.
-function! go#path#Detect() abort
-  let gopath = go#path#Default()
-
-  let current_dir = fnameescape(expand('%:p:h'))
-
-  " TODO(arslan): this should be changed so folders or files should be
-  " fetched from a customizable list. The user should define any new package
-  " management tool by it's own.
-
-  " src folders outside $GOPATH
-  let src_roots = finddir("src", current_dir .";", -1)
-
-  " for cases like GOPATH/src/foo/src/bar, pick up GOPATH/src instead of
-  " GOPATH/src/foo/src
-  let src_root = ""
-  if len(src_roots) > 0
-    let src_root = src_roots[-1]
-  endif
-
-  if !empty(src_root)
-    let src_path = fnamemodify(src_root, ':p:h:h') . go#util#PathSep()
-
-    " gb vendor plugin
-    " (https://github.com/constabulary/gb/tree/master/cmd/gb-vendor)
-    let gb_vendor_root = src_path . "vendor" . go#util#PathSep()
-    if isdirectory(gb_vendor_root) && !s:HasPath(gb_vendor_root)
-      let gopath = gb_vendor_root . go#util#PathListSep() . gopath
-    endif
-
-    if !s:HasPath(src_path)
-      let gopath =  src_path . go#util#PathListSep() . gopath
-    endif
-  endif
-
-  " Godeps
-  let godeps_root = finddir("Godeps", current_dir .";")
-  if !empty(godeps_root)
-    let godeps_path = join([fnamemodify(godeps_root, ':p:h:h'), "Godeps", "_workspace" ], go#util#PathSep())
-
-    if !s:HasPath(godeps_path)
-      let gopath =  godeps_path . go#util#PathListSep() . gopath
-    endif
-  endif
-
-  " Fix up the case where initial $GOPATH is empty,
-  " and we end up with a trailing :
-  let gopath = substitute(gopath, ":$", "", "")
-  return gopath
-endfunction
-
 " BinPath returns the binary path of installed go tools.
 function! go#path#BinPath() abort
   let bin_path = go#config#BinPath()

doc/vim-go.txt

@@ -1579,16 +1579,6 @@ There is also the |:GoBuildTags| convenience command to change or remove build
 tags.
 >
   let g:go_build_tags = ''
-<
-                                                    *'g:go_autodetect_gopath'*
-
-Automatically modify GOPATH for certain directory structures, such as for
-the `godep` tool which stores dependencies in the `Godeps` folder. What this
-means is that all tools are now working with the newly modified GOPATH. So
-|:GoDef| for example jumps to the source inside the `Godeps` (vendored)
-source. Currently `godep` and `gb` are supported. By default it's disabled.
->
-  let g:go_autodetect_gopath = 0
 <
                                                       *'g:go_textobj_enabled'*
 

ftplugin/go.vim

@@ -124,19 +124,6 @@ augroup vim-go-buffer
     " previous buffer's diagnostics aren't used.
     "autocmd BufWinEnter <buffer> call go#lsp#ClearDiagnosticHighlights()
   endif
-
-  autocmd BufEnter <buffer>
-        \  if go#config#AutodetectGopath() && !exists('b:old_gopath')
-        \|   let b:old_gopath = exists('$GOPATH') ? $GOPATH : -1
-        \|   let $GOPATH = go#path#Detect()
-        \| endif
-  autocmd BufLeave <buffer>
-        \  if exists('b:old_gopath')
-        \|   if b:old_gopath isnot -1
-        \|     let $GOPATH = b:old_gopath
-        \|   endif
-        \|   unlet b:old_gopath
-        \| endif
 augroup end
 
 " restore Vi compatibility settings

plugin/go.vim

@@ -279,12 +279,7 @@ function! s:register()
     return
   endif
 
-  let l:RestoreGopath = function('s:noop')
-  if go#config#AutodetectGopath()
-    let l:RestoreGopath = go#util#SetEnv('GOPATH', go#path#Detect())
-  endif
   call go#lsp#DidOpen(expand('<afile>:p'))
-  call call(l:RestoreGopath, [])
 endfunction
 
 function! s:noop(...) abort