Changes to auto-download of tools

autoload/gopher/system.vim

@@ -32,14 +32,17 @@ fun! s:init() abort
     call gopher#info('installing gopls; this may take a minute')
     call s:tool('gopls')
   endif
+  " goimports is similarly useful, but not directly referenced by gopher.vim
   if !executable('goimports')
-    call gopher#info('installing gopls; this may take a minute')
+    call gopher#info('installing goimports; this may take a minute')
     call s:tool('goimports')
   endif
 endfun
 
 " Setup modules and install all tools.
 fun! gopher#system#setup() abort
+  call s:setup_debug('running with g:gopher_setup flags: %s', get(g:, 'gopher_setup', []))
+
   if !s:download(1)
     return
   endif
@@ -256,25 +259,40 @@ fun! s:tool(name) abort
     return ''
   endif
 
-  let l:tool = s:tools[a:name]
-  let l:bin = s:gobin . '/' . a:name
-
-  " We already ran go install and there is a binary.
-  if l:tool[1] && filereadable(l:bin)
+  if index(get(g:, 'gopher_setup', []), 'no-auto-install') > -1
     return a:name
   endif
 
+  let l:no_vendor_gobin = index(get(g:, 'gopher_setup', []), 'no-vendor-gobin') > -1
+  let l:tool            = s:tools[a:name]
+  let l:bin             = s:gobin . '/' . a:name
+
+  if l:tool[1]
+    if l:no_vendor_gobin && exepath(a:name)
+      call s:setup_debug('%s: already in PATH; not doing anything', a:name)
+      return a:name
+    endif
+    if !l:no_vendor_gobin && filereadable(l:bin)
+      call s:setup_debug('%s: %s already exists; not doing anything', a:name, l:bin)
+      return a:name
+    endif
+  endif
+
   if !s:download(0)
     return
   endif
 
   try
-    let l:old_gobin =  exists('$GOBIN')       ? $GOBIN       : -1
-    let l:old_gomod =  exists('$GO111MODULE') ? $GO111MODULE : -1
+    if !l:no_vendor_gobin
+      let l:old_gobin = exists('$GOBIN') ? $GOBIN : -1
+      let $GOBIN = s:gobin
+    endif
 
-    let $GOBIN = s:gobin
+    let l:old_gomod =  exists('$GO111MODULE') ? $GO111MODULE : -1
     let $GO111MODULE = 'on'  " In case user set to 'off'
 
+    call s:setup_debug('%s: running go install %s', a:name, l:tool[0])
+
     let l:out = system(printf('cd %s && go install %s',
       \ shellescape(s:gotools), shellescape(l:tool[0])))
     if v:shell_error
@@ -284,7 +302,9 @@ fun! s:tool(name) abort
     " Record go install ran.
     let s:tools[a:name][1] = 1
   finally
-    call gopher#system#restore_env('GOBIN', l:old_gobin)
+    if !l:no_vendor_gobin
+      call gopher#system#restore_env('GOBIN', l:old_gobin)
+    endif
     call gopher#system#restore_env('GO111MODULE', l:old_gomod)
   endtry
 
@@ -450,5 +470,11 @@ fun! gopher#system#cache(name, ...) abort
   return [l:c[1], v:true]
 endfun
 
+fun! s:setup_debug(msg, ...) abort
+  if gopher#has_debug('setup')
+    call call('gopher#info', ['setup: ' . a:msg] + a:000)
+  endif
+endfun
+
 
 call s:init()  " At end so entire file is parsed.

doc/gopher.txt

@@ -244,8 +244,35 @@ COMMANDS                                                     *gopher-commands*
         Make sure all dependent tools are downloaded and compiled. Normally
         this is done automatically after you start Vim so it's not required to
         manually run it.
-        It's may still be useful to run as post-install/update hook, so you
-        don't have to wait for stuff to install or update on first usage.
+
+        Add the `setup` flag to |g:gopher_debug| to show more information
+        about what it's doing.
+
+        You need to set the |filetype| to `go` to run this as a post-install
+        script, since it's only loaded for Go files; for example: >
+                vim +'set ft=go' +GoSetup +'q!'
+<
+        *g:gopher_setup* = `[]`
+                A list of flags to control |:GoSetup| behaviour; allowed
+                values:
+
+                no-auto-install         Don't automatically download or
+                                        install tools upon first use; it will
+                                        be an error if a tool doesn't exist.
+                                        This is useful if you run |:GoSetup|
+                                        manually after installing and are
+                                        _sure_ all the required tools exist
+                                        and want a minor performance boost.
+
+                no-vendor-gobin         By default the tools are installed to
+                                        a "vendored" `$GOBIN` in the
+                                        gopher.vim directory to ensure 1) the
+                                        correct versions are used and 2) to
+                                        not interfere with anything else that
+                                        might be installed on the system. If
+                                        this is disabled it will run a
+                                        "normal" `go install` without setting
+                                        `$GOBIN`.
 
 :GoDiag[!] {report, clear}                                           *:GoDiag*
         Print diagnostic information. Also see |g:gopher_debug|.
@@ -467,7 +494,9 @@ just a command are documented in the command.
 
         commands    Records all shell commands; use |:GoDiag| or
                     `gopher#system#history()` to view. The last 5 commands are
-                    always saved with limited output.
+                    always saved with limited output irregardless of this flag.
+
+        setup       Be verbose about what |:GoSetup| does.
 
 *g:gopher_override_vimgo* = (undefined)
         Override vim-go; this removes all vim-go commands, autocommands,