go.mod file support

autoload/go/config.vim

@@ -278,6 +278,14 @@ function! go#config#SetAsmfmtAutosave(value) abort
   let g:go_asmfmt_autosave = a:value
 endfunction
 
+function! go#config#ModFmtAutosave() abort
+	return get(g:, "go_mod_fmt_autosave", 1)
+endfunction
+
+function! go#config#SetModFmtAutosave(value) abort
+  let g:go_mod_fmt_autosave = a:value
+endfunction
+
 function! go#config#DocMaxHeight() abort
   return get(g:, "go_doc_max_height", 20)
 endfunction

autoload/go/mod.vim

@@ -0,0 +1,140 @@
+let s:go_major_version = ""
+
+function! go#mod#Format() abort
+  " go mod only exists in `v1.11`
+  if empty(s:go_major_version)
+    let tokens = matchlist(go#util#System("go version"), '\d\+.\(\d\+\) ')
+    let s:go_major_version = str2nr(tokens[1])
+  endif
+
+  if s:go_major_version < "11" 
+    call go#util#EchoError("Go v1.11 is required to format go.mod file")
+    return
+  endif
+
+  let fname = fnamemodify(expand("%"), ':p:gs?\\?/?')
+
+  " Save cursor position and many other things.
+  let l:curw = winsaveview()
+
+  " Write current unsaved buffer to a temp file
+  let l:tmpname = tempname() . '.mod'
+  call writefile(go#util#GetLines(), l:tmpname)
+  if go#util#IsWin()
+    let l:tmpname = tr(l:tmpname, '\', '/')
+  endif
+
+  let current_col = col('.')
+  let l:args = ['go', 'mod', 'edit', '--fmt', l:tmpname]
+  let [l:out, l:err] = go#util#Exec(l:args)
+  let diff_offset = len(readfile(l:tmpname)) - line('$')
+
+  if l:err == 0
+    call go#mod#update_file(l:tmpname, fname)
+  else
+    let errors = s:parse_errors(fname, l:out)
+    call s:show_errors(errors)
+  endif
+
+  " We didn't use the temp file, so clean up
+  call delete(l:tmpname)
+
+  " Restore our cursor/windows positions.
+  call winrestview(l:curw)
+
+  " be smart and jump to the line the new statement was added/removed
+  call cursor(line('.') + diff_offset, current_col)
+
+  " Syntax highlighting breaks less often.
+  syntax sync fromstart
+endfunction
+
+" update_file updates the target file with the given formatted source
+function! go#mod#update_file(source, target)
+  " remove undo point caused via BufWritePre
+  try | silent undojoin | catch | endtry
+
+  let old_fileformat = &fileformat
+  if exists("*getfperm")
+    " save file permissions
+    let original_fperm = getfperm(a:target)
+  endif
+
+  call rename(a:source, a:target)
+
+  " restore file permissions
+  if exists("*setfperm") && original_fperm != ''
+    call setfperm(a:target , original_fperm)
+  endif
+
+  " reload buffer to reflect latest changes
+  silent edit!
+
+  let &fileformat = old_fileformat
+  let &syntax = &syntax
+
+  let l:listtype = go#list#Type("GoModFmt")
+
+  " the title information was introduced with 7.4-2200
+  " https://github.com/vim/vim/commit/d823fa910cca43fec3c31c030ee908a14c272640
+  if has('patch-7.4.2200')
+    " clean up previous list
+    if l:listtype == "quickfix"
+      let l:list_title = getqflist({'title': 1})
+    else
+      let l:list_title = getloclist(0, {'title': 1})
+    endif
+  else
+    " can't check the title, so assume that the list was for go fmt.
+    let l:list_title = {'title': 'Format'}
+  endif
+
+  if has_key(l:list_title, "title") && l:list_title['title'] == "Format"
+    call go#list#Clean(l:listtype)
+  endif
+endfunction
+
+" parse_errors parses the given errors and returns a list of parsed errors
+function! s:parse_errors(filename, content) abort
+  let splitted = split(a:content, '\n')
+
+  " list of errors to be put into location list
+  let errors = []
+  for line in splitted
+    let tokens = matchlist(line, '^\(.\{-}\):\(\d\+\):\s*\(.*\)')
+    if !empty(tokens)
+      call add(errors,{
+            \"filename": a:filename,
+            \"lnum":     tokens[2],
+            \"text":     tokens[3],
+            \ })
+    endif
+  endfor
+
+  return errors
+endfunction
+
+" show_errors opens a location list and shows the given errors. If the given
+" errors is empty, it closes the the location list
+function! s:show_errors(errors) abort
+  let l:listtype = go#list#Type("GoModFmt")
+  if !empty(a:errors)
+    call go#list#Populate(l:listtype, a:errors, 'Format')
+    call go#util#EchoError("GoModFmt returned error")
+  endif
+
+  " this closes the window if there are no errors or it opens
+  " it if there is any
+  call go#list#Window(l:listtype, len(a:errors))
+endfunction
+
+function! go#mod#ToggleModFmtAutoSave() abort
+  if go#config#ModFmtAutosave()
+    call go#config#SetModFmtAutosave(0)
+    call go#util#EchoProgress("auto mod fmt disabled")
+    return
+  end
+
+  call go#config#SetModFmtAutosave(1)
+  call go#util#EchoProgress("auto mod fmt enabled")
+endfunction

doc/vim-go.txt

@@ -806,6 +806,11 @@ CTRL-t
 
     Toggles |'g:go_fmt_autosave'|.
 
+                                                     *:GoModFmtAutoSaveToggle*
+:GoModFmtAutoSaveToggle
+
+    Toggles |'g:go_mod_fmt_autosave'|.
+
                                                      *:GoAsmFmtAutoSaveToggle*
 :GoAsmFmtAutoSaveToggle
 
@@ -880,6 +885,13 @@ CTRL-t
           }
       }
 <
+                                                                  *:GoModFmt*
+:GoModFmt
+
+    Filter the current go.mod buffer through "go mod edit -fmt" command.  It
+    tries to preserve cursor position and avoids replacing the buffer with
+    stderr output.
+
 ==============================================================================
 MAPPINGS                                                        *go-mappings*
 
@@ -1097,6 +1109,10 @@ Calls `:GoImport` for the current package
 Generate if err != nil { return ... } automatically which infer the type of
 return values and the numbers.
 
+                                                                *(go-mod-fmt)*
+
+Calls |:GoModFmt| for the current buffer
+
 ==============================================================================
 TEXT OBJECTS                                                 *go-text-objects*
 
@@ -1287,7 +1303,15 @@ doesn't break. However it's slows (creates/deletes a file for every save) and
 it's causing problems on some Vim versions. By default it's disabled. >
 
   let g:go_fmt_experimental = 0
+
 <
+                                                     *'g:go_mod_fmt_autosave'*
+
+Use this option to auto |:GoModFmt| on save. By default it's enabled >
+
+  let g:go_mod_fmt_autosave = 1
+<
+
                                                *'g:go_doc_keywordprg_enabled'*
 
 Use this option to run `godoc` on words under the cursor with |K|; this will
@@ -1497,10 +1521,10 @@ that was called. Supported values are "", "quickfix", and "locationlist".
 Specifies the type of list to use for command outputs (such as errors from
 builds, results from static analysis commands, etc...). When an expected key
 is not present in the dictionary, |'g:go_list_type'| will be used instead.
-Supported keys are "GoBuild", "GoErrCheck", "GoFmt", "GoInstall", "GoLint",
-"GoMetaLinter", "GoMetaLinterAutoSave", "GoModifyTags" (used for both
-:GoAddTags and :GoRemoveTags), "GoRename", "GoRun", and "GoTest".  Supported
-values for each command are "quickfix" and "locationlist".
+Supported keys are "GoBuild", "GoErrCheck", "GoFmt", "GoModFmt", "GoInstall",
+"GoLint", "GoMetaLinter", "GoMetaLinterAutoSave", "GoModifyTags" (used for
+both :GoAddTags and :GoRemoveTags), "GoRename", "GoRun", and "GoTest".
+Supported values for each command are "quickfix" and "locationlist".
 >
   let g:go_list_type_commands = {}
 <
@@ -1874,6 +1898,13 @@ filetype.
 The `gohtmltmpl` filetype is automatically set for `*.tmpl` files; the
 `gotexttmpl` is never automatically set and needs to be set manually.
 
+==============================================================================
+                                                    *gomod* *ft-gomod-syntax*
+go.mod file syntax~
+
+The `gomod` 'filetype' provides syntax highlighting for Go's module file 
+`go.mod`
+
 
 ==============================================================================
 DEBUGGER                                                            *go-debug*

ftdetect/gofiletype.vim

@@ -31,4 +31,9 @@ au BufReadPost *.s call s:gofiletype_post()
 
 au BufRead,BufNewFile *.tmpl set filetype=gohtmltmpl
 
+" make sure we explicitly look for a `go.mod` and the `module` starts from the
+" beginning
+au BufNewFile,BufRead go.mod
+	\ if getline(1) =~ '^module.*' | set filetype=gomod |  endif
+
 " vim: sw=2 ts=2 et

ftplugin/go/commands.vim

@@ -23,6 +23,9 @@ command! -range=0 GoSameIdsAutoToggle call go#guru#AutoToogleSameIds()
 command! -nargs=* -range GoAddTags call go#tags#Add(<line1>, <line2>, <count>, <f-args>)
 command! -nargs=* -range GoRemoveTags call go#tags#Remove(<line1>, <line2>, <count>, <f-args>)
 
+" -- mod
+command! -nargs=0 -range GoModFmt call go#mod#Format()
+
 " -- tool
 command! -nargs=* -complete=customlist,go#tool#ValidFiles GoFiles echo go#tool#Files(<f-args>)
 command! -nargs=0 GoDeps echo go#tool#Deps()

ftplugin/gomod.vim

@@ -0,0 +1,15 @@
+" gomod.vim: Vim filetype plugin for Go assembler.
+
+if exists("b:did_ftplugin")
+  finish
+endif
+let b:did_ftplugin = 1
+
+let b:undo_ftplugin = "setl fo< com< cms<"
+
+setlocal formatoptions-=t
+
+setlocal comments=s1:/*,mb:*,ex:*/,://
+setlocal commentstring=//\ %s
+
+" vim: sw=2 ts=2 et

ftplugin/gomod/commands.vim

@@ -0,0 +1,3 @@
+command! -nargs=0 -range GoModFmt call go#mod#Format()
+
+command! -nargs=0 GoModFmtAutoSaveToggle call go#mod#ToggleModFmtAutoSave()

ftplugin/gomod/mappings.vim

@@ -0,0 +1 @@
+nnoremap <silent> <Plug>(go-mod-fmt) :<C-u>call go#mod#Format()<CR>

plugin/go.vim

@@ -226,6 +226,13 @@ function! s:asmfmt_autosave()
   endif
 endfunction
 
+function! s:modfmt_autosave()
+  " go.mod code formatting on save
+  if get(g:, "go_mod_fmt_autosave", 1)
+    call go#mod#Format()
+  endif
+endfunction
+
 function! s:metalinter_autosave()
   " run gometalinter on save
   if get(g:, "go_metalinter_autosave", 0)
@@ -253,6 +260,7 @@ augroup vim-go
   endif
 
   autocmd BufWritePre *.go call s:fmt_autosave()
+  autocmd BufWritePre *.mod call s:modfmt_autosave()
   autocmd BufWritePre *.s call s:asmfmt_autosave()
   autocmd BufWritePost *.go call s:metalinter_autosave()
   autocmd BufNewFile *.go call s:template_autocreate()

syntax/gomod.vim

@@ -0,0 +1,45 @@
+" gomod.vim: Vim syntax file for go.mod file
+"
+" Quit when a (custom) syntax file was already loaded
+if exists("b:current_syntax")
+  finish
+endif
+
+syntax case match
+
+" match keywords
+syntax keyword gomodModule  module
+syntax keyword gomodRequire require
+syntax keyword gomodExclude exclude
+syntax keyword gomodReplace replace
+
+" require, exclude and replace can be also grouped into block
+syntax region gomodRequire start='require (' end=')' transparent contains=gomodRequire,gomodVersion
+syntax region gomodExclude start='exclude (' end=')' transparent contains=gomodExclude,gomodVersion
+syntax region gomodReplace start='replace (' end=')' transparent contains=gomodReplace,gomodVersion
+
+" set highlights
+highlight default link gomodModule  Keyword
+highlight default link gomodRequire Keyword
+highlight default link gomodExclude Keyword
+highlight default link gomodReplace Keyword
+
+" comments are always in form of // ...
+syntax region gomodComment  start="//" end="$" contains=@Spell
+highlight default link gomodComment Comment
+
+" make sure quoted import paths are higlighted
+syntax region gomodString start=+"+ skip=+\\\\\|\\"+ end=+"+ 
+highlight default link gomodString  String 
+
+" replace operator is in the form of '=>'
+syntax match gomodReplaceOperator "\v\=\>"
+highlight default link gomodReplaceOperator Operator
+
+
+" highlight semver, note that this is very simple. But it works for now
+syntax match gomodVersion "v\d\+\.\d\+\.\d\+"
+syntax match gomodVersion "v\d\+\.\d\+\.\d\+-.*"
+highlight default link gomodVersion Identifier
+
+let b:current_syntax = "gomod"