Support :GBrowse {url} outside of Git repository

autoload/fugitive.vim

@@ -6051,9 +6051,34 @@ augroup END
 
 " Section: :GBrowse
 
+function! s:BrowserOpen(url, mods, echo_copy) abort
+  let url = substitute(a:url, '[ <>\|"]', '\="%".printf("%02X",char2nr(submatch(0)))', 'g')
+  let mods = s:Mods(a:mods)
+  if a:echo_copy
+    if has('clipboard')
+      let @+ = url
+    endif
+    return 'echo '.string(url)
+  elseif exists(':Browse') == 2
+    return 'echo '.string(url).'|' . mods . 'Browse '.url
+  elseif exists(':OpenBrowser') == 2
+    return 'echo '.string(url).'|' . mods . 'OpenBrowser '.url
+  else
+    if !exists('g:loaded_netrw')
+      runtime! autoload/netrw.vim
+    endif
+    if exists('*netrw#BrowseX')
+      return 'echo '.string(url).'|' . mods . 'call netrw#BrowseX('.string(url).', 0)'
+    elseif exists('*netrw#NetrwBrowseX')
+      return 'echo '.string(url).'|' . mods . 'call netrw#NetrwBrowseX('.string(url).', 0)'
+    else
+      return 'echoerr ' . string('Netrw not found. Define your own :Browse to use :GBrowse')
+    endif
+  endif
+endfunction
+
 function! fugitive#BrowseCommand(line1, count, range, bang, mods, arg, args) abort
   let dir = s:Dir()
-  exe s:DirCheck(dir)
   try
     let arg = a:arg
     if arg =~# '^++remote='
@@ -6085,12 +6110,18 @@ function! fugitive#BrowseCommand(line1, count, range, bang, mods, arg, args) abo
     if rev ==# ''
       let rev = s:DirRev(@%)[1]
     endif
-    if rev =~# '^:\=$'
-      let expanded = s:Relative()
-    elseif rev =~? '^\a\a\+:[\/][\/]' && rev !~? '^fugitive:'
-      let expanded = s:Expand(substitute(rev, '\\\@<!#\|\\\@<!%\ze\w', '\\&', 'g'))
-    else
+    if rev =~? '^\a\a\+:[\/][\/]' && rev !~? '^fugitive:'
+      let rev = substitute(rev, '\\\@<![#!]\|\\\@<!%\ze\w', '\\&', 'g')
+    elseif rev ==# ':'
+      let rev = ''
+    endif
     let expanded = s:Expand(rev)
+    if expanded =~? '^\a\a\+:[\/][\/]' && expanded !~? '^fugitive:'
+      return s:BrowserOpen(s:Slash(expanded), a:mods, a:bang)
+    endif
+    exe s:DirCheck(dir)
+    if empty(expanded)
+      let expanded = s:Relative(':(top)', dir)
     endif
     let cdir = FugitiveVimPath(fugitive#CommonDir(dir))
     for subdir in ['tags/', 'heads/', 'remotes/']
@@ -6112,9 +6143,6 @@ function! fugitive#BrowseCommand(line1, count, range, bang, mods, arg, args) abo
         let type = 'blob'
       endif
       let path = path[1:-1]
-    elseif full =~? '^\a\a\+:[\/][\/]'
-      let path = s:Slash(full)
-      let type = 'url'
     elseif empty(s:Tree(dir))
       let path = '.git/' . full[strlen(dir)+1:-1]
       let type = ''
@@ -6243,9 +6271,6 @@ function! fugitive#BrowseCommand(line1, count, range, bang, mods, arg, args) abo
           \ 'line1': line1,
           \ 'line2': line2}
 
-    if type ==# 'url'
-      let url = path
-    else
     let url = ''
     for Handler in get(g:, 'fugitive_browse_handlers', [])
       let url = call(Handler, [copy(opts)])
@@ -6253,35 +6278,12 @@ function! fugitive#BrowseCommand(line1, count, range, bang, mods, arg, args) abo
         break
       endif
     endfor
-    endif
 
     if empty(url)
       call s:throw("No GBrowse handler installed for '".raw."'")
     endif
 
-    let url = substitute(url, '[ <>\|"]', '\="%".printf("%02X",char2nr(submatch(0)))', 'g')
-    let mods = s:Mods(a:mods)
-    if a:bang
-      if has('clipboard')
-        let @+ = url
-      endif
-      return 'echo '.string(url)
-    elseif exists(':Browse') == 2
-      return 'echo '.string(url).'|' . mods . 'Browse '.url
-    elseif exists(':OpenBrowser') == 2
-      return 'echo '.string(url).'|' . mods . 'OpenBrowser '.url
-    else
-      if !exists('g:loaded_netrw')
-        runtime! autoload/netrw.vim
-      endif
-      if exists('*netrw#BrowseX')
-        return 'echo '.string(url).'|' . mods . 'call netrw#BrowseX('.string(url).', 0)'
-      elseif exists('*netrw#NetrwBrowseX')
-        return 'echo '.string(url).'|' . mods . 'call netrw#NetrwBrowseX('.string(url).', 0)'
-      else
-        return 'echoerr ' . string('Netrw not found. Define your own :Browse to use :GBrowse')
-      endif
-    endif
+    return s:BrowserOpen(url, a:mods, a:bang)
   catch /^fugitive:/
     return 'echoerr ' . string(v:exception)
   endtry

doc/fugitive.txt

@@ -212,9 +212,6 @@ that are part of Git repositories).
                                                 *:GBrowse*
 :GBrowse                Open the current file, blob, tree, commit, or tag
                         in your browser at the upstream hosting provider.
-                        If a range is given, it is appropriately appended to
-                        the URL as an anchor.
-
                         Upstream providers can be added by installing an
                         appropriate Vim plugin.  For example, GitHub can be
                         supported by installing rhubarb.vim, available at
@@ -222,16 +219,18 @@ that are part of Git repositories).
 
 :GBrowse {object}       Like :GBrowse, but for a given |fugitive-object|.
 
-:GBrowse [...]@{remote} Force using the given remote rather than the remote
-                        for the current branch.  The remote is used to
-                        determine which upstream repository to link to.
-
 :{range}GBrowse [args]  Appends an anchor to the URL that emphasizes the
                         selected lines. This also forces the URL to include a
                         commit rather than a branch name so it remains valid
                         if the file changes.  You can give a range of "0" to
                         force this behavior without including an anchor.
 
+:GBrowse [...]@{remote} Force using the given remote rather than the remote
+                        for the current branch.  The remote is used to
+                        determine which upstream repository to link to.
+
+:GBrowse {url}          Open an arbitrary URL in your browser.
+
 :[range]GBrowse! [args] Like :GBrowse, but put the URL on the clipboard rather
                         than opening it.