Emulate entering vim popup, more like Neovim float

This updates the behaviour when Vim popup is enabled to work more like
Neovim floating windows or the preview window. Entering a vim popup is
emulated by initially disabling popup keymaps, and only enabling them
once the popup is marked as "entered", which means the default behaviour
is now almost identical for Vim popup, Neovim float and preview window.

Running :GitMessenger opens the Vim popup, running it again enables the
keymaps so you can navigate within the popup, running it again closes
the popup, and g:git_messenger_always_into_popup is also respected.

Author: mmrwoods

README.md

@@ -265,7 +265,9 @@ Setting `v:false` to this variable removes all the margins.
 
 When this value is set to `v:true`, enables the use of popup windows in Vim. This feature is
 experimental, and has some limitations as it is not possible to enter a popup window in Vim (unlike
-floating windows in Neovim). Similar to using Neovim with `g:git_messenger_always_into_popup` set to `v:true`.
+floating windows in Neovim). Entering a popup is emulated by initially disabling keyboard mappings
+for the popup window, and only enabling them when it been marked as "entered", either by running the
+`:GitMessenger` command a second time, or with `g:git_messenger_always_into_popup` set to `v:true`.
 
 #### `g:git_messenger_vimpopup_win_opts` (Default `{}`)
 

autoload/gitmessenger/popup.vim

@@ -68,6 +68,7 @@ let s:popup.scroll = funcref('s:popup__scroll')
 
 function! s:popup__into() dict abort
     if self.type ==# 'popup'
+        let self.entered = v:true
         return
     endif
     let winnr = self.get_winnr()
@@ -174,6 +175,10 @@ endfunction
 let s:popup.vimpopup_keymaps = funcref('s:popup__vimpopup_keymaps')
 
 function! s:popup__vimpopup_win_filter(win_id, key) dict abort
+    " if popup not marked as entered, do not handle any keys
+    if !self.entered
+        return 0
+    endif
     " Note: default q handler assumes we are in the popup window, but in Vim we
     " cannot enter the popup window, so we override the handling here for now
     let keymaps = self.vimpopup_keymaps()
@@ -286,6 +291,11 @@ function! s:popup__open() dict abort
             " Note: setbufvar() seems necessary to trigger Filetype autocmds
             call setbufvar(winbufnr(win_id), '&filetype', self.opts.filetype)
         endif
+        if has_key(self.opts, 'enter') && self.opts.enter
+            let self.entered = v:true
+        else
+            let self.entered = v:false
+        endif
         " Allow multiple invocations of :GitMessenger command to toggle popup
         " See gitmessenger#popup#close_current_popup() and gitmessenger#new()
         let b:__gitmessenger_popup = self " local to opener, removed by callback
@@ -493,6 +503,9 @@ function! gitmessenger#popup#close_current_popup() abort
     if !exists('b:__gitmessenger_popup')
         return 0
     endif
+    if b:__gitmessenger_popup.type ==# 'popup' && !b:__gitmessenger_popup.entered
+        return 0
+    endif
     call b:__gitmessenger_popup.close()
     " TODO?: Back to opened_at pos by setpos()
     return 1

doc/git-messenger.txt

@@ -301,8 +301,11 @@ might be useful when you enable borders of popup window with
 
 When this value is set to |v:true|, enables the use of popup windows in Vim.
 This feature is experimental, and has some limitations as it is not possible
-to enter a popup window in Vim (unlike floating windows in Neovim). Similar
-to using Neovim with |g:git_messenger_always_into_popup| set to |v:true|.
+to enter a popup window in Vim (unlike floating windows in Neovim). Entering a
+popup is emulated by initially disabling keyboard mappings for the popup
+window, and only enabling them when it been marked as "entered", either by
+running the |:GitMessenger| command a second time, or with
+|g:git_messenger_always_into_popup| set to |v:true|.
 
 *g:git_messenger_vimpopup_win_opts* (Default |{}|)