vim-patch:9.0.1443: ending Insert mode when accessing a hidden prompt buffer (#22984)

Problem:    Ending Insert mode when accessing a hidden prompt buffer.
Solution:   Don't stop Insert mode when it was active before. (closes vim/vim#12237)

https://github.com/vim/vim/commit/05a627c3d4e42a18f76c14828d68ee4747118211

Co-authored-by: Bram Moolenaar <Bram@vim.org>

4 files changed, 24 insertions, 0 deletions

diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index f1ce919942..726344a42b 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -1421,6 +1421,8 @@ void aucmd_prepbuf(aco_save_T *aco, buf_T *buf)
   aco->save_curwin_handle = curwin->handle;
   aco->save_curbuf = curbuf;
   aco->save_prevwin_handle = prevwin == NULL ? 0 : prevwin->handle;
+  aco->save_State = State;
+
   if (win != NULL) {
     // There is a window for "buf" in the current tab page, make it the
     // curwin.  This is preferred, it has the least side effects (esp. if
@@ -1497,6 +1499,10 @@ void aucmd_restbuf(aco_save_T *aco)
 win_found:
     // May need to stop Insert mode if we were in a prompt buffer.
     leaving_window(curwin);
+    // Do not stop Insert mode when already in Insert mode before.
+    if (aco->save_State & MODE_INSERT) {
+      stop_insert_mode = false;
+    }
     // Remove the window.
     win_remove(curwin, NULL);
     pmap_del(handle_T)(&window_handles, curwin->handle);
diff --git a/src/nvim/autocmd.h b/src/nvim/autocmd.h
index 791b589167..6dbd18ba7c 100644
--- a/src/nvim/autocmd.h
+++ b/src/nvim/autocmd.h
@@ -32,6 +32,7 @@ typedef struct {
   bufref_T new_curbuf;            ///< new curbuf
   char *globaldir;                ///< saved value of globaldir
   bool save_VIsual_active;        ///< saved VIsual_active
+  int save_State;                 ///< saved State
 } aco_save_T;
 
 typedef struct AutoCmd_S AutoCmd;
diff --git a/test/functional/legacy/prompt_buffer_spec.lua b/test/functional/legacy/prompt_buffer_spec.lua
index 6c72cde855..5c3f8a6f8c 100644
--- a/test/functional/legacy/prompt_buffer_spec.lua
+++ b/test/functional/legacy/prompt_buffer_spec.lua
@@ -247,6 +247,7 @@ describe('prompt buffer', function()
 
       func DoAppend()
         call appendbufline('prompt', '$', 'Test')
+        return ''
       endfunc
     ]])
     feed('asomething<CR>')
@@ -254,7 +255,12 @@ describe('prompt buffer', function()
     neq(prev_win, meths.get_current_win())
     feed('exit<CR>')
     eq(prev_win, meths.get_current_win())
+    eq({ mode = 'n', blocking = false }, meths.get_mode())
     command('call DoAppend()')
     eq({ mode = 'n', blocking = false }, meths.get_mode())
+    feed('i')
+    eq({ mode = 'i', blocking = false }, meths.get_mode())
+    command('call DoAppend()')
+    eq({ mode = 'i', blocking = false }, meths.get_mode())
   end)
 end)
diff --git a/test/old/testdir/test_prompt_buffer.vim b/test/old/testdir/test_prompt_buffer.vim
index 43d8bb4789..2cc3f19b59 100644
--- a/test/old/testdir/test_prompt_buffer.vim
+++ b/test/old/testdir/test_prompt_buffer.vim
@@ -271,6 +271,7 @@ func Test_prompt_appending_while_hidden()
 
       func DoAppend()
         call appendbufline('prompt', '$', 'Test')
+        return ''
       endfunc
   END
   call writefile(script, 'XpromptBuffer', 'D')
@@ -283,11 +284,21 @@ func Test_prompt_appending_while_hidden()
 
   call term_sendkeys(buf, "exit\<CR>")
   call TermWait(buf)
+  call assert_notmatch('-- INSERT --', term_getline(buf, 10))
 
   call term_sendkeys(buf, ":call DoAppend()\<CR>")
   call TermWait(buf)
   call assert_notmatch('-- INSERT --', term_getline(buf, 10))
 
+  call term_sendkeys(buf, "i")
+  call TermWait(buf)
+  call assert_match('-- INSERT --', term_getline(buf, 10))
+
+  call term_sendkeys(buf, "\<C-R>=DoAppend()\<CR>")
+  call TermWait(buf)
+  call assert_match('-- INSERT --', term_getline(buf, 10))
+
+  call term_sendkeys(buf, "\<Esc>")
   call StopVimInTerminal(buf)
 endfunc