vim-patch:9.1.0582: Printed line doesn't overwrite colon when pressing Enter in Ex mode

Problem:  Printed line no longer overwrites colon when pressing Enter in
          Ex mode (after 9.1.0573).
Solution: Restore the behavior of pressing Enter in Ex mode.
          (zeertzjq)

closes: vim/vim#15258

https://github.com/vim/vim/commit/7d664bf0eb2cb25cb77933c8b7f11ca09929e7b8

3 files changed, 30 insertions, 8 deletions

diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 1d20829d3c..b252ba2b20 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -2426,13 +2426,17 @@ char *ex_errmsg(const char *const msg, const char *const arg)
   return ex_error_buf;
 }
 
+/// The "+" string used in place of an empty command in Ex mode.
+/// This string is used in pointer comparison.
+static char exmode_plus[] = "+";
+
 /// Handle a range without a command.
 /// Returns an error message on failure.
 static char *ex_range_without_command(exarg_T *eap)
 {
   char *errormsg = NULL;
 
-  if (*eap->cmd == '|' || exmode_active) {
+  if (*eap->cmd == '|' || (exmode_active && eap->cmd != exmode_plus + 1)) {
     eap->cmdidx = CMD_print;
     eap->argt = EX_RANGE | EX_COUNT | EX_TRLBAR;
     if ((errormsg = invalid_range(eap)) == NULL) {
@@ -2491,7 +2495,7 @@ int parse_command_modifiers(exarg_T *eap, const char **errormsg, cmdmod_T *cmod,
     if (*eap->cmd == NUL && exmode_active
         && getline_equal(eap->ea_getline, eap->cookie, getexline)
         && curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count) {
-      eap->cmd = "+";
+      eap->cmd = exmode_plus;
       if (!skip_only) {
         ex_pressedreturn = true;
       }
diff --git a/test/functional/legacy/ex_mode_spec.lua b/test/functional/legacy/ex_mode_spec.lua
index 574c3e4069..e033898d7a 100644
--- a/test/functional/legacy/ex_mode_spec.lua
+++ b/test/functional/legacy/ex_mode_spec.lua
@@ -48,7 +48,7 @@ describe('Ex mode', function()
     command('set noincsearch nohlsearch inccommand=')
     local screen = Screen.new(60, 6)
     screen:attach()
-    command([[call setline(1, ['foo foo', 'foo foo', 'foo foo'])]])
+    command([[call setline(1, repeat(['foo foo'], 4))]])
     command([[set number]])
     feed('gQ')
     screen:expect([[
@@ -110,12 +110,24 @@ describe('Ex mode', function()
       :^                                                           |
     ]])
 
+    -- The printed line should overwrite the colon
+    feed('<CR>')
+    screen:expect([[
+      {8:  2 }foo foo                                                 |
+          ^^^q                                                    |
+      {8:  2 }foo foo                                                 |
+      {8:  3 }foo foo                                                 |
+      {8:  4 }foo foo                                                 |
+      :^                                                           |
+    ]])
+
     feed(':vi<CR>')
     screen:expect([[
       {8:  1 }foo bar                                                 |
       {8:  2 }foo foo                                                 |
-      {8:  3 }^foo foo                                                 |
-      {1:~                                                           }|*2
+      {8:  3 }foo foo                                                 |
+      {8:  4 }^foo foo                                                 |
+      {1:~                                                           }|
                                                                   |
     ]])
   end)
diff --git a/test/old/testdir/test_ex_mode.vim b/test/old/testdir/test_ex_mode.vim
index 622a591c98..f55ba87a3e 100644
--- a/test/old/testdir/test_ex_mode.vim
+++ b/test/old/testdir/test_ex_mode.vim
@@ -69,7 +69,7 @@ func Test_Ex_substitute()
   CheckRunVimInTerminal
   let buf = RunVimInTerminal('', {'rows': 6})
 
-  call term_sendkeys(buf, ":call setline(1, ['foo foo', 'foo foo', 'foo foo'])\<CR>")
+  call term_sendkeys(buf, ":call setline(1, repeat(['foo foo'], 4))\<CR>")
   call term_sendkeys(buf, ":set number\<CR>")
   call term_sendkeys(buf, "gQ")
   call WaitForAssert({-> assert_match(':', term_getline(buf, 6))}, 1000)
@@ -91,8 +91,14 @@ func Test_Ex_substitute()
 
   " Pressing enter in ex mode should print the current line
   call term_sendkeys(buf, "\<CR>")
-  call WaitForAssert({-> assert_match('  3 foo foo',
-        \ term_getline(buf, 5))}, 1000)
+  call WaitForAssert({-> assert_match('  3 foo foo', term_getline(buf, 5))}, 1000)
+  call WaitForAssert({-> assert_match(':', term_getline(buf, 6))}, 1000)
+
+  " The printed line should overwrite the colon
+  call term_sendkeys(buf, "\<CR>")
+  call WaitForAssert({-> assert_match('  3 foo foo', term_getline(buf, 4))}, 1000)
+  call WaitForAssert({-> assert_match('  4 foo foo', term_getline(buf, 5))}, 1000)
+  call WaitForAssert({-> assert_match(':', term_getline(buf, 6))}, 1000)
 
   call term_sendkeys(buf, ":vi\<CR>")
   call WaitForAssert({-> assert_match('foo bar', term_getline(buf, 1))}, 1000)