vim-patch:9.0.2037: A few remaining cmdline completion issues with C-E/Y (#25686)

Problem:  A few remaining cmdline completion issues with C-E/Y
Solution: Fix cmdline completion fuzzy/Ctrl-E/Ctrl-Y/options when not
          used at the end

Fix cmdline completion fuzzy/Ctrl-E/Ctrl-Y/options when not used at the end

A few places in the cmdline completion code only works properly when the
user hits Tab (or 'wildchar') at the end of the cmdline, even though
it's supposed to work even in the middle of the line.

For fuzzy search, `:e ++ff`, and `:set hl=`, fix completion code to make
sure to use `xp_pattern_len` instead of assuming the entire `xp_pattern`
is the search pattern (since it contains texts after the cursor).

Fix Ctrl-E / Ctrl-Y to not jump to the end when canceling/accepting a
wildmenu completion. Also, make them work even when not using
`set wildoptions+=pum` as there is no drawback to doing so.
(Related issue where this was brought up: vim/vim#13331)

closes: vim/vim#13362

https://github.com/vim/vim/commit/209ec90b9b9bd948d76511c9cd2b17f47a97afe6

Cherry-pick ex_getln.c changes from patch 9.0.2035.

Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>

9 files changed, 148 insertions, 56 deletions

diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index 3cc9515fef..496c047a4a 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -267,7 +267,7 @@ int nextwild(expand_T *xp, int type, int options, bool escape)
     char *p1;
     if (cmdline_fuzzy_completion_supported(xp)) {
       // If fuzzy matching, don't modify the search string
-      p1 = xstrdup(xp->xp_pattern);
+      p1 = xstrnsave(xp->xp_pattern, xp->xp_pattern_len);
     } else {
       p1 = addstar(xp->xp_pattern, xp->xp_pattern_len, xp->xp_context);
     }
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index c52937b6c1..98da044bb4 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -4241,7 +4241,8 @@ int expand_argopt(char *pat, expand_T *xp, regmatch_T *rmp, char ***matches, int
 
   // Special handling of "ff" which acts as a short form of
   // "fileformat", as "ff" is not a substring of it.
-  if (strcmp(xp->xp_pattern, "ff") == 0) {
+  if (xp->xp_pattern_len == 2
+      && strncmp(xp->xp_pattern, "ff", xp->xp_pattern_len) == 0) {
     *matches = xmalloc(sizeof(char *));
     *numMatches = 1;
     (*matches)[0] = xstrdup("fileformat=");
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 2759dc9bb5..9d0e3d542a 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -861,6 +861,16 @@ static uint8_t *command_line_enter(int firstc, int count, int indent, bool clear
 
   cmdmsg_rl = false;
 
+  // We could have reached here without having a chance to clean up wild menu
+  // if certain special keys like <Esc> or <C-\> were used as wildchar. Make
+  // sure to still clean up to avoid memory corruption.
+  if (cmdline_pum_active()) {
+    cmdline_pum_remove();
+  }
+  wildmenu_cleanup(&ccline);
+  s->did_wild_list = false;
+  s->wim_index = 0;
+
   ExpandCleanup(&s->xpc);
   ccline.xpc = NULL;
 
@@ -1247,13 +1257,14 @@ static int command_line_execute(VimState *state, int key)
     s->c = wildmenu_translate_key(&ccline, s->c, &s->xpc, s->did_wild_list);
   }
 
-  if (cmdline_pum_active() || s->did_wild_list) {
+  int wild_type = 0;
+  const bool key_is_wc = (s->c == p_wc && KeyTyped) || s->c == p_wcm;
+  if ((cmdline_pum_active() || s->did_wild_list) && !key_is_wc) {
     // Ctrl-Y: Accept the current selection and close the popup menu.
     // Ctrl-E: cancel the cmdline popup menu and return the original text.
     if (s->c == Ctrl_E || s->c == Ctrl_Y) {
-      const int wild_type = (s->c == Ctrl_E) ? WILD_CANCEL : WILD_APPLY;
+      wild_type = (s->c == Ctrl_E) ? WILD_CANCEL : WILD_APPLY;
       (void)nextwild(&s->xpc, wild_type, WILD_NO_BEEP, s->firstc != '@');
-      s->c = Ctrl_E;
     }
   }
 
@@ -1262,7 +1273,7 @@ static int command_line_execute(VimState *state, int key)
   // 'wildcharm' or Ctrl-N or Ctrl-P or Ctrl-A or Ctrl-L).
   // If the popup menu is displayed, then PageDown and PageUp keys are
   // also used to navigate the menu.
-  bool end_wildmenu = (!(s->c == p_wc && KeyTyped) && s->c != p_wcm && s->c != Ctrl_Z
+  bool end_wildmenu = (!key_is_wc && s->c != Ctrl_Z
                        && s->c != Ctrl_N && s->c != Ctrl_P && s->c != Ctrl_A
                        && s->c != Ctrl_L);
   end_wildmenu = end_wildmenu && (!cmdline_pum_active()
@@ -1366,6 +1377,12 @@ static int command_line_execute(VimState *state, int key)
   }
 
   s->do_abbr = true;             // default: check for abbreviation
+
+  // If already used to cancel/accept wildmenu, don't process the key further.
+  if (wild_type == WILD_CANCEL || wild_type == WILD_APPLY) {
+    return command_line_not_changed(s);
+  }
+
   return command_line_handle_key(s);
 }
 
diff --git a/test/functional/fixtures/wildpum/Xdir/XdirA/XdirB/XfileC b/test/functional/fixtures/wildpum/Xnamedir/XdirA/XdirB/XfileC
index e69de29bb2..e69de29bb2 100644
--- a/test/functional/fixtures/wildpum/Xdir/XdirA/XdirB/XfileC
+++ b/test/functional/fixtures/wildpum/Xnamedir/XdirA/XdirB/XfileC
diff --git a/test/functional/fixtures/wildpum/Xdir/XdirA/XfileB b/test/functional/fixtures/wildpum/Xnamedir/XdirA/XfileB
index e69de29bb2..e69de29bb2 100644
--- a/test/functional/fixtures/wildpum/Xdir/XdirA/XfileB
+++ b/test/functional/fixtures/wildpum/Xnamedir/XdirA/XfileB
diff --git a/test/functional/fixtures/wildpum/Xdir/XfileA b/test/functional/fixtures/wildpum/Xnamedir/XfileA
index e69de29bb2..e69de29bb2 100644
--- a/test/functional/fixtures/wildpum/Xdir/XfileA
+++ b/test/functional/fixtures/wildpum/Xnamedir/XfileA
diff --git a/test/functional/ui/popupmenu_spec.lua b/test/functional/ui/popupmenu_spec.lua
index 38649a2be3..bfa4b7f14e 100644
--- a/test/functional/ui/popupmenu_spec.lua
+++ b/test/functional/ui/popupmenu_spec.lua
@@ -3096,7 +3096,7 @@ describe('builtin popupmenu', function()
           :sign define culhl= culhl=^      |
         ]])
 
-        feed('<C-U>e Xdi<Tab><Tab>')
+        feed('<C-U>e Xnamedi<Tab><Tab>')
         screen:expect([[
                                           |
           {1:~                               }|
@@ -3105,9 +3105,9 @@ describe('builtin popupmenu', function()
           {1:~                               }|
           {1:~                               }|
           {1:~                               }|
-          {1:~      }{s: XdirA/         }{1:         }|
-          {1:~      }{n: XfileA         }{1:         }|
-          :e Xdir/XdirA/^                  |
+          {1:~          }{s: XdirA/         }{1:     }|
+          {1:~          }{n: XfileA         }{1:     }|
+          :e Xnamedir/XdirA/^              |
         ]])
 
         -- Pressing <Down> on a directory name should go into that directory
@@ -3120,9 +3120,9 @@ describe('builtin popupmenu', function()
           {1:~                               }|
           {1:~                               }|
           {1:~                               }|
-          {1:~            }{s: XdirB/         }{1:   }|
-          {1:~            }{n: XfileB         }{1:   }|
-          :e Xdir/XdirA/XdirB/^            |
+          {1:~                }{s: XdirB/       }{1: }|
+          {1:~                }{n: XfileB       }{1: }|
+          :e Xnamedir/XdirA/XdirB/^        |
         ]])
 
         -- Pressing <Up> on a directory name should go to the parent directory
@@ -3135,9 +3135,9 @@ describe('builtin popupmenu', function()
           {1:~                               }|
           {1:~                               }|
           {1:~                               }|
-          {1:~      }{s: XdirA/         }{1:         }|
-          {1:~      }{n: XfileA         }{1:         }|
-          :e Xdir/XdirA/^                  |
+          {1:~          }{s: XdirA/         }{1:     }|
+          {1:~          }{n: XfileA         }{1:     }|
+          :e Xnamedir/XdirA/^              |
         ]])
 
         -- Pressing <C-A> when the popup menu is displayed should list all the
@@ -3511,6 +3511,49 @@ describe('builtin popupmenu', function()
           :sign define^                    |
         ]])
 
+        -- pressing <C-E> to end completion should work in middle of the line too
+        feed('<Esc>:set wildchazz<Left><Left><Tab>')
+        screen:expect([[
+                                          |
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~   }{s: wildchar       }{1:            }|
+          {1:~   }{n: wildcharm      }{1:            }|
+          :set wildchar^zz                 |
+        ]])
+        feed('<C-E>')
+        screen:expect([[
+                                          |
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          :set wildcha^zz                  |
+        ]])
+
+        -- pressing <C-Y> should select the current match and end completion
+        feed('<Esc>:set wildchazz<Left><Left><Tab><C-Y>')
+        screen:expect([[
+                                          |
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          {1:~                               }|
+          :set wildchar^zz                 |
+        ]])
+
         feed('<Esc>')
 
         -- check positioning with multibyte char in pattern
@@ -3726,13 +3769,13 @@ describe('builtin popupmenu', function()
       end)
 
       -- oldtest: Test_wildmenu_pum_clear_entries()
-      it('wildoptions=pum when using Ctrl-E as wildchar vim-patch:9.0.1030', function()
+      it('wildoptions=pum when using odd wildchar', function()
         screen:try_resize(30, 10)
         exec([[
           set wildoptions=pum
           set wildchar=<C-E>
         ]])
-        feed(':sign <C-E><C-E>')
+        feed(':sign <C-E>')
         screen:expect([[
                                         |
           {1:~                             }|
diff --git a/test/old/testdir/test_cmdline.vim b/test/old/testdir/test_cmdline.vim
index 00c894058e..61ee59068d 100644
--- a/test/old/testdir/test_cmdline.vim
+++ b/test/old/testdir/test_cmdline.vim
@@ -82,38 +82,38 @@ func Test_complete_list()
 endfunc
 
 func Test_complete_wildmenu()
-  call mkdir('Xdir1/Xdir2', 'p')
-  call writefile(['testfile1'], 'Xdir1/Xtestfile1')
-  call writefile(['testfile2'], 'Xdir1/Xtestfile2')
-  call writefile(['testfile3'], 'Xdir1/Xdir2/Xtestfile3')
-  call writefile(['testfile3'], 'Xdir1/Xdir2/Xtestfile4')
+  call mkdir('Xwilddir1/Xdir2', 'pR')
+  call writefile(['testfile1'], 'Xwilddir1/Xtestfile1')
+  call writefile(['testfile2'], 'Xwilddir1/Xtestfile2')
+  call writefile(['testfile3'], 'Xwilddir1/Xdir2/Xtestfile3')
+  call writefile(['testfile3'], 'Xwilddir1/Xdir2/Xtestfile4')
   set wildmenu
 
   " Pressing <Tab> completes, and moves to next files when pressing again.
-  call feedkeys(":e Xdir1/\<Tab>\<Tab>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/\<Tab>\<Tab>\<CR>", 'tx')
   call assert_equal('testfile1', getline(1))
-  call feedkeys(":e Xdir1/\<Tab>\<Tab>\<Tab>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/\<Tab>\<Tab>\<Tab>\<CR>", 'tx')
   call assert_equal('testfile2', getline(1))
 
   " <S-Tab> is like <Tab> but begin with the last match and then go to
   " previous.
-  call feedkeys(":e Xdir1/Xtest\<S-Tab>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/Xtest\<S-Tab>\<CR>", 'tx')
   call assert_equal('testfile2', getline(1))
-  call feedkeys(":e Xdir1/Xtest\<S-Tab>\<S-Tab>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/Xtest\<S-Tab>\<S-Tab>\<CR>", 'tx')
   call assert_equal('testfile1', getline(1))
 
   " <Left>/<Right> to move to previous/next file.
-  call feedkeys(":e Xdir1/\<Tab>\<Right>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/\<Tab>\<Right>\<CR>", 'tx')
   call assert_equal('testfile1', getline(1))
-  call feedkeys(":e Xdir1/\<Tab>\<Right>\<Right>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/\<Tab>\<Right>\<Right>\<CR>", 'tx')
   call assert_equal('testfile2', getline(1))
-  call feedkeys(":e Xdir1/\<Tab>\<Right>\<Right>\<Left>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/\<Tab>\<Right>\<Right>\<Left>\<CR>", 'tx')
   call assert_equal('testfile1', getline(1))
 
   " <Up>/<Down> to go up/down directories.
-  call feedkeys(":e Xdir1/\<Tab>\<Down>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/\<Tab>\<Down>\<CR>", 'tx')
   call assert_equal('testfile3', getline(1))
-  call feedkeys(":e Xdir1/\<Tab>\<Down>\<Up>\<Right>\<CR>", 'tx')
+  call feedkeys(":e Xwilddir1/\<Tab>\<Down>\<Up>\<Right>\<CR>", 'tx')
   call assert_equal('testfile1', getline(1))
 
   " this fails in some Unix GUIs, not sure why
@@ -123,9 +123,9 @@ func Test_complete_wildmenu()
     set wildcharm=<C-Z>
     cnoremap <C-J> <Down><C-Z>
     cnoremap <C-K> <Up><C-Z>
-    call feedkeys(":e Xdir1/\<Tab>\<C-J>\<CR>", 'tx')
+    call feedkeys(":e Xwilddir1/\<Tab>\<C-J>\<CR>", 'tx')
     call assert_equal('testfile3', getline(1))
-    call feedkeys(":e Xdir1/\<Tab>\<C-J>\<C-K>\<CR>", 'tx')
+    call feedkeys(":e Xwilddir1/\<Tab>\<C-J>\<C-K>\<CR>", 'tx')
     call assert_equal('testfile1', getline(1))
     set wildcharm=0
     cunmap <C-J>
@@ -134,21 +134,21 @@ func Test_complete_wildmenu()
 
   " Test for canceling the wild menu by adding a character
   redrawstatus
-  call feedkeys(":e Xdir1/\<Tab>x\<C-B>\"\<CR>", 'xt')
-  call assert_equal('"e Xdir1/Xdir2/x', @:)
+  call feedkeys(":e Xwilddir1/\<Tab>x\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"e Xwilddir1/Xdir2/x', @:)
 
   " Completion using a relative path
-  cd Xdir1/Xdir2
+  cd Xwilddir1/Xdir2
   call feedkeys(":e ../\<Tab>\<Right>\<Down>\<C-A>\<C-B>\"\<CR>", 'tx')
   call assert_equal('"e Xtestfile3 Xtestfile4', @:)
   cd -
 
   " test for wildmenumode()
   cnoremap <expr> <F2> wildmenumode()
-  call feedkeys(":cd Xdir\<Tab>\<F2>\<C-B>\"\<CR>", 'tx')
-  call assert_equal('"cd Xdir1/0', @:)
-  call feedkeys(":e Xdir1/\<Tab>\<F2>\<C-B>\"\<CR>", 'tx')
-  call assert_equal('"e Xdir1/Xdir2/1', @:)
+  call feedkeys(":cd Xwilddir\<Tab>\<F2>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"cd Xwilddir1/0', @:)
+  call feedkeys(":e Xwilddir1/\<Tab>\<F2>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"e Xwilddir1/Xdir2/1', @:)
   cunmap <F2>
 
   " Test for canceling the wild menu by pressing <PageDown> or <PageUp>.
@@ -159,9 +159,15 @@ func Test_complete_wildmenu()
   call feedkeys(":sign \<Tab>\<PageUp>\<Left>\<Right>\<C-A>\<C-B>\"\<CR>", 'tx')
   call assert_equal('"TestWildMenu', @:)
 
+  " Test for Ctrl-E/Ctrl-Y being able to cancel / accept a match
+  call feedkeys(":sign un zz\<Left>\<Left>\<Left>\<Tab>\<C-E> yy\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sign un yy zz', @:)
+
+  call feedkeys(":sign un zz\<Left>\<Left>\<Left>\<Tab>\<Tab>\<C-Y> yy\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sign unplace yy zz', @:)
+
   " cleanup
   %bwipe
-  call delete('Xdir1', 'rf')
   set nowildmenu
 endfunc
 
@@ -1046,6 +1052,9 @@ func Test_cmdline_complete_argopt()
   call assert_equal('edit', getcompletion('read ++bin ++edi', 'cmdline')[0])
 
   call assert_equal(['fileformat='], getcompletion('edit ++ff', 'cmdline'))
+  " Test ++ff in the middle of the cmdline
+  call feedkeys(":edit ++ff zz\<Left>\<Left>\<Left>\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal("\"edit ++fileformat= zz", @:)
 
   call assert_equal('dos', getcompletion('write ++ff=d', 'cmdline')[0])
   call assert_equal('mac', getcompletion('args ++fileformat=m', 'cmdline')[0])
@@ -2513,7 +2522,7 @@ func Test_wildmenu_pum()
       call feedkeys(":edit $VIMRUNTIME/\<Tab>\<Left>\<C-U>ab\<Tab>")
     endfunc
   [CODE]
-  call writefile(commands, 'Xtest')
+  call writefile(commands, 'Xtest', 'D')
 
   let buf = RunVimInTerminal('-S Xtest', #{rows: 10})
 
@@ -2571,12 +2580,12 @@ func Test_wildmenu_pum()
   call VerifyScreenDump(buf, 'Test_wildmenu_pum_13', {})
 
   " Directory name completion
-  call mkdir('Xdir/XdirA/XdirB', 'p')
-  call writefile([], 'Xdir/XfileA')
-  call writefile([], 'Xdir/XdirA/XfileB')
-  call writefile([], 'Xdir/XdirA/XdirB/XfileC')
+  call mkdir('Xnamedir/XdirA/XdirB', 'pR')
+  call writefile([], 'Xnamedir/XfileA')
+  call writefile([], 'Xnamedir/XdirA/XfileB')
+  call writefile([], 'Xnamedir/XdirA/XdirB/XfileC')
 
-  call term_sendkeys(buf, "\<C-U>e Xdi\<Tab>\<Tab>")
+  call term_sendkeys(buf, "\<C-U>e Xnamedi\<Tab>\<Tab>")
   call VerifyScreenDump(buf, 'Test_wildmenu_pum_14', {})
 
   " Pressing <Right> on a directory name should go into that directory
@@ -2651,13 +2660,13 @@ func Test_wildmenu_pum()
   call VerifyScreenDump(buf, 'Test_wildmenu_pum_31', {})
 
   " Tests a directory name contained full-width characters.
-  call mkdir('Xdir/あいう', 'p')
-  call writefile([], 'Xdir/あいう/abc')
-  call writefile([], 'Xdir/あいう/xyz')
-  call writefile([], 'Xdir/あいう/123')
+  call mkdir('Xnamedir/あいう', 'p')
+  call writefile([], 'Xnamedir/あいう/abc')
+  call writefile([], 'Xnamedir/あいう/xyz')
+  call writefile([], 'Xnamedir/あいう/123')
 
   call term_sendkeys(buf, "\<C-U>set wildmode&\<CR>")
-  call term_sendkeys(buf, ":\<C-U>e Xdir/あいう/\<Tab>")
+  call term_sendkeys(buf, ":\<C-U>e Xnamedir/あいう/\<Tab>")
   call VerifyScreenDump(buf, 'Test_wildmenu_pum_32', {})
 
   " Pressing <C-A> when the popup menu is displayed should list all the
@@ -2679,7 +2688,7 @@ func Test_wildmenu_pum()
 
   " After using <C-A> to expand all the filename matches, pressing <Up>
   " should not open the popup menu again.
-  call term_sendkeys(buf, "\<C-E>\<C-U>:cd Xdir/XdirA\<CR>")
+  call term_sendkeys(buf, "\<C-E>\<C-U>:cd Xnamedir/XdirA\<CR>")
   call term_sendkeys(buf, ":e \<Tab>\<C-A>\<Up>")
   call VerifyScreenDump(buf, 'Test_wildmenu_pum_36', {})
   call term_sendkeys(buf, "\<C-E>\<C-U>:cd -\<CR>")
@@ -2737,10 +2746,18 @@ func Test_wildmenu_pum()
   call term_sendkeys(buf, "\<PageUp>")
   call VerifyScreenDump(buf, 'Test_wildmenu_pum_50', {})
 
+  " pressing <C-E> to end completion should work in middle of the line too
+  call term_sendkeys(buf, "\<Esc>:set wildchazz\<Left>\<Left>\<Tab>")
+  call VerifyScreenDump(buf, 'Test_wildmenu_pum_51', {})
+  call term_sendkeys(buf, "\<C-E>")
+  call VerifyScreenDump(buf, 'Test_wildmenu_pum_52', {})
+
+  " pressing <C-Y> should select the current match and end completion
+  call term_sendkeys(buf, "\<Esc>:set wildchazz\<Left>\<Left>\<Tab>\<C-Y>")
+  call VerifyScreenDump(buf, 'Test_wildmenu_pum_53', {})
+
   call term_sendkeys(buf, "\<C-U>\<CR>")
   call StopVimInTerminal(buf)
-  call delete('Xtest')
-  call delete('Xdir', 'rf')
 endfunc
 
 " Test for wildmenumode() with the cmdline popup menu
@@ -3406,6 +3423,17 @@ func Test_fuzzy_completion_custom_func()
   set wildoptions&
 endfunc
 
+" Test for fuzzy completion in the middle of a cmdline instead of at the end
+func Test_fuzzy_completion_in_middle()
+  set wildoptions=fuzzy
+  call feedkeys(":set ildar wrap\<Left>\<Left>\<Left>\<Left>\<Left>\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"set wildchar wildcharm wrap", @:)
+
+  call feedkeys(":args ++odng zz\<Left>\<Left>\<Left>\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"args ++encoding= zz", @:)
+  set wildoptions&
+endfunc
+
 " Test for :breakadd argument completion
 func Test_cmdline_complete_breakadd()
   call feedkeys(":breakadd \<C-A>\<C-B>\"\<CR>", 'tx')
diff --git a/test/old/testdir/test_options.vim b/test/old/testdir/test_options.vim
index cc3f21b86b..1a3a909344 100644
--- a/test/old/testdir/test_options.vim
+++ b/test/old/testdir/test_options.vim
@@ -621,6 +621,9 @@ func Test_set_completion_string_values()
   "       \        {idx, val -> val != ':'}),
   "       \ '')
   " call assert_equal([], getcompletion('set hl+=8'..hl_display_modes, 'cmdline'))
+  " Test completion in middle of the line
+  " call feedkeys(":set hl=8b i\<Left>\<Left>\<Tab>\<C-B>\"\<CR>", 'xt')
+  " call assert_equal("\"set hl=8bi i", @:)
 
   "
   " Test flag lists