patch 9.2.0209: freeze during wildmenu completion

Problem:  Vim may freeze if setcmdline() is called while the wildmenu or
          cmdline popup menu is active (rendcrx)
Solution: Cleanup completion state if cmdbuff_replaced flag has been set
          (Yasuhiro Matsumoto)

fixes:  #19742
closes: #19744

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Yasuhiro Matsumoto <mattn.jp@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/ex_getln.c

@@ -1899,6 +1899,21 @@ getcmdline_int(
 	    c = safe_vgetc();
 	} while (c == K_IGNORE || c == K_NOP);
 
+	// If the cmdline was replaced externally (e.g. by setcmdline()
+	// during an <expr> mapping), clean up the wildmenu completion
+	// state to avoid using stale completion data.
+	if (ccline.cmdbuff_replaced && xpc.xp_numfiles > 0)
+	{
+	    if (cmdline_pum_active())
+		cmdline_pum_remove(&ccline, FALSE);
+	    (void)ExpandOne(&xpc, NULL, NULL, 0, WILD_FREE);
+	    did_wild_list = FALSE;
+	    xpc.xp_context = EXPAND_NOTHING;
+	    wim_index = 0;
+	    wildmenu_cleanup(&ccline);
+	}
+	ccline.cmdbuff_replaced = FALSE;
+
 	// Skip wildmenu during history navigation via Up/Down keys
 	if (c == K_WILD && did_hist_navigate)
 	{
@@ -4518,6 +4533,7 @@ set_cmdline_str(char_u *str, int pos)
 
     p->cmdpos = pos < 0 || pos > p->cmdlen ? p->cmdlen : pos;
     new_cmdpos = p->cmdpos;
+    p->cmdbuff_replaced = TRUE;
 
     redrawcmd();
 

src/structs.h

@@ -716,6 +716,8 @@ typedef struct
     char_u	*xp_arg;	// user-defined expansion arg
     int		input_fn;	// when TRUE Invoked for input() function
 #endif
+    int		cmdbuff_replaced; // when TRUE cmdline was replaced externally
+				  // (e.g. by setcmdline())
 } cmdline_info_T;
 
 /*

src/testdir/test_cmdline.vim

@@ -4488,6 +4488,23 @@ func Test_setcmdline()
   call feedkeys(":a\<CR>", 'tx')
   call assert_equal('let foo=0', @:)
   cunmap a
+
+  " setcmdline() during wildmenu completion should not freeze.
+  " Stripping completion state when cmdline was replaced externally.
+  set wildmenu
+  call mkdir('Xsetcmdlinedir', 'pR')
+  call writefile([], 'Xsetcmdlinedir/Xfile1')
+  call writefile([], 'Xsetcmdlinedir/Xfile2')
+  func g:SetCmdLineEmpty()
+    call setcmdline('', 1)
+    return "\<Left>"
+  endfunc
+  cnoremap <expr> a g:SetCmdLineEmpty()
+  call feedkeys(":e Xsetcmdlinedir/\<Tab>a\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"', @:)
+  cunmap a
+  delfunc g:SetCmdLineEmpty
+  set nowildmenu
 endfunc
 
 func Test_rulerformat_position()

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    209,
 /**/
     208,
 /**/