patch 9.1.1573: Memory leak when pressing Ctrl-D in cmdline mode

Problem:  Memory leak when pressing Ctrl-D in cmdline mode
          (after 9.1.1571).
Solution: Free prev_cmdbuff before assigning to it.
          (zeertzjq).

Existing tests already cover this. This change fixes the CI failure.

closes: #17807

Signed-off-by: zeertzjq <[email protected]>
Signed-off-by: Christian Brabandt <[email protected]>

Author: zeertzjq

src/ex_getln.c

@@ -1822,6 +1822,8 @@ getcmdline_int(
 	int end_wildmenu;
 	int prev_cmdpos = ccline.cmdpos;
 
+	VIM_CLEAR(prev_cmdbuff);
+
 	redir_off = TRUE;	// Don't redirect the typed command.
 				// Repeated, because a ":redir" inside
 				// completion may switch it on.
@@ -2574,10 +2576,7 @@ getcmdline_int(
 
 #ifdef FEAT_SEARCH_EXTRA
 	if (!is_state.incsearch_postponed)
-	{
-	    VIM_CLEAR(prev_cmdbuff);
 	    continue;
-	}
 #endif
 
 cmdline_changed:
@@ -2595,8 +2594,6 @@ getcmdline_int(
 			    ccline.cmdbuff, prev_cmdpos) != 0)))
 	    trigger_cmd_autocmd(cmdline_type, EVENT_CMDLINECHANGED);
 
-	VIM_CLEAR(prev_cmdbuff);
-
 	// Trigger CursorMovedC autocommands.
 	if (ccline.cmdpos != prev_cmdpos)
 	    trigger_cmd_autocmd(cmdline_type, EVENT_CURSORMOVEDC);

src/version.c

@@ -719,6 +719,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1573,
 /**/
     1572,
 /**/