patch 9.0.0967: leaking memory from autocmd windows

Problem:    Leaking memory from autocmd windows.
Solution:   Free window when auc_win is not NULL.

src/autocmd.c

@@ -653,12 +653,7 @@ free_all_autocmds(void)
     }
     ga_clear(&augroups);
 
-    for (int i = 0; i < AUCMD_WIN_COUNT; ++i)
+    // aucmd_win[] is freed in win_free_all()
-	if (aucmd_win[i].auc_win_used)
-	{
-	    aucmd_win[i].auc_win_used = FALSE;
-	    win_remove(aucmd_win[i].auc_win, NULL);
-	}
 }
 #endif
 
@@ -1553,12 +1548,11 @@ aucmd_prepbuf(
 	for (auc_idx = 0; auc_idx < AUCMD_WIN_COUNT; ++auc_idx)
 	    if (!aucmd_win[auc_idx].auc_win_used)
 	    {
-		auc_win = win_alloc_popup_win();
+		if (aucmd_win[auc_idx].auc_win == NULL)
+		    aucmd_win[auc_idx].auc_win = win_alloc_popup_win();
+		auc_win = aucmd_win[auc_idx].auc_win;
 		if (auc_win != NULL)
-		{
-		    aucmd_win[auc_idx].auc_win = auc_win;
 		    aucmd_win[auc_idx].auc_win_used = TRUE;
-		}
 		break;
 	    }
 
@@ -1667,6 +1661,9 @@ win_found:
 	// Remove the window and frame from the tree of frames.
 	(void)winframe_remove(curwin, &dummy, NULL);
 	win_remove(curwin, NULL);
+
+	// The window is marked as not used, but it is not freed, it can be
+	// used again.
 	aucmd_win[aco->use_aucmd_win_idx].auc_win_used = FALSE;
 	last_status(FALSE);	    // may need to remove last status line
 

src/eval.c

@@ -5084,8 +5084,9 @@ garbage_collect(int testing)
     FOR_ALL_TAB_WINDOWS(tp, wp)
 	abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
 								  NULL, NULL);
+    // window-local variables in autocmd windows
     for (int i = 0; i < AUCMD_WIN_COUNT; ++i)
-	if (aucmd_win[i].auc_win_used)
+	if (aucmd_win[i].auc_win != NULL)
 	    abort = abort || set_ref_in_item(
 		    &aucmd_win[i].auc_win->w_winvar.di_tv, copyID, NULL, NULL);
 #ifdef FEAT_PROP_POPUP

src/globals.h

@@ -984,8 +984,9 @@ EXTERN win_T	*curwin;	// currently active window
 #define AUCMD_WIN_COUNT 5
 
 typedef struct {
-  win_T	*auc_win;	// window used in aucmd_prepbuf()
+  win_T	*auc_win;	// Window used in aucmd_prepbuf().  When not NULL the
-  int	auc_win_used;	// this auc_win is being used
+			// window has been allocated.
+  int	auc_win_used;	// This auc_win is being used.
 } aucmdwin_T;
 
 EXTERN aucmdwin_T aucmd_win[AUCMD_WIN_COUNT];

src/quickfix.c

@@ -6639,10 +6639,10 @@ load_dummy_buffer(
 
 	    // restore curwin/curbuf and a few other things
 	    aucmd_restbuf(&aco);
-	}
 
-	if (newbuf_to_wipe.br_buf != NULL && bufref_valid(&newbuf_to_wipe))
+	    if (newbuf_to_wipe.br_buf != NULL && bufref_valid(&newbuf_to_wipe))
-	    wipe_buffer(newbuf_to_wipe.br_buf, FALSE);
+		wipe_buffer(newbuf_to_wipe.br_buf, FALSE);
+	}
 
 	// Add back the "dummy" flag, otherwise buflist_findname_stat() won't
 	// skip it.

src/screen.c

@@ -2439,7 +2439,7 @@ retry:
     FOR_ALL_TAB_WINDOWS(tp, wp)
 	win_free_lsize(wp);
     for (int i = 0; i < AUCMD_WIN_COUNT; ++i)
-	if (aucmd_win[i].auc_win_used)
+	if (aucmd_win[i].auc_win != NULL)
 	    win_free_lsize(aucmd_win[i].auc_win);
 #ifdef FEAT_PROP_POPUP
     // global popup windows
@@ -2484,7 +2484,7 @@ retry:
 	}
     }
     for (int i = 0; i < AUCMD_WIN_COUNT; ++i)
-	if (aucmd_win[i].auc_win_used
+	if (aucmd_win[i].auc_win != NULL
 		&& aucmd_win[i].auc_win->w_lines == NULL
 		&& win_alloc_lines(aucmd_win[i].auc_win) == FAIL)
 	{

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    967,
 /**/
     966,
 /**/

src/window.c

@@ -3293,10 +3293,10 @@ win_free_all(void)
 	tabpage_close(TRUE);
 
     for (int i = 0; i < AUCMD_WIN_COUNT; ++i)
-	if (aucmd_win[i].auc_win_used)
+	if (aucmd_win[i].auc_win != NULL)
 	{
 	    (void)win_free_mem(aucmd_win[i].auc_win, &dummy, NULL);
-	    aucmd_win[i].auc_win_used = FALSE;
+	    aucmd_win[i].auc_win = NULL;
 	}
 
     while (firstwin != NULL)