vim-patch:9.0.0967: leaking memory from autocmd windows

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

https://github.com/vim/vim/commit/84497cd06f06516f6ce727ea00c47792ce16dc70

Co-authored-by: Bram Moolenaar <Bram@vim.org>

4 files changed, 17 insertions, 16 deletions

diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index 17dac87013..6efb05ab45 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -665,12 +665,7 @@ void free_all_autocmds(void)
   })
   map_destroy(int, String)(&map_augroup_id_to_name);
 
-  for (int i = 0; i < AUCMD_WIN_COUNT; ++i) {
-    if (aucmd_win[i].auc_win_used) {
-      aucmd_win[i].auc_win_used = false;
-      win_remove(aucmd_win[i].auc_win, NULL);
-    }
-  }
+  // aucmd_win[] is freed in win_free_all()
 }
 #endif
 
@@ -1418,10 +1413,12 @@ void aucmd_prepbuf(aco_save_T *aco, buf_T *buf)
   if (win == NULL) {
     for (auc_idx = 0; auc_idx < AUCMD_WIN_COUNT; auc_idx++) {
       if (!aucmd_win[auc_idx].auc_win_used) {
-        win_alloc_aucmd_win(auc_idx);
+        if (aucmd_win[auc_idx].auc_win == NULL) {
+          win_alloc_aucmd_win(auc_idx);
+          need_append = false;
+        }
         auc_win = aucmd_win[auc_idx].auc_win;
         aucmd_win[auc_idx].auc_win_used = true;
-        need_append = false;
         break;
       }
     }
@@ -1520,6 +1517,8 @@ win_found:
       grid_free(&curwin->w_grid_alloc);
     }
 
+    // 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;
 
     if (!valid_tabpage_win(curtab)) {
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index d316d60efa..c4afd6934c 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -4174,8 +4174,9 @@ bool garbage_collect(bool testing)
       ABORTING(set_ref_in_fmark)(wp->w_jumplist[i].fmark, copyID);
     }
   }
+  // 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) {
       ABORTING(set_ref_in_item)(&aucmd_win[i].auc_win->w_winvar.di_tv, copyID, NULL, NULL);
     }
   }
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index feeaae1d7f..9b4ef66b14 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -429,8 +429,9 @@ EXTERN win_T *curwin;        // currently active window
 enum { AUCMD_WIN_COUNT = 5, };
 
 typedef struct {
-  win_T *auc_win;    ///< window used in aucmd_prepbuf()
-  int auc_win_used;  ///< this auc_win is being used
+  win_T *auc_win;     ///< Window used in aucmd_prepbuf().  When not NULL the
+                      ///< window has been allocated.
+  bool auc_win_used;  ///< This auc_win is being used.
 } aucmdwin_T;
 
 EXTERN aucmdwin_T aucmd_win[AUCMD_WIN_COUNT];
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 984287cf81..2927855073 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -3092,18 +3092,18 @@ void win_free_all(void)
     win_remove(lastwin, NULL);
     int dummy;
     (void)win_free_mem(wp, &dummy, NULL);
-    for (int i = 0; i < AUCMD_WIN_COUNT; ++i) {
+    for (int i = 0; i < AUCMD_WIN_COUNT; i++) {
       if (aucmd_win[i].auc_win == wp) {
-        aucmd_win[i].auc_win_used = false;
+        aucmd_win[i].auc_win = NULL;
       }
     }
   }
 
-  for (int i = 0; i < AUCMD_WIN_COUNT; ++i) {
-    if (aucmd_win[i].auc_win_used) {
+  for (int i = 0; i < AUCMD_WIN_COUNT; i++) {
+    if (aucmd_win[i].auc_win != NULL) {
       int dummy;
       (void)win_free_mem(aucmd_win[i].auc_win, &dummy, NULL);
-      aucmd_win[i].auc_win_used = false;
+      aucmd_win[i].auc_win = NULL;
     }
   }