vim-patch:9.1.2001: cursor may end up in wrong window after :botright copen (#37056)

Problem:  After :botright copen and closing the quikfix window, the
          cursor ends up in the wrong window. The problem is fr_child
          always points to the first (leftmost for FR_ROW, topmost for
          FR_COL) child frame. When do :vsplit, the new window is
          created on the left, and frame_insert() updates the parent's
          fr_child to point to this new left window.
Solution: Create a snapshot before open the quickfix window and restore
          it when close it (glepnir).

closes: vim/vim#18961

b43f9ded7e

Co-authored-by: glepnir <glephunter@gmail.com>

src/nvim/buffer_defs.h

@@ -821,9 +821,10 @@ struct diffline_S {
   int lineoff;
 };
 
-#define SNAP_HELP_IDX   0
-#define SNAP_AUCMD_IDX 1
-#define SNAP_COUNT     2
+#define SNAP_HELP_IDX       0
+#define SNAP_AUCMD_IDX      1
+#define SNAP_QUICKFIX_IDX   2
+#define SNAP_COUNT          3
 
 /// Tab pages point to the top frame of each tab page.
 /// Note: Most values are NOT valid for the current tab page!  Use "curwin",

src/nvim/quickfix.c

@@ -3884,6 +3884,13 @@ static int qf_open_new_cwindow(qf_info_T *qi, int height)
     flags = IS_QF_STACK(qi) ? WSP_BOT : WSP_BELOW;
   }
   flags |= WSP_NEWLOC;
+
+  // Create a snapshot for quickfix window (not for location list)
+  // so that when closing it, we can restore to the previous window
+  if (IS_QF_STACK(qi)) {
+    flags |= WSP_QUICKFIX;
+  }
+
   if (win_split(height, flags) == FAIL) {
     return FAIL;  // not enough room for window
   }

src/nvim/window.c

@@ -1057,6 +1057,12 @@ int win_split(int size, int flags)
     clear_snapshot(curtab, SNAP_HELP_IDX);
   }
 
+  if (flags & WSP_QUICKFIX) {
+    make_snapshot(SNAP_QUICKFIX_IDX);
+  } else {
+    clear_snapshot(curtab, SNAP_QUICKFIX_IDX);
+  }
+
   return win_split_ins(size, flags, NULL, 0, NULL) == NULL ? FAIL : OK;
 }
 
@@ -2747,6 +2753,7 @@ int win_close(win_T *win, bool free_buf, bool force)
   }
 
   bool help_window = false;
+  bool quickfix_window = false;
 
   // When closing the help window, try restoring a snapshot after closing
   // the window.  Otherwise clear the snapshot, it's now invalid.
@@ -2756,6 +2763,12 @@ int win_close(win_T *win, bool free_buf, bool force)
     clear_snapshot(curtab, SNAP_HELP_IDX);
   }
 
+  if (bt_quickfix(win->w_buffer)) {
+    quickfix_window = true;
+  } else {
+    clear_snapshot(curtab, SNAP_QUICKFIX_IDX);
+  }
+
   win_T *wp;
   bool other_buffer = false;
 
@@ -2861,10 +2874,10 @@ int win_close(win_T *win, bool free_buf, bool force)
   int dir;
   wp = win_free_mem(win, &dir, NULL);
 
-  if (help_window) {
+  if (help_window || quickfix_window) {
     // Closing the help window moves the cursor back to the current window
     // of the snapshot.
-    win_T *prev_win = get_snapshot_curwin(SNAP_HELP_IDX);
+    win_T *prev_win = get_snapshot_curwin(help_window ? SNAP_HELP_IDX : SNAP_QUICKFIX_IDX);
     if (win_valid(prev_win)) {
       wp = prev_win;
     }
@@ -2939,10 +2952,10 @@ int win_close(win_T *win, bool free_buf, bool force)
 
   split_disallowed--;
 
-  // After closing the help window, try restoring the window layout from
-  // before it was opened.
-  if (help_window) {
-    restore_snapshot(SNAP_HELP_IDX, close_curwin);
+  // After closing the help or quickfix window, try restoring the window
+  // layout from before it was opened.
+  if (help_window || quickfix_window) {
+    restore_snapshot(help_window ? SNAP_HELP_IDX : SNAP_QUICKFIX_IDX, close_curwin);
   }
 
   // If the window had 'diff' set and now there is only one window left in

src/nvim/window.h

@@ -10,16 +10,17 @@
 
 /// arguments for win_split()
 enum {
-  WSP_ROOM    = 0x01,   ///< require enough room
-  WSP_VERT    = 0x02,   ///< split/equalize vertically
-  WSP_HOR     = 0x04,   ///< equalize horizontally
-  WSP_TOP     = 0x08,   ///< window at top-left of shell
-  WSP_BOT     = 0x10,   ///< window at bottom-right of shell
-  WSP_HELP    = 0x20,   ///< creating the help window
-  WSP_BELOW   = 0x40,   ///< put new window below/right
-  WSP_ABOVE   = 0x80,   ///< put new window above/left
-  WSP_NEWLOC  = 0x100,  ///< don't copy location list
-  WSP_NOENTER = 0x200,  ///< don't enter the new window
+  WSP_ROOM     = 0x01,   ///< require enough room
+  WSP_VERT     = 0x02,   ///< split/equalize vertically
+  WSP_HOR      = 0x04,   ///< equalize horizontally
+  WSP_TOP      = 0x08,   ///< window at top-left of shell
+  WSP_BOT      = 0x10,   ///< window at bottom-right of shell
+  WSP_HELP     = 0x20,   ///< creating the help window
+  WSP_BELOW    = 0x40,   ///< put new window below/right
+  WSP_ABOVE    = 0x80,   ///< put new window above/left
+  WSP_NEWLOC   = 0x100,  ///< don't copy location list
+  WSP_NOENTER  = 0x200,  ///< don't enter the new window
+  WSP_QUICKFIX = 0x400,  ///< creating the quickfix window
 };
 
 enum {

test/old/testdir/test_quickfix.vim

@@ -6980,4 +6980,15 @@ func Test_vimgrep_dummy_buffer_keep()
   %bw!
 endfunc
 
+func Test_quickfix_restore_current_win()
+  let curwin = win_getid()
+  vsplit Xb
+  wincmd p
+  botright copen
+  cclose
+
+  call assert_equal(curwin, win_getid())
+  bw! Xb
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab