terminal: handle size when switching buffers in window

src/nvim/buffer.c

@@ -1472,6 +1472,10 @@ void set_curbuf(buf_T *buf, int action)
     if (old_tw != curbuf->b_p_tw)
       check_colorcolumn(curwin);
   }
+
+  if (bufref_valid(&prevbufref) && prevbuf->terminal != NULL) {
+    terminal_check_size(prevbuf->terminal);
+  }
 }
 
 /*

src/nvim/buffer_defs.h

@@ -1034,10 +1034,13 @@ struct window_S {
   int w_width;                      /* Width of window, excluding separation. */
   int w_vsep_width;                 /* Number of separator columns (0 or 1). */
 
+  // inner size of window, which can be overriden by external UI
   int w_height_inner;
   int w_width_inner;
+  // external UI request. If non-zero, the inner size will use this.
   int w_height_request;
   int w_width_request;
+
   /*
    * === start of cached values ====
    */

src/nvim/ex_cmds.c

@@ -2678,6 +2678,10 @@ int do_ecmd(
 
 
 theend:
+  if (bufref_valid(&old_curbuf) && old_curbuf.br_buf->terminal != NULL) {
+    terminal_check_size(old_curbuf.br_buf->terminal);
+  }
+
   if (did_inc_redrawing_disabled) {
     RedrawingDisabled--;
   }

src/nvim/move.c

@@ -1452,7 +1452,8 @@ void scroll_cursor_bot(int min_scroll, int set_topbot)
          curwin->w_topline = loff.lnum) {
       loff.lnum = curwin->w_topline;
       topline_back(&loff);
-      if (loff.height == MAXCOL || used + loff.height > curwin->w_height_inner) {
+      if (loff.height == MAXCOL
+          || used + loff.height > curwin->w_height_inner) {
         break;
       }
       used += loff.height;

src/nvim/terminal.c

@@ -337,19 +337,16 @@ void terminal_close(Terminal *term, char *msg)
 void terminal_check_size(Terminal *term)
 {
   if (term->closed) {
-    // TODO: WTF does this mean:
-    // If two windows display the same terminal and one is closed by keypress.
     return;
   }
+
   int curwidth, curheight;
   vterm_get_size(term->vt, &curheight, &curwidth);
   uint16_t width = 0, height = 0;
 
-  bool window_seen = false;
 
   FOR_ALL_TAB_WINDOWS(tp, wp) {
     if (wp->w_buffer && wp->w_buffer->terminal == term) {
-      window_seen = true;
       const uint16_t win_width =
         (uint16_t)(MAX(0, wp->w_width_inner - win_col_off(wp)));
       width = MAX(width, win_width);
@@ -357,6 +354,8 @@ void terminal_check_size(Terminal *term)
     }
   }
 
+  // if no window displays the terminal, or such all windows are zero-height,
+  // don't resize the terminal.
   if ((curheight == height && curwidth == width) || height == 0 || width == 0) {
     return;
   }

src/nvim/ui.c

@@ -453,7 +453,7 @@ void ui_grid_resize(handle_T grid_handle, int width, int height, Error *error)
   }
 
   // non-positive indicates no request
-  wp->w_height_request = (int)MAX(height,0);
-  wp->w_width_request = (int)MAX(width,0);
+  wp->w_height_request = (int)MAX(height, 0);
+  wp->w_width_request = (int)MAX(width, 0);
   win_set_inner_size(wp);
 }

src/nvim/window.c

@@ -4126,7 +4126,7 @@ void win_alloc_lines(win_T *wp)
 {
   wp->w_lines_valid = 0;
   assert(wp->w_height_inner >= 0);
-  // TODO(bfredl) :this should work, add call to win_set_inner_size?
+  // TODO(bfredl): this should work, add call to win_set_inner_size?
   // wp->w_lines = xcalloc(wp->w_height_inner+1, sizeof(wline_T));
   wp->w_lines = xcalloc(MAX(wp->w_height_inner + 1, Rows), sizeof(wline_T));
 }