Fix cursor position at x=0 changing to x=1 on resize

Fixes #5635

docs/changelog.rst

@@ -46,6 +46,8 @@ Detailed list of changes
 
 - Wayland GNOME: Fix ghosting when using :opt:`background_tint` (:iss:`5605`)
 
+- Fix cursor position at x=0 changing to x=1 on resize (:iss:`5635`)
+
 0.26.4 [2022-10-17]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

kitty/rewrap.h

@@ -81,7 +81,7 @@ rewrap_inner(BufType *src, BufType *dest, const index_type src_limit, HistoryBuf
             for (TrackCursor *t = track; !t->is_sentinel; t++) {
                 if (t->is_tracked_line && src_x <= t->x && t->x < src_x + num) {
                     t->y = dest_y;
-                    t->x = dest_x + (t->x - src_x + 1);
+                    t->x = dest_x + (t->x - src_x + (t->x > 0));
                 }
             }
             src_x += num; dest_x += num;

kitty/screen.c

@@ -368,6 +368,7 @@ screen_resize(Screen *self, unsigned int lines, unsigned int columns) {
     if (n == NULL) return false;
     Py_CLEAR(self->main_linebuf); self->main_linebuf = n;
     if (is_main) setup_cursor(cursor);
+    /* printf("old_cursor: (%u, %u) new_cursor: (%u, %u) beyond_content: %d\n", self->cursor->x, self->cursor->y, cursor.after.x, cursor.after.y, cursor.is_beyond_content); */
     setup_cursor(main_saved_cursor);
     grman_resize(self->main_grman, self->lines, lines, self->columns, columns);
 
@@ -396,7 +397,6 @@ screen_resize(Screen *self, unsigned int lines, unsigned int columns) {
     clear_selection(&self->selections);
     clear_selection(&self->url_ranges);
     self->last_visited_prompt.is_set = false;
-    /* printf("old_cursor: (%u, %u) new_cursor: (%u, %u) beyond_content: %d\n", self->cursor->x, self->cursor->y, cursor_x, cursor_y, cursor_is_beyond_content); */
 #define S(c, w) c->x = MIN(w.after.x, self->columns - 1); c->y = MIN(w.after.y, self->lines - 1);
     S(self->cursor, cursor);
     S((&(self->main_savepoint.cursor)), main_saved_cursor);

kitty_tests/screen.py

@@ -332,6 +332,17 @@ class TestScreen(BaseTest):
         s.resize(s.lines - 1, s.columns)
         self.ae(x_before, s.cursor.x)
 
+    def test_cursor_position_after_resize(self):
+        # test x position remains the same after resize
+        s = self.create_screen()
+        s.draw('abc')
+        b = s.cursor.x
+        s.resize(7, s.columns)
+        self.assertEqual(s.cursor.x, b)
+        s.cursor.x = 0
+        s.resize(5, s.columns)
+        self.assertEqual(s.cursor.x, 0)
+
     def test_scrollback_fill_after_resize(self):
         def prepare_screen(content=()):
             ans = self.create_screen(options={'scrollback_fill_enlarged_window': True})