master 93fb14d0c8: Avoid recentering when point enters invisible text at BOL

[Eli Zaretskii]

branch: master
commit 93fb14d0c805f492f0107c5ddd2914cde6d219b5
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Avoid recentering when point enters invisible text at BOL
    
    * src/xdisp.c (try_cursor_movement): Don't say we must scroll when
    point is inside invisible text at beginning of a glyph row.
    (Bug#58793)
---
 src/xdisp.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/src/xdisp.c b/src/xdisp.c
index 557cb60631..32675cd76a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -18926,7 +18926,7 @@ try_cursor_movement (Lisp_Object window, struct 
text_pos startp,
              while (MATRIX_ROW_BOTTOM_Y (row) < last_y
                     && MATRIX_ROW_END_CHARPOS (row) == PT
                     && row < MATRIX_MODE_LINE_ROW (w->current_matrix)
-                    && MATRIX_ROW_START_CHARPOS (row+1) == PT
+                    && MATRIX_ROW_START_CHARPOS (row+1) >= PT
                     && !cursor_row_p (row))
                ++row;
 
@@ -19023,7 +19023,12 @@ try_cursor_movement (Lisp_Object window, struct 
text_pos startp,
                 rc = CURSOR_MOVEMENT_SUCCESS;
            }
 
-         if (PT < MATRIX_ROW_START_CHARPOS (row)
+         if ((PT < MATRIX_ROW_START_CHARPOS (row)
+              && (row == MATRIX_FIRST_TEXT_ROW (w->current_matrix)
+                  /* Don't give up if point is inside invisible text
+                     at the beginning of its glyph row.  */
+                  || (MATRIX_ROW_END_CHARPOS (row-1)
+                      == MATRIX_ROW_START_CHARPOS (row))))
              || PT > MATRIX_ROW_END_CHARPOS (row))
            {
              /* if PT is not in the glyph row, give up.  */
@@ -19105,12 +19110,23 @@ try_cursor_movement (Lisp_Object window, struct 
text_pos startp,
                 continuation lines' rows is implemented for
                 bidi-reordered rows.  */
              bool rv = false;
+             bool pt_invis = false;
+             Lisp_Object val = get_char_property_and_overlay (make_fixnum (PT),
+                                                              Qinvisible,
+                                                              Qnil, NULL);
+
+             if (TEXT_PROP_MEANS_INVISIBLE (val) != 0)
+               pt_invis = true;
 
              do
                {
                  bool at_zv_p = false, exact_match_p = false;
 
-                 if (MATRIX_ROW_START_CHARPOS (row) <= PT
+                 /* If point is in invisible text, we cannot assume
+                    it must be after row's start position, since the
+                    row could have invisible text at its beginning
+                    where point is located.  */
+                 if ((pt_invis || MATRIX_ROW_START_CHARPOS (row) <= PT)
                      && PT <= MATRIX_ROW_END_CHARPOS (row)
                      && cursor_row_p (row))
                    rv |= set_cursor_from_row (w, row, w->current_matrix,
@@ -19142,16 +19158,8 @@ try_cursor_movement (Lisp_Object window, struct 
text_pos startp,
                             invisible text?  In that case, we trust
                             'set_cursor_from_row' to do its job and
                             find the best position for the cursor.  */
-                         if (!exact_match_p)
-                           {
-                             Lisp_Object val =
-                               get_char_property_and_overlay (make_fixnum (PT),
-                                                              Qinvisible,
-                                                              Qnil, NULL);
-
-                             if (TEXT_PROP_MEANS_INVISIBLE (val) != 0)
-                               exact_match_p = true;
-                           }
+                         if (!exact_match_p && pt_invis)
+                           exact_match_p = true;
                        }
                      if (at_zv_p || exact_match_p)
                        {