Fix sxhash-equal on bytecodes, markers, etc.

Problem reported by Pip Cet (Bug#38912#14).
* doc/lispref/objects.texi (Equality Predicates):
Document better when ‘equal’ looks inside objects.
* doc/lispref/windows.texi (Window Configurations):
Don’t say that ‘equal’ looks inside window configurations.
* etc/NEWS: Mention the change.
* src/fns.c (internal_equal):
Do not look inside window configurations.
(sxhash_obj): Hash markers, byte-code function objects,
char-tables, and font objects consistently with Fequal.
* src/window.c (compare_window_configurations):
Now static.  Remove last argument.  Caller changed.
* test/lisp/ffap-tests.el (ffap-other-window--bug-25352):
Use compare-window-configurations, not ‘equal’.
* test/src/fns-tests.el (test-sxhash-equal): New test.

1 files changed, 5 insertions, 16 deletions

diff --git a/src/window.c b/src/window.c
index ff17cd88f38..8cdad27b664 100644
--- a/src/window.c
+++ b/src/window.c
@@ -7976,19 +7976,17 @@ foreach_window_1 (struct window *w, bool (*fn) (struct window *, void *),
 /* Return true if window configurations CONFIGURATION1 and CONFIGURATION2
    describe the same state of affairs.  This is used by Fequal.
 
-   IGNORE_POSITIONS means ignore non-matching scroll positions
-   and the like.
+   Ignore non-matching scroll positions and the like.
 
    This ignores a couple of things like the dedication status of
    window, combination_limit and the like.  This might have to be
    fixed.  */
 
-bool
+static bool
 compare_window_configurations (Lisp_Object configuration1,
-                               Lisp_Object configuration2,
-                               bool ignore_positions)
+                               Lisp_Object configuration2)
 {
-  register struct save_window_data *d1, *d2;
+  struct save_window_data *d1, *d2;
   struct Lisp_Vector *sws1, *sws2;
   ptrdiff_t i;
 
@@ -8006,9 +8004,6 @@ compare_window_configurations (Lisp_Object configuration1,
       || d1->frame_menu_bar_lines != d2->frame_menu_bar_lines
       || !EQ (d1->selected_frame, d2->selected_frame)
       || !EQ (d1->f_current_buffer, d2->f_current_buffer)
-      || (!ignore_positions
-          && (!EQ (d1->minibuf_scroll_window, d2->minibuf_scroll_window)
-              || !EQ (d1->minibuf_selected_window, d2->minibuf_selected_window)))
       || !EQ (d1->focus_frame, d2->focus_frame)
       /* Verify that the two configurations have the same number of windows.  */
       || sws1->header.size != sws2->header.size)
@@ -8041,12 +8036,6 @@ compare_window_configurations (Lisp_Object configuration1,
              equality.  */
           || !EQ (sw1->parent, sw2->parent)
           || !EQ (sw1->prev, sw2->prev)
-          || (!ignore_positions
-              && (!EQ (sw1->hscroll, sw2->hscroll)
-                  || !EQ (sw1->min_hscroll, sw2->min_hscroll)
-                  || !EQ (sw1->start_at_line_beg, sw2->start_at_line_beg)
-                  || NILP (Fequal (sw1->start, sw2->start))
-                  || NILP (Fequal (sw1->pointm, sw2->pointm))))
           || !EQ (sw1->left_margin_cols, sw2->left_margin_cols)
           || !EQ (sw1->right_margin_cols, sw2->right_margin_cols)
           || !EQ (sw1->left_fringe_width, sw2->left_fringe_width)
@@ -8071,7 +8060,7 @@ This function ignores details such as the values of point
 and scrolling positions.  */)
   (Lisp_Object x, Lisp_Object y)
 {
-  if (compare_window_configurations (x, y, true))
+  if (compare_window_configurations (x, y))
     return Qt;
   return Qnil;
 }