Avoid assertion violations with variable-weight fonts

* src/font.c (font_score, font_delete_unmatched): Don't assume
weight, slant, and width properties of the font must be fixnums:
some variable-weight fonts violate that assumption.  Reported
by Sean Whitton <spwhitton@spwhitton.name>.  This is for builds
with Fontconfig < v2.11.91, for which the fix in
'ftfont_pattern_entity' cannot work.  (Bug#52888)

diff --git a/src/font.c b/src/font.c
index 266e5bc75c61826c978f324fbb57f6319c226c37..7e0219181c9196c7b7750f6472a68985f171654b 100644 (file)
--- a/src/font.c
+++ b/src/font.c
@@ -2183,7 +2183,9 @@ font_score (Lisp_Object entity, Lisp_Object *spec_prop)
 
   /* Score three style numeric fields.  Maximum difference is 127. */
   for (i = FONT_WEIGHT_INDEX; i <= FONT_WIDTH_INDEX; i++)
-    if (! NILP (spec_prop[i]) && ! EQ (AREF (entity, i), spec_prop[i]))
+    if (! NILP (spec_prop[i])
+       && ! EQ (AREF (entity, i), spec_prop[i])
+       && FIXNUMP (AREF (entity, i)))
       {
        EMACS_INT diff = ((XFIXNUM (AREF (entity, i)) >> 8)
                          - (XFIXNUM (spec_prop[i]) >> 8));
@@ -2764,26 +2766,31 @@ font_delete_unmatched (Lisp_Object vec, Lisp_Object spec, int size)
        {
          if (FIXNUMP (AREF (spec, prop)))
            {
-             int required = XFIXNUM (AREF (spec, prop)) >> 8;
-             int candidate = XFIXNUM (AREF (entity, prop)) >> 8;
+             if (!FIXNUMP (AREF (entity, prop)))
+               prop = FONT_SPEC_MAX;
+             else
+               {
+                 int required = XFIXNUM (AREF (spec, prop)) >> 8;
+                 int candidate = XFIXNUM (AREF (entity, prop)) >> 8;
 
-             if (candidate != required
+                 if (candidate != required
 #ifdef HAVE_NTGUI
-                 /* A kludge for w32 font search, where listing a
-                    family returns only 4 standard weights: regular,
-                    italic, bold, bold-italic.  For other values one
-                    must specify the font, not just the family in the
-                    :family attribute of the face.  But specifying
-                    :family in the face attributes looks for regular
-                    weight, so if we require exact match, the
-                    non-regular font will be rejected.  So we relax
-                    the accuracy of the match here, and let
-                    font_sort_entities find the best match.  */
-                 && (prop != FONT_WEIGHT_INDEX
-                     || eabs (candidate - required) > 100)
+                     /* A kludge for w32 font search, where listing a
+                        family returns only 4 standard weights: regular,
+                        italic, bold, bold-italic.  For other values one
+                        must specify the font, not just the family in the
+                        :family attribute of the face.  But specifying
+                        :family in the face attributes looks for regular
+                        weight, so if we require exact match, the
+                        non-regular font will be rejected.  So we relax
+                        the accuracy of the match here, and let
+                        font_sort_entities find the best match.  */
+                     && (prop != FONT_WEIGHT_INDEX
+                         || eabs (candidate - required) > 100)
 #endif
-                 )
-               prop = FONT_SPEC_MAX;
+                     )
+                   prop = FONT_SPEC_MAX;
+               }
            }
        }
       if (prop < FONT_SPEC_MAX