Fix crash in fontset-info

[gnu-emacs] / src / fontset.c

diff --git a/src/fontset.c b/src/fontset.c
index c0303fa5a34d25f4b1e40bcedb6de04ec179462d..5fc92feb130b344df91a8b7c55711d393e14fc6d 100644 (file)
--- a/src/fontset.c
+++ b/src/fontset.c
@@ -892,18 +892,46 @@ face_for_char (struct frame *f, struct face *face, int c,
   if (ASCII_CHAR_P (c) || CHAR_BYTE8_P (c))
     return face->ascii_face->id;
 
-#ifdef HAVE_NS
-  if (face->font)
+  if (c > 0 && EQ (CHAR_TABLE_REF (Vchar_script_table, c), Qsymbol))
     {
-      /* Fonts often have characters in other scripts, like symbol, even if they
-         don't match script: symbol.  So check if the character is present
-         in the current face first.  Only enable for NS for now, but should
-         perhaps be general?  */
+      /* Fonts often have characters for punctuation and other
+         symbols, even if they don't match the 'symbol' script.  So
+         check if the character is present in the current ASCII face
+         first, and if so, use the same font as used by that face.
+         This avoids unnecessarily switching to another font when the
+         frame's default font will do.  We only do this for symbols so
+         that users could still setup fontsets to force Emacs to use
+         specific fonts for characters from other scripts, because
+         choice of fonts is frequently affected by cultural
+         preferences and font features, not by font coverage.
+         However, these considerations are unlikely to be relevant to
+         punctuation and other symbols, since the latter generally
+         aren't specific to any culture, and don't require
+         sophisticated OTF features.  */
       Lisp_Object font_object;
-      XSETFONT (font_object, face->font);
-      if (font_has_char (f, font_object, c)) return face->id;
-    }
+
+      if (face->ascii_face->font)
+       {
+         XSETFONT (font_object, face->ascii_face->font);
+         if (font_has_char (f, font_object, c))
+           return face->ascii_face->id;
+       }
+
+#if 0
+      /* Try the current face.  Disabled because it can cause
+        counter-intuitive results, whereby the font used for some
+        character depends on the characters that precede it on
+        display.  See the discussion of bug #15138.  Note that the
+        original bug reported in #15138 was in a situation where face
+        == face->ascii_face, so the above code solves that situation
+        without risking the undesirable consequences.  */
+      if (face->font)
+       {
+         XSETFONT (font_object, face->font);
+         if (font_has_char (f, font_object, c)) return face->id;
+       }
 #endif
+    }
 
   fontset = FONTSET_FROM_ID (face->fontset);
   eassert (!BASE_FONTSET_P (fontset));
@@ -1074,7 +1102,7 @@ fontset_pattern_regexp (Lisp_Object pattern)
         expression matching.  */
       ptrdiff_t regexsize = (SBYTES (pattern)
                             + (ndashes < 14 ? 2 : 5) * nstars
-                            + 2 * nescs + 1);
+                            + 2 * nescs + 3);
       USE_SAFE_ALLOCA;
       p1 = regex = SAFE_ALLOCA (regexsize);
 
@@ -1955,7 +1983,7 @@ format is the same as above.  */)
                  for (j = 0; j < ASIZE (val); j++)
                    {
                      elt = AREF (val, j);
-                     if (FONT_OBJECT_P (RFONT_DEF_OBJECT (elt)))
+                     if (!NILP (elt) && FONT_OBJECT_P (RFONT_DEF_OBJECT (elt)))
                        {
                          Lisp_Object font_object = RFONT_DEF_OBJECT (elt);
                          Lisp_Object slot, name;
@@ -2143,7 +2171,6 @@ syms_of_fontset (void)
   DEFSYM (Qfontset_info, "fontset-info");
   Fput (Qfontset_info, Qchar_table_extra_slots, make_number (1));
 
-  DEFSYM (Qprepend, "prepend");
   DEFSYM (Qappend, "append");
   DEFSYM (Qlatin, "latin");