From: Mattias Engdegård <mattiase@acm.org>
Date: Sun, 16 Jan 2022 10:58:00 +0000 (+0100)
Subject: Fix Fchar_syntax for non-ASCII in unibyte buffers
X-Git-Tag: emacs-29.0.90~2905
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=b929bdaeb6bcb919d4d1a5d02713cdcac3fc44d0;p=emacs.git

Fix Fchar_syntax for non-ASCII in unibyte buffers

Fchar_syntax did not convert unibyte characters to multibyte when the
current buffer was unibyte, in contrast to `char-syntax` in
byte-compiled code (bug#53260).

* src/bytecode.c (exec_byte_code): Call out to Fchar_syntax;
the dynamic frequency is too low to justify inlining here, and it
did lead to implementations diverging.
* src/syntax.c (Fchar_syntax): Convert non-ASCII unibyte values to
multibyte.
* test/src/syntax-tests.el (syntax-char-syntax): New test.
---

diff --git a/src/bytecode.c b/src/bytecode.c
index 472992be180..b7e65d05aef 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -1167,13 +1167,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
 	  NEXT;
 
 	CASE (Bchar_syntax):
-	  {
-	    CHECK_CHARACTER (TOP);
-	    int c = XFIXNAT (TOP);
-	    if (NILP (BVAR (current_buffer, enable_multibyte_characters)))
-	      c = make_char_multibyte (c);
-	    XSETFASTINT (TOP, syntax_code_spec[SYNTAX (c)]);
-	  }
+	  TOP = Fchar_syntax (TOP);
 	  NEXT;
 
 	CASE (Bbuffer_substring):
diff --git a/src/syntax.c b/src/syntax.c
index 9df878b8edf..13c36fdf3cd 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -1101,10 +1101,11 @@ this is probably the wrong function to use, because it can't take
 `syntax-after' instead.  */)
   (Lisp_Object character)
 {
-  int char_int;
   CHECK_CHARACTER (character);
-  char_int = XFIXNUM (character);
+  int char_int = XFIXNAT (character);
   SETUP_BUFFER_SYNTAX_TABLE ();
+  if (NILP (BVAR (current_buffer, enable_multibyte_characters)))
+    char_int = make_char_multibyte (char_int);
   return make_fixnum (syntax_code_spec[SYNTAX (char_int)]);
 }
 
diff --git a/test/src/syntax-tests.el b/test/src/syntax-tests.el
index 3b9f21cde37..751a900a23e 100644
--- a/test/src/syntax-tests.el
+++ b/test/src/syntax-tests.el
@@ -506,4 +506,19 @@ the `parse-partial-sexp's are expected to stop.  See
     (should (parse-partial-sexp 1 1))
     (should-error (parse-partial-sexp 2 1))))
 
+(ert-deftest syntax-char-syntax ()
+  ;; Verify that char-syntax behaves identically in interpreted and
+  ;; byte-compiled code (bug#53260).
+  (let ((cs (byte-compile (lambda (x) (char-syntax x)))))
+    ;; Use a unibyte buffer with a syntax table using symbol syntax
+    ;; for raw byte 128.
+    (with-temp-buffer
+      (set-buffer-multibyte nil)
+      (let ((st (make-syntax-table)))
+        (modify-syntax-entry (unibyte-char-to-multibyte 128) "_" st)
+        (set-syntax-table st)
+        (should (equal (eval '(char-syntax 128) t) ?_))
+        (should (equal (funcall cs 128) ?_))))
+    (list (char-syntax 128) (funcall cs 128))))
+
 ;;; syntax-tests.el ends here