From 16f54832c0ddd0cc553d4231d95778ed91ed5218 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 4 Oct 2014 15:09:46 +0300
Subject: [PATCH] Fixed a crash in 'C-x =' and in RLE followed by PDF; fixed
 'C-x =' display.

---
 lisp/descr-text.el | 15 +++++++++++----
 lisp/simple.el     | 20 ++++++++++++--------
 src/bidi.c         | 15 +++++++++------
 3 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/lisp/descr-text.el b/lisp/descr-text.el
index 02ed55b5bdf..7d5964cb368 100644
--- a/lisp/descr-text.el
+++ b/lisp/descr-text.el
@@ -434,13 +434,20 @@ relevant to POS."
                     code (encode-char char charset)))
         (setq code char))
       (cond
-       ;; Append a PDF character to directional embeddings and
-       ;; overrides, to prevent potential messup of the following
-       ;; text.
-       ((memq char '(?\x202a ?\x202b ?\x202d ?\x202e))
+       ;; Append a PDF character to left-to-right directional
+       ;; embeddings and overrides, to prevent potential messup of the
+       ;; following text.
+       ((memq char '(?\x202a ?\x202d))
 	(setq char-description
 	      (concat char-description
 		      (propertize (string ?\x202c) 'invisible t))))
+       ;; Append a PDF character followed by LRM to right-to-left
+       ;; directional embeddings and overrides, to prevent potential
+       ;; messup of the following numerical text.
+       ((memq char '(?\x202b ?\x202e))
+	(setq char-description
+	      (concat char-description
+		      (propertize (string ?\x202c ?\x200e) 'invisible t))))
        ;; Append a LRM character to any strong character to avoid
        ;; messing up the numerical codepoint.
        ((memq (get-char-code-property char 'bidi-class) '(R AL))
diff --git a/lisp/simple.el b/lisp/simple.el
index cdff8d7fc3a..69c64b6de7b 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -1216,15 +1216,19 @@ in *Help* buffer.  See also the command `describe-char'."
   (interactive "P")
   (let* ((char (following-char))
 	 (bidi-fixer
-	  (cond ((memq char '(?\x202a ?\x202b ?\x202d ?\x202e))
-		 ;; If the character is one of LRE, LRO, RLE, RLO, it
-		 ;; will start a directional embedding, which could
-		 ;; completely disrupt the rest of the line (e.g., RLO
-		 ;; will display the rest of the line right-to-left).
-		 ;; So we put an invisible PDF character after these
-		 ;; characters, to end the embedding, which eliminates
-		 ;; any effects on the rest of the line.
+	  ;; If the character is one of LRE, LRO, RLE, RLO, it will
+	  ;; start a directional embedding, which could completely
+	  ;; disrupt the rest of the line (e.g., RLO will display the
+	  ;; rest of the line right-to-left).  So we put an invisible
+	  ;; PDF character after these characters, to end the
+	  ;; embedding, which eliminates any effects on the rest of
+	  ;; the line.  For RLE and RLO we also append an invisible
+	  ;; LRM, to avoid reordering the following numerical
+	  ;; characters.
+	  (cond ((memq char '(?\x202a ?\x202d))
 		 (propertize (string ?\x202c) 'invisible t))
+		((memq char '(?\x202b ?\x202e))
+		 (propertize (string ?\x202c ?\x200e) 'invisible t))
 		;; Strong right-to-left characters cause reordering of
 		;; the following numerical characters which show the
 		;; codepoint, so append LRM to countermand that.
diff --git a/src/bidi.c b/src/bidi.c
index aad867887b1..eee2a9c623b 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -1763,10 +1763,10 @@ bidi_resolve_explicit (struct bidi_it *bidi_it)
     }
   else
     {
-	/* LRI, RLI, and FSI increment, and PDF decrements, the
-	   embedding level of the _following_ characters, so we must
-	   first look at the type of the previous character to support
-	   that.  */
+      /* LRI, RLI, and FSI increment, and PDF decrements, the
+	 embedding level of the _following_ characters, so we must
+	 first look at the type of the previous character to support
+	 that.  */
       switch (prev_type)
 	{
 	case RLI:	/* X5a */
@@ -2518,7 +2518,7 @@ bidi_level_of_next_char (struct bidi_it *bidi_it)
     {
       int bob = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
 		 ? 0 : 1);
-      bidi_type_t prev_type = bidi_it->prev.type;
+      bidi_type_t prev_type = bidi_it->type;
       bidi_type_t type_for_neutral = bidi_it->next_for_neutral.type;
       ptrdiff_t pos_for_neutral = bidi_it->next_for_neutral.charpos;
 
@@ -2553,7 +2553,10 @@ bidi_level_of_next_char (struct bidi_it *bidi_it)
 	  && bidi_explicit_dir_char (bidi_it->ch)
 	  && type_for_neutral != UNKNOWN_BT
 	  && bidi_it->charpos < pos_for_neutral)
-	type = prev_type;
+	{
+	  type = prev_type;
+	  eassert (type != UNKNOWN_BT);
+	}
     }
   else
     type = UNKNOWN_BT;
-- 
2.39.5