Avoid assertion violations in Rmail due to newline cache

 src/search.c (find_newline): Avoid assertion violations in
 CHAR_TO_BYTE when a portion of the buffer was deleted and we look
 for newlines near the end of the buffer.  This happens in Rmail
 hen JIT font-lock fontifies a newly displayed portion of the
 buffer.

2 files changed, 14 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index a2ac5389f20..ca5f85a0157 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2015-02-28  Eli Zaretskii  <eliz@gnu.org>
+
+        * search.c (find_newline): Avoid assertion violations in
+        CHAR_TO_BYTE when a portion of the buffer was deleted and we look
+        for newlines near the end of the buffer.  This happens in Rmail
+        hen JIT font-lock fontifies a newly displayed portion of the
+        buffer.
+
 2015-02-23  Eli Zaretskii  <eliz@gnu.org>
 
         * w32fns.c (Fw32__menu_bar_in_use): New internal function.
diff --git a/src/search.c b/src/search.c
index eec642ecb20..73641813604 100644
--- a/src/search.c
+++ b/src/search.c
@@ -731,6 +731,12 @@ find_newline (ptrdiff_t start, ptrdiff_t start_byte, ptrdiff_t end,
                                                start, &next_change);
                 if (result)
                   {
+                    /* When the cache revalidation is deferred,
+                       next-change might point beyond ZV, which will
+                       cause assertion violation in CHAR_TO_BYTE below.
+                       Limit next_change to ZV to avoid that.  */
+                    if (next_change > ZV)
+                      next_change = ZV;
                     start = next_change;
                     lim1 = next_change = end;
                   }