Filter out bidi marks in rfc2047 and rfc2231 encoding. (see #3827)

Filter out U+200F RIGHT-TO-LEFT MARK and U+200E LEFT-TO-RIGHT MARK in
rfc2047 and 2231 encoded fields.  GNU Screen has a bug that corrupts
the display, and can cause the wrong email to appear to be selected in
the index.  Until screen fixes the issue, filter it out in mutt.

1 files changed, 8 insertions, 0 deletions

diff --git a/mbyte.c b/mbyte.c
index fb96a714..470686c9 100644
--- a/mbyte.c
+++ b/mbyte.c
@@ -548,6 +548,14 @@ int mutt_filter_unprintable (char **s)
     }
     if (!IsWPrint (wc))
       wc = '?';
+    /* HACK:
+     * Work around a gnu screen bug. See ticket #3827.
+     * Filter out the RIGHT-TO-LEFT and LEFT-TO-RIGHT bidi marks because
+     * they result in screen corruption.
+     */
+    else if (Charset_is_utf8 &&
+             ((wc == (wchar_t)0x200f) || (wc == (wchar_t)0x200e)))
+      wc = '?';
     k2 = wcrtomb (scratch, wc, &mbstate2);
     scratch[k2] = '\0';
     mutt_buffer_addstr (b, scratch);