templatefilters: add "utf8" to get utf-8 bytes from local-encoding text This will be applied prior to "|json" filter. This sounds like odd, but it is necessary to handle local-encoding text as well as raw filename bytes. Because filenames are bytes in Mercurial and Unix world, {filename|json} should preserve the original byte sequence, which implies {x|json} -> '"' toutf8b(x) '"' On the other hand, most template strings are in local encoding. Because "|json" filter have to be byte-transparent to filenames, we need something to annotate an input as a local string, that's what "|utf8" will do. {x|utf8|json} -> '"' toutf8b(fromlocal(x)) '"' "|utf8" is an explicit call, so aborts if input bytes can't be converted to UTF-8.

--- a/mercurial/templatefilters.py	Sun Dec 27 17:16:45 2015 +0900
+++ b/mercurial/templatefilters.py	Sun Dec 27 17:45:05 2015 +0900
@@ -377,6 +377,10 @@
     """:emailuser: Any text. Returns the user portion of an email address."""
     return util.emailuser(text)
 
+def utf8(text):
+    """:utf8: Any text. Converts from the local character encoding to UTF-8."""
+    return encoding.fromlocal(text)
+
 def xmlescape(text):
     text = (text
             .replace('&', '&')
@@ -422,6 +426,7 @@
     "urlescape": urlescape,
     "user": userfilter,
     "emailuser": emailuser,
+    "utf8": utf8,
     "xmlescape": xmlescape,
 }