templater: always join() over a wrapped object (BC)

This is a behavior change in a sense that join() of a byte string is no
longer "implementation dependent." Before, if a byte string was backed by
a lazy generator, join() would concatenate each chunk with the specified
separator, which seems wrong. The new behavior is always join() each byte.

TypeError on join() over uniterable is also fixed.

mercurial/templatefuncs.py

@@ -36,6 +36,7 b' from .utils import ('
 )
 
 evalrawexp = templateutil.evalrawexp
+evalwrapped = templateutil.evalwrapped
 evalfuncarg = templateutil.evalfuncarg
 evalboolean = templateutil.evalboolean
 evaldate = templateutil.evaldate
@@ -327,17 +328,11 b' def join(context, mapping, args):'
         # i18n: "join" is a keyword
         raise error.ParseError(_("join expects one or two arguments"))
 
-    joinset = evalrawexp(context, mapping, args[0])
+    joinset = evalwrapped(context, mapping, args[0])
     joiner = " "
     if len(args) > 1:
         joiner = evalstring(context, mapping, args[1])
-    if isinstance(joinset, templateutil.wrapped):
-        return joinset.join(context, mapping, joiner)
-    # TODO: rethink about join() of a byte string, which had no defined
-    # behavior since a string may be either a bytes or a generator.
-    # TODO: fix type error on join() of non-iterable
-    joinset = templateutil.unwrapvalue(context, mapping, joinset)
-    return templateutil.joinitems(pycompat.maybebytestr(joinset), joiner)
+    return joinset.join(context, mapping, joiner)
 
 @templatefunc('label(label, expr)')
 def label(context, mapping, args):

tests/test-command-template.t

@@ -3249,6 +3249,17 b' Test manifest/get() can be join()-ed as '
   $ hg log -R latesttag -r tip -T '{join(get(extras, "branch"), "")}\n'
   default
 
+Test join() over string
+
+  $ hg log -R latesttag -r tip -T '{join(rev|stringify, ".")}\n'
+  1.1
+
+Test join() over uniterable
+
+  $ hg log -R latesttag -r tip -T '{join(rev, "")}\n'
+  hg: parse error: 11 is not iterable
+  [255]
+
 Test min/max of integers
 
   $ hg log -R latesttag -l1 -T '{min(revset("9:10"))}\n'