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

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.

--- a/mercurial/templatefuncs.py	Tue Mar 20 23:56:26 2018 +0900
+++ b/mercurial/templatefuncs.py	Sat Apr 21 17:00:21 2018 +0900
@@ -36,6 +36,7 @@
 )
 
 evalrawexp = templateutil.evalrawexp
+evalwrapped = templateutil.evalwrapped
 evalfuncarg = templateutil.evalfuncarg
 evalboolean = templateutil.evalboolean
 evaldate = templateutil.evaldate
@@ -327,17 +328,11 @@
         # 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):

--- a/tests/test-command-template.t	Tue Mar 20 23:56:26 2018 +0900
+++ b/tests/test-command-template.t	Sat Apr 21 17:00:21 2018 +0900
@@ -3249,6 +3249,17 @@
   $ 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'