templatefuncs: use evaldate() where seems appropriate

templatefuncs: use evaldate() where seems appropriate

This means date("today") is allowed.

Also fixes evaldate() to forcibly use the custom error message if specified.

--- a/mercurial/templatefuncs.py	Sun Mar 18 15:55:31 2018 +0900
+++ b/mercurial/templatefuncs.py	Sun Mar 18 15:58:22 2018 +0900
@@ -52,18 +52,16 @@
         # i18n: "date" is a keyword
         raise error.ParseError(_("date expects one or two arguments"))
 
-    date = evalfuncarg(context, mapping, args[0])
+    date = evaldate(context, mapping, args[0],
+                    # i18n: "date" is a keyword
+                    _("date expects a date information"))
     fmt = None
     if len(args) == 2:
         fmt = evalstring(context, mapping, args[1])
-    try:
-        if fmt is None:
-            return dateutil.datestr(date)
-        else:
-            return dateutil.datestr(date, fmt)
-    except (TypeError, ValueError):
-        # i18n: "date" is a keyword
-        raise error.ParseError(_("date expects a date information"))
+    if fmt is None:
+        return dateutil.datestr(date)
+    else:
+        return dateutil.datestr(date, fmt)
 
 @templatefunc('dict([[key=]value...])', argspec='*args **kwargs')
 def dict_(context, mapping, args):

--- a/mercurial/templateutil.py	Sun Mar 18 15:55:31 2018 +0900
+++ b/mercurial/templateutil.py	Sun Mar 18 15:58:22 2018 +0900
@@ -330,6 +330,10 @@
         return dateutil.parsedate(thing)
     except AttributeError:
         raise error.ParseError(err or _('not a date tuple nor a string'))
+    except error.ParseError:
+        if not err:
+            raise
+        raise error.ParseError(err)
 
 def evalinteger(context, mapping, arg, err=None):
     return unwrapinteger(evalrawexp(context, mapping, arg), err)