diff -r b1239aeef4d9 -r 918944f53aac mercurial/templatekw.py
--- a/mercurial/templatekw.py	Sun Jul 29 21:25:37 2018 +0900
+++ b/mercurial/templatekw.py	Sun Jul 29 21:28:51 2018 +0900
@@ -582,6 +582,12 @@
     repo = context.resource(mapping, 'repo')
     return repo.root
 
+@templatekeyword('size', requires={'fctx'})
+def showsize(context, mapping):
+    """Integer. Size of the current file in bytes. (EXPERIMENTAL)"""
+    fctx = context.resource(mapping, 'fctx')
+    return fctx.size()
+
 @templatekeyword("successorssets", requires={'repo', 'ctx'})
 def showsuccessorssets(context, mapping):
     """Returns a string of sets of successors for a changectx. Format used