cat: add support for log-like template keywords and functions

mercurial/cmdutil.py

@@ -2290,6 +2290,7 b' def _updatecatformatter(fm, ctx, matcher'
     if decode:
         data = ctx.repo().wwritedata(path, data)
     fm.startitem()
+    fm.context(ctx=ctx)
     fm.write('data', '%s', data)
     fm.data(abspath=path, path=matcher.rel(path))
 

tests/test-cat.t

@@ -65,10 +65,10 b' Test fileset'
 
 Test template output
 
-  $ hg --cwd tmp cat ../b ../c -T '== {path} ({abspath}) ==\n{data}'
-  == ../b (b) ==
+  $ hg --cwd tmp cat ../b ../c -T '== {path} ({abspath}) r{rev} ==\n{data}'
+  == ../b (b) r2 ==
   1
-  == ../c (c) ==
+  == ../c (c) r2 ==
   3
 
   $ hg cat b c -Tjson --output -