[PATCH 01 of 10] revlog: split a `_revisiondata` method to file `revision` job

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at octobus.net>
# Date 1565190888 -7200
#      Wed Aug 07 17:14:48 2019 +0200
# Node ID 3b49bb04851ea501f005e7a58403fee3b1c52958
# Parent  4710384df490f426ba53055537b16030dc61d957
# EXP-Topic rawdata
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 3b49bb04851e
revlog: split a `_revisiondata` method to file `revision` job

We are about to introduce more public method to access revision data (eg:
`rawdata`). revset subclass tend to recursively call `revision` which will
create all kind of issue with the coming series. To avoid them we introduce an
explicit difference between the internal call and the public all. This will be
useful for later work anyway (so the subclass issue is just moving it earlier in
the series). I am not sure if the subclass are actually doing something
sensible. However, I am certain I don't want to be rabbit holed into figuring it
out right now.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1651,6 +1651,9 @@ class revlog(object):
         treated as raw data when applying flag transforms. 'raw' should be set
         to True when generating changegroups or in debug commands.
         """
+        return self._revisiondata(nodeorrev, _df, raw=raw)
+
+    def _revisiondata(self, nodeorrev, _df=None, raw=False):
         if isinstance(nodeorrev, int):
             rev = nodeorrev
             node = self.node(rev)