changegroup: rename "dh" to the clearer "deltaheads" We have a lot of frequently used abbreviations, but this is not one of them.

changegroup: rename "srccontent" to "cgnodes" It's the list of nodes in the incoming changegroup, so "cgnodes" made more sense to me.

revlog: rename list of nodes from "content" to "nodes" It seems like the reason for "content" is that the variable contains the nodes that the changegroup "contains", see e234eda20984 (revlog: make addgroup returns a list of node contained in the added source, 2012-01-13), but "nodes" seems much clearer.

revlog: delete obsolete comment The comment seems to refer to code that was deleted in 557988c691d1 (revlog.addgroup(): always use _addrevision() to add new revlog entries, 2010-10-08).

revlog: delete dead assignment in addgroup()

pycompat: move the queue related definitions below queue import This helps in understanding why empty and queue are there.

pycompat: move multiline comments above a function to function doc pycompat.py is unorganized and looks ugly. Next few patches will try to make it look more cleaner so that adding more code is easy and reading code also. This patch moves the multiline comments above functions to function docs. While moving, I improved the comments and make them better suitable for func doc. While I was here I drop a unrequired and misplaced comment.

py3: replace dict.iterkeys() with iter(dict) dict.iterkeys() does not exists on Python 3.

py3: explicitly convert dict.values() to a list on py3 dict.values() returns a dict_values() object, so we need to pass it into list() explicitly to get one.

py3: alias long to int and xrange to range in test-ancestor.py on Python 3