import: allow processing of extra part header during import As we have a way for extension to add more header, we need a way for them to actually process them. We add a basic hook points to alter the changeset (especially extra) before we commit. There would be more to do for a full featured hooking, but this currently fit my needs.

extract: parse 'nodeid' using the generic mechanism Parsing 'nodeid' is very simple and a good first test.

extract: parse 'branch' using the generic mechanism Parsing 'branch' is very simple and a good first test.

extract: parse 'date' using the generic mechanism Parsing 'date' is very simple and a good first test.

extract: add some facility for extensible header parsing We need a way for extension to extend the header we can parse. We start with a very simple mechanism that will be used in the next changeset.

extract: remove the 'user' variable It is not heavily used enough to justify being something other than a dictionary entry.

extract: use a single return The differences between both returns are now very thin, we factor out that part.

extract: move 'nodeid' assignment where it is parsed The is one setter and no consumer, we can move it there directly.

extract: move 'date' assignment where it is parsed There is one setter and no consumer, we can move it there directly.

extract: assign user to 'data' earlier This is used in both case, we can assign it once.