dirstate-v2: backup the data file during the transaction (issue6730) If we backup of the docket, without doing a backup of the data file, we highly risk restoring a docket pointing to a missing file in the future. So we now backup the data-file alongside the docket.

dirstate-v2: display a possible issue with transaction If we backup the dirstate without the data file, we can end up in an inconsistent state of the transaction is rolled back.

test-dirstate: do not get out of the test directory It looks like we were doing one `cd ..` too many.

rust-matchers: fix behavior of `IncludeMatcher` with multiple includes This change adds a test for this fix as well as an additional test case that was useful in debugging this behavior.

compare-disco: support for `file` nodes specification This leverage the `nodefromfile` feature in core. This make it possible for callers to no longer pay the subset computation cost (and to make sure the subset is the right one, even when the base repository is different)

compare-disco: move case parsing into its own function This is open the way to the next changeset that will allow to specify a list of heads.

compare-disco: add an option to skip the case If we already know the context, we can save a lot of display space by skipping the case. This also open the way to speedup to the way we specify the subsets. (the code is hacky, but this is a quicky and dirty debug script)

compare-disco: display a header by default This help us to understand the output. (the code is hacky, but this is a quicky and dirty debug script)

compare-disco: prepare for primitive argument parsing We need to be able to configure a couple of things, so lets prepare the code for it. (the code is hacky, but this is a quicky and dirty debug script)

tests: improve portability by no longer using the flag [tar --force-local] A different way of making sure the path is not interpreted as a URL is to never give this path to [tar], instead making tar read from stdin.