revlog: make the index always return the same tuple
It is simpler to manage the diferrence in on disk format in the internal index
code itself and lets the rest of the code always handle the same object.
This will become even more important when the data we store will be entirely
different (for example the changelog does not need the "linkrev" field.
We start with item reading, we will deal with item writing in the next
changesets.
Differential Revision: https://phab.mercurial-scm.org/D10568
#require cargo test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "$TESTDIR"/../rust
Check if Cargo.lock is up-to-date. Will fail with a 101 error code if not.
$ cargo check --locked --all --quiet
However most CIs will run `cargo build` or similar before running the tests, so we need to check if it was modified
$ testrepohg diff Cargo.lock