rust: remove newly redundant `use` statements with the 2021 edition prelude https://doc.rust-lang.org/edition-guide/rust-2021/prelude.html

rust: move all crates in the main workspace to edition 2021 We've changed our minimum Rust version to 1.61.0 in the previous patch, and edition 2021 predates that version.

rust: upgrade supported Rust toolchain version A few months ago¹, a decision was made to move the Rust toolchain target to whatever Debian Testing was tracking. I didn't have the bandwidth to act on it until now. This is starting to be even more problematic than before, now that edition 2021 is out. The CI has been updated to track the current Debian testing version, 1.61.0. [1] https://lists.mercurial-scm.org/pipermail/mercurial-packaging/2022-April/000338.html

branching: merge stable into default

tests: fix test-sparse-revlog This one is not covered by the CIbecause I requires an expensive artifact to be cached. So it goes out of think on regular basis (we should fix that…) The test ouput was affected by e706bb41fdb3 as we filtering now happens sooner, removing for the output.

Added signature for changeset c890d8b8bc59

Added tag 6.3.1 for changeset c890d8b8bc59

relnotes: add 6.3.1

memory-usage: fix `hg log --follow --rev R F` space complexity When running `hg log --follow --rev REVS FILES`, the log code will walk the history of all FILES starting from the file revisions that exists in each REVS. Before doing so, it looks if the files actually exists in the target revisions. To do so, it opens the manifest of each revision in REVS to look up if we find the associated items in FILES. Before this changeset this was done in a way that created a changectx for each target revision, keeping them in memory while we look into each file. If the set of REVS is large, this means keeping the manifest for each entry in REVS in memory. That can be large… if REV is in the form `::X`, this can quickly become huge and saturate the memory. We have seen usage allocating 2GB per second until memory runs out. So this changeset invert the two loop so that only one revision is kept in memory during the operation. This solve the memory explosion issue.

tests: run many tests in $TESTTMP/repo instead of $TESTTMP This is useful so we can store other files in $TESTTMP (in particular tests that use docket files (nodemap, dirstate-v2) keep file uids in $TESTTMP/UID)