config: track the "level" of a value Config value now remember the "level" of the config that loaded it. This will be used to ensure good priority management for alias. Differential Revision: https://phab.mercurial-scm.org/D9926

config: track "source" along side value Currently the source is stored in a entirely different way than the data. This is impractical. Especially if we are about to add more of such metadata. So lets put them back together. Differential Revision: https://phab.mercurial-scm.org/D9925

config: use a new `alter` method in `fixconfig` The `set` function is doing various work related to metadata (eg: the source, later the level). However the `fixconfig` call only updating some values according to standard processing, not changing any of the related metadata. So we introduce a new method and use it there. Differential Revision: https://phab.mercurial-scm.org/D9924

copies-rust: remove an unnecessary format!() inside assert!() The `assert!()` macro supports formatting. Rust 2021 no longer supports an unnecessary `format!()` inside it. I noticed because I recently update my Rust toolchain and `test-check-cargo-lock.t` started failing. Differential Revision: https://phab.mercurial-scm.org/D10085

copies: tests and fix parallel computation of changed file information The code was mixing variable name and misbehaving in some case. This changeset fix it and also add a tests to validate it does not regress. Without the fix, the parallel-upgrade misbehavior in random ways. Differential Revision: https://phab.mercurial-scm.org/D10084

config: test priority involving alias and cli Differential Revision: https://phab.mercurial-scm.org/D9920