setup: make the version computation process more resistant The tag fetching might return and empty string¹, from there everything derails quickly. As setup tools becomes more picky about version format we make the whole seems a bit more robust. The resulting version will be obviously weird, but at least it will actually install itself. [1] This is a problem we will address in the next changesets.

bundlerepo: enforce the requirements declared by the underlying repository Previously, `hg log -r 'bundle()' -R bundle.hg` was failing for me when run from source, complaining about an unknown parent, when the system installed `hg` didn't. Some debugging showed the index was 0 length. It turned out that I didn't have the C extensions compiled, which a simple `hg log -r .` was able to indicate. The problem being that the RequirementError got handled by RepoError, which uses an empty directory as a fallback to process the bundle.

scmutil: make checknewlabel() allow "_" in otherwise numeric names (issue6737)

storageutil: match node length with repository

rust-narrow: fix loop that never loops This was caught by `clippy`. I guess the narrow tests leave something to be desired, since this previously only checked the first valid pattern.

dirstate: enforce holding the lock while doing any changes This seems like a sensible sanity check. This already caught the issue in largefile. This will catch more issue when we start using similar context manager for operation other than the parent changes.

largefile: make sure we hold the lock when updating the second dirstate The largefile extension uses a second dirstate file (and object) to track some states. In some situations, it is lazily updated when needed. These operations might not have the lock taken. This means they might conflict and race with other ongoing operations. So we now take the lock to do these operations. This was caught by the next commit.

dirstate: rename `@requires_no_parents_change` too This match the rename of the context manager.

dirstate: rename `@requires_parents_change` to `@requires_changing_parents` This match the rename of the context manager.

dirstate: write dirstate on successful exit of changing_parents context This is the first step toward having more sensible and predicatable write patterns for the dirstate. Having better write/rollback patterns will greatly reduce and clarify the needs to backup the dirstate.