branching: merge default into stable

transaction: drive the aberratant branch special case away shoo shoo shoo shoo. Happy to remove this awful special case (that I introduced myself last week…)

transaction: remove the `branch` backup for transaction We can now back it up at the end of the transaction as we do for the rest of the dirstate.

dirstate: deprecate calling `setbranch` without a transaction parameter The new way is now enforced.

branch: pass current transaction when writing branch for transaction backup This will requires more change soon (as we can simplify this backup). This will be done in later changesets.

branch: pass current transaction when writing branch in shelve

branch: pass current transaction when writing branch in import

branch: pass current transaction when writing branch in backout command

branch: pass current transaction when writing branch in branch command

branch: pass current transaction when writing branch in merge

branch: pass current transaction when writing branch in rebase

branch: pass current transaction when writing branch in keyword

branch: pass current transaction when writing branch in histedit

dirstate: write the `branch` as part of the transaction if any Bypassing the transaction means we could get out of sync with the dirstatemap content. The branch is stil written right away if no transaction is around, but at least it no longer bypass the transaction. Actual caller of this still need to be updated.

dirstate: factor the transaction abort logic We will need it in more occasion if the branch is to be written as part of the transaction.

dirstate: use a context manager to handle the file used for writing the branch This is more modern.

style: rewrap `ui.deprecwarn` declaration This get easier to read, especially with the type annotation.

branching: merge stable into default The clippy god had to be appeased on some aspect.

narrow: read pending file when applicable Now that this is part of the transaction, this is necessary to make sure we read the right data in hooks (if any).

hghave: drop py27 and py35 support These versions of python are no longer supported by Mercurial.

hghave: byteify a path passed to a core API It looks like this predicate isn't used at all(?)

rust: box ConfigValueParseError to avoid large result types clippy emits a warning that all the Result types are way too large because of HgError includes ConfigValueParseError as one of the variants, so its size is 136 bytes. By boxing ConfigValueParseError we're hopefully making everything faster "for free".

dirstate: drop `identity` from the public API We no longer needs it.

delta-find: rename `delta-reuse-policy` to `pulled-delta-reuse-policy` This make it clearer which type of delta we are talking about.

config-item: declare undeclared path suboption This should prevent issue like the previous commit.

delta-find: declare the "paths..*:delta-reuse-policy option While looking into renaming the option I realized it was not declared.

delta-find: adjust the default candidate group chunk size We move from 10 to 20 as the default as some usage in the wild saw a small degradation in storage quality when using `10`.

record: extract a closure to the module level This clean up is almost as gratuituous as this closure was.

record: drop a now useless overlay that grab the lock Since 28dfb2df4ab9, commit grab the wlock and the extra layer grabing the lock in record is no longer needed. We clean up the code to make this simpler (and add a small assert for extra security against future change).

bundlerepo: fix string interpolation Matt Harbison is saying we cannot `%s` a type into a byte string and that seems reasonable.