exchange: simplify unbundle locking using context managers Differential Revision: https://phab.mercurial-scm.org/D393

util: add base class for transactional context managers We have at least three types with a close() and a release() method where the close() method is supposed to be called on success and the release() method is supposed to be called last, whether successful or not. Two of them (transaction and dirstateguard) already have identical implementations of __enter__ and __exit__. Let's extract a base class for this, so we reuse the code and so the third type (transactionmanager) can also be used as a context manager. Differential Revision: https://phab.mercurial-scm.org/D392

exchange: remove need for "locked" variable The transactionmanager() constructor just assigned a few variables and cannot fail, so it's safe to move it inside the earlier try/except. Differential Revision: https://phab.mercurial-scm.org/D391

exchange: drop now-unnecessary "local" from lock name variables Since fda0867cfe03 (exchange: drop support for lock-based unbundling (BC), 2017-08-06), there is no more remote locking. Differential Revision: https://phab.mercurial-scm.org/D390

exchange: remove 'locallocked' member from pushop object The variable has been used only within a single function since 94e2862dbcfb (push: elevate phase transaction to cover entire operation, 2014-11-21), so there's no need to keep it on the pushop object. Differential Revision: https://phab.mercurial-scm.org/D389

rebase: change "result would have 3 parent" error message (BC) The old error message "cannot use revision REV as base, result would have 3 parents" is confusing - why use REV as base? why add a new parent?. This patch changes it to "cannot move parent", which seems better. Differential Revision: https://phab.mercurial-scm.org/D342

drawdag: allow override file contents via comments This makes drawdag more flexible, and allow us to create non-clean merges in test cases. Differential Revision: https://phab.mercurial-scm.org/D385

phabricator: add --amend option to phabsend Previously `hg phabsend` was imitating `hg email` and won't mutate changesets. That works fine with reviewer-push workflow, reviewers run `phabread`, `import`. However, it does not work well with author-push workflow. Namely, the author needs to run extra commands to get the right commit message, and remove the local tag after push. This patch solves those issues by adding the `--amend` option, so local changesets will have the right commit message, and tags become unnecessary. Test Plan: Given the following DAG: o 17 o 16 | o 15 | @ 14 |/ o 13 o 12 Run `hg phabsend '(13::)-17' --amend`, check the new DAG looks like: o 21 | o 20 | @ 19 |/ o 18 | o 17 | x 16 | x 13 |/ o 12 And commit messages are updated to contain the `Differential Revision` lines. Use `phabread` to make sure Phabricator has the amended node recorded. Also check `phabsend .` followed by a `phabsend . --amend`, the commit message will be updated and the tag will be removed. Differential Revision: https://phab.mercurial-scm.org/D122

rebase: rewrite core algorithm (issue5578) (issue5630) "defineparents" is the core algorithm of rebase. The old code has too many tech debts (like outdated comments, confusing assertions, etc) and is very error-prone to be improved. This patch rewrites "defineparents" to make the code easier to reason about, and solve a bunch of issues, including: - Assertion error: no base found (demonstrated by D212, issue5578) - Asymmetric result (demonstrated by D211, "F with one parent") - Wrong new parent (demonstrated by D262, "C':A'A'") - "revlog index out of range" (demonstrated by D262, issue5630) - "nothing to merge" (demonstrated by D262) As a side effect, merge base decision has been made more solid - rebase now prints out explicitly what could go wrong when it cannot find a unique suitable merge base. .. fix:: Issue 5578, Issue 5630 Core rebase algorithm has been rewritten to be more robust. Differential Revision: https://phab.mercurial-scm.org/D21

phabricator: remove an unnecessary writediffproperties call This was introduced by D229. Thanks Yuya for finding it! Differential Revision: https://phab.mercurial-scm.org/D366

releasenotes: minor bug fix for index error while serializing Differential Revision: https://phab.mercurial-scm.org/D356

label: rename log.trouble into log.instability The renaming is done according to https://www.mercurial-scm.org/wiki/CEDVocabulary. Differential Revision: https://phab.mercurial-scm.org/D259