phases: micro-optimize newheads() to not create context objects

phases: remove excessive optimization from newheads() (issue5939) This function is intended to compute 'heads(::heads - roots::)', but it failed because 'heads + parents(roots)' missed sibling branches of the roots. That's why the public heads slipped down from D to B in the example added by 2a227782e754 "tests: add test demonstrating phase loss when cloning": > E draft > |\Z draft > | Y draft > D | public > | X draft > C/ public > B public > A public where heads = {E, Z}, roots = {X}

rebase: remove unused variable "release" and an extra blank line Differential Revision: https://phab.mercurial-scm.org/D3947

rebase: remove unnecessary confirm block Removed unnecessary 'if confirm:' block as that thing is now handled at 'finally'. Differential Revision: https://phab.mercurial-scm.org/D3945

rebase: in --confirm option just abort if hit a conflict Before this patch, it was prompting the user in both cases 1) when there is no conflict 2) when there is at least one conflict. But for simplicity we can just abort if we hit a conflict and no need to prompt in that case. Differential Revision: https://phab.mercurial-scm.org/D3944

pullbundle: fix handling of gzip bundlespecs Differential Revision: https://phab.mercurial-scm.org/D3933

tests: add test demonstrating phase loss when cloning (issue5939) The added tests demonstrate that phases exchange when using the listkeys based phases exchange fails to preserve public phase in a certain scenario when a merge is a phase root. Both non-bundle2 and bundle2 prior to the binary phase data part are buggy. Differential Revision: https://phab.mercurial-scm.org/D3932

scmutil: rewrite docstring for filecache The old docstring was incorrect in that it said that subsequent calls perform a stat() and refresh the object if things change. This is not how things work: __get__ populates obj.__dict__[self.sname] with the result of the decorated function and returns this value without validation on subsequent calls, if available. The correct usage of this type is kinda wonky. It would probably benefit from a refactor. But I don't have time to do that right now. But we can change the docstring so others aren't entrapped by its lies (like I was when using repofilecache in a Mozilla extension). Differential Revision: https://phab.mercurial-scm.org/D3943

rebase: correct misleading message in --confirm option Differential Revision: https://phab.mercurial-scm.org/D3939

rebase: make sure we don't loose the return code in --confirm option return _dorebase() to make sure it returns 'return code'. Differential Revision: https://phab.mercurial-scm.org/D3938

rebase: use revnums (not nodes) for set of extinct revisions There is no need to convert extinct revisions to nodeids. Differential Revision: https://phab.mercurial-scm.org/D3942

rebase: avoid converting from nodes to revnums twice In the case where the node has successors, but none of them is an ancestor of the destination, we would iterate over the successor nodes twice, check if they're in the repo and convert them to revnums. I doubt it's a measureable cost, but it gets simpler this way too. Differential Revision: https://phab.mercurial-scm.org/D3941

rebase: reduce scope of a variable Differential Revision: https://phab.mercurial-scm.org/D3940

context: rename descendant() to isancestorof() This makes the direction much clearer, IMO. Differential Revision: https://phab.mercurial-scm.org/D3936

copies: delete now-unnecessary check for "a == b" before "a.descendant(b)" Unnecessary since 879cbdde63df (revlog: do inclusive descendant testing (API), 2018-06-21). Differential Revision: https://phab.mercurial-scm.org/D3935

revlog: delete isdescendantrev() in favor of isancestorrev() As agreed on by Boris, Yuya, and me on D3929. Differential Revision: https://phab.mercurial-scm.org/D3934

rebase: add --confirm option This feature adds a functionality in rebase to confirm before applying changes. When there is no conflict and user confirm to apply actions, we just finish the unfinished rebase. But when there is a conflict and user confirm to apply actions then we can't just finish rebasing using rbsrt._finishrebase() because in-memory merge doesn't support conflicts, so we have to abort and run on-disk merge in this case. And if user doesn't confirm to apply actions then simply abort the rebase. Differential Revision: https://phab.mercurial-scm.org/D3870

revlog: introduce a isancestorrev() and use it in rebase Differential Revision: https://phab.mercurial-scm.org/D3931

revlog: make isdescendantrev(a, b) check if a < b This check was taken from rebase.py. It seems to make sense to move it here, but I haven't done any measurements. Differential Revision: https://phab.mercurial-scm.org/D3930

revlog: replace descendant(b, a) by isdescendantrev(a, b) (API) The "is" is to match "isancestor" and to make it clear that it doesn't return a descendant. The "rev" is to make it clear that it's not about nodeids (unlike e.g. isancestor()). The argument order change is just seems more natural (and makes isancestor() less confusing). Differential Revision: https://phab.mercurial-scm.org/D3929

revlog: move comment about commonancestorsheads where it's used Differential Revision: https://phab.mercurial-scm.org/D3928

removeemptydirs: add test for `hg split` inside a disappearing directory Differential Revision: https://phab.mercurial-scm.org/D3927

fncache: avoid loading the filename cache when not actually modifying it With time, fncache can become very large. The mozilla-central repo for example, has a 31M and growing fncache file. Loading this file takes time (280ms for the mozilla-central repository). In many scenarios, we don't need to load fncache at all. For example, when committing changes to existing files, or pushing such commits to another clone. This patch detects when a name is added via store.vfs(), and only loads the cache if a) the data metadata file doesn't already exist, or b) when opening for appending, the data or metadata file exists but has size (a transaction rollback leaves behind such files). Benchmarks (run on Macos 10.13 on a 2017-model Macbook Pro with Core i7 2.9GHz and flash drive), each test without and with patch run 5 times: * committing to an existing file, against the mozilla-central repository. Baseline real time average 2.3736, with patch 1.9884. * unbundling a large changeset consisting *only* of existing-file modifications (159 revisions, 1050 modifications, mozilla-central 4a250a0e4f29:beea9ac7d823), into a clone limited to the ancestor revision of that revset). Baseline real time average 1.5048, with patch 1.3108.

tests: add diff color trailing whitespace test

scmutil: fix shortesthexnodeidprefix on Python 3 for 0-prefixed nodes This fixes test-bookmarks.t on Python 3 (which had regressed.) Differential Revision: https://phab.mercurial-scm.org/D3926

tests: add missing b prefix in test-context.py # skip-blame just a b prefix Differential Revision: https://phab.mercurial-scm.org/D3925

manifest: just duplicate the definition of items as iteritems The forwarding trick was failing test-check-interfaces on Python 3. Duplicating a line of code is easy enough I'm doing that rather than try and figure out what's going on in any kind of detail. Differential Revision: https://phab.mercurial-scm.org/D3924

tests: properly sort imports in test-nointerrupt.t Somehow this was only detected in Python 3. Differential Revision: https://phab.mercurial-scm.org/D3923

revlog: adjust doctest examples to be portable to Python 3 The range() builtin returns a special object rather than a list, but we really wanted a list in these examples. Differential Revision: https://phab.mercurial-scm.org/D3922

py3: whitelist 3 more passing tests caught with the ratchet Differential Revision: https://phab.mercurial-scm.org/D3921