transaction: avoid file stat ambiguity only for files in blacklist Advancing mtime by os.utime() fails for EPERM, if the target file is owned by another. bff5ccbe5ead and related changes made some code paths give advancing mtime up in such case, to fix issue5418. This causes file stat ambiguity (again), if it is owned by another. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan To avoid file stat ambiguity in such case, especially for .hg/dirstate, ed66ec39933f made vfs.rename() copy the target file, and advance mtime of renamed one again, if EPERM (see issue5584 for detail). But straightforward "copy if EPERM" isn't reasonable for truncation of append-only files at rollbacking, because rollbacking might cost much for truncation of many filelogs, even though filelogs aren't filecache-ed. Therefore, this patch introduces blacklist "checkambigfiles", and avoids file stat ambiguity only for files specified in this blacklist. This patch consists of two parts below, which should be applied at once in order to avoid regression. - specify 'checkambig=True' at vfs.open(mode='a') in _playback() according to checkambigfiles - invoke _playback() with checkambigfiles - add transaction.__init__() checkambigfiles argument, for _abort() - make localrepo instantiate transaction with _cachedfiles - add rollback() checkambigfiles argument, for "hg rollback/recover" - make localrepo invoke rollback() with _cachedfiles After this patch, straightforward "copy if EPERM" will be reasonable at closing the file opened with checkambig=True, because this policy is applied only on files, which are listed in blacklist "checkambigfiles".

localrepo: store path and vfs location of cached properties This information is used to make transaction handle these files specially, in order to avoid file stat ambiguity of them. Gathering information about cached files via annotation classes can avoid overlooking properties newly introduced in the future.

template: add successors template Add a 'successorssets' template that returns the list of all closest known sucessorssets for a changectx. The elements of the list are changesets. The "closest successors" are the first locally known revisions encountered while, walking successors markers. It uses successorsets previously modified to support the closest argument. This logic respect repository filtering. So hidden revision will be skipped by this logic unless --hidden is specified. Since we only display the visible predecessors, this template will not display anything in most case. It makes a good candidate for inclusion in the default log output. I updated the test-obsmarker-template.t test file introduced with the predecessors template to test successorssets template.

template: add tests for more complex cases We add new tests for improving the coverage of existing obs-markers related template (predecessors) and the new one we are introducing (successorssets).

obsolete: closest divergent support Add a closest argument to successorssets changing the definition of latest successors. With "closest=false" (current behavior), latest successors are "leafs" on the obsmarker graph. They don't have any successor and are known locally. With "closest=true", latest successors are the closest locally-known changesets that are visible in the repository or repoview. Closest successors can be then obsolete, orphan. This will be used in a later patch to show the closest successor of changesets with the successorssets template.

obsolete: pass cache argument of successors set explicitly We plan to add a new argument to successorsets. But first we need to update all callers to pass cache argument explicitly to avoid arguments confusion.

obsolete: small doc update for 'successorssets' Clarify successorssets documentation before we start updating the main function. This patch serie will introduce the successorssets template, the opposite of predecessor templates. Successors will use successorssets function and requires some improvement so before doing that, we clean up successorssets a bit.

phabricator: do not read a same revision twice It's possible to set up non-linear dependencies in Phabricator like: o D4 |\ | o D3 | | o | D2 |/ o D1 The old `phabread` code will print D1 twice. This patch adds de-duplication to prevent that. Test Plan: Construct the above dependencies in a Phabricator test instance and make sure the old code prints D1 twice while the new code won't.

patch: make parsepatch optionally trim context lines Previously there is a suspicious `if False and delta > 0` which dates back to the beginning of hgext/record.py (b2607267236d). The "trimming context lines" feature could be useful (and is used by the next patch). So let's enable it. This patch adds a new `maxcontext` parameter to `recordhunk` and `parsepatch`, changing the `if False` condition to respect it. The old `trimcontext` implementation is also wrong - it does not update `toline` correctly and it does not do the right thing for `before` context. A doctest was added to guard us from making a similar mistake again. Since `maxcontext` is set to `None` (unlimited), there is no behavior change.

phabricator: try to fetch differential revisions in batch Previously, we read Differential Revisions one by one by calling `differential.query`. Fetching them one by one is suboptimal. Unfortunately, there is no Conduit API that allows us to get a stack of diffids using a single API call. This patch tries to be smarter using a simple heuristic: when fetching D59 as a stack, previous IDs like D51, D52, D53, ..., D58 are likely belonging to a same stack so just fetch them as well. Since `differential.query` only returns cheap metadata without expensive diff content, it shouldn't be a big problem for the server. Using a test Phabricator instance, this patch reduces `phabread` reading a 10 patch stack from about 13 to 30 seconds to 8 seconds.