amend: error out if the note is greater than 255bytes In obsmarker we can't store keys and values of more than 255 bytes in metadata. If we try to do so, ProgrammingError is raised. The note flag to amend stores the note in obsmetadata. If a user will try to store a larger note, he will encounter ProgrammingError which is wrong. We must error out early. Thanks to Yuya for warning about this. Differential Revision: https://phab.mercurial-scm.org/D1179

show: move configitems to core chgserver.py is also checking the config and will get: devel-warn: accessing unregistered config item: 'commands.show.aliasprefix' at: mercurial/chgserver.py:109 if the config is not registered. Differential Revision: https://phab.mercurial-scm.org/D1178

chgserver: do not treat HG as sensitive environ when CHGHG is set When `$CHGHG` is set, `$HG` is ignored by the chg client. Removing it from chg's sensitive environment list would avoid starting up servers unnecessarily when `$CHGHG` is the same while `$HG` is different. Differential Revision: https://phab.mercurial-scm.org/D1177

fsmonitor: declare missing config options These were added in 4aa57627692a. Attempting to run the test harness with fsmonitor enabled spews a whole bunch of devel warnings due to these options not be declared. Differential Revision: https://phab.mercurial-scm.org/D1176

fsmonitor: warn when fsmonitor could be used fsmonitor can significantly speed up operations on large working directories. But fsmonitor isn't enabled by default, so naive users may not realize there is a potential to make Mercurial faster. This commit introduces a warning to working directory updates when fsmonitor could be used. The following conditions must be met: * Working directory is previously empty * New working directory adds >= N files (currently 50,000) * Running on Linux or MacOS * fsmonitor not enabled * Warning not disabled via config override Because of the empty working directory restriction, most users will only see this warning during `hg clone` (assuming very few users actually do an `hg up null`). The addition of a warning may be considered a BC change. However, clone has printed warnings before. Until recently, Mercurial printed a warning with the server's certificate fingerprint when it wasn't explicitly trusted for example. The warning goes to stderr. So it shouldn't interfere with scripts parsing meaningful output. The OS restriction was on the advice of Facebook engineers, who only feel confident with watchman's stability on the supported platforms. .. feature:: Print warning when fsmonitor isn't being used on a large repository Differential Revision: https://phab.mercurial-scm.org/D894

merge: additional test cases to show merge-halting behavior In the previous patches, we allowed the user to specify that a merge process should be halted when a filemerge fails. This patch adds tests that show additional places this logic can be utilized -- via the options to do additional post-filemerge checks to determine if a file merge was successful. Differential Revision: https://phab.mercurial-scm.org/D952

rebase: add support to output nodechanges This patch adds support to rebase to show the changes in node once the rebase is complete. This will be extremely helpful for automation purposes and editors such as Nuclide. The output is a dictionary of predecessor hash as key and a list of successors' hashes. The successors one is a list as there can be many successors for a single predecessor in case of split and it will good to have a generic output format. This patch adds tests for the same. A new file is created for the patch as existing files related to rebase has their own purpose and there will be more formatter support coming for rebase in next cycle. Thanks to Jun for suggesting to use fm.data(). Differential Revision: https://phab.mercurial-scm.org/D1173

ui: move request exit handlers to global state Since the ui objects can be created with the 'load' class method, it is possible to lose the exit handlers information from the old ui instance. For example, running 'test-bad-extension.t' leads to this situation where chg creates a new ui instance which does not copy the exit handlers from the earlier ui instance. For exit handlers, which are special cases anyways, it probably makes sense to have a global state of the handlers. This would ensure that the exit handlers registered once are definitely executed at the end of the request. Test Plan: Ran all the tests without '--chg' option. This also fixes the 'test-bad-extension.t' with the '--chg' option. Differential Revision: https://phab.mercurial-scm.org/D1166

sparse-read: skip gaps too small to be worth splitting Splitting at too small gaps might not be worthwhile. With this changeset, we stop considering splitting on too small gaps. The threshold is configurable. We arbitrarily pick 256K as a default value because it seems "okay". Further testing on various repositories and setups will be needed to tune it. The option name is 'experimental.sparse-read.min-gap-size`, and replaces `experimental.sparse-read.min-block-size` which is not used any more.

sparse-read: move from a recursive-based approach to a heap-based one The previous recursive approach was trying to optimise each read slice to have a good density. It had the tendency to over-optimize smaller slices while leaving larger hole in others. The new approach focuses on improving the combined density of all the reads, instead of the individual slices. It slices at the largest gaps first, as they reduce the total amount of read data the most efficiently. Another benefit of this approach is that we iterate over the delta chain only once, reducing the overhead of slicing long delta chains. On the repository we use for tests, the new approach shows similar or faster performance than the current default linear full read. The repository contains about 450,000 revisions with many concurrent topological branches. Tests have been run on two versions of the repository: one built with the current delta constraint, and the other with an unlimited delta span (using 'experimental.maxdeltachainspan=0') Below are timings for building 1% of all the revision in the manifest log using 'hg perfrevlogrevisions -m'. Times are given in seconds. They include the new couple of follow-up changeset in this series. delta-span standard unlimited linear-read 922s 632s sparse-read 814s 566s

subrepo: implement 'unshare' for Mercurial subrepos I think there's a slight hole here in that a subrepo could be shared, removed from .hgsub, and then it's not part of context.substate (so not iterated over). But the push command has the same hole IIRC, and I think removing a subrepo is an edge case. The import hack is a copy/paste of subrepo.subrepo().

share: move the implementation of 'unshare' to the 'hg' module This will be used to setup unsharing subrepos. Usually cmdutil is used for this purpose. But the implementation needs hg.copystore(), and the hg module already imports cmdutil.

show: use labelcset() template alias for work (and stack) views By reusing labelcset() template alias from map-cmdline.default we can now display obsolescence information in `hg show work/stack`.

phases: pass phase names to hooks instead of internal values

configitems: document the choice of using 'match' instead of 'search'

configitems: do not directly match generic items Before this changesets, a literal '.*:foo$' config would match a registered '.*:foo$' generic. This is wrong since generic should be matched through regular exception only. This changeset fixes this problem. Thanks for to Yuya Nishihara for spotting the issue.

obsfate: fix obsfate_printer with empty date list When the list of dates is empty, `min` and `max` would raises a ValueError. Protect against this case by checking that the date list is not empty. I didn't add a test because I couldn't find a reproducing test case.

config: gather allowdivergence under the evolution namespace Grouping all evolution related-config under the experimental.evolution namespace would helps the future migration outside [experimental]. Differential Revision: https://phab.mercurial-scm.org/D1155

config: remove stabilization.* aliases Stabilization config items were never part of a release, remove them now that we cleaned up the evolution related configuration. Differential Revision: https://phab.mercurial-scm.org/D1154

config: rename stabilization.track-operation We want to get rid of stabilization.* configuration, back out to the old configuration 'evolution.track-operation'. Differential Revision: https://phab.mercurial-scm.org/D1153

config: rename stabilization.bundle-obsmarker We want to get rid of stabilization.* configuration, back out to the old configuration 'evolution.bundle-obsmarker'. Differential Revision: https://phab.mercurial-scm.org/D1152

config: use 'experimental.evolution.exchange' Extract 'experimental.evolution' = exchange as 'experimental.evolution.exchange'. We keep the new option in the 'experimental.evolution' namespace in order to stay coherent with other options ('experimental.evolution.bundle-obsmarker' and 'experimental.evolution.track-operation') ease the renaming as possibly 'evolution.exchange'. Differential Revision: https://phab.mercurial-scm.org/D1151

config: use 'experimental.evolution.allowunstable' Extract 'experimental.evolution' = allowunstable as 'experimental.evolution.allowunstable'. We keep the new option in the 'experimental.evolution' namespace in order to stay coherent with other options ('experimental.evolution.bundle-obsmarker' and 'experimental.evolution.track-operation') ease the renaming as possibly 'evolution.allowunstable'. Differential Revision: https://phab.mercurial-scm.org/D1150

config: use 'experimental.evolution.create-markers' Extract 'experimental.evolution' = createmarkers as 'experimental.evolution.createmarkers'. We keep the new option in the 'experimental.evolution' namespace in order to stay coherent with other options ('experimental.evolution.bundle-obsmarker' and 'experimental.evolution.track-operation') ease the renaming as possibly 'evolution.createmarkers'. Differential Revision: https://phab.mercurial-scm.org/D1149

config: replace experimental.stabilization by experimental.evolution We replace 'experimental.stabilization=all' by 'experimental.evolution=true' as we will extract individual config in their own config in later patches. Differential Revision: https://phab.mercurial-scm.org/D1148

config: update evolution-related config Update the evolution helpers function to support both old-style configuration and new-style configuration: experimental.evolution=all is renamed into experimental.evolution=true experimental.evolution=createmarkers is renamed into experimental.evolution.createmarkers=true experimental.evolution=allowunstable is renamed into experimental.evolution.allowunstable=true experimental.evolution=exchange is renamed into experimental.evolution.exchange=true We choose to not rename individual config options; keeping the same names would easy the transition for users but it's something that could be easily done in the future. Differential Revision: https://phab.mercurial-scm.org/D1147

config: invert evolution-related configuration aliases We want to split the evolution-related configuration and back-out the renaming from evolution.* to stabilization.*. First invert the configuration and aliases, so next changesets will be cleaner. Differential Revision: https://phab.mercurial-scm.org/D1146

parsers: allow clang-format here # skip-blame because parsers.c is mechanically rewritten by clang-format with no semantic change. Differential Revision: https://phab.mercurial-scm.org/D1170