server: introduce a 'experimental.single-head-per-branch' option When the option is set, the repository will reject any transaction adding multiple heads to the same named branch. For now we reject all scenario with multiple heads. One could imagine handling closed branches differently. We prefer to keep things simple for now. The feature might get extended later. Branch closing is not the best experience Mercurial has to offer anyway.

scmutil: extra utility to display a reasonable amount of nodes Push have some logic to display a reasonable amount nodes. We extract it to an utility function to make it reusable.

uncommit: unify functions _uncommitdirstate and _unamenddirstate to one The _unamenddirstate() function was inspired by _uncommitdirstate() function as the logic was same but we were unable to use the latter function directly. So previous patch introduced the _unamenddirstate() function and now this patch unifies both the function and we have a _fixdirstate() function. Adding function in previous patch and unifying in a later patch makes the reasoning easier and also leaves the last patch dedicated to what it is meant to be. Differential Revision: https://phab.mercurial-scm.org/D971

unamend: move fb extension unamend to core unamend extension adds an unamend command which undoes the effect of the amend command. This patch moves the unamend command from that extension to uncommit extension and this one does not completely undoes the effect of amend command as it creates a new commit, rather than reviving the old one back. This also adds tests for the same. .. feature:: A new unamend command in uncommit extension which undoes the effect of the amend command by creating a new changeset which was there before amend and moving the changes that were amended to the working directory. Differential Revision: https://phab.mercurial-scm.org/D821

color: respect HGPLAINEXCEPT=color to allow colors while scripting (issue5749) I'd also like --color=always on the command-line to override HGPLAIN=1 et al, but that's more work, and this seems like a better fix. We've got a fair number of programs that actually want to automate hg and get colored output to users, so they should set HGPLAINEXCEPT=alias (what we usually recommend), but this has been breaking them because they then lose color. .. feature:: The ``HGPLAINEXCEPT`` environment variable can now include ``color`` to allow automatic output colorization in otherwise automated environments. Differential Revision: https://phab.mercurial-scm.org/D1532

test-ssh: do not actually look up "brokenrepository" by DNS

largefiles: explicitly set the source and sink types to 'hg' for lfconvert I stumbled into this prior to adding the type indicator on the source and sink, but there's no reason to try to infer the types for this conversion.

lfs: add a repo requirement for this extension when converting to lfs This covers both the vanilla repo -> lfs repo and largefiles -> lfs conversions. The largefiles extension adds the requirement directly, because it has a dedicated command to convert. Using the convert extension is better, because it supports more features. I'd like ideas about how to ensure that converting away from lfs works on all files. (See comments in test-lfs.t)

convert: allow the sink object to be wrapped when the extension isn't loaded The next patch will wrap the conversion code, in order to write out a requirement for 'lfs' when appropriate. Wrapping convcmd.convertsink() in an afterloaded callback works fine when the convert extension is enabled by the user. The problem here is that lfconvert uses the convert extension, whether or not it was formally enabled by the user. My first attempt was to have lfs install an afterloaded callback that would wrap the convert sink if convert was loaded, or wrap lfconvert if it wasn't. Then the lfconvert override could install an afterloaded callback to try wrapping the convert sink again, before calling the original lfconvert. But that breaks down if largefiles can't load the convert extension on the fly. [1] Further, some tests were failing with an error indicating that the size of the afterloaded list changed while iterating it. Yuya mentioned that maybe some bits of convert could be moved into core, but I'm not sure where to draw that line. The convertsink() method depends on the list of sinks, which in turn depends on the sink classes. [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-November/108038.html

convert: save an indicator of the repo type for sources and sinks This seems like basic info to have, and will be used shortly when deciding whether or not to wrap the class for lfs conversions. The other option is to just add a function to each class. But this seems better in that the strings aren't duplicated, and the constructor for most of these will run even if the VCS isn't installed, so it's easier to catch errors.

lfs: add a repo requirement for this extension once an lfs file is committed Largefiles does the same thing (also delayed until the first largefile commit), to prevent access to the repo without the extension. In the case of this extension, not having the extension loaded while accessing an lfs file results in cryptic errors about "missing processor for flag '0x2000'". If enabled locally but not remotely, the cryptic error message is about no common changegroup version. (It wants '03', which is currently experimental.) The largefiles extension looks for any tracked file that starts with '.hglf/'. Unfortunately, that doesn't work here. I didn't see any way to get the files that were just committed, without doing a full status. But since there's no secondary check on adding an lfs file once the extension is loaded and a threshold set, the best practice is to only enable this locally on a repo that needs it. That should minimize the unnecessary overhead for repos without an lfs file.

Added signature for changeset a92b9f8e11ba

Added tag 4.4.2 for changeset a92b9f8e11ba

merge: check created file dirs for path conflicts only once (issue5716) In large repositories, updates involving the creation of many files check the same directories repeatedly in the wctx manifest. Move these checks out to a separate loop to avoid repeated checks hitting the manifest. Differential Revision: https://phab.mercurial-scm.org/D1226

merge: cache unknown dir checks (issue5716) As mentioned in D1222, the recent pathconflicts change regresses update performance in large repositories when many files are being updated. To mitigate this, we introduce two caches of directories that have already found to be either: - unknown directories, but which are not aliased by files and so don't need to be checked if they are files again; and - missing directores, which cannot cause path conflicts, and cannot contain a file that causes a path conflict. When checking the paths of a file, testing against this caches means we can skip tests that involve touching the filesystem. Differential Revision: https://phab.mercurial-scm.org/D1224

dispatch: add HGPLAIN=+strictflags to restrict early parsing of global options If this feature is enabled, early options are parsed using the global options table. As the parser stops processing options when non/unknown option is encountered, it won't mistakenly take an option value as a new early option. Still "--" can be injected to terminate the parsing (e.g. "hg -R -- log"), I think it's unlikely to lead to an RCE. To minimize a risk of this change, new fancyopts.earlygetopt() path is enabled only when +strictflags is set. Also the strict parser doesn't support '--repo', a short for '--repository' yet. This limitation will be removed later. As this feature is backward incompatible, I decided to add a new opt-in mechanism to HGPLAIN. I'm not pretty sure if this is the right choice, but I'm thinking of adding +feature/-feature syntax to HGPLAIN. Alternatively, we could add a new environment variable. Any bikeshedding is welcome. Note that HGPLAIN=+strictflags doesn't work correctly in chg session since command arguments are pre-processed in C. This wouldn't be easily fixed.

fancyopts: add early-options parser compatible with getopt() The next patch will add a flag for strict parsing of early options, where we'll have to parse all early options at once instead of processing them one-by-one by dispatch._earlygetopt(). That's why I decided to hook fancyopts(). All dispatch._early*opt() functions is planned to be replaced with this function. But in this stable series, only the strict mode will be handled by fancyopts.earlygetopt().

largefiles: pay attention to dropped standin files when updating largefiles Previously, the largefile for a dropped standin would be deleted here, and then restored from the cache. This had the effect of clobbering uncommitted changes if a revert caused the file to be forgotten, which is not what happens with a normal file. Now the removal and update is skipped for dropped largefiles, and the corresponding standin is deleted from disk. This was noticed when working on issue5738 because the forgotten standin files were left behind, and that changes the behavior of the next rename to that directory. My first attempt was to cleanup the standins before calling this. That failed, because this function deletes the largefile if the corresponding standin is missing. This function is called by the revert command, merge (and therefore update), and patch, via the scmutil.marktouched() override. So it should be pretty narrow in scope. I didn't mark issue5738 as fixed because the move related issues can still happen if the main tree and the .hglf subtree get out of sync somehow. I don't see an easy fix for that, but that should be an edge case. If whoever queues this thinks it is good enough to close out the bug and can cram it into the summary, go for it.

test-largefiles: demonstrate problems with renaming and reverting a directory These things were uncovered looking at issue5738. First, if the destination directory exists under .hglf, the source is moved under the destination instead of renaming the last component for `hg mv srcdir dstdir`. This is extra confusing, because it occurs even if the user visible destination (i.e. the path _not_ under .hglf) does not exist. Additionally, when a largefile is forgotten via revert, any modifications end up getting clobbered. For normal files, the forgotten file is left unchanged, as shown by test-import.t. The forget command on a largefile will correctly leave the file unmodified.

tests: add globs for Windows

cat: record the current behavior of wildcard matches in subrepos Mercurial subrepos support any match patterns.

match: remove doc about undefined behavior of visitdir() This was added by 8545bd381504, but core matchers support visitdir() of arbitrary locations since 2773540c3650, and verifier._verifymanifest() doesn't seem to strictly obey the restriction. I have no idea how important this API contract is for third-party extensions. That's why this patch is RFC.

merge with stable

hgweb: add .jshintrc with some basic rules This file is picked up automatically by jshint, so no extra changes required in test-check-jshint.t.