revlog: extract 'buildtext' closure function from _addrevision

revlog: choose between ifh and dfh once for all

revlog: refactor out the selection of candidate revisions The new function will be useful to retrieve all the revisions which will be needed to determine the best delta, and parallelize the computation of the necessary diffs.

py3: use email.parser module to parse email messages Before this patch we use email.Parser.Parser() from the email module which is not available on Python 3. On Python 2: >>> import email >>> import email.parser as emailparser >>> email.Parser.Parser is emailparser.Parser True

rust: convert Unix path to CString transparently On Unix, path is just a sequence of bytes. We shouldn't convert it to UTF-8 string.

rust: extract function to convert Path to platform CString It can be better on Unix.

pylint: add a check for multiple statement on a single line Now that they are all cleaned up, we can install a check so that no new occurrence appears. Differential Revision: https://phab.mercurial-scm.org/D1834

style: remove multiple statement on a single line in zeroconf Differential Revision: https://phab.mercurial-scm.org/D1833

style: remove multiple statement on a single line This is similar to the change made in 5326e4ef1dab. Differential Revision: https://phab.mercurial-scm.org/D1832

pylint: split command line argument on multiple lines This clarify the important line in that configuration. Differential Revision: https://phab.mercurial-scm.org/D1831

phabricator: use named group for parsing differential reviews lines Differential Revision: https://phab.mercurial-scm.org/D1801

vfs: drop text mode flag (API) It's useless on Python 3. .. api:: ``text=False|True`` option is dropped from the vfs interface because of Python 3 compatibility issue. Use ``util.tonativeeol/fromnativeeol()`` to convert EOL manually.

lfs: convert EOL of hgrc before appending to bytes IO Text IO is useless on Python 3 as it must be a unicode stream.

largefiles: convert EOL of hgrc before appending to bytes IO Text IO is useless on Python 3 as it must be a unicode stream.

share: convert EOL of hgrc before writing to bytes IO Text IO is useless on Python 3 as it must be a unicode stream.

subrepo: convert EOL of hgrc before writing to bytes IO Follows up f2f0a777b2e2. Text IO is useless on Python 3 as it must be a unicode stream.

clone: use utility function to write hgrc

share: use context manager or utility function to write file

lfs: migrate most file filtering from threshold to custom filter Migrate `lfs.threshold` to more powerful `lfs.filter` added by D4990618 so people can specify what files to be stored in LFS with more flexibility. This patch was authored by Jun Wu for the fb-experimental repo, to avoid using matcher for efficiency[1]. All I've changed here is to register the new 'lfs.track' default so that the tests run cleanly, and adapt the subsequent language changes. Migrating the remaining uses of 'lfs.threshold' can be done separately since there's a fallback in place. [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-December/109388.html

test-lfs: bump the number on test repo11 and higher This will allow a Facebook patch that creates 'repo11' to be imported without breaking a bunch of tests, or requiring edits on the fly.

fileset: add a lightweight file filtering language This patch was inspired by one that Jun Wu authored for the fb-experimental repo, to avoid using matcher for efficiency[1]. We want a way to specify what files will be converted to LFS at commit time. And per discussion, we also want to specify what files to skip, text diff, or merge in another config option. The current `lfs.threshold` config option could not satisfy complex needs. I'm putting it in a core package because Augie floated the idea of also using it for narrow and sparse. Yuya suggested farming out to fileset.parse(), which added support for more symbols. The only fileset element not supported here is 'negate'. (List isn't supported by filesets either.) I also changed the 'always' token to the 'all()' predicate for consistency, and introduced 'none()' to improve readability in a future tracked file based config. The extension operator was changed from '.' to '**', to match how recursive path globs are specified. Finally, I changed the path matcher from '/' to 'path:' at Yuya's suggestion, for consistency with matcher. Unfortunately, ':' is currently reserved in filesets, so this has to be quoted to be processed as a string instead of a symbol[2]. We should probably revisit that, because it's seriously ugly. But it's only used by an experimental extension, and I think using a file based config for LFS may drive some more tweaks, so I'm settling for this for now. I reserved all of the glob characters in fileset except '.' and '_' for the extension test because those are likely valid extension characters. Sample filter settings: all() # everything size(">20MB") # larger than 20MB !**.txt # except for .txt files **.zip | **.tar.gz | **.7z # some types of compressed files "path:bin" # files under "bin" in the project root [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-December/109387.html [2] https://www.mercurial-scm.org/pipermail/mercurial-devel/2018-January/109729.html

fileset: split the logic for matching a size expression to a separate method This will be used in the next patch to build a simple filtering language, but where we won't have an mctx.

lfs: drop deprecated remote store config options The last of these were removed from fb-experimental in 86884a51e9aa, and we might as well clean this up before the freeze.

py3: use bytes instead of pycompat.bytestr Follow up for 35fb3367f72d. Differential Revision: https://phab.mercurial-scm.org/D1854

test-pull-r: explicitly kill server processes Differential Revision: https://phab.mercurial-scm.org/D1855

bookmarks: add bookmarks to hidden revs if directaccess config is set This patch adds support to add bookmarks to hidden revs if `experimental.directaccessi=True` config is set. A warning is also printed saying "accessing hidden changeset <revhash>". Differential Revision: https://phab.mercurial-scm.org/D1813

visibility: pass a normal repo to _getfilteredreason There is no reason to pass an unfiltered-repo to _getfilteredreason and successorssets, so use a normal repo instead. Differential Revision: https://phab.mercurial-scm.org/D1853

visibility: make the filtered message translatable Introduce a filtered message table to ease translation of these messages. Differential Revision: https://phab.mercurial-scm.org/D1852

visibility: fix a comment introduced before which is not up-to-date 265cd9e19d26 introduced a comment in _filterederror that was not updated with the latest iterations of the patch, fix the comment. Differential Revision: https://phab.mercurial-scm.org/D1851

rust: avoid redundant 'static lifetime 'static is apparently automatic for const variables. Differential Revision: https://phab.mercurial-scm.org/D1846

pull: hold wlock for the full operation when --update is used With now, the wlock is not held between the pull and the update. This can lead to race condition and make logic checking to post pull results more complicated (eg: with _afterlock).

hgweb: drop support of browsers that don't understand <canvas> (BC) Internet Explorer 8 and below need excanvas aka ExplorerCanvas to support canvas tag at all. We used to vendor the library in Mercurial, but IE8 was discontinued and all support for it ceased in January 2016. We should do the same and remove excanvas library. Apart from just cleaning up code, this will also make downstream Debian packages stop depending on libjs-excanvas, for example.

rust: add TODO about lifetime of program_name variable Per review comment in D1581. Differential Revision: https://phab.mercurial-scm.org/D1847

rust: move import of PathBuf By moving it to the single function that uses it, we eliminate a #cfg. Differential Revision: https://phab.mercurial-scm.org/D1845

perf: do not import util.queue This was added by af25237be091. But util.queue is not a module and is not importable. I guess it wasn't noticed because of demandimport. Differential Revision: https://phab.mercurial-scm.org/D1848

rust: move Cargo.lock If you do a `cargo build` in rust/, Cargo will create rust/Cargo.lock. Furthermore, the previous rust/hgcli/Cargo.lock appears to not even be consulted because the auto-generated rust/Cargo.lock varied from rust/hgcli/Cargo.lock. This commit moves Cargo.lock to where Cargo expects it to be. While we're here, bump the version of libc to the latest available. Differential Revision: https://phab.mercurial-scm.org/D1844

run-tests: fix regular expression for path test The previous regexp would match the empty string. This fixes a mistake added in 964212780daf. Differential Revision: https://phab.mercurial-scm.org/D1843

perf: add threading capability to perfbdiff Since we are releasing the GIL during diffing, it is interesting to see how a thread pool would perform on diffing. We add a new `--threads` argument to commands. Synchronizing the thread pool is a bit complex because we want to be able to reuse it from one run to another. On my computer (i7 with 4 cores + hyperthreading), I get the following data for about 12000 revisions: threads wall comb wall gain comb overhead none 31.596715 31.59 0.00% 0.00% 1 31.621228 31.62 -0.08% 0.09% 2 16.406202 32.8 48.08% 3.83% 3 11.598334 34.76 63.29% 10.03% 4 9.205421 36.77 70.87% 16.40% 5 8.517604 42.51 73.04% 34.57% 6 7.94645 47.58 74.85% 50.62% 7 7.434972 51.92 76.47% 64.36% 8 7.070638 55.34 77.62% 75.18% Compared to the feature disabled (threads=0), the overhead is negligible with the threading code (threads=1), and the gain is already 48% with two threads.

upgraderepo: select correct deltareuse depending on actions Only 'redeltafulladd' was taken into account because of a small typo.

revsetlang: add %p specifier to format list of function arguments This will be used to construct parameters passed to _matchfiles().

revsetlang: unnest inner functions from formatspec()

revsetlang: fix quoting of %ls string Before, "'" wasn't escaped appropriately. This also changes the separator '\0' to '\\0', but that's okay as a string token is unescaped.

revsetlang: catch invalid value passed to formatspec() The scope of AttributeError is narrowed because it's more likely to be triggered by mistake.

revsetlang: check incomplete revspec format character

revsetlang: check number of arguments passed to formatspec()

revsetlang: catch invalid format character with %l prefix listexp() could call argtype() with an invalid format character, but that wasn't checked before.

py3: add 8 new passing tests to the whitelist Differential Revision: https://phab.mercurial-scm.org/D1800

py3: use list() to get a list of items using dict.items() dict.items() on Python 3 returns a generator over the values of the dictionary, hence we can't delete elements while iterating over dict.items() in Python 3. Differential Revision: https://phab.mercurial-scm.org/D1799

py3: convert dict keys' to str before passing as kwargs We have pycompat.strkwargs() which converts the keys of a dict to str and returns that. Differential Revision: https://phab.mercurial-scm.org/D1798

py3: make sure we open the file to write in bytes mode Differential Revision: https://phab.mercurial-scm.org/D1797

py3: don't use dict.iterkeys() Instead of iterating of dict.iterkeys(), let's iterate of dict as that will be equivalent and dict.iterkeys() is not present in Python 3. Differential Revision: https://phab.mercurial-scm.org/D1796

py3: use pycompat.bytestr() instead of str() Differential Revision: https://phab.mercurial-scm.org/D1795

py3: make regular expressions bytes by prepending b'' Regexes start with r'' and hence transformer skips adding b'' there. # skip-blame because we are just adding b'' Differential Revision: https://phab.mercurial-scm.org/D1794

py3: slice on bytes instead of indexing Indexing returns the ascii value on Python 3. Differential Revision: https://phab.mercurial-scm.org/D1793

py3: use node.hex(h.digest()) instead of h.hexdigest() hashlib.sha1.hexdigest() returns str on Python 3. Differential Revision: https://phab.mercurial-scm.org/D1792

tests: make autodiff.py work on Python 3 This patch adds b'' to string literal to make it compatible with in-core Python 3 compatibility. # skip-blame because we are just adding b'' Differential Revision: https://phab.mercurial-scm.org/D1791

py3: use pycompat.ziplist instead of inbuilt zip zip just like map on Python 3 returns a generator object instead of list. This results in error if we try to iterate over the result once we consume it. We have added pycompat.ziplist which returns a list. Differential Revision: https://phab.mercurial-scm.org/D1790

py3: use bytes and open() instead of file() in test-diff-upgrade.t file() is not present in Python 3. Differential Revision: https://phab.mercurial-scm.org/D1789

exchange: use context manager for locks and transaction in unbundle() Note that the transactionmanager doesn't actually create a transaction -- that is done the first time .transaction() is called on it (if at all). Consequently, .close() and .release() won't do anything if no transaction has been created. This makes it a little unusual, but it still works as a context manager. Differential Revision: https://phab.mercurial-scm.org/D1841

bookmarks: use context managers for locks and transaction in pushbookmark() Differential Revision: https://phab.mercurial-scm.org/D1840

bookmarks: use context managers for lock and transaction in update() Differential Revision: https://phab.mercurial-scm.org/D1839

phase: use context managers for lock and transaction Differential Revision: https://phab.mercurial-scm.org/D1838

obsolete: use context manager for transaction in pushmarker() Differential Revision: https://phab.mercurial-scm.org/D1837

obsolete: use context manager for lock in pushmarker() Differential Revision: https://phab.mercurial-scm.org/D1836

obsolete: use context manager for transaction in createmarkers() Differential Revision: https://phab.mercurial-scm.org/D1835

visibility: improve the message when accessing filtered obsolete rev When trying to access filtered revision, it is likely because they have been obsoleted by an obs-marker. The current message shows how to access the revision anyway: abort: hidden revision '13bedc178fce'! But in the case of an obsoleted revision, the user is likely to want to update to or use the successor of the revision. We update the message to display more information about the obsolescence fate of the revision in the following cases: abort: hidden revision '13bedc178fce' is pruned! abort: hidden revision '13bedc178fce' has diverged! abort: hidden revision '13bedc178fce' was rewritten as X, Y and 2 more! Differential Revision: https://phab.mercurial-scm.org/D1591

tests: add b'' to string literals where bytes are required Since we are internally dealing with bytes only, we need to use bytes in the tests too. This is one of the many patches which will make all the tests completely use bytes. # skip-blame because we are just adding b'' Differential Revision: https://phab.mercurial-scm.org/D1788

rust: implementation of `hg` This commit provides a mostly-working implementation of the `hg` script in Rust along with scaffolding to support Rust in the repository. If you are familiar with Rust, the contents of the added rust/ directory should be pretty straightforward. We create an "hgcli" package that implements a binary application to run Mercurial. The output of this package is an "hg" binary. Our Rust `hg` (henceforth "rhg") essentially is a port of the existing `hg` Python script. The main difference is the creation of the embedded CPython interpreter is handled by the binary itself instead of relying on the shebang. In that sense, rhg is more similar to the "exe wrapper" we currently use on Windows. However, unlike the exe wrapper, rhg does not call the `hg` Python script. Instead, it uses the CPython APIs to import mercurial modules and call appropriate functions. The amount of code here is surprisingly small. It is my intent to replace the existing C-based exe wrapper with rhg. Preferably in the next Mercurial release. This should be achievable - at least for some Mercurial distributions. The future/timeline for rhg on other platforms is less clear. We already ship a hg.exe on Windows. So if we get the quirks with Rust worked out, shipping a Rust-based hg.exe should hopefully not be too contentious. Now onto the implementation. We're using python27-sys and the cpython crates for talking to the CPython API. We currently don't use too much functionality of the cpython crate and could have probably cut it out. However, it does provide a reasonable abstraction over unsafe {} CPython function calls. While we still have our fair share of those, at least we're not dealing with too much refcounting, error checking, etc. So I think the use of the cpython crate is justified. Plus, there is not-yet-implemented functionality that could benefit from cpython. I see our use of this crate only increasing. The cpython and python27-sys crates are not without their issues. The cpython crate didn't seem to account for the embedding use case in its design. Instead, it seems to assume that you are building a Python extension. It is making some questionable decisions around certain CPython APIs. For example, it insists that PyEval_ThreadsInitialized() is called and that the Python code likely isn't the main thread in the underlying application. It is also missing some functionality that is important for embedded use cases (such as exporting the path to the Python interpreter from its build script). After spending several hours trying to wrangle python27-sys and cpython, I gave up and forked the project on GitHub. Our Cargo.toml tracks this fork. I'm optimistic that the upstream project will accept our contributions and we can eventually unfork. There is a non-trivial amount of code in our custom Cargo build script. Our build.rs (which is called as part of building the hgcli crate): * Validates that the Python interpreter that was detected by the python27-sys crate provides a shared library (we only support shared library linking at this time - although this restriction could be loosened). * Validates that the Python is built with UCS-4 support. This ensures maximum Unicode compatibility. * Exports variables to the crate build allowing the built crate to e.g. find the path to the Python interpreter. The produced rhg should be considered alpha quality. There are several known deficiencies. Many of these are documented with inline TODOs. Probably the biggest limitation of rhg is that it assumes it is running from the ./rust/target/<target> directory of a source distribution. So, rhg is currently not very practical for real-world use. But, if you can `cargo build` it, running the binary *should* yield a working Mercurial CLI. In order to support using rhg with the test harness, we needed to hack up run-tests.py so the path to Mercurial's Python files is set properly. The change is extremely hacky and is only intended to be a stop-gap until the test harness gains first-class support for installing rhg. This will likely occur after we support running rhg outside the source directory. Despite its officially alpha quality, rhg copes extremely well with the test harness (at least on Linux). Using `run-tests.py --with-hg ../rust/target/debug/hg`, I only encounter the following failures: * test-run-tests.t -- Warnings emitted about using an unexpected Mercurial library. This is due to the hacky nature of setting the Python directory when run-tests.py detected rhg. * test-devel-warnings.t -- Expected stack trace missing frame for `hg` (This is expected since we no longer have an `hg` script!) * test-convert.t -- Test running `$PYTHON "$BINDIR"/hg`, which obviously assumes `hg` is a Python script. * test-merge-tools.t -- Same assumption about `hg` being executable with Python. * test-http-bad-server.t -- Seeing exit code 255 instead of 1 around line 358. * test-blackbox.t -- Exit code 255 instead of 1. * test-basic.t -- Exit code 255 instead of 1. It certainly looks like we have a bug around exit code handling. I don't think it is severe enough to hold up review and landing of this initial implementation. Perfect is the enemy of good. Differential Revision: https://phab.mercurial-scm.org/D1581

lfs: improve the error message for a missing remote blob It seems better to print the name known to the user, not the internal file. The previous code unconditionally set 'p.filename'. That potentially made the attribute None, and would be printed as such in _gitlfsremote._checkforservererror() instead of "unknown". Normally, files are printed relative to CWD, but I don't see a way to get the repo path to make that adjustment. The test modified here apparently only runs within Facebook, but a print statement confirmed the name change. I tried uploading the blob to a different remote store (so the git server never saw it), and also killing the git server and removing the blob directory, and removing the 'lfs.db' file. All resulted in a message: abort: LFS server claims required objects do not exist: bdc26931acfb734b142a8d675f205becf27560dc461f501822de13274fe6fc8a! So I have no idea how to make this test generally runnable.

filelog: add the ability to report the user facing name This will be used by lfs, but is probably generally useful. There are various bits of code that reverse engineer this from the index or data file names, but it seems better to just store it. Especially if there's experimenting with backing storage other than revlog.

hgweb: make different kinds of commits look differently on /graph Regular hg log -G uses different symbols for some graph nodes, such as commits that close branches and hidden commits. It also marks the currently checked out commit with "@". Since hg serve is sometimes used/recommended as a more visual alternative to CLI, it makes sense to port these features to hgweb. "graphnode" includes the style of a particular node and also if it's currently checked out or not, both at the same time. This is different from hg log -G (which uses templatekw.showgraphnode), where there's only place for one character, but hgweb doesn't have this limitation, since it uses <canvas> and not plain text. I'm using one string of 1 or 2 characters in this patch, it's not the most self-explanatory format, but it's concise, uses the same characters as hg log -G, and is internal to hgweb (i.e. not used for json-graph). I'm more or less fine with how things look visually, but there's still room for improvement. Feel free to criticise or point me to good-looking graphs of this kind for inspiration.

clonebundle: make it possible to retrieve the initial bundle through largefile By setting the default path early enough, we make it possible to retrieve a clone bundle as a largefile from the repository we are cloning. But... why? Clone bundle is a great feature to speeds up clone of large repository. However one of the main obstacle for clone bundle deployment is the authentication scheme. For non public project, just putting a static file on some random CDN is not an option as we have to make sure people have the proper permission to retrieves the bundle. On the other hand, 'largefiles' already have all the necessary logic to serve arbitrary binary files -after- an authentication checks. So reusing an existing large file infrastructure can be a significant shortcut to clone bundle in this kind of closed environment. The idea might seems strange, but the necessary update to the large file extensions are quite small while the benefits are huge. In addition, since all the extra logic live in the 'largefiles' extensions, core does not have to know anything about it.

largefiles: add support for 'largefiles://' url scheme This changesets allows Mercurial to transparently download content from the configured largefile store. This handle all authentication and largefile protocol details. The target usecase is to leverage largefile infrastructure for clone bundle. See next changeset for details

largefiles: add a 'debuglfput' command to put largefile into the store We add a new debug command able to add arbitrary new files into the largefile store. This will be useful for debugging, testing and other unholy usecase.

debug: add a 'debugdownload' command This command resolve and fetch and URL through the Mercurial logic. Mercurial logic add various headers (including authentication) while resolving an URL so the commands helps with building the same request Mercurial would be doing. A new test file is created because we'll add more logic regarding Mercurial download logic and it will grow to a reasonable size.

revsetlang: raise ParseError to report invalid format character It's more common in revset and templater than raising Abort. I have a couple more patches to address exceptions caused by bad format string passed to revset() template function.

revsetlang: use iterator to track current argument in formatspec()

revsetlang: unnest "if True" in formatrevspec()

revsetlang: use str.find() to scan expr in formatspec() There should be no need to walk character one by one in Python.

revsetlang: avoid string concatenation in formatspec()

test-glog: hook cmdutil.getlogrevs() so -frREV is rewritten accordingly Before, these tests didn't match the real behavior of "log -frREV".

test-glog: dump computed set It's more important than the revset expression built from command options.

test-glog: drop uninteresting nodes from AST output This makes future test changes more readable.

lfs: remove the verification option when writing to the local store This partially reverts 417e8e040102 and bb6a80fc969a. But since there's now a dedicated download function, there's no functional change. The last sentence in the commit message of the latter is wrong- write() didn't need the one time hash check if verification wasn't requested. I suspect I missed 'read()' in there ("... but _read()_ also needs to do a one time check..."), because that did fail without the hash check before linking to the usercache. The write() method simply took the same check for consistency. While here, clarify that the write() method is *only* for storing content directly from filelog, which has already checked the hash. If someone can come up with a way to bridge the differences between writing to a file and sending a urlreq.request across the wire, we can create an upload() function and cleanup read() in a similar way. About the only common thread I see is an open() that verifies the content before returning a file descriptor.

lfs: use the localstore download method to transfer from remote stores Both gitlfsremote and file based remotes benefit from not requiring the whole file in memory (though the whole file is still loaded when passing through the revlog interface). With a method specific to downloading from a remote store, the misleading 'use hg verify' hint is removed. The behavior is otherwise unchanged, in that a download from both remote store types will yield a copy of the blob via util.atomictempfile. There's no response payload defined for the non 'download' actions, but the previous code attempted to read the payload in this case anyway. This refactored code made that more obvious, so any payload is printed as a debug message, just in case.

lfs: introduce a localstore method for downloading from remote stores The current local.write() method requires the full data, which means concatenating file chunks in memory when downloading from a git server. The dedicated method downloads in chunks, verifies the content on the fly, and creates the usercache hardlink if successful. It can also be used for the file system based remotestore. An explicit division of labor between downloading from a remote store (which should be verified) and writing to the store because of a commit or similar (which doesn't need verification), seems clearer. I can't figure out how to make a similar function for upload, because for a file remote store, it's a simple open/read/write operation. For a gitremote store, it's open the file and a urlreq.request(), and process that.

win32: do not call GetVolumePathName() with the minimum buffer length It fails on Windows XP even though the doc says "a safer but slower way to set the size of the return buffer is to call the GetFullPathName function, and then make sure that the buffer size is at least the same size as the full path that GetFullPathName returns." https://msdn.microsoft.com/en-us/library/windows/desktop/aa364996(v=vs.85).aspx Well, more "safe" way would be to simply rely on MAX_PATH for common scenarios.

win32: allocate buffer of maximum length for GetVolumeInformation() It's documented that "the maximum buffer size is MAX_PATH+1", which is slightly larger than 256. https://msdn.microsoft.com/en-us/library/windows/desktop/aa364993(v=vs.85).aspx

log: drop unused expr from return value of getlogrevs() Future patches will move some processing of the --follow option out of _makelogrevset(), where the returned 'expr' value will be less consistent with the 'revs'. So let's remove it from the public interface.

log: don't expand aliases in revset built from command options Only -rREV should be rewritten with user aliases.

graphlog: remove redundant check for empty revs

log: remove redundant handling of --limit A returned 'revs' set is pre-filtered by cmdutil.getlogrevs(). The result of displayer.flush() isn't used anymore, so removed.

log: use smartset.slice() to limit number of revisions to be displayed

log: merge getlogrevs() and getgraphlogrevs() cmdutil.graphlog() is updated to receive (revs, filematcher) as arguments to make sure that opts['graph'] is set when getlogrevs() is invoked.

revset: parse x^:: as (x^):: (issue5764) We have to make '::' a valid primary expression to parse 'x^::' as '(x)^(::)' first, but that doesn't change the language because a prefix operator '::y' precedes a primary '::'. I can't think of an intuitive meaning of '::', so it's just rejected. Given 'x::y' can be considered to default to {x = roots(), y = heads()}, '::' could be 'roots()::heads()', which seems not any useful.

test-run-tests: stabilize the test (issue5735) Previously there is a race condition because things happen in this order: 1. Check shouldStop 2. If shouldStop is false, print the diff 3. Call fail() -> set shouldStop The check and set should really happen in a same critical section. This patch adds a lock to address the issue. Test Plan: Run `run-tests.py -l test-run-tests.t` 20 times on gcc112 and the race condition does not reproduce. Differential Revision: https://phab.mercurial-scm.org/D1830