lfs: show a friendly message when pushing lfs to a server without lfs enabled Upfront disclaimer: I don't know anything about the wire protocol, and this was pretty much cargo-culted from largefiles, and then clonebundles, since it seems more modern. I was surprised that exchange.push() will ensure all of the proper requirements when exchanging between two local repos, but doesn't care when one is remote. All this new capability marker does is inform the client that the extension is enabled remotely. It may or may not contain commits with external blobs. Open issues: - largefiles uses 'largefiles=serve' for its capability. Someday I hope to be able to push lfs blobs to an `hg serve` instance. That will probably require a distinct capability. Should it change to '=serve' then? Or just add an 'lfs-serve' capability then? - The flip side of this is more complicated. It looks like largefiles adds an 'lheads' command for the client to signal to the server that the extension is loaded. That is then converted to 'heads' and sent through the normal wire protocol plumbing. A client using the 'heads' command directly is kicked out with a message indicating that the largefiles extension must be loaded. We could do similar with 'lfsheads', but then a repo with both largefiles and lfs blobs can't be pushed over the wire. Hopefully somebody with more wire protocol experience can think of something else. I see 'x-hgarg-1' on some commands in the tests, but not on heads, and didn't dig any further.

lfs: allow non-lfs exchanges when the extension is only enabled on one side Once the 'lfs' requirement is added, the extension must be loaded on both sides, and changegroup3 used. But there's no reason that I can see for bailing with cryptic errors if lfs is not required, but randomly enabled somewhere.

lfs: add the 'lfs' requirement in the changegroup transaction introducing lfs A hook like this is how largefiles manages to do the same. Largefiles uses a changegroup hook, but this uses pretxnchangegroup because that actually causes the transaction to rollback in the unlikely event that writing the requirements out fails. Sadly, the requires file itself isn't rolled back if a subsequent hook fails, but that seems trivial. Now that commit, changegroup and convert are covered, I don't think there's any way to get an lfs repo without the requirement. The grep exit code is blotted out of some test-lfs-serve.t tests now showing the requirement, because run-tests.py doesn't support conditionalizing the exit code.

test-lfs: add tests covering http exchanges This tries to test every combination of having the extension enabled/disabled on each side, and then push/pull/clone/identify lfs and non-lfs content. SSH is ignored here, because there's enough going on as it is. The root issue here is again that requirements are not exchanged and preserved on push/pull/clone. Doing so should eliminate the cryptic error messages when using `hg serve`. The 500 server error is triggered by "ValueError: no common changegroup version", because the extension forces changegroup3. Or, if changegroup3 is enabled manually, it is triggered by "abort: missing processor for flag '0x2000'!". Sadly, run-tests.py doesn't support conditionalizing the exit code like it does lines of output. Therefore, a couple of tests blot out the exit code by appending "|| true", since these failures will go away shortly anyway.

test-lfs: add tests covering local exchanges The root issue here is that requirements are not exchanged and preserved on push/pull. This can be handled with a changegroup hook. Testing for remote exchanges is much more extensive (it's possible for one process or the other to not have the extension loaded at all), so it is added separately.

smartset: split generatorset classes to avoid cycle I uncovered a cycle manifesting in a memory leak by running `hgperfrevset '::tip'`. The cycle was due to generatorset.__init__ assigning a bound method to self.__contains__. Internet sleuthing revealed that assigning a bound method to an instance attribute always creates a cycle. This commit creates two new variants of generatorset for the special cases of ascending and descending generators. The special implementations of __contains__ have been extracted to these classes where they are defined as __contains__. generatorset now implements __new__ and changes the spawned type to one of the new classes if needed. Differential Revision: https://phab.mercurial-scm.org/D1780

merge: raise before running mergedriver if using IMM Merge driver scripts run in the working copy, so disable with IMM for now. Differential Revision: https://phab.mercurial-scm.org/D1781

scmutil: use a tuple of possible values instead of using startswith() This patch also adds a review comment which is helpful as inline comment. Differential Revision: https://phab.mercurial-scm.org/D1761

show: use revlog function to compute length of the longest shortest node As the core part of shortest() was extracted at 448725a2ef73, we no logner need a templater.

commands: use the new API to access hidden changesets in various commands In previous patches, we have added an internal API to unhide hidden changesets. This patch makes the following command use that api in nowarn mode i.e. there will be no warning while accessing hidden changesets. cat, diff, export, files, heads, identify, log, manifest, parents, status This patch also adds test demonstarting the behaviour. .. feature:: Accessing hidden changesets Set config option 'experimental.directaccess = True' to access hidden changesets from read only commands. Differential Revision: https://phab.mercurial-scm.org/D1735

scmutil: add utility fn to return repo object with user passed revs unhidden There has been a need for accessing hidden changesets by default without passing --hidden. This is currently done using the directaccess extension but is bit hacky. This patch adds a utility function to return a repo object having user passed revisions unhidden. This functionality will live behind a config option and won't be the default behaviour. There is also a config option added by this patch which tells whether we want to unhide only those revisions whose hashes are passed or should we consider revisions numbers also. Differential Revision: https://phab.mercurial-scm.org/D1733

repoview: add a new filtername for accessing hidden commits This patch adds a new filter 'visible-hidden' for repository and will be used to return a repo object with user passed revisions unhidden. Unlike the directaccess extension in fb-hgext and previous series adding the functionality, this time we introduce only one new filter as whether to warn user or not is handled by scmutil.unhidehashlikerevs(). Differential Revision: https://phab.mercurial-scm.org/D1734

revsetlang: add utility function to return hash like symbols from the tree Functionalities like unhiding changesets whose rev/hash is passed by the user required the knowledge of rev/hashes in the user provided specs. This patch adds functions which can parse tree object and return a list of such values. Differential Revision: https://phab.mercurial-scm.org/D1732

repoview: add visibilityexception argument to filterrevs() and related fns After this patch, filterrevs() can take an optional argument visibilityexceptions which is a set of revs which should be exception to being hidden. The visibilityexceptions will be passed to the function computing hidden revisions for that filtername and are considered there while calculating the set of hidden revs. Differential Revision: https://phab.mercurial-scm.org/D1747

repoview: add visibilityexceptions as an optional argument to repo.filtered() This will help us in having an API where we can pass the filtername and the visibilityexceptions to get a new repo object. Visibility exceptions are the revs which must be visible even they should in theory belong to the hidden set. They are required as there has been desire to have a functionality to access hidden changesets using certain commands without passing --hidden. After this patch we can make those changesets visibility exceptions so that we can access them without requiring a unfiltered repo. Differential Revision: https://phab.mercurial-scm.org/D1746

streamclone: move wire protocol status code from wireproto command This consolidates the code for the streaming clone wire protocol format into streamclone.py. It also eliminates a generator wrapper, which might make streaming clones slightly faster. Differential Revision: https://phab.mercurial-scm.org/D1754

histedit: add ui.log for action count Differential Revision: https://phab.mercurial-scm.org/D1751

run-tests: extract sorting of tests to own function TestRunner._run() is a large function and is difficult to follow. Let's extract the test sorting to its own function to make it shorter. When I refactored run-tests.py several years ago, I put a lot of functionality in methods. The prevailing Mercurial style is to use functions - not classes - where possible. While refactoring the code, I decided to undo this historical mistake of mine by moving the code to a standalone function. Differential Revision: https://phab.mercurial-scm.org/D1750

run-tests: remove dead code related to temp directory Differential Revision: https://phab.mercurial-scm.org/D1749

rebase: switch ui.log calls to common style The old style raised errors in some cases. Differential Revision: https://phab.mercurial-scm.org/D1748

hgweb: link to successors of obsoleted changesets _siblings() prepare various useful properties to use in templates. This function usually prepares parents and children of changesets for use in hgweb templates, but it can be used for successors too. It's needed because item['successors'] is a _hybrid object that works well when used in regular templates, but in hgweb templates work slightly differently and can't get hex nodes of the successors, which are required for these links to work.

hgweb: display fate of obsolete changesets Operations that obsolete changesets store enough metadata to explain what happened after the fact. One way to get that metadata is showsuccsandmarkers function, which returns a list of successors of a particular changeset and appropriate obsolescence markers. Templates have a set of experimental functions that have names starting with obsfate. This patch uses some of these functions to interpret output of succsandmarkers() and produce human-friendly messages that describe what happened to an obsolete changeset, e.g. "pruned" or "rewritten as 6:3de5eca88c00". In commonentry(), succsandmarkers property is made callable so it's only executed on demand; this saves time when changeset is not obsolete, and also in e.g. /shortlog view, where there are a lot of changesets, but we don't need to show each and every one in detail. In spartan theme, succsandmarkers is used instead of the simple "obsolete: yes", in other themes a new line is added to /rev page.

test-ssh: stabilize for Windows Previously, this complained: remote: '.' is not recognized as an internal or external command, remote: operable program or batch file. Making this a python script apparently revealed some races[1]. Thanks to Yuya for suggesting this. [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-December/109094.html

templater: register keywords to defaults table Since the keywords are permanent, there should be no need to pass them by a temporary mapping.