py3: listify the return value of filter() filter() on Python 3 returns a filter object. Differential Revision: https://phab.mercurial-scm.org/D2515

py3: use '%d' instead of '%s' for ints Differential Revision: https://phab.mercurial-scm.org/D2514

py3: add 14 new passing tests to whitelist Differential Revision: https://phab.mercurial-scm.org/D2511

py3: use util.forcebytestr to convert str to bytes Differential Revision: https://phab.mercurial-scm.org/D2498

sshpeer: factor out code for creating peers from pipes An upcoming commit will want to instantiate an SSH peer via an alternate mechanism that doesn't require running a new `ssh` command. To facilitate that, we extract the code for creating a peer from pipes to its own function. Differential Revision: https://phab.mercurial-scm.org/D2391

py3: add b'' prefixes in tests/test-rollback.t This makes the test run succesfully on Python 3. There is just a b'' prefix extra in the output. # skip-blame because we added just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D2510

py3: add b'' prefix in tests/test-revlog-v2.t After this, the test works on Python 3. There is some extra return value by open().write() I think which needs to be handled. # skip-blame because just b'' prefix Differential Revision: https://phab.mercurial-scm.org/D2509

py3: add b'' prefixes in tests/test-revlog.t # skip-blame because just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D2508

py3: make sure we open the file in bytes mode This makes the test pass on Python 3. Differential Revision: https://phab.mercurial-scm.org/D2507

py3: add b'' prefixes in tests/test-revlog-ancestry.py # skip-blame because just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D2506

py3: port the markdirver extension in tests/test-resolve.t Differential Revision: https://phab.mercurial-scm.org/D2505

py3: backout changeset 56635c506608 which wrongly added couple of b'' I am not sure what I was thinking when I added that but while fixing rebase tests, I revisited the file and found that I did wrong. I am sorry for this. Differential Revision: https://phab.mercurial-scm.org/D2504

py3: add a missing b'' in tests/bruterebase.py Differential Revision: https://phab.mercurial-scm.org/D2503

py3: use '%d' for integers instead of b'%s' Differential Revision: https://phab.mercurial-scm.org/D2502

py3: make sure we write in mergestate in bytes mode Differential Revision: https://phab.mercurial-scm.org/D2501

py3: add b'' prefixes in tests/test-rebase-scenario-global.t # skip-blame because just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D2500

py3: replace str() calls with their preferred bytes equivalent Differential Revision: https://phab.mercurial-scm.org/D2499

py3: convert error messages to bytes using util.forcebytestr() Differential Revision: https://phab.mercurial-scm.org/D2497

py3: slice over bytes or use startswith() to prevent getting ascii values Differential Revision: https://phab.mercurial-scm.org/D2496

narrow: drop safehasattr() checks for always-present repo.narrowmatch I've added checks for repo.narrowmatch().always() in order to restore some of the fast paths for non-narrow repos. Differential Revision: https://phab.mercurial-scm.org/D2495

narrow: move narrowmatch-related methods to localrepo This patch makes it so localrepo.narrowmatch() and a few more are always available, which will let us simplify the use sites a bit. narrowmatch() will return an always-matcher in non-narrow repos (just like it did when it lived in the narrow extension). Differential Revision: https://phab.mercurial-scm.org/D2494

narrow: remove dependency from narrowspec module to hg module Differential Revision: https://phab.mercurial-scm.org/D2493

narrow: reduce depedence on narrowspec.save() I think narrowspec should be a simple, low-level module and not depend on the hg module. This prepares for moving that dependency out of narrowspec. Differential Revision: https://phab.mercurial-scm.org/D2492

narrow: always wrap repo It's simpler to always wrap the repo. This prepares for moving narrowrepo.narrowmatch() onto localrepo by showing that it's now safe to always wrap the repo (and thus always define narrowmatch() etc.). Note that since narrowmatch() returns an always-matcher (rather than None) in non-narrow repos, this may mean a performance hit when the narrow extension is enabled because it adds a no-op filtering step in various places against the always-matcher. I'll restore some of that soon. Differential Revision: https://phab.mercurial-scm.org/D2491

narrow: consider both local and remote matchers in narrowchangegroup The existing code that picked one or the other seemed very suspicious. This patch makes us intersect the local matcher with the matcher from the remote, which seems better. It fixes one test case and makes another one that used to crash no longer crash, but instead silently succeed with a push that's lossy, so that remains to be fixed. The real reason for doing this now is that I'm going to move narrowrepo.narrowmatch() onto localrepo and then it will always be defined, which would otherwise break this code. Differential Revision: https://phab.mercurial-scm.org/D2490

narrow: move checking for narrow requirement into _narrowmatch() We want to move narrowmatch() and others into core, so we need to get rid of the dependence on the "narrow_opts" from the closure in narrowrepo.wraprepo(). We can simply check if the narrow requirement is set. I think that seems like an improvement regardless of moving narrowmatch(). Differential Revision: https://phab.mercurial-scm.org/D2489

narrow: move changegroup.supportedoutgoingversions() override to core Also document why we need cg3 or higher. Differential Revision: https://phab.mercurial-scm.org/D2488

narrow: move requirement constant to core My short-term goal is to move narrowrepo.narrowmatch() onto localrepo and this is a necessary step for that. I put the constant in changegroup.py, unlike REVLOGV2_REQUIREMENT, which is in localrepo.py, since we'll need to access it from the changegroup module eventually. Differential Revision: https://phab.mercurial-scm.org/D2487

remotenames: don't inherit the remotenames class from dict class The remotenames class was moved from hgremotenames extension. The class in hgremotenames extension used to extend dict because updating bookmark was done through a dict-like interface or Sean (smf) wanted it to be that way. But now, we can remove the inheritance from the dict class as updating bookmark is not done using a dict-like interface. Thanks to Martin von Zweigbergk for spotting this. Differential Revision: https://phab.mercurial-scm.org/D2361

run-tests: cache hghave results Spawning a process on Windows is expensive. I've got a version of test-lfs-test-server.t locally which prints the http request/responses that totals 819 lines, with 149 conditional lines, 11 #if tests, and 2 test cases. It takes just under 1 minute with this change to run both cases, vs just over 2 minutes without this change. Worse, when I explored adding ui.debug to the test, it takes 13 minutes due to all of the mismatches and retests, vs less than 1 minute with this change. Overall, the difference when running all tests is negligible- 103 minutes with this change, vs 105 without when using -j9. It also looks like an exit value of 2 from `hghave` is treated specially, but there's nothing preventing 2 missing features from also using this value.

run-tests: resume raising an exception when a server fails to start Prior to 93228b2a1fc0, this exception was raised before the diff could be printed. By raising the exception after printing the diff, the location of the failure can be identified, but it is also easier to locate test runs where this occurs. The test bot maintains a list of failed tests, separate from the wall of diff output.

py3: use print as a function in tests/test-hgrc.t print was made a function in Python 3. Differential Revision: https://phab.mercurial-scm.org/D2480

py3: use '%d' to convert integers to bytes Differential Revision: https://phab.mercurial-scm.org/D2479

py3: add b'' prefixes in tests/test-extension.t We are now close to getting this test pass on Python 3. # skip-blame because just b'' prefixes. Differential Revision: https://phab.mercurial-scm.org/D2478

py3: convert os.devnull to bytes using pycompat.bytestr os.devnull returns str on Python 3. Differential Revision: https://phab.mercurial-scm.org/D2477

py3: fix more keyword arguments handling Differential Revision: https://phab.mercurial-scm.org/D2476

py3: make sure regexes are bytes # skip-blame because we are adding just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D2475

py3: use pycompat.strurl to convert url to str Differential Revision: https://phab.mercurial-scm.org/D2474

bookmarks: write bookmarks file deterministically Bookmarks are internally stored as an unsorted dictionary. Let's at least write out the bookmarks file in a deterministic order so it is easier to test, diff, etc. Differential Revision: https://phab.mercurial-scm.org/D2469

phases: write phaseroots deterministically self.phaseroots is a list of sets of binary nodes. Let's sort the nodes before writing so the phaseroots file is written out deterministically. Differential Revision: https://phab.mercurial-scm.org/D2468

internals: document bundle2 format It seems like a good idea to have thorough documentation of the bundle2 data format, including the format of each part and the capabilities. The added documentation is far from complete. For example, we don't fully capture the semantics of each capability and part. But a start is better than nothing, which was pretty much where we were before. Differential Revision: https://phab.mercurial-scm.org/D2298

py3: convert bytes to str using encoding.strfromlocal using encoding.strfromlocal because sender is provided from user config or argument. Differential Revision: https://phab.mercurial-scm.org/D2460

py3: use encoding.strtolocal() to convert str to bytes Differential Revision: https://phab.mercurial-scm.org/D2459

py3: use email.utils module instead of email.Utils On py2: >>> import email >>> import email.utils as eutil >>> email.Utils.parseaddr is eutil.parseaddr True >>> email.Utils.formatdate is eutil.formatdate True email.Utils is not present on Python 3. Differential Revision: https://phab.mercurial-scm.org/D2453

py3: slice over bytes or use .startswith() to prevent getting ascii values Differential Revision: https://phab.mercurial-scm.org/D2457

py3: use '%d' for integers instead of '%s' Differential Revision: https://phab.mercurial-scm.org/D2455

templatekw: add 'requires' flag to switch to exception-safe interface The current templatekw interface, f(repo, ctx, templ, **args), is horrible because it's quite easy to encounter TypeError, ValueError, etc. It's also bad for Python 3 porting due to the **kwargs issue. This patch introduces a flag to switch to new f(context, mapping) API seen in templater functions. The requirement spec isn't verified (yet) because context.resource() can gracefully raise a ResourceUnavailable exception, but it's planned to be used as a filter in the help, such as "Revision Keywords" (if 'ctx' in requires), "File Keywords" (if 'fctx' in requires), etc. showauthor() is ported to the new API as an example. 20 more follows.

templater: specialize ResourceUnavailable error so that it can be caught See the next patch how it will be used.

templater: move specialized exception types to top I'm going to add one more exception type.

templatekw: minimize resource dependency of {envvars} and {termwidth} These keywords can be evaluated without a repo.

templatekw: simply override {graphwidth} function by mapping variable

remotenames: drop redundant templatekw names from help text Also removed the second "List of" phrase, which is obvious from the type "List of strings."

narrow: drop redundant templatekw/revset names from help text ":<name>:" is automatically added by the registrar.

run-tests: don't mask errors when a server fails to start There are sporadic instances of this on Windows. They seem to happen more frequently after the test machine is rebooted, although the only way to hit it on my laptop is to loop certain tests with -j9 for hours. The problem with masking out the specific failure is that there's no way to know if it's the same line in the test that's failing, or if it is random. The justification for adding this masking in 52e9e63f1495 was that the failures occur regularly, but that's not the case anymore. The port number is still printed, in case that turns out to be useful.

py3: use bytes instead of str in isinstance Internally we use bytes everywhere, and str on Python 3 is unicodes, so we need to make sure we are doing the right check. Differential Revision: https://phab.mercurial-scm.org/D2458

py3: convert a map expression into list comprehension map returns a map object on Python 3 and here we wanted a list instead. Differential Revision: https://phab.mercurial-scm.org/D2456

py3: use email.generator module instead of email.Generator On py2: >>> import email >>> import email.generator as emailgen >>> email.Generator.Generator is emailgen.Generator True email.Generator is not present on Python 3. Differential Revision: https://phab.mercurial-scm.org/D2454

py3: use pycompat.strkwargs to convert kwargs keys to str Differential Revision: https://phab.mercurial-scm.org/D2452

py3: whitelist test-push-http.t as passing Differential Revision: https://phab.mercurial-scm.org/D2451

util: handle fileno() on Python 3 throwing io.UnsupportedOperation Fortunately, the exception exists on Python 2 so we don't have to do something weirder than this. Differential Revision: https://phab.mercurial-scm.org/D2450

wireproto: use %d to encode an int, not a %s Differential Revision: https://phab.mercurial-scm.org/D2449

httppeer: explicitly catch urlerr.httperror and re-raise On Python 3 it seems urllib.error.HTTPError doesn't set the .args field of the exception to have any contents, which then breaks our socket.error catch. This works around that issue. Differential Revision: https://phab.mercurial-scm.org/D2448

hgweb: pass exception message to builtin Exception ctor as sysstr If we don't do this, the bytes gets repr()ed on Python 3 and we get bogus error strings sent to clients. Ick. Differential Revision: https://phab.mercurial-scm.org/D2447

bundle2: part id is an int, use %d to make it bytes Differential Revision: https://phab.mercurial-scm.org/D2446

bundle2: **strkwargs love on various kwargs constructions Differential Revision: https://phab.mercurial-scm.org/D2445

http: drop custom http client logic Eight and a half years ago, as my starter bug on code.google.com, I investigated a mysterious "broken pipe" error from seemingly random clients[0]. That investigation revealed a tragic story: the Python standard library's httplib was (and remains) barely functional. During large POSTs, if a server responds early with an error (even a permission denied error!) the client only notices that the server closed the connection and everything breaks. Such server behavior is implicitly legal under RFC 2616 (the latest HTTP RFC as of when I was last working on this), and my understanding is that later RFCs have made it explicitly legal to respond early with any status code outside the 2xx range. I embarked, probably foolishly, on a journey to write a new http library with better overall behavior. The http library appears to work well in most cases, but it can get confused in the presence of proxies, and it depends on select(2) which limits its utility if a lot of file descriptors are open. I haven't touched the http library in almost two years, and in the interim the Python community has discovered a better way[1] of writing network code. In theory some day urllib3 will have its own home-grown http library built on h11[2], or we could do that. Either way, it's time to declare our current confusingly-named "http2" client logic and move on. I do hope to revisit this some day: it's still garbage that we can't even respond with a 401 or 403 without reading the entire POST body from the client, but the goalposts on writing a new http client library have moved substantially. We're almost certainly better off just switching to requests and eventually picking up their http fixes than trying to live with something that realistically only we'll ever use. Another approach would be to write an adapter so that Mercurial can use pycurl if it's installed. Neither of those approaches seem like they should be investigated prior to a release of Mercurial that works on Python 3: that's where the mindshare is going to be for any improvements to the state of the http client art. 0: http://web.archive.org/web/20130501031801/http://code.google.com/p/support/issues/detail?id=2716 1: http://sans-io.readthedocs.io/ 2: https://github.com/njsmith/h11 Differential Revision: https://phab.mercurial-scm.org/D2444

statichttprepo: move HTTPRangeHandler from byterange and delete the latter It turns out we've been toting around 472 lines of Python just for this 20-ish line class that teaches urllib how to handle '206 Partial Content'. byterange.py showed up in my \sstr\( Python 3 dragnet, and found itself having overstayed its welcome in our codebase. # no-check-commit because we're moving code that has to have foo_bar naming. Differential Revision: https://phab.mercurial-scm.org/D2443

filemerge: do what the context __bytes__ does, but locally str() here is clearly the wrong thing, and I think the code is clearer when it doesn't just depend on the magic __{str,bytes}__ behavior. I decided to grep around for \sstr\( and see what low-hanging fruit that showed me. This was part of that hunt. That grep pattern still has some things worth exploring. Differential Revision: https://phab.mercurial-scm.org/D2442

py3: convert known-int values to bytes using %d I decided to grep around for \sstr\( and see what low-hanging fruit that showed me. This was part of that hunt. That grep pattern still has some things worth exploring. Differential Revision: https://phab.mercurial-scm.org/D2441

py3: hunt down str(exception) instances and use util.forcebytestr I decided to grep around for \sstr\( and see what low-hanging fruit that showed me. This was part of that hunt. That grep pattern still has some things worth exploring. Differential Revision: https://phab.mercurial-scm.org/D2440

subrepo: use util.forcebytestr() instead of str() on exception Differential Revision: https://phab.mercurial-scm.org/D2437

tests: add missing b prefixes in test-commit.t # skip-blame just some b prefixes Differential Revision: https://phab.mercurial-scm.org/D2436

commitextras: fix on Python 3 by using sysstrs for __dict__ ops I'm dubious of the __dict__ shenanigans in use here, but lack the enthusiasm for figuring out why that was done right now. # skip-blame just some r prefixes Differential Revision: https://phab.mercurial-scm.org/D2435

util: use pycompat.bytestr() instead of str() This fixes at least some environment variable prints for util.system() callers on Python 3. Yay! Differential Revision: https://phab.mercurial-scm.org/D2434

showconfig: allow multiple section.name selectors (issue5797) This seems useful and we can disambiguate the output format solely by the type of the command arguments.

showconfig: use set to filter sections and entry names Before, an entry matching the specified section could be printed twice if the selector wasn't unique. "sections" and "items" are renamed because it's hard to distinguish "sections" from the loop variable "section".

util: factor out shellsplit() function It turned out to be more than the simple posix=True|False flag, so let's introduce a platform function. I also made it py3 ready.

diff: do not split function name if character encoding is unknown Only ASCII characters can be split reliably at any byte positions, so let's just leave long multi-byte sequence long. It's probably less bad than putting an invalid byte sequence into a diff. This doesn't try to split the first ASCII slice from multi-byte sequence because a combining character may follow.

histedit: use repo.revs() instead of repo.set() where revisions are needed Follows up 72da480db4a5. This is just a micro optimization, but looks slightly nicer.

acl: replace bare getpass.getuser() by platform function Follows up dbadf28d4db0. bytestr() shouldn't be applied here because getuser() isn't guaranteed to be all in ASCII. This change means GetUserNameA() is used on Windows, but that's probably better than trying to get the current user name in UNIX way.

context: remove basectx.__int__ (API) basectx is the only type in the repo having __int__ implemented. This magic method can result in unexpected coercion. Furthermore, having it implemented is wrong for some contexts, since rev() may return None in some cases. Previous commits removed known cases in core where contexts are coerced to integers. So let's delete basectx.__int__. This commit is a bit dangerous. While the test suite passes, there are likely still some callers in core that rely on __int__ that don't have test coverage. An alternative would be to issue a deprecation warning and let this bake for a few releases. .. api:: context.basectx no longer implements __int__. Context instances will no longer cast to ints. Consumers should call ``ctx.rev()`` instead. Differential Revision: https://phab.mercurial-scm.org/D2433

patchbomb: resolve revs before evaluating %ld revset Weaning off of basectx.__rev__. Differential Revision: https://phab.mercurial-scm.org/D2432

histedit: resolve revs before evaluating %ld revset We want to stop relying on basectx.__int__. That means we can't use the %ld revset operator with an iterable of contexts. So we expand an iterable of contexts into a list of revs before calling into the revset. Perhaps it would be worthwhile to add a revset format operator that recognizes context instances so we can just pass contexts as revset arguments? Differential Revision: https://phab.mercurial-scm.org/D2431

split: use ctx.rev() instead of %d % ctx And rename a variable for clarity while we're here. This is part of our effort to wean off basectx.__int__. Differential Revision: https://phab.mercurial-scm.org/D2430

commands: use ctx.rev() instead of %d % ctx Weaning off basectx.__int__. Differential Revision: https://phab.mercurial-scm.org/D2429

cmdutil: use ctx.rev() instead of %d % ctx Weaning off basectx.__int__. Differential Revision: https://phab.mercurial-scm.org/D2428

rebase: use ctx.rev() instead of %d % ctx Weaning away from basectx.__int__. Differential Revision: https://phab.mercurial-scm.org/D2427

histedit: use ctx.rev() instead of %d % ctx Weaning off basectx.__int__. Differential Revision: https://phab.mercurial-scm.org/D2426

histedit: rename variables so they have "ctx" in them It is convention for context instances to end with "ctx." Until we have type annotations, this makes auditing much, much easier. Differential Revision: https://phab.mercurial-scm.org/D2425

cmdutil: use ctx.rev() instead of int(ctx) Continuing to wean off basectx.__int__. Differential Revision: https://phab.mercurial-scm.org/D2424

templatekw: use ctx.rev() instead of casting context to int basectx has __int__ implemented. Per mailing list discussion with Yuya, we don't like having this implemented because it is too much magic and in some cases rev() will return None, which isn't an int. So convert a `'%d' % ctx` to ctx.rev() instead. Differential Revision: https://phab.mercurial-scm.org/D2423

py3: fix handling of keyword arguments at more places The keys of keyword arguments of Python 3 should be str, which is why we need to prevent getting the b'' prefix added by the transformer or convert keys to str using pycompat.strkwargs() Differential Revision: https://phab.mercurial-scm.org/D2420

py3: use '%d' for integers instead of '%s' Differential Revision: https://phab.mercurial-scm.org/D2419

merge with stable

py3: use '//' for integer division in hgweb/common.py '/' on Python 3 does the float division. Differential Revision: https://phab.mercurial-scm.org/D2422

py3: use util.forcebytestr to convert error messages to bytes Differential Revision: https://phab.mercurial-scm.org/D2421

py3: add b'' prefixes to config options in test/badserverext.py Differential Revision: https://phab.mercurial-scm.org/D2418

py3: replace file() with open() file() is not present in Python 3. Differential Revision: https://phab.mercurial-scm.org/D2417

py3: make sure regexes are bytes # skip-blame because we added just b'' prefix Differential Revision: https://phab.mercurial-scm.org/D2416

py3: convert dict.items() to list explicitly On python 3, dict.items() returns a dict_items object which cannot be sorted. Differential Revision: https://phab.mercurial-scm.org/D2415

py3: whitelist another 8 passing tests Differential Revision: https://phab.mercurial-scm.org/D2414

py3: use '//' for integer divisions Differential Revision: https://phab.mercurial-scm.org/D2413

py3: use "%d" for integers instead of "%s" util.parsedate() returns a tuple of integers. Writing this patch, I wish we had some type hinting. Differential Revision: https://phab.mercurial-scm.org/D2412

py3: use util.forcebytestr instead of str to convert error messages Differential Revision: https://phab.mercurial-scm.org/D2411

py3: use pycompat.byteskwargs() to fix keyword arguments handling I missed these when I fixed keyword arguments handling in the whole file. Differential Revision: https://phab.mercurial-scm.org/D2410

setup: only allow Python 3 from a source checkout (issue5804) People are running `pip install Mercurial` with Python 3 and that is working because not everything performs a Python version compatibility check. Modern versions of pip do recognize the "python_requires" keyword (https://packaging.python.org/tutorials/distributing-packages/#python-requires) which we set if using setuptools. But this isn't set nor recognized everywhere. To prevent people from accidentally installing Mercurial with Python 3 until Python 3 is officially supported, have setup.py fail when run with Python 3. But don't fail if we're running from a source checkout, as we don't want to anger Mercurial developers hacking on Python 3 nor Mercurial's test automation running from source checkouts. People running setup.py from source checkouts could still fall through a Python 3 crack. But at least the `pip install Mercurial` attempt will get nipped in the bud.

tests: add HTTP POST and PUT support to the $LOGDATE$ substitution The lfs serving code uses both POST and PUT requests (and there's existing support for POST).

py3: make regex bytes in hgweb/webcommands.py # skip-blame because just b'' prefix

py3: replace types.NoneType with type(None) types.NoneType is not present in Python 3.

py3: add missing b'' in test-arbitraryfilectx.t # skip-blame as just b'' prefix

py3: pass ctx.rev() instead of ctx in range()

py3: add b'' prefixes in test-alias.t # skip-blame as it's just b'' prefixes

py3: add b'' prefixes in test-revset.t # skip-blame because it's just b''

py3: make sure we use bytes in generate-working-copy-states.py

py3: fix keyword arguments handling in hgext/acl.py # skip-blame because we added r'' prefixes

py3: use pycompat.bytestr to convert str returned by getpass.getuser to bytes

py3: add b'' prefixes in test-abort-checkin.t # skip-blame because we just added a b'' prefix.

py3: add b'' prefixes in test-dispatch.py # skip-blame because this is just adding b'' prefixes

cleanup: say goodbye to manifestv2 format This experiment was a bust: we'd hoped for smaller repository sizes, but things got larger. Google ended up rolling out tree manifests in a format that's compatible with the original manifest format, and I believe Facebook is doing the same. This code was never implemented as native speedups, so I'm pretty comfortable saying nobody is using the experimental feature. Let's rip it out. I noticed this code still kicking around because I was investigating a repo corruption issue for timeless. .. bc:: Support for the experimental manifestv2 format has been removed, as it was never completed and failed to meet expectations. Differential Revision: https://phab.mercurial-scm.org/D2393

wireproto: document the wonky push protocol for SSH It took me several minutes to figure out how the "unbundle" protocol worked. It turns out that the SSH protocol handler sends an empty reply that is interpreted as "OK to send" and only then does the client send the bundle payload. On top of that, the response is different depending on whether the operation was successful or not. I nearly pulled out my hair deciphering this. Differential Revision: https://phab.mercurial-scm.org/D2385