sslutil: properly detect which TLS versions are supported by the ssl module For the record, I contacted the CPython developers to remark that unconditionally defining ssl.PROTOCOL_TLSv1_1 / ssl.PROTOCOL_TLSv1_2 is problematic: https://github.com/python/cpython/commit/6e8cda91d92da72800d891b2fc2073ecbc134d98#r39569316

sslutil: remove dead code (that failed if only TLS 1.0 is available) We ensure in setup.py that TLS 1.1 or TLS 1.2 is present.

config: remove unused hostsecurity.disabletls10warning config

sslutil: remove dead code (that downgraded default minimum TLS version) We ensure in setup.py that TLS 1.1 or TLS 1.2 is present.

sslutil: remove comment referring to unsupported legacy stacks

setup: require that Python has TLS 1.1 or TLS 1.2 This ensures that Mercurial never downgrades the minimum TLS version from TLS 1.1+ to TLS 1.0+ and enables us to remove that compatibility code. It is reasonable to expect that distributions having Python 2.7.9+ or having backported modern features to the ssl module (which we require) have a OpenSSL version supporting TLS 1.1 or TLS 1.2, as this is the main reason why distributions would want to backport these features. TLS 1.1 and TLS 1.2 are often either both enabled or both not enabled. However, both can be disabled independently, at least on current Python / OpenSSL versions. For the record, I contacted the CPython developers to remark that unconditionally defining ssl.PROTOCOL_TLSv1_1 / ssl.PROTOCOL_TLSv1_2 is problematic: https://github.com/python/cpython/commit/6e8cda91d92da72800d891b2fc2073ecbc134d98#r39569316

sslutil: check for OpenSSL without TLS 1.0 support in one case It can only happen if supportedprotocols gets fixed to contain only correct items (see the FIXME above in the file).

sslutil: don't set minimum TLS version to 1.0 if 1.2 but not 1.1 is available This case isn't very likely, but possible, especially if supportedprotocols gets fixed to contain only correct items (see the FIXME above in the file).

sslutil: add FIXME about supportedprotocols possibly containing too many items

sslutil: fix names of variables containing minimum protocol strings When working in this module, I found it very confusing that "protocol" as a variable name could mean either "minimum protocol string" or an exact version (as a string or ssl.PROTOCOL_* value). This patch prefixes variables of the former type with "minimum".

sslutil: stop returning argument as third return value of protocolsettings() The third return value was always the same as the argument.

relnotes: note that we now require modern SSL/TLS features in Python

tests: stop checking for optional, now impossible output In 7dd63a8cb1ee, the code that could output that line was removed.

rust: remove one more occurrence of re2 Differential Revision: https://phab.mercurial-scm.org/D8601

scmutil: clarify getuipathfn comment Differential Revision: https://phab.mercurial-scm.org/D8600

githelp: add some minimal help for pickaxe functionality Due to a conversation in work chat, I realized this is actually pretty well-hidden in Mercurial. Differential Revision: https://phab.mercurial-scm.org/D8590

rust: remove duplicate import Differential Revision: https://phab.mercurial-scm.org/D8456

tests: remove "sslcontext" check Now that we require the presence of ssl.SSLContext in setup.py, the check would always return `True`.

sslutil: eliminate `_canloaddefaultcerts` by constant-folding code using it

tests: remove "defaultcacerts" check `sslutil._canloaddefaultcerts` is always true (and will be removed).

sslutil: eliminate `modernssl` by constant-folding code using it

hgweb: avoid using `sslutil.modernssl` `sslutil.modernssl` is going to be removed. Since the point of using this attribute was to check the importability of the `sslutil`, a different attribute can be used. `sslutil.wrapserversocket` is used because it’s anyway used a few lines below.

sslutil: remove comments referring to removed SSLContext emulation class

sslutil: remove code checking for presence of ssl.SSLContext Now that we require the presence of ssl.SSLContext in setup.py, we can remove this code.

setup: require a Python version with modern SSL features This increases the minimum security baseline of Mercurial and enables us to remove compatibility code for supporting older, less secure Python versions.

sslutil: set `_canloaddefaultcerts` to `True` if `ssl.SSLContext` is present The `load_default_certs()` method was already present when `ssl.SSLContext` was backported to Python 2.7 (https://hg.python.org/cpython/rev/221a1f9155e2).

filemerge: add __bytes__ for absentfilectx This will at _least_ aid some upcoming debugging. Differential Revision: https://phab.mercurial-scm.org/D8592

mergestate: move staticmethod _filectxorabsent to module level I suspect this was a static method just because it made merge.py feel less messy, but now we have a mergestate package so we can do better. Differential Revision: https://phab.mercurial-scm.org/D8591

rust: remove support for `re2` With the performance issues with `regex` figured out and fixed in previous patches and `regex` newly gaining support for empty alternations, there is no reason to keep `re2` around anymore. It's only *marginally* faster at creating the regex which saves at most a couple of ms, but gets beaten by `regex` in every other aspect. This removes the Rust/C/C++ bridge (hooray!), the `with-re2` feature, the conditional code that goes with it, the documentation and relevant part of the debug/module output. Differential Revision: https://phab.mercurial-scm.org/D8594

rust-dependencies: update `regex` to 1.3.9 Version `1.3.8` introduces support for empty alternations, which makes previously disallowed patterns usable in `regex`. From a user's perspective, this means that glob patterns like `*.py{,c}` will no longer generate an "invalid" regex and will use the Rust path. `1.3.9` is a bugfix release, might as well update to the latest one. Differential Revision: https://phab.mercurial-scm.org/D8593

cleanup: remove compatibility code for Python < 2.7.4 The minimum supported Python version was recently raised to 2.7.4.

cleanup: eliminate procutil.quotecommand() After some compatibility code was removed, the function was the identity function on all platforms.

cleanup: remove compatibility code for Python < 2.7.1 The minimum supported Python version was recently raised to 2.7.4.

grep: reduce the cost of pathauditor checks when grepping working copy Running `time hg grep zxczxczxczxczxc -l` on mozilla-central: before: real 0m20,000s user 0m15,796s sys 0m4,189s after: real 0m10,903s user 0m8,964s sys 0m1,916s if vfs didn't call pathauditor at all: real 0m7,781s user 0m5,968s sys 0m1,790s Differential Revision: https://phab.mercurial-scm.org/D8582

grep: test that paths get audited Differential Revision: https://phab.mercurial-scm.org/D8581

grep: add test coverage of behavior on symlinks Differential Revision: https://phab.mercurial-scm.org/D8580

help: fix description of revlog version 2 Differential Revision: https://phab.mercurial-scm.org/D8576

files: speed up `hg files` when no flags change display It's not the first time I see slowness from this command slow down tools built on top of hg. The majority of the time is spent merely printing the result before this change, which is clearly not how it should be (especially since the computation of the result also looks slow). Running `hg files` in mozilla-central: parent revision: 1,260s this commit: 0,683s this commit without batching ui.write: 0,931s this commit replacing the body of the loop with `pass`: 0,566s This looks like a prime candidate for a rust fast path, but until then, it seems reasonable to optimize the python. Differential Revision: https://phab.mercurial-scm.org/D8586

sshpeer: make client print (likely) server errors on stderr (BC) so `hg clone -q` or `hg pull -q` don't print `abort: no suitable response from remote hg!` with no indication of what went wrong. There are other errors still silenced by -q (like failing to push due to a server hook), but the current change covers a good fraction of the problem (all errors setting up the ssh connection, no such remote repository, no access to the repository). Differential Revision: https://phab.mercurial-scm.org/D8584

sshpeer: add test showing that -q silences remote errors Differential Revision: https://phab.mercurial-scm.org/D8583

scmutil: speed up relativization of paths when it's a no-op Running commands from the root is commmon, in particular for automation. Running `hg files > /tmp/a` from the root of mozilla-central on linux: before: real 0m1,510s user 0m1,387s sys 0m0,090s after: real 0m1,266s user 0m1,165s sys 0m0,073s (there are 280k paths, so this was costing ~1us per path somehow) Differential Revision: https://phab.mercurial-scm.org/D8585

context: implement mergestate() method This will let us have the mergestate storage be controlled by the context. In particular, for working contexts we should use the existing mergestate, but for overlay contexts it's inappropriate to drop files in .hg/merge. Differential Revision: https://phab.mercurial-scm.org/D8551

mergestate: split out merge state handling code from main merge module There's already some pretty reasonable encapsulation here, but I want to make the mergestate storage a property of the context so memctx instances can do a reasonable thing. This is the first step in a reshuffle to make that easier. Differential Revision: https://phab.mercurial-scm.org/D8550

tests: add coverage for repo.changelog.children() in the git extension Differential Revision: https://phab.mercurial-scm.org/D8548

tests: add coverage for repo.changelog.findmissing() in test-git-interop.t This at least does a basic test of the method. It's not super-complete, but it's better than the nothing we'd otherwise have. Differential Revision: https://phab.mercurial-scm.org/D8547

relnotes: add API change note per request in D8502 Differential Revision: https://phab.mercurial-scm.org/D8549

merge with stable

grep: grep the working copy faster `hg grep qqqq` in the mercurial repo: before: 0,859s after: 0,233s `hg grep somethingwithnomatch` in mozilla-central: before: 51s after: 19s This is probably also a tiny bug fix, because the code was looking up a node for filename `pfn` on a filelog for filename `fn`, which are most of the time the same filename, but don't have to be. Ignoring performance and the bug fix, the code should have the same behavior. Differential Revision: https://phab.mercurial-scm.org/D8545

grep: stop computing information for --diff when unnecessary This is one reason why `hg grep pattern` essentially does `hg cat -r . 'set:**'` inside. There is no speed improvement in this commit, because the rest of the code still greps data from filelog instead of working copy when possible. Differential Revision: https://phab.mercurial-scm.org/D8544

grep: don't go in an infinite loop when given empty regex Differential Revision: https://phab.mercurial-scm.org/D8543

grep: improve test coverage Differential Revision: https://phab.mercurial-scm.org/D8542

phabricator: avoid passing None to pycompat.fsdecode Differential Revision: https://phab.mercurial-scm.org/D8525

setup: stop asking cargo to spam It prints this kind of stuff by default: Compiling regex v1.3.6 Compiling rand v0.7.3 Compiling crossbeam-deque v0.7.3 which is way better than we ask for before this change, which is screen after screen of compilation commands and irrelevant warnings in crates we use. Differential Revision: https://phab.mercurial-scm.org/D8537

git: implement some changelog methods Differential Revision: https://phab.mercurial-scm.org/D8540

git: avoid looking-up parents for the null commit Differential Revision: https://phab.mercurial-scm.org/D8541

git: fix probable missing return Differential Revision: https://phab.mercurial-scm.org/D8539

rust: fix warning about unnecessary mut If there's a reason to use mut (like compability with older compilers), then we should stick `#[allow(unused_mut)]` on the declaration. Differential Revision: https://phab.mercurial-scm.org/D8538

upgrade: support upgrade and downgrade from persistent nodemap The requirements is now recognised and dealt with and the associated files properly handled. The persistent nodemap should be ready for usage in the field now. Differential Revision: https://phab.mercurial-scm.org/D8431

status: also support for `traversedir` callback in the Rust fast-path Repeating the performance numbers from the `hg-core` change: Running `hg clean/purge` on Netbeans' repo (100k files): ``` | No-op | 30% unknown -------------------------- Rust | 1.0s | 1.67s C | 2.0s | 2.87s ``` Differential Revision: https://phab.mercurial-scm.org/D8520

rust-hg-cpython: update status bridge with the new `traversedir` support Differential Revision: https://phab.mercurial-scm.org/D8519

rust-status: collect traversed directories if required Some commands (`hg purge` notably) register the `traversedir` callback on their matcher to run said callback every time a directory is traversed. This is the first of three patches, further broadening Rust support for status. Unfortunately, there is no way around collecting a full `Vec` (or any other owned datastructure, like a radix tree) and pushing it back up the Python layer since keeping the Python callback in a closure would mean giving up multithreading because of the GIL, which is obviously unacceptable. Performance is still a lot better than the Python+C path. Running `hg clean/purge` on Netbeans' repo (100k files): ``` | No-op | 30% unknown -------------------------- Rust | 1.0s | 1.67s C | 2.0s | 2.87s ``` Differential Revision: https://phab.mercurial-scm.org/D8518

rust-status: don't dispatch unknown file when traversing if not listing unknowns This usually isn't a (functional) problem since we ignore the unknown files anyway, but when specifically using `hg purge`, unknown files were iterated over regardless of the option being true. This is both more correct and more efficient. Differential Revision: https://phab.mercurial-scm.org/D8517

status: update comment to reflect the more recent situation This is a gratuitous cleanup. Differential Revision: https://phab.mercurial-scm.org/D8516

hooks: provide access to transaction changes for internal hooks External hooks are skipped here as the environment often has a size limit in the low MBs and that can easily be reached by larger transactions. Differential Revision: https://phab.mercurial-scm.org/D8490

rust-regex: add test for verbatim regex syntax This makes sure it's not modified. Differential Revision: https://phab.mercurial-scm.org/D8508

rust-regex: prevent nonsensical `.*.*` pattern from happening Differential Revision: https://phab.mercurial-scm.org/D8507

rust-regex: fix issues with regex anchoring and performance It turns out that the way I tried to work around `regex`'s behavior difference with `re2` and Python's `re` was 1) buggy and 2) much more complicated than needed. In a few words: `regex` adds `.*` on either side of patterns when no start or end anchor is present. My previous workaround put `^` or `$` for every pattern, which is wrong even without the other 2 bugs on top of it. Using `^(?:<patterns>)` right at the end of the `regex` path fixes the issue. I've opened an issue to get a build option instead: https://github.com/rust-lang/regex/issues/675 Differential Revision: https://phab.mercurial-scm.org/D8506

diff: avoid going from contexts to nodes and back This will allow us to pass in-memory contexts that may not have a valid node to the diffing logic. Differential Revision: https://phab.mercurial-scm.org/D8503

cleanup: avoid extra node/ctx conversions in logcmdutil.diffordiffstat I'm about to write some code that wants to pass a memctx to diffordiffstat, but this feels like a meritorious cleanup anyway, since the first thing this method does is turn nodes into contexts, and most callers have a context handy. Differential Revision: https://phab.mercurial-scm.org/D8502

pyoxidizer: formatting bazel definitions This meets the Bazel style guide: https://docs.bazel.build/versions/master/skylark/bzl-style.html and was mostly done automatically with buildifier. Differential Revision: https://phab.mercurial-scm.org/D8521

revisions: parse "x123" as "nodeid starting with 123" without prefixhexnode `experimental.revisions.prefixhexnode` makes it so the template function `shortest()` uses an "x" prefix to disambiguate between short nodeids and revnums. That config has so far also been used for enabling parsing of "x123" unambiguously as a nodeid. That makes it a little annoying for people who have prefixhexnode=yes to share such nodeids with people who have prefixhexnode=no ("x123" will be considered invalid for them). There seems to be little harm in allowing that parsing for everyone. We still let e.g. bookmark names like "x123" take precedence over the nodeid, so that's not a concern. The only thing I can think of is that people get used to the "x" prefix being valid, making it impossible for us to change to a different prefix if we wanted to do that when graduating the feature. Differential Revision: https://phab.mercurial-scm.org/D8514

status: use cmdutil.check_at_most_one_arg() for checking --rev/--change There are apparently no tests for this either. Differential Revision: https://phab.mercurial-scm.org/D8511

diff: use cmdutil.check_at_most_one_arg() for checking --rev/--change The same check was done in extdiff as well, so I fixed that too. There are apparently no tests for this. Differential Revision: https://phab.mercurial-scm.org/D8510

copy: give better error message when no source paths found with --at-rev The new error message matches what we show when marking copies in the working copy. Differential Revision: https://phab.mercurial-scm.org/D8496

tests: show poor error message for `hg cp -A --at-rev . non-existent dst` Differential Revision: https://phab.mercurial-scm.org/D8495

copy: to find copy source, walk parent of revision we're marking copies in As shown in the previous patch, `hg cp --after --at-rev . src dst` fails if `src` is not in `.`. It seems obvious that you should always walk the *parent* of the revision you're marking copies in, but that's not how it was done for the working copy, and I didn't think to change it when marking copies in a non-working-copy commit. This patch fixes that by walking the parent commit instead, but only if we're marking copies for a non-working-copy commit. We need to leave the working-copy code unchanged because it depends on the weird behavior of `workingctx.walk()`. With these changes, there's very little overlap between the working-copy version and the non-working-copy version of `walkpats()`, but I've refrained from cleaning that up on the stable branch. Differential Revision: https://phab.mercurial-scm.org/D8494

tests: show that `hg cp -A --at-rev .` doesn't work for renames I clearly forgot to implement (and test) support for marking of renames when I added support for marking of copies :( Differential Revision: https://phab.mercurial-scm.org/D8493

rust-matchers: add TODO about incomplete `Display` for `IncludeMatcher` This is purely for future reference, I don't think this is a problem right now, since the `Display` is *only* used to ease debugging and has no real users. Differential Revision: https://phab.mercurial-scm.org/D8492

rust-filepatterns: match exact `rootglob`s with a `HashSet`, not in the regex This optimization yields some very interesting results in `rootglob`-heavy repositories. I build a test repository of the following structure: ``` root /<uuid>/build/empty_file ... repeat for 4000 entries ``` and a `.hgignore` containing the corresponding 4000 `rootglob` entries pointing to all `build/` folders. Rust+c `hg status` goes from 350ms down to 110ms. Differential Revision: https://phab.mercurial-scm.org/D8491

dirstate: force _checkexec to return a bool posix.checkexec can return True, False, or None. The rust status implementation expects a boolean, so make sure _checkexec returns a boolean. Differential Revision: https://phab.mercurial-scm.org/D8432

locking: wait for locks in `hg cp` and `hg mv` I traced this back to revision 1822 (64df422), and there's no explanation why we would prefer to error out instead of waiting for the locks. Differential Revision: https://phab.mercurial-scm.org/D8464

nodemap: teach `hg debugformat` about the persistent nodemap option We have a new requirement, we should display it. Differential Revision: https://phab.mercurial-scm.org/D8430

upgrade: support the --quiet flag The command is currently very verbose with a various bit of output being time sensitive or randomized. The make invocation bulky and hard to match in the test. We move various message from `ui.write` to `ui.status` in order for the `--quiet` flag to have effect and helps the situation. As a side benefit, we can replace the various redirection to > /dev/null with the --quiet flag. Differential Revision: https://phab.mercurial-scm.org/D8429

upgrade: clearly list optimisations This makes the command operation clearer. And this will be necessary to have a short version of this information with the next changesets, teaching `hg debugupgraderepo` about `--quiet`. Differential Revision: https://phab.mercurial-scm.org/D8428

nodemap: move the mode option to storage.revlog.nodemap.mode The option stay experimental as long as the main feature is. Differential Revision: https://phab.mercurial-scm.org/D8422

nodemap: move the option for mmap usage to storage.revlog.nodemap.mmap The option is stay experimental as long as the main feature is. Differential Revision: https://phab.mercurial-scm.org/D8421

nodemap: move and update the commend about persistence being experimental The comment was at the wrong place (on the developer option instead of the activation switch). So we move it at the right location and update it. Differential Revision: https://phab.mercurial-scm.org/D8420

nodemap: move the main switch to the `format` section The config to enable persistent nodemap is now `format.use-persistent-nodemap`. However the option remain marked as experimental because it only improve performance for people using the rust extensions. Differential Revision: https://phab.mercurial-scm.org/D8419

nodemap: drop the 'exp-' prefix for internal opener option The feature is now in a descent shape and we can consider having it "less" experimental. We won't be able to make it "totally" non-experimental, because its benefit rely on rust, which is totally experimental. Differential Revision: https://phab.mercurial-scm.org/D8418

nodemap: gate the feature behind a new requirement Now that the feature is working smoothly, a question was still open, should we gate the feature behind a new requirement or just treat it as a cache to be warmed by those who can and ignored by other. The advantage of using the cache approach is a transparent upgrade/downgrade story, making the feature easier to move to. However having out of date cache can come with a significant performance hit for process who expect an up to date cache but found none. In this case the file needs to be stored under `.hg/cache`. The "requirement" approach guarantee that the persistent nodemap is up to date. However, it comes with a less flexible activation story since an explicite upgrade is required. In this case the file can be stored in `.hg/store`. This wiki page is relevant to this questions: https://www.mercurial-scm.org/wiki/ComputedIndexPlan So which one should we take? Another element came into plan, the persistent nodemap use the `add` method of the transaction, it is used to keep track of a file content before a transaction in case we need to rollback it back. It turns out that the `transaction.add` API does not support file stored anywhere than `.hg/store`. Making it support file stored elsewhere is possible, require a change in on disk transaction format. Updating on disk file requires… introducing a new requirements. As a result, we pick the second option "gating the persistent nodemap behind a new requirements". Differential Revision: https://phab.mercurial-scm.org/D8417

nodemap: move on disk file to version 1 The current format contains the information we need, lets freeze it before the release. Differential Revision: https://phab.mercurial-scm.org/D8416

nodemap: add a new mode value, "strict" When "strict" is set, operation will refuse to use the slow path and abort if they would. This is useful for testing, benchmarking and server operation. Differential Revision: https://phab.mercurial-scm.org/D8415

nodemap: add a new mode option, with an optional "warn" value When "warn" is set, user will get notified when the slow code, used for compatibility is used. This can help people to detect situation were using that feature will give them a slowdown instead of a speedup. Differential Revision: https://phab.mercurial-scm.org/D8414

nodemap: also warm manifest nodemap with other caches The `hg debugupdatecache` command now also warm the persistent nodemap for the manifest (when applicable). Differential Revision: https://phab.mercurial-scm.org/D8411

nodemap: also use persistent nodemap for manifest The manifest as a different usage pattern than the changelog. First, while the lookup in changelog are not garanteed to match, the lookup in the manifest nodemap come from changelog and will exist in the manifest. In addition, looking up a manifest almost always result in unpacking a manifest an operation that rarely come cheap. Nevertheless, using a persistent nodemap provide a significant gain for some operations. For our measurementw, we use `hg cat --rev REV FILE` on the our reference mozilla-try. On this repository the persistent nodemap cache is about 29 MB in side for a total store side of 11,988 MB File with large history (file: b2g/config/gaia.json, revision: 195a1146daa0) no optimisation: 0.358s using mmap for index: 0.297s (-0.061s) persistent nodemap for changelog only: 0.275s (-0.024s) persistent nodemap for manifest too: 0.258s (-0.017s) File with small history (file: .hgignore, revision: 195a1146daa0) no optimisation: 0.377s using mmap for index: 0.296s (-0.061s) persistent nodemap for changelog only: 0.274s (-0.022s) persistent nodemap for manifest too: 0.257s (-0.017s) Same file but using a revision (8ba995b74e18) with a smaller manifest (3944829 bytes vs 10 bytes) no optimisation: 0.192s (-0.185s) using mmap for index: 0.131s (-0.061s) persistent nodemap for changelog only: 0.106s (-0.025s) persistent nodemap for manifest too: 0.087s (-0.019s) Differential Revision: https://phab.mercurial-scm.org/D8410

nodemap: create files in the repository used in the test We need a manifest with more content to test persistent nodemap for manifest. This change the repository content and affect all the hashes. Differential Revision: https://phab.mercurial-scm.org/D8409

rust-matchers: add timing tracing to regex compilation This might be useful to diagnose later performance issues or just to show the difference between engines. Differential Revision: https://phab.mercurial-scm.org/D8498

merge with stable

merge with stable

copies: fix the changeset based algorithm regarding merge In 99ebde4fec99, we changed the list of files stored into the `files` field. This lead to the changeset centric copy algorithm to break in various merge situation involving merge. Older information could reach the merge through `p1`, and while information from `p2` was strictly fresher, it would get overwritten anyway. We update the situation with more details about which revision introduces rename information. This help use making the right decision in case of merge. We are now running a more comprehensive suite of test with include this kind of situation. The behavior differ slightly from the filelog based in a couple of instance. There is mostly two distinct cases: 1) there are conflicting rename information in a merge (different rename history on each side). In this case the filelog based implementation arbitrarily pick a side based on the file-revision-number. So it depends on a local factor. The changeset centric algorithm will use a deterministic approach, by picking the information coming from the first parent of the merge. This is stable across different clone. 2) rename information related to file that exist in both source and destination. The filelog based implementation do not even try to detect these, however the changeset centric one get them for "free" (it is simpler to detect them than not). The new implementation focus on correctness. Performance improvement will come later. Differential Revision: https://phab.mercurial-scm.org/D8244

merge with stable

rust-chg: clean up excessive indents Differential Revision: https://phab.mercurial-scm.org/D8450

rust-chg: do not terminate tokio runtime until pager exits We no longer need to spawn a task just to keep the pager handle. The pager handle can be held by ChgUiHandler since the handler itself is not consumed and recreated across async calls. Differential Revision: https://phab.mercurial-scm.org/D8449

rust-chg: modernize entry function Finally the entire build passes. There's a bug that run() no longer waits for the spawned pager, which will be fixed by the next patch. Differential Revision: https://phab.mercurial-scm.org/D8448

rust-chg: reimplement locator by using async/await and tokio-0.2 connect_spawned() is rewritten from scratch by using std::process. Before, it would select completion of either connection or server process. New code could be implemented as such, but it's much simpler to occasionally run try_wait() to detect server death. Differential Revision: https://phab.mercurial-scm.org/D8447

rust-chg: reimplement ChgClientExt as ChgClient wrapper ChgClient is no longer an extension trait because: a. Client object is not consumed and recreated in future-0.3 world, which unblocks writing a simple wrapper struct. b. async fn isn't allowed in trait. Overall, the API should become simpler. Differential Revision: https://phab.mercurial-scm.org/D8446

rust-chg: reimplement run_command operation as async function The crafted state machine is no longer needed thanks to async/await. The state machine is basically rewritten as follows: - Ready(..) -> return .. - PollAgain(..) -> run .. and await - Err(..) -> return Err(..) Differential Revision: https://phab.mercurial-scm.org/D8445

rust-chg: reimplement uihandler by using async-trait and tokio-0.2 We no longer have to consume self and arguments. Differential Revision: https://phab.mercurial-scm.org/D8444

rust-chg: have attach_io() simply take reference of AsRawFd object We no longer have to deal with the restriction of the Future type. Before, these file objects couldn't be references and that's the only reason why we had to make stderr an Option<T>. This fixes future type deduction issue of stderr = None, where rustc would complain that T of Option<T> couldn't be deduced. Differential Revision: https://phab.mercurial-scm.org/D8443

rust-chg: reimplement attach_io operation as async function In short, MessageLoop<Connection> was redesigned as Protocol<Connection>, and the protocol methods no longer consume self. API changes are briefly documented in the following page: https://docs.rs/tokio-hglib/0.3.0/tokio_hglib/struct.Protocol.html Differential Revision: https://phab.mercurial-scm.org/D8442

rust-chg: upgrade to futures-0.3 based libraries And do some trivial fixes: - BytesMut::put_u32_be() -> put_u32() - tokio_process -> tokio::process, CommandExt -> Command, spawn_async() -> spawn(), stdin() -> stdin - tokio_timer::sleep() -> tokio::time::delay_for() Differential Revision: https://phab.mercurial-scm.org/D8441

rust-chg: exclude futures-dependent modules from build and break things It's impractical to upgrade the codebase incrementally since futures 0.1 and 0.3 APIs are fundamentally different. So this patch temporarily excludes futures-dependent modules from the build. These modules will be upgraded and re-enabled one by one. Differential Revision: https://phab.mercurial-scm.org/D8440