wireproto: add request IDs to frames One of my primary goals with the new wire protocol is to make operations faster and enable both client and server-side operations to scale to multiple CPU cores. One of the ways we make server interactions faster is by reducing the number of round trips to that server. With the existing wire protocol, the "batch" command facilitates executing multiple commands from a single request payload. The way it works is the requests for multiple commands are serialized. The server executes those commands sequentially then serializes all their results. As an optimization for reducing round trips, this is very effective. The technical implementation, however, is pretty bad and suffers from a number of deficiencies. For example, it creates a new place where authorization to run a command must be checked. (The lack of this checking in older Mercurial releases was CVE-2018-1000132.) The principles behind the "batch" command are sound. However, the execution is not. Therefore, I want to ditch "batch" in the new wire protocol and have protocol level support for issuing multiple requests in a single round trip. This commit introduces support in the frame-based wire protocol to facilitate this. We do this by adding a "request ID" to each frame. If a server sees frames associated with different "request IDs," it handles them as separate requests. All of this happening possibly as part of the same message from client to server (the same request body in the case of HTTP). We /could/ model the exchange the way pipelined HTTP requests do, where the server processes requests in order they are issued and received. But this artifically constrains scalability. A better model is to allow multi-requests to be executed concurrently and for responses to be sent and handled concurrently. So the specification explicitly allows this. There is some work to be done around specifying dependencies between multi-requests. We take the easy road for now and punt on this problem, declaring that if order is important, clients must not issue the request until responses to dependent requests have been received. This commit focuses on the boilerplate of implementing the request ID. The server reactor still can't manage multiple, in-flight request IDs. This will be addressed in a subsequent commit. Because the wire semantics have changed, we bump the version of the media type. Differential Revision: https://phab.mercurial-scm.org/D2869

wireproto: buffer output frames when in half duplex mode Previously, when told that a response was ready, the server reactor would instruct the caller to send frames immediately. This was OK as an initial implementation. But it would not work for half-duplex connections where the sender can't receive until all data has been transmitted - such as httplib based clients. In this commit, we teach the reactor that output frames should be buffered until end of input is seen. This required a new event to inform the reactor of end of input. The result from that event will instruct the consumer to send all buffered frames. The HTTP server is buffered by default. This change effectively hides the complexity of buffering within the reactor so that transports need not be concerned about it. This helps keep the transports "dumb" and will make implementing multiple requests-responses per atomic exchange (like an HTTP request) much simpler. Differential Revision: https://phab.mercurial-scm.org/D2860

wireproto: define and implement responses in framing protocol Previously, we only had client-side frame types defined. This commit defines and implements basic support for server-side frame types. We introduce two frame types - one for representing the raw bytes result of a command and another for representing error results. The types are quite primitive and behavior will expand over time. But you have to start somewhere. Our server reactor gains methods to react to an intent to send a response. Again, following the "sans I/O" pattern, the reactor doesn't actually send the data. Instead, it gives the caller a generator to frames that it can send out over the wire. Differential Revision: https://phab.mercurial-scm.org/D2858

wireproto: implement basic command dispatching for HTTPv2 Now that we can ingest frames and decode them to requests to run commands, we are able to actually run those commands. So this commit starts to implement that. There are numerous shortcomings. We can't operate on commands with "*" arguments. We can only emit bytesresponse results. We don't yet issue a response in the unified framing protocol. But it's a start. Differential Revision: https://phab.mercurial-scm.org/D2857

wireproto: nominally don't expose "batch" to version 2 wire transports The unified frame-based protocol will (eventually) support multiple requests per client transmission. This means that the [very hacky] "batch" command has no purpose existing in this protocol. This commit marks the command as applying to v1 transports only. But because SSHv2 == SSHv1 currently, we had to hack it back in for the SSHv2 transport. Bleh. Tests changed because the capabilities string changed. The order of tokens in the string is not important. Differential Revision: https://phab.mercurial-scm.org/D2856

wireproto: implement basic frame reading and processing We just implemented support for writing frames. Now let's implement support for reading them. The bulk of the new code is for a class that maintains the state of a server. Essentially, you construct an instance, feed frames to it, and it tells you what you should do next. The design is inspired by the "sans I/O" movement and the reactor pattern. We don't want to perform I/O or any major blocking event during frame ingestion because this arbitrarily limits ways that server pieces can be implemented. For example, it makes it much harder to swap in an alternate implementation based on asyncio or do crazy things like have requests dispatch to other processes. We do still implement readframe() which does I/O. But it is decoupled from the server reactor. And important parsing of frame headers is a standalone function. So I/O is only needed to obtain frame data. Because testing server-side ingest is useful and difficult on running servers, we create a new "debugreflect" endpoint that will echo back to the client what was received and how it was interpreted. This could be useful for a server admin, someone implementing a client. But immediately, it is useful for testing: we're able to demonstrate that frames are parsed correctly and turned into requests to run commands without having to implement command dispatch on the server! In addition, we implement Python level unit tests for the reactor. This is vastly more efficient than sending requests to the "debugreflect" endpoint and vastly more powerful for advanced testing. Differential Revision: https://phab.mercurial-scm.org/D2852

wireproto: define and implement protocol for issuing requests The existing HTTP and SSH wire protocols suffer from a host of flaws and shortcomings. I've been wanting to rewrite the protocol for a while now. Supporting partial clone - which will require new wire protocol commands and capabilities - and other advanced server functionality will be much easier if we start from a clean slate and don't have to be constrained by limitations of the existing wire protocol. This commit starts to introduce a new data exchange format for use over the wire protocol. The new protocol is built on top of "frames," which are atomic units of metadata + data. Frames will make it easier to implement proxies and other mechanisms that want to inspect data without having to maintain state. The existing frame metadata is very minimal and it will evolve heavily. (We will eventually support things like concurrent requests, out-of-order responses, compression, side-channels for status updates, etc. Some of these will require additions to the frame header.) Another benefit of frames is that all reads are of a fixed size. A reader works by consuming a frame header, extracting the payload length, then reading that many bytes. No lookahead, buffering, or memory reallocations are needed. The new protocol attempts to be transport agnostic. I want all that's required to use the new protocol to be a pair of unidirectional, half-duplex pipes. (Yes, we will eventually make use of full-duplex pipes, but that's for another commit.) Notably, when the SSH transport switches to this new protocol, stderr will be unused. This is by design: the lack of stderr on HTTP harms protocol behavior there. By shoehorning everything into a pair of pipes, we can have more consistent behavior across transports. We currently only define the client side parts of the new protocol, specifically the bits for requesting that a command run. This keeps the new code and feature small and somewhat easy to review. We add support to `hg debugwireproto` for writing frames into HTTP request bodies. Our tests that issue commands to the new HTTP endpoint have been updated to transmit frames. The server bits haven't been touched to consume the frames yet. This will occur in the next commit... Astute readers may notice that the command name is transmitted in both the HTTP request URL and the command request frame. This is partially a kludge from me initially implementing the frame-based protocol for SSH first. But it is also a feature: I intend to eventually support issuing multiple commands per HTTP request. This will allow us to replace the abomination that is the "batch" wire protocol command with a protocol-level mechanism for performing multi-dispatch. Because I want the frame-based protocol to be as similar as possible across transports, I'd rather we (redundantly) include the command name in the frame than differ behavior between transports that have out-of-band routing information (like HTTP) readily available. Differential Revision: https://phab.mercurial-scm.org/D2851

wireproto: define content negotiation for HTTPv2 HTTP messages communicate their media types and what media types they can understand via the Content-Type and Accept header, respectively. While I don't want the wire protocol to lean too heavily on HTTP because I'm aiming for the wire protocol to be as transport agnostic as possible, it is nice to play by the spec if possible. This commit defines our media negotiation mechanism for version 2 of the HTTP protocol. Essentially, we mandate the use of a new media type and how clients and servers should react to various headers or lack thereof. The name of the media type is a placeholder. We purposefully don't yet define the format of the new media type because that's a lot of work. I feel pretty strongly that we should use Content-Type. I feel less strongly about Accept. I think it is reasonable for servers to return the media type that was submitted to them. So we may strike this header before the protocol is finished... Differential Revision: https://phab.mercurial-scm.org/D2850

hgweb: also set Content-Type header Our HTTP/WSGI server may convert the Content-Type HTTP request header to the CONTENT_TYPE WSGI environment key and not set HTTP_CONTENT_TYPE. Other WSGI server implementations do this, so I think the behavior is acceptable. So assuming this HTTP request header could get "lost" by the WSGI server, let's restore it on the request object like we do for Content-Length. FWIW, the WSGI server may also *invent* a Content-Type value. The default behavior of Python's RFC 822 message class returns a default media type if Content-Type isn't defined. This is kind of annoying. But RFC 7231 section 3.1.1.5 does say the recipient may assume a media type of application/octet-stream. Python's defaults are for text/plain (given we're using an RFC 822 parser). But whatever. Differential Revision: https://phab.mercurial-scm.org/D2849

wireproto: require POST for all HTTPv2 requests Wire protocol version 1 transfers argument data via request headers by default. This has historically caused problems because servers institute limits on the length of individual HTTP headers as well as the total size of all request headers. Mercurial servers can advertise the maximum length of an individual header. But there's no guarantee any intermediate HTTP agents will accept headers up to that length. In the existing wire protocol, server operators typically also key off the HTTP request method to implement authentication. For example, GET requests translate to read-only requests and can be allowed. But read-write commands must use POST and require authentication. This has typically worked because the only wire protocol commands that use POST modify the repo (e.g. the "unbundle" command). There is an experimental feature to enable clients to transmit argument data via POST request bodies. This is technically a better and more robust solution. But we can't enable it by default because of servers assuming POST means write access. In version 2 of the wire protocol, the permissions of a request are encoded in the URL. And with it being a new protocol in a new URL space, we're not constrained by backwards compatibility requirements. This commit adopts the technically superior mechanism of using HTTP request bodies to send argument data by requiring POST for all commands. Strictly speaking, it may be possible to send request bodies on GET requests. But my experience is that not all HTTP stacks support this. POST pretty much always works. Using POST for read-only operations does sacrifice some RESTful design purity. But this API cares about practicality, not about being in Roy T. Fielding's REST ivory tower. There's a chance we may relax this restriction in the future. But for now, I want to see how far we can get with a POST only API. Differential Revision: https://phab.mercurial-scm.org/D2837

wireproto: define permissions-based routing of HTTPv2 wire protocol Now that we have a scaffolding for serving version 2 of the HTTP protocol, let's start implementing it. A good place to start is URL routing and basic request processing semantics. We can focus on content types, capabilities detect, etc later. Version 2 of the HTTP wire protocol encodes the needed permissions of the request in the URL path. The reasons for this are documented in the added documentation. In short, a) it makes it really easy and fail proof for server administrators to implement path-based authentication and b) it will enable clients to realize very early in a server exchange that authentication will be required to complete the operation. This latter point avoids all kinds of complexity and problems, like dealing with Expect: 100-continue and clients finding out later during `hg push` that they need to provide authentication. This will avoid the current badness where clients send a full bundle, get an HTTP 403, provide authentication, then retransmit the bundle. In order to implement command checking, we needed to implement a protocol handler for the new wire protocol. Our handler is just small enough to run the code we've implemented. Tests for the defined functionality have been added. I very much want to refactor the permissions checking code and define a better response format. But this can be done later. Nothing is covered by backwards compatibility at this point. Differential Revision: https://phab.mercurial-scm.org/D2836

wireproto: support /api/* URL space for exposing APIs I will soon be introducing a new version of the HTTP wire protocol. One of the things I want to change with it is the URL routing. I want to rely on URL paths to define endpoints rather than the "cmd" query string argument. That should be pretty straightforward. I was thinking about what URL space to reserve for the new protocol. We /could/ put everything at a top-level path. e.g. /wireproto/* or /http-v2-wireproto/*. However, these constrain us a bit because they assume there will only be 1 API: version 2 of the HTTP wire protocol. I think there is room to grow multiple APIs. For example, there may someday be a proper JSON API to query or even manipulate the repository. And I don't think we should have to create a new top-level URL space for each API nor should we attempt to shoehorn each future API into the same shared URL space: that would just be too chaotic. This commits reserves the /api/* URL space for all our future API needs. Essentially, all requests to /api/* get routed to a new WSGI handler. By default, it 404's the entire URL space unless the "api server" feature is enabled. When enabled, requests to "/api" list available APIs. URLs of the form /api/<name>/* are reserved for a particular named API. Behavior within each API is left up to that API. So, we can grow new APIs easily without worrying about URL space conflicts. APIs can be registered by adding entries to a global dict. This allows extensions to provide their own APIs should they choose to do so. This is probably a premature feature. But IMO the code is easier to read if we're not dealing with API-specific behavior like config option querying inline. To prove it works, we implement a very basic API for version 2 of the HTTP wire protocol. It does nothing of value except facilitate testing of the /api/* URL space. We currently emit plain text responses for all /api/* endpoints. There's definitely room to look at Accept and other request headers to vary the response format. But we have to start somewhere. Differential Revision: https://phab.mercurial-scm.org/D2834

url: support suppressing Accept header Sending this header automatically could interfere with future testing and client behavior. Let's add a knob to disable the behavior. We don't have a control for User-Agent because urllib will send it if we don't set something. I don't feel like hacking into the bowels of urllib to figure out how to suppress that. UA shouldn't be used for anything meaningful. So it shouldn't pose any problems beyond non-determinism (since the header has the Mercurial version in it). Differential Revision: https://phab.mercurial-scm.org/D2843

util: don't log low-level I/O calls for HTTP peer `hg debugwireproto` is useful for testing HTTP interactions. Possibly more useful than `get-with-headers.py`. But one thing that makes it annoying for mid-level tests is that it logs all API calls, such as readline(). This makes output - especially headers - overly verbose. This commit teaches our file and socket observers to not log API calls on functions dealing with data. We change the behavior of `hg debugwireproto` to enable this mode by default. --debug can be added to restore the previous behavior. As the test changes demonstrate, this makes tests much easier to read. As a bonus, it also removes some required (glob) over lengths in system call results. One thing that's lacking is knowing which side sent data. But we can fix this in a follow-up once it becomes a problem. Differential Revision: https://phab.mercurial-scm.org/D2842

rebase: rename conclude[memory]node() to commit[memory]node() The functions do little more than commit at this point. Differential Revision: https://phab.mercurial-scm.org/D2924

rebase: pass in "user" instead of "ctx" to conclude[memory]node() This was the only remaining part of the context object that was needed. Differential Revision: https://phab.mercurial-scm.org/D2923

rebase: look up default date outside of conclude[memory]node() Differential Revision: https://phab.mercurial-scm.org/D2922

rebase: move config override out of conclude[memory]node() Differential Revision: https://phab.mercurial-scm.org/D2921

rebase: pass in entire "overrides" dict to conclude[memory]node() As with previous patches, this was done the same way in both functions, so let's make the caller do it instead. Differential Revision: https://phab.mercurial-scm.org/D2920

rebase: pass in "keepbranch" to conclude[memory]node() Both functions calculated the same "keepbranch" value from the "keepbranches" we passed in, so let's make the caller do it instead. Differential Revision: https://phab.mercurial-scm.org/D2919

rebase: inline _makextrafn() now that we have only one caller Also avoid even creating a function since we just end up calling it right away. Differential Revision: https://phab.mercurial-scm.org/D2918

rebase: pass in "extra" itself into conclude[memory]node() We were passing in a function instead for no clear reason (probably historical, but I haven't bothered looking). Differential Revision: https://phab.mercurial-scm.org/D2917

rebase: look up commit message to reuse outside of conclude[memory]node() This was done the same way in both functions, so let's let the single caller do it. Differential Revision: https://phab.mercurial-scm.org/D2916

rebase: pass in ctx, not rev, to conclude[memory]node() They both need it and there's no locking that might make the results different, so let's do it in one place. This also lets us move out more common code in the following patches. Differential Revision: https://phab.mercurial-scm.org/D2915

rebase: extract common _concludenode() _rebasenode() and _finishrebase() had a lot of code in common. This commit extracts some of that. This means we will also have a single caller of concludenode() and concludememorynode(), which gives us a place to put code that is common between those two functions (which is quite a bit). Differential Revision: https://phab.mercurial-scm.org/D2914

rebase: store rebase state after each commit Before this patch, we stored the rebase state early in the processing of a node, before we updated the rebase state to indicate that the node was processed. This meant that we could redo the working copy merge and run into conflicts. However, this only happened in the --collapse case if the rebase was interrupted while editing the final commit message; in the case earlier interruptions, we would instead detect the in-process revision by finding two dirstate parents. This patch moves the writing of the rebase state to after we have completed the revision completely, and, importantly, after we have updated the rebase state to mark it done. This means we'll realize that all nodes have been rebased in the case mentioned above of editing the final commit message of a --collapse. See change to test case. I also moved the writing outside of the large if/elif block in _rebasenode(). This shouldn't matter much, but seems cleaner. One observable effect is if rebase was interrupted just after ignoring an obsolete node ("not rebasing ####, already in destination"), we used to come up with the same decision after --continue too, but after this patch we'll instead say "already rebased ###". This seems more consistent, since that's what we would do with obsolete nodes that had been marked done earlier in the process (not only just before the interruption). Differential Revision: https://phab.mercurial-scm.org/D2913

rebase: register status file generator only once when using single transaction rebase.storestatus() behaved differently depending on whether a transaction is passed to it. If a transaction is passed, it registers a "file generator" that runs when the transaction commits. If no transaction was passed, it writes the rebase state immediately. This imprecise timing of the writing makes it hard to reason about, so let's make it more explicit which behavior we're getting by checking if we have a transaction before calling it. For the single-transaction case, move the call to storestatus(tr) early and do it only once since it's only going to write the file (at most) once anyway. Differential Revision: https://phab.mercurial-scm.org/D2912

tests: add some more tests to test-rebase-collapse.t Some of these are currently broken. Differential Revision: https://phab.mercurial-scm.org/D2911

tests: use drawdag in test-rebase-collapse.t This makes the tests shorter (410 lines -> 240 lines), faster (17s -> 12s), and easier to read (the setup for each test case is just before the test, and we can refer to commits by name). Differential Revision: https://phab.mercurial-scm.org/D2910

rebase: remove unused default argument values from conclude[memory]node() It's only "commitmsg" that we don't always pass. Differential Revision: https://phab.mercurial-scm.org/D2909

rebase: get "inmemory" state directly from rebase runtime As far as I can tell, rbsrt.inmemory is equivalent to rbsrt.wctx.isinmemory(), so let's use the shorter form. Differential Revision: https://phab.mercurial-scm.org/D2908

commands: use keyword arguments in update function This will help us in having a dictionary with the values of all the arguments and we can add more flags without adding an argument to the function. Differential Revision: https://phab.mercurial-scm.org/D2896

rebase: pass "inmemory" directly to _definedestmap() We no longer reassign rbsrt.inmemory in _definedestmap(), so we don't need to pass the whole rebase runtime instance anymore, thus making it clear that it won't be updated. Differential Revision: https://phab.mercurial-scm.org/D2905

hgweb: explain instabilities of unstable changesets (the rest of the themes)

test-merge-tools: stabilize for Windows See fe5c4b795999.

test-http-protocol: drop an extraneous glob for Windows

merge with stable

hgweb: evaluate the "default" value as template Strictly speaking, everything in the map file is a template. So let's not take out an unparsed template string.

templater: use named function to expand template against mapping dict (API) And replace __call__(t, **mapping) in favor of generate(t, mapping). I prefer a named function here since the templater isn't a simple function-like object. .. api:: The templater is no longer callable. Use ``templater.generate(t, mapping)`` instead of ``templater(t, **pycompat.strkwargs(mapping))``.

highlight: peek Content-Type header set by hgweb There should be no need to re-render the mimetype template since it's set before dispatching webcommands.

obsolete: add a note that explains creating aliases for marker flags

repair: rename _backup to backupbundle A future commit will introduce a caller from outside the module. The function should have already been public because histedit was calling it. Differential Revision: https://phab.mercurial-scm.org/D2666

templatefuncs: do not stringify result of if*() expression Returning a generator means that the result is a byte string. I can't find any reason to make the "if" condition lazy since it is evaluated anyway when {if()} has to be evaluated. So let's simply make if*() return an input expression unmodified.

templater: add brief doc about internal data types Hopefully this will help reviewing upcoming my series. Start small.

debugcommands: support sending HTTP requests with debugwireproto We implement an action that can issue an HTTP request. We can define headers via arguments and specify a file to use for the HTTP request body. The request uses the HTTP peer's opener, which is already configured for auth, etc. This is both good and bad. Good in that we get some nice behavior out of the box. Bad in that some HTTP request headers are added automatically. Differential Revision: https://phab.mercurial-scm.org/D2841

debugcommands: support connecting to HTTP peers Now that we have the plumbing for logging socket activity, let's hook it up to `hg debugwireproto` so we can collect low-level activity on sockets. The new code is a bit incomplete. But it is better than nothing: `hg debugwireproto` is still heavily evolving. The added test demonstrates some interesting behavior. For example, we're calling socket.makefile() and doing I/O on that. TIL. We're also sending an "Accept-Encoding: identity" request header. Differential Revision: https://phab.mercurial-scm.org/D2726

url: add HTTP handler that uses a proxied socket Now that we have a socket proxy that can log I/O, we need to teach mechanisms that open URLs how to use it. We invent a custom HTTP handler class that knows how to proxy sockets as soon as they are opened. We teach the high-level opener() to accept logging arguments so a logging HTTP handler can be constructed. We don't yet support intercepting HTTPS sockets because I don't want to go down that rabbit hole. For the record, the urllib API is crazy and it took way too long to figure out at what levels I needed to plug in to modify the socket. # no-check-commit because we must name http_open that way Differential Revision: https://phab.mercurial-scm.org/D2722

util: observable proxy objects for sockets We previously introduced proxy objects and observers for file objects to help implement low-level tests for the SSH wire protocol. In this commit, we do the same for sockets in order to help test the HTTP server. We only proxy/observe some socket methods. I didn't feel like implementing all the methods because there are so many of them and implementing them will provide no short term value. We can always implement them later. # no-check-commit because we implement foo_bar methods on stdlib types Differential Revision: https://phab.mercurial-scm.org/D2721

hgweb: allow defining Server response header for HTTP server By default, the string contains the Python version. Server operators may want to change this. Because we like deterministic tests, we change the test harness to always set this value to a known string. Various globs over the server header have now been removed. # no-check-commit because we add version_string() Differential Revision: https://phab.mercurial-scm.org/D2840

tests: use $HTTP_DATE$ for Date header Support for the $HTTP_DATE$ substitution was recently added. Let's adopt it more widely. We had to tweak the substitution to be case insensitive, since HTTP headers are case insensitive. I also found a minor test issue not globbing over the length of the Server response header. Differential Revision: https://phab.mercurial-scm.org/D2839

debugcommands: introduce actions to perform deterministic reads "readavailable" is useful as a debugging device to see what data is available on a pipe. But the mechanism isn't deterministic because what's available on a pipe is highly conditional on timing, system load, OS behavior, etc. This makes it not suitable for tests. We introduce "ereadline," "read," and "eread" for performing deterministic I/O operations (at least on blocking file descriptors). We stop short of converting existing consumers of "readavailable" in tests because we're working out race conditions and deadlocks on Windows. But the goal is to eventually move tests away from "readavailable" to these new APIs. Differential Revision: https://phab.mercurial-scm.org/D2720

httppeer: refactor how httppeer is created (API) Previously, we passed a bunch of arguments to httppeer.__init__, validated them, then possibly constructed a valid instance. A short while ago, we refactored sshpeer so all the validation and setup work occurs before the constructor. We introduced a makepeer() to hold most of this logic. This commit gives httppeer the same treatment. As a sign that the previous design was poor, __del__ no longer conditionally checks for the presence of an attribute that may not be defined (it is always defined in the new code). .. api:: httppeer.httppeer.__init__ now takes additional arguments. Instances should be obtained by calling httppeer.instance() or httppeer.makepeer() instead. Differential Revision: https://phab.mercurial-scm.org/D2725

bundle: condition the changegroup part when creating a new bundle We will generate stream bundle in the next changesets which doesn't need the changegroup part. Differential Revision: https://phab.mercurial-scm.org/D1951

stack: return a sorted smartrev by default Most stack customers will display a list of revisions, sort it by default. Differential Revision: https://phab.mercurial-scm.org/D2399

histedit: use the new stack definition for histedit Now that we have a common stack definition, use it in the hg histedit command. Differential Revision: https://phab.mercurial-scm.org/D2398

show: use the new stack definition for show stack Now that we have a common stack definition, use it in the hg show stack command. Differential Revision: https://phab.mercurial-scm.org/D2397

stack: import Evolve stack test file Import Evolve stack test file for starting to have good coverage on stack definition. Differential Revision: https://phab.mercurial-scm.org/D2396

stack: add a new module for stack-related commands Bootstrap the module with a function that returns the stack for the current revision. The definition of the stack is ihnerited from histedit default revset and used by hg show stack. Differential Revision: https://phab.mercurial-scm.org/D2395

filemerge: use a single temp dir instead of temp files This can help to remove the clutter from UIs that display just the filenames; instead of seeing foo~local.C9ru9r.txt and foo~base.2DMV22.txt (in the /tmp directory on most platforms), we create a single new directory and use that, producing filenames like /tmp/hgmerge.C9ru9r/foo~local.txt. Differential Revision: https://phab.mercurial-scm.org/D2888

filemerge: move temp file unlinks to _maketempfiles Differential Revision: https://phab.mercurial-scm.org/D2887

hgweb: refactor multirequest to be a dict of lists ... instead of a list of 2-tuples. This makes key lookups faster. The only downside is we lose total ordering of all entries. But we weren't relying on that before, so it's no loss. Differential Revision: https://phab.mercurial-scm.org/D2881

py3: use "%d" % int instead of str(int) We need to use bytes internally. Differential Revision: https://phab.mercurial-scm.org/D2895

py3: use pycompat.bytestr() in dirstate.py This prevents extra b'' prefixes in output. Differential Revision: https://phab.mercurial-scm.org/D2894

py3: make tests/test-log-linerange.t work on Python 3 Made sure we write bytes to file and we suppress the return value of open(). Differential Revision: https://phab.mercurial-scm.org/D2893

py3: use print as a function in tests/test-narrow-clone-non-narrow-server.t Differential Revision: https://phab.mercurial-scm.org/D2892

tests: stop over-specifying tempfile name Python 3 has more random characters in the default template, which is fine. Differential Revision: https://phab.mercurial-scm.org/D2676

wireproto: explicitly flush stdio to prevent stalls on Windows This is the key to fixing the hangs on Windows in D2720[1]. I put flushes in a bunch of other places that didn't help, but I suspect that's more a lack of test coverage than anything else. Chasing down stuff like this is pretty painful. I'm wondering if we can put a proxy around sys.stderr (and sys.stdout?) on Windows (only when daemonized?) that will flush on every write (or at least every write with a '\n'). [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2018-March/113352.html

test-lfs: glob over some output changes These changes started with 2090044a288d. They aren't important to LFS testing.

templater: factor out helper that renders named template as string This is quite common in non-web templating, and **kwargs expansion is annoying because of the unicode-ness of Python3.

templater: rename .render(mapping) to .renderdefault(mapping) (API) I'm going to add templ.render(t, mapping) and templ.generate(t, mapping) in place of stringify(templ(t, **mapping)) and templ(t, **mapping) respectively. .. api:: The ``render(mapping)`` method of the templater has been renamed to ``renderdefault(mapping)``.

templater: fix invalid reference of runsymbol in doctest Oversight at da710c3df4dc. I was just lucky that this lambda function is never evaluated.

cmdutil: drop redundant import of merge module

annotate: add support for template keywords and functions depending on ctx

formatter: unblock storing fctx as a template resource To keep templateformatter._renderitem() simple, a repo instance is looked through ctx if available. This is probably good for future subrepo support where ctx.repo() may be different from the global repo.

templater: process mapping dict by resource callables A resource item is a callable, so let's make it look up a resource object by itself.

templater: convert resources to a table of callables for future extension I'm going to add a full templating support to the annotate command. As the annotate is a filectx-oriented command, we'll need a way to look up a ctx from a bounded fctx only when necessary. This is the minimal change to support that. I'm thinking of defining a proper interface to look up template resources to fix other issues, but that isn't ready yet. (Changes from V1: just updated tests and patch descriptions.)

merge with stable

hgweb: convert an assert to a ProgrammingError Because assert may get optimized away. Differential Revision: https://phab.mercurial-scm.org/D2882

filemerge: give some variables in _xmerge more descriptive names Differential Revision: https://phab.mercurial-scm.org/D2886

rebase: allow in-memory merge of the working copy parent Before this patch and when the rebase involved the working copy parent (and thus the working copy too), we would not do in-memory rebase even if requested to. The in-code comment explains that the reason had something to do with avoiding an extra update, but I don't know which update that refers to. Perhaps an earlier version of the code used to update to the destination before rebasing even if in-memory rebase was requested? That seems to not be done at least since aa660c1203a9 (rebase: do not bail on uncomitted changes if rebasing in-memory, 2017-12-07). To see if this still made it slower, I create a single tiny commit on top of one branch of the mozilla-unified repo (commit a1098c82 to be exact) and rebased it to another branch (commit d4e9a7be). Before this patch that took 11.8s and after this patch it took 8.6s (I only did two runs each, but the timings were very consistent). Differential Revision: https://phab.mercurial-scm.org/D2876

uncommit: simplify condition for keeping commit We used to keep the commit if it would have become empty and --keep was not passed. Since we just changed it so we also keep it if any patterns were passed on the command line, the only remaining case where we prune the commit is when no arguments were passed and --keep was not passed either, we can simplify the "not files and not allowempty" to just "not allowempty". Let's also rename "allowempty" to "keepcommit" since it's no longer about allowing an empty commit. Differential Revision: https://phab.mercurial-scm.org/D2891

uncommit: document when the commit will be pruned Differential Revision: https://phab.mercurial-scm.org/D2890

uncommit: leave empty commit if all files are uncommitted We had instructions for our internal users to add copy information after commit like this: hg uncommit <srcfile> <dstfile> hg cp --after <srcfile> <dstfile> hg amend That usually works, but if the rename was the only change in that commit, then the commit would get pruned. It's easy to fix the recipe: just pass the --keep option. However, it seems too subtle, so I think this is an indication that the commit should not be pruned if any patterns were given. Differential Revision: https://phab.mercurial-scm.org/D2862

test-template-engine: do not evaluate unused keywords by custom engine If the custom engine, "mytemplater", were installed as the default, it would enter to an infinite recursion at stringify(v) because template keywords may generate a nested mapping containing the same keywords. Spotted by a future patch which will replace context.resource('templ')(...) with context.process(...).

py3: make test-template-engine.t bytes-safe

test-template-engine: deduplicate methods of custom template engine

revbranchcache: advertise and use 'rbc' exchange capability The feature is now advertised and use. Updating the branchmap cache can be very expensive (up to minutes on large repository) and fetching revision branch data is about 80% of that. Exchanging the rev branch cache over the wire really help to recover from branch map invalidation. (There is a good chance other in flight chance would conflict on test-http-bad-server.t and other. So here is a small note to help update that test again: capabilities=19bytes, part-107bytes)

revbranchcache: disable the new part for narrow hg bundle The lack of some revisions confuses the new cache part. To simplify things, we disable it for now.

revbranchcache: add the necessary bit to send 'rbc' data over bundle2 Getbundle is now capable of sending rev-branch-cache information for the changesets it bundle. The data sent are mostly nodes so it is quite compact. The goal of the rev-branch-cache is to speed up branch map computation, especially when the branchmap gets invalidated so we send data for all exchanged changesets. In addition, computing the relevant heads to send in case of partial pulling would be challenging. The feature is still inactive since the capability is not advertised yet.

bundle: include advisory rev branch cache part in bundle2 bundle `hg bundle` command producing bundle2 will now include an optional part containing the revision-branch cache data. The data sent are mostly nodes so it is quite compact. The goal of the rev-branch-cache is to speed up branch map computation, especially when the branchmap gets invalidated so we send data for all exchanged changesets. In addition, computing the relevant heads to send in case of partial pulling would be challenging. As a reminder, the rev branch cache data significantly speed up branch computation. Having it around provides a small speedup to pull/clone and much higher tolerance to branch map cache invalidation that might happens from later commands. On the Mercurial repository, computing the visible branchmap from scratch move from 2.00 seconds to 0.34s (a -83% speedup). Using this new part, Unbundling the full Mercurial repository moves from 25.736 seconds to 24.030 seconds (around -7% speedup). The bundle size increase is around 3% (from 22.43 MB to 23.13MB) On an half a million revision repository with twenty thousand branches, computing the branchmap moves from 75 seconds to 45 second (-40%) if the caches is used. A bundle containing 50 000 changesets in such repository get a 0.5% size increase from such part for a -3% unbundling time speedup.

rev-branch-cache: add a function to generate a part The function is able to produce a rbc part consumed by the function introduced into previous changesets. More details on usage and impact in the next changesets.

revbranchcache: add a bundle2 handler for a rbc part We add the necessary bit to process a part containing rev-branch-cache information. The local rev branch cache is then updated with the received information. Computing branch cache can become a significant part of the time spent pulling.

revbranchcache: add a public function to update the data We want to exchange more cached data over the wire. To do so, we need a clean way to update the cache on the receiving ends.

httppeer: consolidate _requestbuilder assignments and document I collapsed multiple assignments because they don't appear to be necessary. We don't invoke the requestbuilder in anything called during __init__. So there's no reason to not define it earlier AFAICT. This seemingly useless attribute is actually an extension point. Document it as such. (A previous version of this patch removed the attribute because it appeared to just be an alias.) Differential Revision: https://phab.mercurial-scm.org/D2723

commands: don't check for merge.update() truthiness AFAICT ``stats`` is always a tuple in these cases. We don't need to check if the variable has a truthy value. Differential Revision: https://phab.mercurial-scm.org/D2691

httppeer: alias url as urlmod "url" is a common variable name. We do this aliasing elsewhere to avoid shadowing. Differential Revision: https://phab.mercurial-scm.org/D2724