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