commandserver: update comment about setpgid Now setpgid has 2 main purposes: better handling for terminal-generated SIGTSTP, SIGINT, and process-exit-generated SIGHUP. Update the comment to explain things more clearly.

chg: forward SIGINT, SIGHUP to process group These signals are meant to send to a process group, instead of a single process: SIGINT is usually emitted by the terminal and sent to the process group. SIGHUP usually happens to a process group if termination of a process causes that process group to become orphaned. Before this patch, chg will only forward these signals to the single server process. This patch changes it to the server process group. This will allow us to properly kill processes started by the forked server process, like a ssh process. The behavior difference can be observed by setting SSH_ASKPASS to a dummy script doing "sleep 100" and then run "chg push ssh://dest-need-password-auth". Before this patch, the first Ctrl+C will kill the hg process while ssh-askpass and ssh will remain alive. This patch will make sure they are killed properly.

Added signature for changeset 519bb4f9d3a4

Added tag 3.9-rc for changeset 519bb4f9d3a4

merge default into stable for 3.9 code freeze

rbc: fix invalid rbc-revs entries caused by missing cache growth It was in some cases possible to end up writing to the cache file without growing it first. The range assignment in _setcachedata would append instead of writing at the requested position and thus write the new record in the wrong place. To fix this, we avoid looking up in too small caches, and when growing the cache, do it right before writing the new record to it so we know it has been done correctly.

rbc: test case for cache file not growing correctly, causing bad new entries

chg: handle EOF reading data block We recently discovered a case in production that chg uses 100% CPU and is trying to read data forever: recvfrom(4, "", 1814012019, 0, NULL, NULL) = 0 Using gdb, apparently readchannel() got wrong data. It was reading in an infinite loop because rsize == 0 does not exit the loop, while the server process had ended. (gdb) bt #0 ... in recv () at /lib64/libc.so.6 #1 ... in readchannel (...) at /usr/include/bits/socket2.h:45 #2 ... in readchannel (hgc=...) at hgclient.c:129 #3 ... in handleresponse (hgc=...) at hgclient.c:255 #4 ... in hgc_runcommand (hgc=..., args=<optimized>, argsize=<optimized>) #5 ... in main (argc=...486922636, argv=..., envp=...) at chg.c:661 (gdb) frame 2 (gdb) p *hgc $1 = {sockfd = 4, pid = 381152, ctx = {ch = 108 'l', data = 0x7fb05164f010 "st):\nTraceback (most recent call last):\n" "Traceback (most recent call last):\ne", maxdatasize = 1814065152," " datasize = 1814064225}, capflags = 16131} This patch addresses the infinite loop issue by detecting continuously empty responses and abort in that case. Note that datasize can be translated to ['l', ' ', 'l', 'a']. Concatenate datasize and data, it forms part of "Traceback (most recent call last):". This may indicate a server-side channeledoutput issue. If it is a race condition, we may want to use flock to protect the channels.

sslutil: more robustly detect protocol support The Python ssl module conditionally sets the TLS 1.1 and TLS 1.2 constants depending on whether HAVE_TLSv1_2 is defined. Yes, these are both tied to the same constant (I would think there would be separate constants for each version). Perhaps support for TLS 1.1 and 1.2 were added at the same time and the assumption is that OpenSSL either has neither or both. I don't know. As part of developing this patch, it was discovered that Apple's /usr/bin/python2.7 does not support TLS 1.1 and 1.2 (only TLS 1.0)! On OS X 10.11, Apple Python has the modern ssl module including SSLContext, but it doesn't appear to negotiate TLS 1.1+ nor does it expose the constants related to TLS 1.1+. Since this code is doing more robust feature detection (and not assuming modern ssl implies TLS 1.1+ support), we now get TLS 1.0 warnings when running on Apple Python. Hence the test changes. I'm not super thrilled about shipping a Mercurial that always whines about TLS 1.0 on OS X. We may want a follow-up patch to suppress this warning.

osutil: add darwin-only version of os.listdir using cffi

url: drop support for proxying HTTP (not HTTPS) over CONNECT tunneling It's been broken since cca59ef27e60, which made ui argument mandatory. I've tried several combinations of HTTP/HTTPS proxying on old/new Python versions, but I couldn't figure out how to reach this code path. Also, wrapping HTTP connection by SSLSocket seems wrong. My understanding is that self.realhostport is set by _generic_start_transaction() if HTTPS connection is tunneled. This patch removes proxy tunneling from httpconnection.connect() assuming that it was dead code from the beginning. Note that HTTPS over tunneling should be handled by httpsconnection class.

chgserver: rename private functions and variables of chgunixservicehandler self.address has been reanmed to self._realaddress to clarify that it can be different from the address argument.

chgserver: refactor initialization of real/base addresses Instead of overwriting self.address, calculate it from the address argument, which is the base address.

chgserver: reorder functions in chgunixservicehandler This should make it slightly easier to follow the call path.

chgserver: use ui.debug() to print server debug messages commandserver.log() is noop at this time because no client connection is established.

ssl: remove special case of web.cacerts=! from remoteui() It was introduced by b76d8c641746, which is no longer necessary thanks to recent refactoring of sslutil including ef316c653b7f.

bundle2: store changeset count when creating file bundles The bundle2 changegroup part has an advisory param saying how many changesets are in the part. Before this patch, we were setting this part when generating bundle2 parts via the wire protocol but not when generating local bundle2 files. A side effect of not setting the changeset count part is that progress bars don't work when applying changesets. As the tests show, this impacted clone bundles, shelve, backup bundles, `hg unbundle`, and anything touching bundle2 files. This patch adds a backdoor to allow us to pass state from changegroup generation into the unbundler. We store the number of changesets in the changegroup in this state and use it to populate the aforementioned advisory part parameter when generating the bundle2 bundle. I concede that I'm not thrilled by how state is being passed in changegroup.py (it feels a bit hacky). I would love to overhaul the rather confusing set of functions in changegroup.py with something that passes rich objects around instead of e.g. low-level generators. However, given the code freeze for 3.9 is imminent, I'd rather not undertake this endeavor right now. This feels like the easiest way to get the parameter added to the changegroup part.

util: implement a deterministic __repr__ on sortdict `hg debugbundle` is calling repr() on bundle2 part params, which are now util.sortdict instances. Unfortunately, repr() doesn't appear to be deterministic for util.sortdict. So, we implement one. We include the type name because that's the common convention for __repr__ implementations. Having the type name in `hg debugbundle` is a bit ugly. But it's a debug command and I don't care enough to fix it.

bundle2: use a sorted dict for holding parameters An upcoming change that introduces a 2nd part parameter to a part reveals that `hg debugbundle` isn't deterministic because parameters are stored on n plain, unsorted dict. While we could change that command to sort before output, I think the more important underlying issue is that bundle2 reading is taking an ordered data structure and converting it to an unordered one. Plugging in util.sortdict() fixes that problem while preserving API compatibility. This patch also appears to shine light on the fact that we don't have tests verifying parts with multiple parameters roundtrip correctly. That would be a good thing to test (and fuzz)... someday.

wireproto: extract repo filtering to standalone function As part of teaching Mozilla's replication extension to better handle repositories with obsolescence data, I encountered a few scenarios where I wanted built-in wire protocol commands from replication clients to operate on unfiltered repositories so they could have access to obsolete changesets. While the undocumented "web.view" config option provides a mechanism to choose what filter/view hgweb operates on, this doesn't apply to wire protocol commands because wireproto.dispatch() is always operating on the "served" repo. This patch extracts the line for obtaining the repo that wireproto commands operate on to its own function so extensions can monkeypatch it to e.g. return an unfiltered repo. I stopped short of exposing a config option because I view the use case for changing this as a niche feature, best left to the domain of extensions.

url: add distribution and version to user-agent request header (BC) As a server operator, I've always wanted to know what Mercurial version clients are running so I can track version adoption and make informed decisions about which versions of Mercurial to support in extensions. Unfortunately, there is no easy way to discern this today: the best you can do is look for high-level feature usage (e.g. bundle2) or sniff capabilities from bundle2 commands. And these things aren't changed frequently enough to tell you anything that interesting. Nearly every piece of software talking HTTP sends its version in the user agent. This includes web browsers, curl, and even Git. This patch adds the distribution name and version to the user-agent HTTP request header. We choose "Mercurial" for the distribution name because that seems appropriate. The version string comes from __version__. The value is inside parenthesis for a few reasons: * The version *may* contain spaces * Alternate forms like "Mercurial/<version>" imply structure and since the user agent should not be used by servers for protocol or feature negotiation/detection, we don't want to even give the illusion that the value should be parsed. A free form field is the most hostile to parsing. Flagging the patch as BC so it shows up in release notes. This change should be backwards compatible. But I wouldn't be surprised if a server somewhere is filtering on the exact old user agent string. So I want to make noise about this change.

commandserver: use SOMAXCONN as queue size of pending connections The old value 5 was arbitrary chosen. Since there's no practical reason to limit the backlog, this patch simply uses SOMAXCONN as a value large enough.

commandserver: rename _serveworker() to _runworker() "run" sounds more natural as the function does never listen for new connection.

commandserver: separate initialization and cleanup of forked process Separated _initworkerprocess() and _serverequest() can be reused when implementing a prefork service.

commandserver: unindent superfluous "if True" blocks

pycompat: make pycompat demandimport friendly pycompat.py includes hack to import modules whose names are changed in Python 3. We use try-except to load module according to the version of python. But this method forces us to import the modules to raise an ImportError and hence making it demandimport unfriendly. This patch changes the try-except blocks to a single if-else block. To avoid test-check-pyflakes.t complain about unused imports, pycompat.py is excluded from the test.

run-tests: make --local set --with-chg if --chg is used --local should work with chg as well.

run-tests: allow --local to set multiple attributes This is to make the next patch easier to review. It does not change logic.

chg: add pgid to hgclient struct The previous patch makes the server tell the client its pgid. This patch stores it in hgclient_t and adds a function to get it.

commandserver: send pgid in hello message See the next patches for why we need it.

tests: update test certificate generation instructions Suggestions from Anton Shestakov and Julien Cristau to use -subj and faketime, respectively.

sslutil: move comment about protocol constants protocolsettings() is the appropriate place for this comment.

sslutil: support defining cipher list Python 2.7 supports specifying a custom cipher list to TLS sockets. Advanced users may wish to specify a custom cipher list to increase security. Or in some cases they may wish to prefer weaker ciphers in order to increase performance (e.g. when doing stream clones of very large repositories). This patch introduces a [hostsecurity] config option for defining the cipher list. The help documentation states that it is for advanced users only. Honestly, I'm a bit on the fence about providing this because it is a footgun and can be used to decrease security. However, there are legitimate use cases for it, so I think support should be provided.

hghave: add test for Python 2.7+ Setting ciphers in the ssl module requires Python 2.7. Surprisingly, we didn't have a test for running on Python 2.7.

spartan: make different blocks of annotated lines have different colors

monoblue: make different blocks of annotated lines have different colors

gitweb: make different blocks of annotated lines have different colors

paper: make different blocks of annotated lines have different colors

tests: check importing modules in perf.py for historical portability To check importing modules in perf.py for historical portability, this patch lists up files by "hg files" both for "1.2" and tip, and builds up "module whitelist" check from those files. This patch uses "1.2" as earlier side version of "module whitelist", because "mercurial.error" module is a blocker for loading perf.py with Mercurial earlier than 1.2, and just importing "mercurial.error" separately isn't enough.

tests: introduce check-perf-code.py to add extra checks on perf.py This patch introduces tests/check-perf-code.py as a preparation for adding extra checks on contrib/perf.py in subsequent patches (mainly, for historical portability). At this change, check-perf-code.py doesn't add any extra check, and is equal to check-code.py. This makes subsequent patch focus only on adding an extra check on perf.py check-perf-code.py. check-perf-code.py adds extra checks on perf.py by wrapping contrib/check-code.py, because "filtering" by check-code.py (e.g. normalize characters in string literal or comment line) is useful to simplify regexp for check, and avoid false positive matching.

check-code: move fixing up regexp into main procedure This patch makes an extra check pattern to be prepared by "_preparepats()" as similarly as existing patterns, if it is added to "checks" array before invocation of "main()" in check-code.py. This is a part of preparation for adding check-code.py extra checks by another python script in subsequent patch. This is also useful for SkeletonExtensionPlan. https://www.mercurial-scm.org/wiki/SkeletonExtensionPlan

check-code: factor out boot procedure into main This is a part of preparation for adding check-code.py extra checks by another python script in subsequent patch. This is also useful for SkeletonExtensionPlan. https://www.mercurial-scm.org/wiki/SkeletonExtensionPlan

perf: import newer modules separately for earlier Mercurial demandimport of early Mercurial loads an imported module immediately, if a module is imported absolutely by "from a import b" style. Recent perf.py satisfies this condition, because it does: - have "from __future__ import absolute_import" line - use "from a import b" style for modules in "mercurial" package Before this patch, importing modules below prevents perf.py from being loaded by earlier Mercurial, because these aren't available in such Mercurial, even though there are some code paths for Mercurial earlier than 1.9. - branchmap 2.5 (or bcee63733aad) - repoview 2.5 (or 3a6ddacb7198) - obsolete 2.3 (or ad0d6c2b3279) - scmutil 1.9 (or 8b252e826c68) For example, setting "_prereadsize" attribute in perfindex() and perfnodelookup() is effective only with Mercurial earlier than 1.8 (or 61c9bc3da402). After this patch, "mercurial.error" is the only blocker in "from mercurial import" statement for loading perf.py with Mercurial earlier than 1.2. This patch ignores it, because just importing it separately isn't enough.

py3: conditionalize BaseHTTPServer, SimpleHTTPServer and CGIHTTPServer import The BaseHTTPServer, SimpleHTTPServer and CGIHTTPServer has been merged into http.server in python 3. All of them has been merged as util.httpserver to use in both python 2 and 3. This patch adds a regex to check-code to warn against the use of BaseHTTPServer. Moreover this patch also includes updates to lower part of test-check-py3-compat.t which used to remain unchanged.

py3: re-implement the BaseHTTPServer.test() function The function is changed in python 3. So the latest version of function is re-implemented. One can look at https://hg.python.org/cpython/file/3.5/Lib/http/server.py#l1184 and https://hg.python.org/cpython/file/2.7/Lib/BaseHTTPServer.py#l590 to see the change

test-http: use sed instead of fixed-with cut for reading access.log Some systems (like FreeBSD jails) use something other than 127.0.0.1 for localhost, and it's not safe to assume it'll always be the same width. Using sed with a replacement like this sidesteps the problem.

test-serve: add missing globs check-code missed this because of the closing ) in the "bound to" message.

tests: glob whitespace between path and OK in unzip(1) output FreeBSD's unzip(1) uses tabs instead of a run of spaces.

sslutil: print a warning when using TLS 1.0 on legacy Python Mercurial now requires TLS 1.1+ when TLS 1.1+ is supported by the client. Since we made the decision to require TLS 1.1+ when running with modern Python versions, it makes sense to do something for legacy Python versions that only support TLS 1.0. Feature parity would be to prevent TLS 1.0 connections out of the box and require a config option to enable them. However, this is extremely user hostile since Mercurial wouldn't talk to https:// by default in these installations! I can easily see how someone would do something foolish like use "--insecure" instead - and that would be worse than allowing TLS 1.0! This patch takes the compromise position of printing a warning when performing TLS 1.0 connections when running on old Python versions. While this warning is no more annoying than the CA certificate / fingerprint warnings in Mercurial 3.8, we provide a config option to disable the warning because to many people upgrading Python to make the warning go away is not an available recourse (unlike pinning fingerprints is for the CA warning). The warning appears as optional output in a lot of tests.

sslutil: require TLS 1.1+ when supported Currently, Mercurial will use TLS 1.0 or newer when connecting to remote servers, selecting the highest TLS version supported by both peers. On older Pythons, only TLS 1.0 is available. On newer Pythons, TLS 1.1 and 1.2 should be available. Security professionals recommend avoiding TLS 1.0 if possible. PCI DSS 3.1 "strongly encourages" the use of TLS 1.2. Known attacks like BEAST and POODLE exist against TLS 1.0 (although mitigations are available and properly configured servers aren't vulnerable). I asked Eric Rescorla - Mozilla's resident crypto expert - whether Mercurial should drop support for TLS 1.0. His response was "if you can get away with it." Essentially, a number of servers on the Internet don't support TLS 1.1+. This is why web browsers continue to support TLS 1.0 despite desires from security experts. This patch changes Mercurial's default behavior on modern Python versions to require TLS 1.1+, thus avoiding known security issues with TLS 1.0 and making Mercurial more secure by default. Rather than drop TLS 1.0 support wholesale, we still allow TLS 1.0 to be used if configured. This is a compromise solution - ideally we'd disallow TLS 1.0. However, since we're not sure how many Mercurial servers don't support TLS 1.1+ and we're not sure how much user inconvenience this change will bring, I think it is prudent to ship an escape hatch that still allows usage of TLS 1.0. In the default case our users get better security. In the worst case, they are no worse off than before this patch. This patch has no effect when running on Python versions that don't support TLS 1.1+. As the added test shows, connecting to a server that doesn't support TLS 1.1+ will display a warning message with a link to our wiki, where we can guide people to configure their client to allow less secure connections.

sslutil: config option to specify TLS protocol version Currently, Mercurial will use TLS 1.0 or newer when connecting to remote servers, selecting the highest TLS version supported by both peers. On older Pythons, only TLS 1.0 is available. On newer Pythons, TLS 1.1 and 1.2 should be available. Security-minded people may want to not take any risks running TLS 1.0 (or even TLS 1.1). This patch gives those people a config option to explicitly control which TLS versions Mercurial should use. By providing this option, one can require newer TLS versions before they are formally deprecated by Mercurial/Python/OpenSSL/etc and lower their security exposure. This option also provides an easy mechanism to change protocol policies in Mercurial. If there is a 0-day and TLS 1.0 is completely broken, we can act quickly without changing much code. Because setting the minimum TLS protocol is something you'll likely want to do globally, this patch introduces a global config option under [hostsecurity] for that purpose. wrapserversocket() has been taught a hidden config option to define the explicit protocol to use. This is queried in this function and not passed as an argument because I don't want to expose this dangerous option as part of the Python API. There is a risk someone could footgun themselves. But the config option is a devel option, has a warning comment, and I doubt most people are using `hg serve` to run a production HTTPS server (I would have something not Mercurial/Python handle TLS). If this is problematic, we can go back to using a custom extension in tests to coerce the server into bad behavior.

sslutil: prevent CRIME ssl.create_default_context() disables compression on the TLS channel in order to prevent CRIME. I think we should follow CPython's lead and attempt to disable channel compression in order to help prevent information leakage. Sadly, I don't think there is anything we can do on Python versions that don't have an SSLContext, as there is no way to set channel options with the limited ssl API.

sslutil: update comment about create_default_context() While ssl.create_default_context() creates a SSLContext with reasonable default options, we can't use it because it conflicts with our CA loading controls. So replace the comment with reality. (FWIW the comment was written before the existing CA loading code was in place.)

tests: use sslutil.wrapserversocket() Like the built-in HTTPS server, this code was using the ssl module directly and only using TLS 1.0. Like the built-in HTTPS server, we switch it to use sslutil.wrapserversocket() so it can follow better practices.

hgweb: use sslutil.wrapserversocket() This patch transitions the built-in HTTPS server to use sslutil for creating the server socket. As part of this transition, we implement developer-only config options to control CA loading and whether to require client certificates. This eliminates the need for the custom extension in test-https.t to define these. There is a slight change in behavior with regards to protocol selection. Before, we would always use the TLS 1.0 constant to define the protocol version. This would *only* use TLS 1.0. sslutil defaults to TLS 1.0+. So this patch improves the security of `hg serve` out of the box by allowing it to use TLS 1.1 and 1.2 (if available).

sslutil: implement wrapserversocket() wrapsocket() is heavily tailored towards client use. In preparation for converting the built-in server to use sslutil (as opposed to the ssl module directly), we add wrapserversocket() for wrapping a socket to be used on servers.

hgweb: pass ui into preparehttpserver Upcoming patches will need the built-in HTTPS server to be more configurable.

rebase: remove sortedstate-related confusion The following rebase implementation details are frustrating: - storing a list of sorted revision numbers in a field named sortedstate - having sortedstate be a field of the rebaseruntime class - using sortedstate[-1] as opposed to a more intuitive max(self.state) to compute the latest revision in the state This commit fixes those imperfections.

rebase: replace extrafn field with _makeextrafn invocations As per Yuya's advice, we would like to slightly reduce the amount of state which is stored in rebaseruntime class. In this case, we don't need to store extrafn field, as we can produce the necessary value by calling _makeextrafn and the perf overhead is negligible.

mercurial: implement a source transforming module loader on Python 3 The most painful part of ensuring Python code runs on both Python 2 and 3 is string encoding. Making this difficult is that string literals in Python 2 are bytes and string literals in Python 3 are unicode. So, to ensure consistent types are used, you have to use "from __future__ import unicode_literals" and/or prefix literals with their type (e.g. b'foo' or u'foo'). Nearly every string in Mercurial is bytes. So, to use the same source code on both Python 2 and 3 would require prefixing nearly every string literal with "b" to make it a byte literal. This is ugly and not something mpm is willing to do at this point in time. This patch implements a custom module loader on Python 3 that performs source transformation to convert string literals (unicode in Python 3) to byte literals. In effect, it changes Python 3's string literals to behave like Python 2's. In addition, the module loader recognizes well-known built-in functions (getattr, setattr, hasattr) and methods (encode and decode) that barf when bytes are used and prevents these from being rewritten. This prevents excessive source changes to accommodate this change (we would have to rewrite every occurrence of these functions passing string literals otherwise). The module loader is only used on Python packages belonging to Mercurial. The loader works by tokenizing the loaded source and replacing "string" tokens if necessary. The modified token stream is untokenized back to source and loaded like normal. This does add some overhead. However, this all occurs before caching: .pyc files will cache the transformed version. This means the transformation penalty is only paid on first load. As the extensive inline comments explain, the presence of a custom source transformer invalidates assumptions made by Python's built-in bytecode caching mechanism. So, we have to wrap bytecode loading and writing and add an additional header to bytecode files to facilitate additional cache validation when the source transformations change in the future. There are still a few things this code doesn't handle well, namely support for zip files as module sources and for extensions. Since Mercurial doesn't officially support Python 3 yet, I'm inclined to leave these as to-do items: getting a basic module loading mechanism in place to unblock further Python 3 porting effort is more important than comprehensive module importing support. check-py3-compat.py has been updated to ignore frames. This is necessary because CPython has built-in code to strip frames from the built-in importer. When our custom code is present, this doesn't work and the frames get all messed up. The new code is not perfect. It works for now. But once you start chasing import failures you find some edge cases where the files aren't being printed properly. This only burdens people doing future Python 3 porting work so I'm inclined to punt on the issue: the most important thing is for the source transforming module loader to land. There was a bit of churn in test-check-py3-compat.t because we now trip up on str/unicode/bytes failures as a result of source transformation. This is unfortunate but what are you going to do. It's worth noting that other approaches were investigated. We considered using a custom file encoding whose decode() would apply source transformations. This was rejected because it would require each source file to declare its custom Mercurial encoding. Furthermore, when changing the source transformation we'd need to version bump the encoding name otherwise the module caching layer wouldn't know the .pyc file was invalidated. This would mean mass updating every file when the source transformation changes. Yuck. We also considered transforming at the AST layer. However, Python's ast module is quite gnarly and doing AST transforms is quite complicated, even for trivial rewrites. There are whole Python packages that exist to make AST transformations usable. AST transforms would still require import machinery, so the choice was basically to perform source-level, token-level, or ast-level transforms. Token-level rewriting delivers the metadata we need to rewrite intelligently while being relatively easy to understand. So it won. General consensus seems to be that this approach is the best available to avoid bulk rewriting of '' to b''. However, we aren't confident that this approach will never be a future maintenance burden. This approach does unblock serious Python 3 porting efforts. So we can re-evaulate once more work is done to support Python 3.