run-tests: forward Python USER_BASE from site (issue5425) We do this so that any linters installed via pip install --user don't break. See https://docs.python.org/2/library/site.html#site.USER_BASE for a description of what this nonsense is all about. An alternative would be to not set HOME, but that'll cause other problems (see issue2707), or to forward every single path entry from sys.path in PYTHONPATH (which seems sketchy in its own way).

util: improve iterfile so it chooses code path wisely We have performance concerns on "iterfile" as it is 4X slower on normal files. While modern systems have the nice property that reading a "fast" (on-disk) file cannot be interrupted and should be made use of. This patch dumps the related knowledge in comments. And "iterfile" chooses code paths wisely: 1. If it's CPython 3, or PyPY, use the fast path. 2. If fp is a normal file, use the fast path. 3. If fp is not a normal file and CPython version >= 2.7.4, use the same workaround (4x slower) as before. 4. If fp is not a normal file and CPython version < 2.7.4, use another workaround (2x slower but may block longer then necessary) which basically re-invents the buffer + readline logic in Python. This will give us good confidence on both correctness and performance dealing with EINTR in iterfile(fp) for all known supported Python versions.

merge with stable

worker: stop using a separate thread waiting for children Now that we have a SIGCHLD hander, and it could get executed when waiting for I/O. It's no longer necessary to have a separated waitpid thread. So just remove it.

worker: add a SIGCHLD handler to collect worker immediately As planned by previous patches, add a SIGCHLD handler to get notifications about worker exits, and deals with worker failure immediately. Note that the SIGCHLD handler gets unregistered before killworkers(), so SIGCHLD won't interrupt "killworkers" - making it harder to send kill signals to waited processes.

worker: make waitforworkers reentrant We are going to use it in the SIGCHLD handler. The handler will be executed in the main thread with the non-blocking version of waitpid, while the waitforworkers thread runs the blocking version. It's possible that one of them collects a worker and makes the other error out (no child to wait). This patch handles these errors: ECHILD is ignored. EINTR needs a retry. The "pids" set is designed to be only modifiable by "waitforworkers". And we only remove items after a successful waitpid. Since a child process can only be "waitpid"-ed once. It's guaranteed that "pids.remove(p)" won't be called with duplicated "p"s. And once a "p" is removed from "pids", that "p" does not need to be killed or waited any more.

worker: change "pids" to a set There is no need to keep any order of the "pids" array. A set is more efficient for the "remove" operation. And the following patch will use that.

worker: allow waitforworkers to be non-blocking This patch adds a boolean flag to waitforworkers and makes it non-blocking if set to True. This is to make it possible that we can reap our workers while keep other unrelated children untouched, after receiving SIGCHLD.

worker: wait worker pid explicitly Before this patch, waitforworkers uses os.wait() to collect child workers, and only wait len(pids) processes. This can have serious issues if other code spawns new processes and does not reap them: 1. worker.py may get wrong exit code and kill innocent workers. 2. worker.py may continue without waiting for all workers to complete. This patch fixes the issue by using waitpid to wait worker pid explicitly. However, this patch introduces a new issue: worker failure may not be handled immediately. The issue will be addressed in next patches.

worker: move killworkers and waitforworkers up We need to use them in the SIGCHLD handler and SIGCHLD handler should be installed before fork.

osutil: implement setprocname to set process title for some platforms This patch adds a simple setprocname method to osutil. The operation is not defined by any standard and is platform-specific, the current implementation tries to cover some major platforms (ex. Linux, OS X, FreeBSD) that is relatively easy to support. Other platforms (Windows [4], other BSDs, ...) can be added in the future. The current implementation supports two methods to change process title: a. setproctitle if available (works in FreeBSD). b. rewrite argv in place (works in Linux [1] and Mac OS X). [2] [3] [1]: Linux has "prctl(PR_SET_NAME, ...)" but 1) it has 16-byte limit, which is too small; 2) it is not quite equivalent to what we want - it changes "/proc/self/comm", not "/proc/self/cmdline" - "comm" change won't show up in "ps" output unless "-o comm" is used. [2]: The implementation does not rewrite the **environ buffer like some other implementations do, just to make the code simpler and safer. However, this also means the buffer size we can rewrite is significantly shorter. If we are really greedy and want the "environ" space, we can change the implementation later. [3]: It requires a CPython private API: Py_GetArgcArgv to get the original argv. Unfortunately Python 3 makes a copy of argv and returns the wchar_t version, so it is not supported for now. (if we really want to, we could count backwards from "char **environ", given known argc and argv, not sure if that's a good idea - probably not) [4]: The feature is aimed to make it easier for forked command server processes to show what they are doing. Since Windows does not support fork(), despite it's a major platform, its support is not added in this patch.

setup: test setproctitle before building osutil We are going to use setproctitle (provided by FreeBSD) if it's available in the next patch. Therefore provide a macro to give some clues to the C pre-processor so it could choose code path wisely.

patch: remove unused git parameter from patch.diffstat() Since 628a4a9e411d the parameter is not used anymore.

perf: add asv benchmarks Airspeed velocity (ASV) is a python framework for benchmarking Python packages over their lifetime. The results are displayed in an interactive web frontend. Add ASV benchmarks for mercurial that use contrib/perf.py extension that could be run against multiple reference repositories. The benchmark suite now includes revsets from contrib/base-revsets.txt with variants, perftags, perfstatus, perfmanifest and perfheads. Installation requires asv>=0.2, python-hglib and virtualenv This is part of PerformanceTrackingSuitePlan https://www.mercurial-scm.org/wiki/PerformanceTrackingSuitePlan

perf: omit copying ui and redirect to ferr if buffer API is in use This allow to get the output of contrib/perf.py commands using the ui.pushbuffer() API.

manifest: change treemanifestctx to construct subtrees from the manifestlog Previously, treemanifestctx would directly construct its subtrees. By making it get the subtrees through manifestlog.get() we consolidate all treemanifestctx creation into manifestlog.get() and therefore extensions that need to wrap manifestctx creation (like narrow-hg) can intercept manifestctxs at that single place. This also means fetching subtrees will take advantage of the manifestlog ctx cache now, which it did not before.

manifest: make revlog verification optional This patches adds an parameter to manifestlog.get() to disable hash checking. This will be used in an upcoming patch to support treemanifestctx reading sub-trees without loading them from the revlog. (This is already supported but does not go through the manifestlog.get() code path)

debugcommands: move debugbuilddag And we drop some now unused imports from commands.py.

debugcommands: introduce standalone module for debug commands commands.py is our largest .py file by nearly 2x. Debug commands live in a world of their own. So let's extract them to their own module. We start with "debugancestor." We currently reuse the commands table with commands.py and have a hack in dispatch.py for loading debugcommands.py. In the future, we could potentially use a separate commands table and avoid the import of debugcommands.py.

convert: migrate to util.iterfile

match: migrate to util.iterfile

store: migrate to util.iterfile

patch: migrate to util.iterfile

worker: migrate to util.iterfile

util: add iterfile to workaround a fileobj.__iter__ issue with EINTR The fileobj.__iter__ implementation in Python 2.7.12 (hg changeset 45d4cea97b04) is buggy: it cannot handle EINTR correctly. In Objects/fileobject.c: size_t Py_UniversalNewlineFread(....) { .... if (!f->f_univ_newline) return fread(buf, 1, n, stream); .... } According to the "fread" man page: If an error occurs, or the end of the file is reached, the return value is a short item count (or zero). Therefore it's possible for "fread" (and "Py_UniversalNewlineFread") to return a positive value while errno is set to EINTR and ferror(stream) changes from zero to non-zero. There are multiple "Py_UniversalNewlineFread": "file_read", "file_readinto", "file_readlines", "readahead". While the first 3 have code to handle the EINTR case, the last one "readahead" doesn't: static int readahead(PyFileObject *f, Py_ssize_t bufsize) { .... chunksize = Py_UniversalNewlineFread( f->f_buf, bufsize, f->f_fp, (PyObject *)f); .... if (chunksize == 0) { if (ferror(f->f_fp)) { PyErr_SetFromErrno(PyExc_IOError); .... } } .... } It means "readahead" could ignore EINTR, if "Py_UniversalNewlineFread" returns a non-zero value. And at the next time "readahead" got executed, if "Py_UniversalNewlineFread" returns 0, "readahead" would raise a Python error without a incorrect errno - could be 0 - thus "IOError: [Errno 0] Error". The only user of "readahead" is "readahead_get_line_skip". The only user of "readahead_get_line_skip" is "file_iternext", aka. "fileobj.__iter__", which should be avoided. There are multiple places where the pattern "for x in fp" is used. This patch adds a "iterfile" method in "util.py" so we can migrate our code from "for x in fp" to "fox x in util.iterfile(fp)".

filterpyflakes: whitelist listcomp aliasing checking The test change is because of how filterpyflakes is organized - a line number changed.

verify: avoid shadowing two variables with a list comprehension The variable names are clearly worse now, but since we're really just transposing key and value I'm not too worried about the clarity loss.

revset: avoid shadowing a variable with a list comprehension

revlog: avoid shadowing several variables using list comprehensions

minirst: avoid shadowing a variable in a list comprehension

hbisect: avoid shadowing a variable in a list comprehension

filemerge: avoid shadowing a variable in a list comprehension

color: avoid shadowing a variable inside a list comprehension

memory: avoid shadowing variables inside a list comprehension

shelve: move shelve-finishing logic to a separate function With future obs-based shelve, finishing shelve will be different from just aborting a transaction and I would like to keep both variants of this functionality in a separate function.

shelve: move unknown files handling to a separate function This change has nothing to do with future obsshelve introduction, it is done just for readability purposes.

shelve: move actual created commit shelving to a separate function Currently, this code does not have any branching, it just bundles a commit and saves a patch file. Later, obsolescence-based shelve will be added, so this code will also create some obsmarkers and will be one of the few places where obsshelve will be different from traditional shelve.

shelve: move 'nothing changed' messaging to a separate function This has nothing to do with the future obsshelve implementation, I just thought that moving this messaging to a separate function will improve shelve code readability.

shelve: move commitfunc creation to a separate function Special commitfuncs are created as closures at least twice in shelve's code and one time special commitfunc is used within another closure. They all serve very specific purposes like temporarily tweak some configuration or enable editor, etc. This is not immediately important to someone reading shelve code, so I think moving this logic to a separate function is a good idea.

shelve: move mutableancestors to not be a closure There's no value in it being a closure and everyone who tries to read the outer function code will be distracted by it. IMO moving it out significantly improves readability, especially given how clear it is what mutableancestors function does from its name.

shelve: move shelve name generation to a separate function This has nothing to do with future obsshelve introduction, done just for readability purposes.

shelve: move possible shelve file extensions to a single place This and a couple of following patches are a preparation to implementing obsolescense-enabled shelve which was discussed on a Sprint. If this refactoring is not done, shelve is going to look even more hackish than now. This particular commit introduces a slight behavior change. Previously, if only .hg/shelve/name.patch file exists, but .hg/name.hg does not, 'hg shelve -d name' would fail saying "shelve not found". Now deletion will only fail if .patch file does not exist (since .patch is used as an indicator of an existing shelve). Other shelve files being absent are skipped silently to accommodate for future introduction of obs-based shelve, which will mean that for some shelves .hg and .patch files exist, while for others .hg and .oshelve.

manifest: delete manifest.manifest class Now that nothing uses the primary manifest class, we can delete it.

localrepo: delete localrepo.manifest Now that nothing uses normal manifests, we can delete localrepo.manifest.

manifest: remove last uses of repo.manifest Now that all the functionality has been moved to manifestlog/manifestrevlog/etc, we can finally change all the uses of repo.manifest to use the new versions. A future diff will then delete repo.manifest. One additional change in this commit is to change repo.manifestlog to be a @storecache property instead of @property. This is required by some uses of repo.manifest require that it be settable (contrib/perf.py and the static http server). We can't do this in a prior change because we can't use @storecache on this until repo.manifest is no longer used anywhere.

manifest: add unionmanifestlog support As part of deprecating manifest, we need to make the union repo support manifestlog.

manifest: add bundlemanifestlog support As part of deprecating manifest.manifest we need to make bundlerepo support manifestlog.

manifest: make manifestlog use it's own cache As we start to make manifestlog the primary manifest source, the dependency on manifest.manifest will cause circular dependency problems. Let's break this dependency by making manifestlog use it's own cache. In a near future patch we will remove the previous manifest cache so we're not duplicating it.

manifest: delete unused dirlog and _newmanifest functions As part of migrating all manifest functionality out of manifest.manifest, let's migrate a couple spots off of manifest.dirlog() to use the revlog specific accessor. Then we can delete manifest.dirlog() and other unused functions.

manifest: move clearcaches to manifestlog This is part of removing all functionality from manifest.manifest so we can delete the class entirely.

manifest: remove usages of manifest.read Now that the two manifestctx implementations have working read() functions, let's remove the existing uses of manifest.read and drop the function.

manifest: remove dependency on manifestrevlog being able to create trees A future patch will be removing the read() function from the manifest class. Since manifestrevlog currently depends on the read function that manifest implements (as a derived class), we need to break the dependency from manifestrevlog to read(). We do this by adding an argument to manifestrevlog.write() which provides it with the ability to read a manifest. This is good in general because it further separates revlog as the storage format from the actual inmemory data structure implementation.

color: show mode warning based on ui.formatted ui.interactive is only for input and ui.formatted is for output.

protocol: drop unused import of zlib Something weird is happening that breaks pyflakes installed via 'pip install --user'. I haven't had a chance to finish debugging this, but this at least fixes the build.

hook: lower inflated use of sys.__stdout__ and __stderr__ They were introduced at 9f76df0edb7d, where sys.stdout could be replaced by sys.stderr. After that, we've changed the way of stdout redirection by afccc64eea73, so we no longer need to reference the original __stdout__ and __stderr__ objects. Let's move away from using __std*__ objects so we can simply wrap sys.std* objects for Python 3 porting.

hook: flush stdout before restoring stderr redirection There was a similar issue to 8b011ededfb2. If an in-process hook writes to stdout, the data may be buffered. In which case, stdout must be flushed before restoring its file descriptor. Otherwise, remaining data would be sent over the ssh wire and corrupts the protocol. Note that this is a different redirection from the one I've just removed.

hook: do not redirect stdout/err/in to ui while running in-process hooks (BC) It was introduced by a59058fd074a to address command-server issues. After that, I've made a complete fix by 69f86b937035, so we don't need to replace sys.stdio objects to protect the IPC channels. This change means we no longer see data written to sys.stdout/err by an in-process hook on command server. I think that's okay because the canonical way is to use ui functions and in-process hooks should respect the Mercurial API. This will help Python 3 porting, where sys.stdout is TextIO but ui.fout is BytesIO.

merge: change modified indicator to be 20 bytes Previously we indicated that the .hgsubstate file was dirty by adding a '+' to the end of its hash in the wctx manifest. This made is complicated to have new manifest implementations that rely on the node length being fixed. In previous patches we added added and modified node placeholders, so let's use those to indicate dirty here as well. It doesn't look like anything ever depended on this '+' (aside from it being different to the parent), so nothing else needed to change here.

dirstate: change added/modified placeholder hash length to 20 bytes Previously the added/modified placeholder hash for manifests generated from the dirstate was a 21byte long string consisting of the p1 file hash plus a single character to indicate an add or a modify. Normal hashes are only 20 bytes long. This makes it complicated to implement more efficient manifest implementations which rely on the hashes being fixed length. Let's change this hash to just be 20 bytes long, and rely on the astronomical improbability of an actual hash being these 20 bytes (just like we rely on no hash every being the nullid). This changes the possible behavior slightly in that the hash for all added/modified entries in the dirstate manifest will now be the same (so simple node comparisons would say they are equal), but we should never be doing simple node comparisons on these nodes even with the old hashes, because they did not accurately represent the content (i.e. two files based off the same p1 file node, with different working copy contents would have the same hash (even with the appended character) in the old scheme too, so we couldn't depend on the hashes period).

dirstate: change placeholder hash length to 20 bytes Previously the new-node placeholder hash for manifests generated from the dirstate was a 21byte long string of "!" characters. Normal hashes are only 20 bytes long. This makes it complicated to implement more efficient manifest implementations which rely on the hashes being fixed length. Let's change this hash to just be 20 bytes long, and rely on the astronomical improbability of an actual hash being 20 "!" bytes in a row (just like we rely on no hash ever being the nullid). A future diff will do this for added and modified dirstate markers as well, so we're putting the new newnodeid in node.py so there's a common place for these placeholders.

util: remove compressorobj API from compression engines All callers have been replaced with "compressstream." It is quite low-level and redundant with "compressstream." So eliminate it.

hgweb: use compression engine API for zlib compression More low-level compression code elimination because we now have nice APIs. This patch also demonstrates why we needed and implemented the "level" option on the "compressstream" API.

bundle2: use compressstream compression engine API Compression engines now have an API for compressing a stream of chunks. Switch to it and make low-level compression code disappear.

util: add a stream compression API to compression engines It is a common pattern throughout the code to perform compression on an iterator of chunks, yielding an iterator of compressed chunks. Let's formalize that as part of the compression engine API. The zlib and bzip2 implementations allow an optional "level" option to control the compression level. The default values are the same as what the Python modules use. This option will be used in subsequent patches.