commandserver: handle backlog before exiting Previously, when a chg server is exiting, it does not handle connected clients so clients may get ECONNRESET and crash: 1. client connect() # success 2. server shouldexit = True and exit 3. client recv() # ECONNRESET d7875bfbfccb makes this race condition easier to reproduce if a lot of short chg commands are started in parallel. This patch fixes the above issue by unlinking the socket path to stop queuing new connections and processing all pending connections before exit.

commandserver: prevent unlink socket twice This patch changes unixforkingservice so it only calls `self._servicehandler.unlinksocket(self.address)` at most once. This is needed by the next patch.

runtests: check ports on IPv6 address Previously, checkportisavailable only checks ports on the IPv4 address. This patch makes it check IPv6 as well. It'll be useful if "localhost" does not have an IPv4 address, or its IPv4 address does not exist somehow.

zeroconf: fail nicely on IPv6 only system zeroconf only knows how to deal with IPv4; I develop on a system where the only IPv4 address is 127.0.0.1. Teach zeroconf to ignore IPv6 addresses when looking for plausible IPv4 connectivity.

chg: verify XDG_RUNTIME_DIR According to the specification [1], $XDG_RUNTIME_DIR should be ignored unless: The directory MUST be owned by the user, and he MUST be the only one having read and write access to it. Its Unix access mode MUST be 0700. This patch adds a check and ignores it if it does not meet part of the criteria. [1]: https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html

check-code: permit functools.reduce

perf: split obtaining chunks from decompression Previously, the code was similar to what revlog._chunks() was doing, which took a raw data segment and delta chain, obtained buffers for the raw revlog chunks within, and decompressed them. This commit splits the "get raw chunks" action from "decompress." The goal of this change is to more accurately measurely decompression performance. On a ~50k deltachain for a manifest in mozilla-central: ! full ! wall 0.430548 comb 0.440000 user 0.410000 sys 0.030000 (best of 24) ! deltachain ! wall 0.016053 comb 0.010000 user 0.010000 sys 0.000000 (best of 181) ! read ! wall 0.008078 comb 0.010000 user 0.000000 sys 0.010000 (best of 362) ! rawchunks ! wall 0.033785 comb 0.040000 user 0.040000 sys 0.000000 (best of 100) ! decompress ! wall 0.327126 comb 0.320000 user 0.320000 sys 0.000000 (best of 31) ! patch ! wall 0.032391 comb 0.030000 user 0.030000 sys 0.000000 (best of 100) ! hash ! wall 0.012587 comb 0.010000 user 0.010000 sys 0.000000 (best of 233)

smartset: move set classes and related functions from revset module (API) These classes are pretty large and independent from revset computation. 2961 mercurial/revset.py 973 mercurial/smartset.py 3934 total revset.prettyformatset() is renamed to smartset.prettyformat(). Smartset classes are aliased since they are quite common in revset.py.

help: test if "hg help TOPIC" reference is valid It's quite easy to make a reference invalid by mistake.

help: uppercase command placeholder 'command' isn't a valid help topic but a placeholder text. Make it upper case to avoid confusion.

help: show section that couldn't be found For better error indication.

cmdutil: remove forwarding methods per deprecation policy

util: always force line buffered stdout when stdout is a tty (BC) pager replaced stdout with a line buffered version to work around glibc deciding on a buffering strategy on the first write to stdout. This is going to make my next patch hard, as replacing stdout will make tracking time spent blocked on it more challenging. Move the line buffering requirement to util.py, and remove it from pager. This means that the abuse of ui.formatted=True and pager set to cat or equivalent no longer results in a line-buffered output to a pipe, hence (BC), although I don't expect anyone to be affected

localrepo: avoid unnecessary conversion from node to rev changelog.heads() first calls headrevs then converts them to nodes. localrepo.heads() then sorts them using self.changelog.rev function and makes useless conversion back to revs. Instead let's call changelog.headrevs() from localrepo.heads(), sort the output and then convert to nodes. Because headrevs does not support start parameter this optimization only works if start is None.

bundle2: implement a basic __repr__ for bundle2 part We display basic data as the part id and part type. This make debugging bundle2 related code friendlier.

bundle2: drop an outdated comment The function is no longer in "early" stage and have been used in production for years. We can probably drop that part of the docstring...

unbundle: swap conditional branches for clarity This is a small style update for clarity. The previous situation was: if foo: 50 lines else: 2 lines In such case I tend to invert these to get the simpler branch out of the way earlier: if not foo: 2 lines else: 50 lines This makes the conditional and various alternatives fit on the same screen, simpler to read overall.

unbundle: add a small comment to tag the bundle1 case as such This makes the code clearer to understand for someone new to it (or rusted)

unbundle: add a small comment to clarify the 'check_heads' call Bundle2 has its own mechanisms to check for heads (and other) changes, so push using bundle2 is relying on the "check:heads" bundle part of unbundle and the 'check_heads' call is not checking anything. We add a small comment to make this clearer.

pager: don't terminate with extreme prejudice on SIGPIPE (BC) The default SIGPIPE handler causes Mercurial to exit immediately, without running any Python cleanup code (except and finally blocks, atexit handlers etc). This creates problems if you want to do something at exit. If we need a different exit code for broken pipe from pager, then we should code that ourselves in Python; this appears to have been cargo-culted from the fork implementation of pager that's no longer used, where it was needed to stop Broken Pipe errors appearing on the user's terminal.

verify: replace _validpath() by matcher The verifier calls out to _validpath() to check if it should verify that path and the narrowhg extension overrides _validpath() to tell the verifier to skip that path. In treemanifest repos, the verifier calls the same method to check if it should visit a directory. However, the decision to visit a directory is different from the condition that it's a matching path, and narrowhg was working around it by returning True from its _validpath() override if *either* was true. Similar to how one can do "hg files -I foo/bar/ -X foo/" (making the include pointless), narrowhg can be configured to track the same paths. In that case match("foo/bar/baz") would be false, but match.visitdir("foo/bar/baz") turns out to be true, causing verify to fail. This may seem like a bug in visitdir(), but it's explicitly documented to be undefined for subdirectories of excluded directories. When using treemanifests, the walk would not descend into foo/, so verification would pass. However, when using flat manifests, there is no recursive directory walk and the file path "foo/bar/baz" would be passed to _validpath() without "foo/" (actually without the slash) being passed first. As explained above, _validpath() would return true for the file path and "hg verify" would fail. Replacing the _validpath() method by a matcher seems like the obvious fix. Narrowhg can then pass in its own matcher and not have to conflate the two matching functions (for dirs and files). I think it also makes the code clearer.

rebase: fix code comment to refer to right issue (4504, not 4505) The comment was introduced in 8a544fb645bb (rebase: ensure rebase revision remains visible (issue4504), 2015-01-27), which mentions the right issue in the description.

merge with stable

repair: use rawvfs when copying extra store files If we use the normal vfs, store encoding will be applied when we .join() the path to be copied. This results in attempting to copy a file that (likely) doesn't exist. Using the rawvfs operates on the raw file path, which is returned by vfs.readdir(). Users at Mozilla are encountering this, as I've instructed them to run `hg debugupgraderepo` to upgrade to generaldelta. While Mercurial shouldn't deposit any files under .hg/store that require encoding, it is possible for e.g. .DS_Store files to be created by the operating system.

tests: add test demonstrating buggy path handling `hg debugupgraderepo` is currently buggy with regards to path handling when copying files in .hg/store/. Specifically, it applies the store filename encoding to paths instead of operating on raw files. This commit adds a test demonstrating the buggy behavior.

repair: iterate store files deterministically An upcoming test will add a 2nd file. Since readdir() is non-deterministic, add a sorted() to make traversal deterministic.

Added signature for changeset ed5b25874d99

Added tag 4.1.2 for changeset ed5b25874d99

changegroup: store old heads as a set Previously, the "oldheads" variable was a list. On a repository at Mozilla with 46,492 heads, profiling revealed that list membership testing was dominating execution time of applying small changegroups. This patch converts the list of old heads to a set. This makes membership testing significantly faster. On the aforementioned repository with 46,492 heads: $ hg unbundle <file with 1 changeset> before: 18.535s wall after: 1.303s Consumers of this variable only check for truthiness (`if oldheads`), length (`len(oldheads)`), and (most importantly) item membership (`h not in oldheads` - which occurs twice). So, the change to a set should be safe and suitable for stable. The practical effect of this change is that changegroup application and related operations (like `hg push`) no longer exhibit an O(n^2) CPU explosion as the number of heads grows.

subrepo: move prompts out of the if (issue5505) Prompts weren't available in the else clause

exchange: use v2 bundles for modern compression engines (issue5506) Previously, `hg bundle zstd` on a non-generaldelta repo would attempt to use a v1 bundle. This would fail because zstd is not supported on v1 bundles. This patch changes the behavior to automatically use a v2 bundle when the user explicitly requests a bundlespec that is a compression engine not supported on v1. If the bundlespec is <engine>-v1, it is still explicitly rejected because that request cannot be fulfilled.

exchange: reject new compression engines for v1 bundles (issue5506) Version 1 bundles only support a fixed set of compression engines. Before this change, we would accept any compression engine for v1 bundles, even those that may not work on v1. This could lead to an error. We define a fixed set of compression engines known to work with v1 bundles and we add checking to ensure a newer engine (like zstd) won't work with v1 bundles. I also took the liberty of adding test coverage for unknown compression names because I noticed we didn't have coverage of it before.