histedit: remove an unnecessary default value of `b''` for commit message I don't think `ctx.description()` is ever anything falsy other than `b''`. I think the comment added in 4c4232e51167 (histedit: extract common summary code into method, 2016-05-27) is mistaken (I don't see any code following that pattern before the function was added). Differential Revision: https://phab.mercurial-scm.org/D12406

histedit: use new function for getting first line of a string This fixes a crash you can run into if you enter a commit message that's just a "newline-like" byte, like a form feed byte (`hg ci -m \x0f` in Fish). That bug is the motivation for this series. Differential Revision: https://phab.mercurial-scm.org/D12405

templates: extract function to `stringutil` for getting first line of text It's surprisingly hard to get the first line from a string, so let's have our own function in `stringutil` for it. Differential Revision: https://phab.mercurial-scm.org/D12404

templates: make `firstline` filter not keep '\v', '\f' and similar In b288b4bb8448 (hide some functions behind lambdas, so demandload is useful., 2006-02-28), `x.splitlines(1)[0]` was replaced by `x.splitlines(1)[0].rstrip('\r\n')`, i.e. stripping trailing '\r' and '\n'. Combined with the "truthy" `1` passed to `splitlines()` to get it to keep line endings, that results in e.g. trailing '\v' (Line Tabulation) and '\f' (Form Feed) being preserved. I can't see why one would want that, and I doubt that was the intention; I suspect the author just didn't think to instead remove the `1` argument. Perhaps they thought the 1 being passed there - added by themselves in a7e416bf3c1d (improve templating., 2006-02-27) - was to limit the number of splits to 1 (i.e. thinking about it as `maxsplit=1` rather than `keepends=1`). Differential Revision: https://phab.mercurial-scm.org/D12403

pytype: drop py3.6 support Pytype 2022.01.07 only supports 3.7+. Differential Revision: https://phab.mercurial-scm.org/D12400

perf-util: add a `compare-discovery-case` script This script run the same discovery case using multiple variants of the algorithm and report differences in behavior, especially regarding the numbers of roundtrip. Differential Revision: https://phab.mercurial-scm.org/D12399

discovery: also audit the number of queries done In addition to the number of roundtrip, we now also track the number of queries we perform, this is useful to assert the tradeoff between number of roundtrip and the number of queries. Differential Revision: https://phab.mercurial-scm.org/D12398

search-discovery-case: display more information about the interresting case We display information about the total number of revs and the common/missing numbers. This is useful to spot the interresting case. Differential Revision: https://phab.mercurial-scm.org/D12397

subsetmaker: rework the antichain generation to be usable Before this, antichain computation can run for 10s of hours without completion in sight. We use a more direct approach in the computation to keep the computation in complexity in check. With good result. We can now have a full antichain computation on mozilla-try in about one minute. Which is usable. Differential Revision: https://phab.mercurial-scm.org/D12396

subsetmaker: use SortedSet for the scratch variant This provides a massive speedup on wide repository with many heads. For example on mozilla-try, this move from un-usable slow to fairly instant. Differential Revision: https://phab.mercurial-scm.org/D12395

subsetmaker: stabilize the computation of `scratch` subset `heads` is set, order of the element are not deterministic and we need to stabilize that if we want to get reproducible results. Differential Revision: https://phab.mercurial-scm.org/D12394

revlog: recommit 49fd21f32695 with a fix for issue6528 `filelog.size` currently special cases two forms of metadata encoding: - copy data via the parent order as flag bit - censor data by peaking into the raw delta All other forms of metadata encoding including the empty metadata block are mishandled. In `basefilectx.cmp` the empty metadata block is explicitly checked to compensate for this. Restore 49fd21f32695, but disable it for filelog, so that the original flag bit use contines to work. Document all this mess for now in preparation of a proper rework. Differential Revision: https://phab.mercurial-scm.org/D11203

merge-lists: make it possible to specify pattern to match The `merge-lists` tool doesn't know anything about Python other than its regex that attempts to match import lines. Let's make it possible to pass in a custom regex so it's easy to use the tool for e.g. C/C++ `#include` lines or Rust `use` lines (given the limited). Differential Revision: https://phab.mercurial-scm.org/D12392

contrib: add a partial-merge tool for sorted lists (such as Python imports) This is a pretty naive tool that uses a regular expression for matching lines. It is based on a Google-internal tool that worked in a similar way. For now, the regular expression is hard-coded to attempt to match single-line Python imports. The only commit I've found in the hg core repo where the tool helped was commit 9cd6292abfdf. I think that's because we often use multiple imports per import statement. I think this tool is still a decent first step (especially once the regex is made configurable in the next patch). The merging should ideally use a proper Python parser and do the merge at the AST (or CST?) level, but that's significantly harder, especially if you want to preserve comments and whitespace. It's also less generic. Differential Revision: https://phab.mercurial-scm.org/D12380

branching: merge stable into default

merge: stable into default

tests: stop excluding the pycompat module from pyflakes I assume this was skipped because of all of the py2 stuff causing a lot of spew. The "unused" imports are left in place in case any 3rd party stuff is using it. I don't care about most of it, but TortoiseHg uses `io` and `queue`, so minimally I'd like to keep those. Differential Revision: https://phab.mercurial-scm.org/D12423

tests: drop some py2 specific pyflake failures Differential Revision: https://phab.mercurial-scm.org/D12422

util: drop a duplicate import This was already imported several lines above. Differential Revision: https://phab.mercurial-scm.org/D12421

pycompat: drop the pickle import I suspect this is what df56e6bd37f6 meant to eliminate. Differential Revision: https://phab.mercurial-scm.org/D12420

util: restore the util.pickle symbol This was accidently dropped in df56e6bd37f6, which started importing pickle directly. That commit explicitly says it will retain it for compatibility with external stuff though. The unused import in pycompat isn't flagged because that module is skipped. Just importing with a comment seemed cleaner than `import X as Y` and then assigning to a `pickle` variable, just to avoid the pyflakes warning. Differential Revision: https://phab.mercurial-scm.org/D12419

merge: stable into default

completion: install completers to conventional locations Installs the bash and zsh completers to the convential locations so they will automatically be picked up without user intervention. The zsh completer on Debian is still installed to vendor-completions to match their policy. bash: https://github.com/scop/bash-completion#faq zsh: https://github.com/zsh-users/zsh/blob/57305cf245853b8b30895b41a90142dffab97e38/INSTALL#L254 Debian zsh: https://salsa.debian.org/debian/zsh/-/blob/5086b5356abcef8849dc8a09902b7c55f01db3c0/debian/README.Debian#L73

pytype: disable a few errors about Windows specific module attributes These were flagged by pytype 2022.03.21. Differential Revision: https://phab.mercurial-scm.org/D12401

rhg: sort unsupported extensions in error message This caused some flakiness in test output, and is also just better for users. Differential Revision: https://phab.mercurial-scm.org/D12389

hgignore: ignore .testtimes in more location See the inline comment. Differential Revision: https://phab.mercurial-scm.org/D12393

merge: with stable

partial-merge: add support for `.args` config (`$local` etc.) It will be useful to be able to define custom command-line arguments per partial merge tool just like we have for regular merge tools. In particular, I expect the same binary to handle multiple languages, so it will be useful to be able to pass some argument indicating the language, or perhaps simply an argument defining a regex that's used for finding lines to merge as a sorted set. Differential Revision: https://phab.mercurial-scm.org/D12383

filemerge: add support for partial conflict resolution by external tool A common class of merge conflicts is in imports/#includes/etc. It's relatively easy to write a tool that can resolve these conflicts, perhaps by naively just unioning the statements and leaving any cleanup to other tools to do later [1]. Such specialized tools cannot generally resolve all conflicts in a file, of course. Let's therefore call them "partial merge tools". Note that the internal simplemerge algorithm is such a partial merge tool - one that only resolves trivial "conflicts" where one side is unchanged or both sides change in the same way. One can also imagine having smarter language-aware partial tools that merge the AST. It may be useful for such tools to interactively let the user resolve any conflicts it can't resolve itself. However, having the option of implementing it as a partial merge tool means that the developer doesn't *need* to create a UI for it. Instead, the user can resolve any remaining conflicts with their regular merge tool (e.g. `:merge3` or `meld). We don't currently have a way to let the user define such partial merge tools. That's what this patch addresses. It lets the user configure partial merge tools to run. Each tool can be configured to run only on files matching certain patterns (e.g. "*.py"). The tool takes three inputs (local, base, other) and resolves conflicts by updating these in place. For example, let's say the inputs are these: base: ``` import sys def main(): print('Hello') ``` local: ``` import os import sys def main(): print('Hi') ``` other: ``` import re import sys def main(): print('Howdy') ``` A partial merge tool could now resolve the conflicting imports by replacing the import statements in *all* files by the following snippet, while leaving the remainder of the files unchanged. ``` import os import re import sys ``` As a result, simplemerge and any regular merge tool that runs after the partial merge tool(s) will consider the imports to be non-conflicting and will only present the conflict in `main()` to the user. Differential Revision: https://phab.mercurial-scm.org/D12356

branching: merge stable into default