changelog: prefilter in headrevs() In case where headrevs() is called on some revisions, we perform the check that aren't filtered in advance, and switch revlog to use its unchecked form. This allows to work with alternative implementations that don't have knowledge of the filtering system, such as the Rust one.

tests: fixed test too dependent on actual exception wording On one of the machines I use to run the tests prior to submission, the default Python is 2.7.5, with the following wording: must be encoded string without NULL bytes, not str This third form (and possible future ones) are motivation to use a wider catching regexp.

contrib: enforce wrapping too-long lines with () instead of \ This is the style I prefer, and an anecdotal exploration of styles recommended in style guides etc. Further, to quote pep8: > The preferred way of wrapping long lines is by using Python's implied > line continuation inside parentheses, brackets and braces. Long lines > can be broken over multiple lines by wrapping expressions in > parentheses. These should be used in preference to using a backslash > for line continuation. So I think this is a virtuous change. Differential Revision: https://phab.mercurial-scm.org/D5995

cleanup: prefer nested context managers to \-continuations I'd prefer Python accept a tuple of context managers, but alas it isn't meant to be. This will have to suffice. Differential Revision: https://phab.mercurial-scm.org/D5994

cleanup: use () to wrap long lines instead of \ This is a little less brittle, and often helps indentation. In a surprising number of cases the entire cleanup was deleting the \, as the expression was *already* parenthesized in a workable way. Differential Revision: https://phab.mercurial-scm.org/D5993

tests: use () instead of \ to wrap lines This should auto-format more consistently, and is slightly more typical Python. Differential Revision: https://phab.mercurial-scm.org/D5992

merge with stable

copies: do copy tracing based on ctx.p[12]copies() if configured This adds an option to do copy tracing in a changeset-optimized way. If the metadata is stored in filelogs, this is obviously going to be suboptimal. The point is that it provides a way of transitioning to changeset-stored metadata. Some of the tests behave a little differently, but they all seem resonable to me. The config option may very well be renamed later when it's clearer what options we want and how they will behave. When the test suite is run with --extra-config-opt to use the new copy tracing, all tests pass, besides test-copies.t (which fails in the same way as you can see in this patch). `hg debugpathcopies 4.0 4.8` reports 82 copies. With this option enabled, the only difference is this: -mercurial/pure/bdiff.py -> mercurial/cffi/bdiff.py +setup_bdiff_cffi.py -> mercurial/cffi/bdiff.py I believe that happened because it was renamed in different ways on different sides of a merge and the new algorithm arbitrarily prefers copies that happened on p1. The runtime is about 0.85 seconds with the old copy tracing and 5.7 seconds with the new copy tracing. That's kind of slow, but actually better than I had expected. Differential Revision: https://phab.mercurial-scm.org/D5991

context: introduce p[12]copies() methods and debugp[12]copies commands As mentioned earlier, I'm working on support for storing copy metadata in the changeset instead of in the filelog. In order to transition a repo from storing metadata in filelogs to storing it in the changeset, I'm going to provide a config option for reading the metadata from the changeset, but falling back to getting it from the filelog if it's not in the changeset. In this compatiblity mode, the changeset-optmized algorithms will be used. We will then need to convert the filelog copy metadata to look like that provided by changeset copy metadata. This patch introduces methods that do just that. By having these methods here, we can start writing changeset-optimized algorithms that should work already before we add any support for storing the metadata in the changesets. This commit also includes new debugp[12]copies commands and exercises them in test-copies.t. Differential Revision: https://phab.mercurial-scm.org/D5990

copies: filter out copies when target is not in destination manifest When chaining a series of commits that copied a file with a series that removed the destination file, we would still include the copy in the result. Similar to the previous patch, I have checked that `hg status --copies` is not affected by this bug, but I wouldn't be surprised if some commands are. Differential Revision: https://phab.mercurial-scm.org/D5989