shelve: move unshelve-finishing logic to a separate function Finishing unshelve involves two steps now: - stripping a changelog - aborting a transaction Obs-based shelve will not require these things, so isolating this logic into a separate function where the normal/obs-shelve branching is going to be implemented seems to be like a nice idea. Behavior-wise this change moves 'unshelvecleanup' from being between changelog stripping and transaction abortion to being after them. I don't think this has any negative effects.

shelve: move file-forgetting logic to a separate function This is just a readability improvement.

shelve: move rebasing logic to a separate function Rebasing restored shelved commit onto the right destination is done differently in traditional and obs-based unshelve: - for traditional, we just rebase it - for obs-based, we need to check whether a successor of the restored commit already exists in the destination (this might happen when unshelving twice on the same destination) This is the reason why this piece of logic should be in its own function: to not have excessive complexity in the main function.

shelve: move commit restoration logic to a separate function

shelve: move temporary commit creation to a separate function Committing working copy changes before rebasing a shelved commit on top of them is an independent piece of behavior, which fits into its own function. Similar to the previous series, this and a couple of following patches are for unshelve refactoring.

commands: print chunk type in debugrevlog Each data entry ("chunk") in a revlog has a type based on the first byte of the data. This type indicates how to interpret the data. This seems like a useful thing to be able to query through a debug command. So let's add that to `hg debugrevlog`. This does make `hg debugrevlog` slightly slower, as it has to read more than just the index. However, even on the mozilla-unified manifest (which is ~200MB spread over ~350K revisions), this takes <400ms.

perf: add command for measuring revlog chunk operations Upcoming commits will teach revlogs to leverage the new compression engine API so that new compression formats can more easily be leveraged in revlogs. We want to be sure this refactoring doesn't regress performance. So this commit introduces "perfrevchunks" to explicitly test performance of reading, decompressing, and recompressing revlog chunks. Here is output when run on the mozilla-unified repo: $ hg perfrevlogchunks -c ! read ! wall 0.346603 comb 0.350000 user 0.340000 sys 0.010000 (best of 28) ! read w/ reused fd ! wall 0.337707 comb 0.340000 user 0.320000 sys 0.020000 (best of 30) ! read batch ! wall 0.013206 comb 0.020000 user 0.000000 sys 0.020000 (best of 221) ! read batch w/ reused fd ! wall 0.013259 comb 0.030000 user 0.010000 sys 0.020000 (best of 222) ! chunk ! wall 1.909939 comb 1.910000 user 1.900000 sys 0.010000 (best of 6) ! chunk batch ! wall 1.750677 comb 1.760000 user 1.740000 sys 0.020000 (best of 6) ! compress ! wall 5.668004 comb 5.670000 user 5.670000 sys 0.000000 (best of 3) $ hg perfrevlogchunks -m ! read ! wall 0.365834 comb 0.370000 user 0.350000 sys 0.020000 (best of 26) ! read w/ reused fd ! wall 0.350160 comb 0.350000 user 0.320000 sys 0.030000 (best of 28) ! read batch ! wall 0.024777 comb 0.020000 user 0.000000 sys 0.020000 (best of 119) ! read batch w/ reused fd ! wall 0.024895 comb 0.030000 user 0.000000 sys 0.030000 (best of 118) ! chunk ! wall 2.514061 comb 2.520000 user 2.480000 sys 0.040000 (best of 4) ! chunk batch ! wall 2.380788 comb 2.380000 user 2.360000 sys 0.020000 (best of 5) ! compress ! wall 9.815297 comb 9.820000 user 9.820000 sys 0.000000 (best of 3) We already see some interesting data, such as how much slower non-batched chunk reading is and that zlib compression appears to be >2x slower than decompression. I didn't have the data when I wrote this commit message, but I ran this on Mozilla's NFS-based Mercurial server and the time for reading with a reused file descriptor was faster. So I think it is worth testing both with and without file descriptor reuse so we can make informed decisions about recycling file descriptors.

setup: add flag to build_ext to control building zstd Downstream packagers will inevitably want to disable building the vendored python-zstandard Python package. Rather than force them to patch setup.py, let's give them a knob to use. distutils Command classes support defining custom options. It requires setting certain class attributes (yes, class attributes: instance attributes don't work because the class type is consulted before it is instantiated). We already have a custom child class of build_ext, so we set these class attributes, implement some scaffolding, and override build_extensions to filter the Extension instance for the zstd extension if the `--no-zstd` argument is specified. Example usage: $ python setup.py build_ext --no-zstd

drawdag: update test repos by drawing the changelog DAG in ASCII Currently, we have "debugbuilddag" which is a powerful tool to build test cases but not intuitive. We may end up running "hg log" in the test to make the test more readable. This patch adds a "drawdag" extension with a "debugdrawdag" command for similar testing purpose. Unlike the cryptic "debugbuilddag" command, it reads an ASCII graph that is intuitive to human, so the test case can be more readable. Unlike "debugbuilddag", "drawdag" does not require an empty repo. So it can be used to add new changesets to an existing repo. Since the "drawdag" logic is not that trivial and only makes sense for testing purpose, the extension is added to the "tests" directory, to make the core logic clean. If we find it useful (for example, to demonstrate cases and help user understand some cases) and want to ship it by default in the future, we can move it to a ship-by-default "debugdrawdag" at that time.

posix: give checklink a fast path that cache the check file and is read only util.checklink would create a symlink and remove it again. That would sometimes happen multiple times. Write operations are relatively expensive and give disk tear and noise for applications monitoring file system activity. Instead of creating a symlink and deleting it again, just create it once and leave it in .hg/cache/check-link . If the file exists, just verify that os.islink reports true. We will assume that this check is as good as symlink creation not failing. Note: The symlink left in .hg/cache has to resolve to a file - otherwise 'make dist' will fail ... test-symlink-os-yes-fs-no.py does some monkey patching to simulate a platform without symlink support. The slightly different testing method requires additional monkeying.