debugdiscovery: fix swapped heads and roots Patch provided without comment… Differential Revision: https://phab.mercurial-scm.org/D9566

debugdiscovery: display the number of roundtrip used This is a good metric of the complexity of a discovery process. Differential Revision: https://phab.mercurial-scm.org/D9565

copies: make calculating lazy for dir move detection's "addedfiles" The information calculated here was only needed if (a) --debug was specified, or (b) a directory move was plausibly detected. With tree manifests (especially in my pathological repo and with our custom setup), pre-calculating the `u1` and `u2` can be quite slow, and it's not even necessary in many cases. Let's delay calculating it until we know it's actually necessary. This should have no observable differences in output. ### Performance I ran a rebase command in my pathological repo, rebasing two nodes across several public phase commits, but where no directory copies exist in any of the paths I'm tracking. #### Before ``` Time (mean ± σ): 3.711 s ± 0.061 s [User: 0.3 ms, System: 1.5 ms] Range (min … max): 3.640 s … 3.827 s 10 runs ``` #### After ``` Time (mean ± σ): 868.3 ms ± 10.1 ms [User: 0.5 ms, System: 1.2 ms] Range (min … max): 856.6 ms … 883.6 ms 10 runs ``` Differential Revision: https://phab.mercurial-scm.org/D9567

mergetools: add new conflict marker format with diffs in I use 3-way conflict markers. Often when I resolve them, I manually compare one the base with one side and apply the differences to the other side. That can be hard when the conflict marker is large. This patch introduces a new type of conflict marker, which I'm hoping will make it easier to resolve conflicts. The new format uses `<<<<<<<` and `>>>>>>>` to open and close the markers, just like our existing 2-way and 3-way conflict markers. Instead of having 2 or 3 snapshots (left+right or left+base+right), it has a sequence of diffs. A diff looks like this: ``` ------- base +++++++ left a -b +c d ``` A diff that adds one side ("diff from nothing") has a `=======` header instead and does not have have `+` prefixed on its lines. A regular 3-way merge can be viewed as adding one side plus a diff between the base and the other side. It thus has two ways of being represented, depending on which side is being diffed: ``` <<<<<<< ======= left contents on left ------- base +++++++ right contents on -left +right >>>>>>> ``` or ``` <<<<<<< ------- base +++++++ left contents on -right +left ======= right contents on right >>>>>>> ``` I've made it so the new merge tool tries to pick a version that has the most common lines (no difference in the example above). I've called the new tool "mergediff" to stick to the convention of starting with "merge" if the tool tries a regular 3-way merge. The idea came from my pet VCS (placeholder name `jj`), which has support for octopus merges and other ways of ending up with merges of more than 3 versions. I wanted to be able to represent such conflicts in the working copy and therefore thought of this format (although I have not yet implemented it in my VCS). I then attended a meeting with Larry McVoy, who said BitKeeper has an option (`bk smerge -g`) for showing a similar format, which reminded me to actually attempt this in Mercurial. Differential Revision: https://phab.mercurial-scm.org/D9551

diff: deprecate -r option The new `--from`/`--to` options should be enough to support all the uses cases and are easier to understand, so there is no reason that I'm aware of to use `-r` anymore. Differential Revision: https://phab.mercurial-scm.org/D9564

diff: update synopsis to use --from/--to instead of -r Differential Revision: https://phab.mercurial-scm.org/D9563

diff: describe behavior by using --from/--to instead of varying revision count I very recently updated the documentation to prefer `--from`/`--to` over `-r`, but I missed the plain-text description of how the command behaves when given different numbers of revisions (I guess I just scanned the text for "-r"). This patch fixes that. Differential Revision: https://phab.mercurial-scm.org/D9562

histedit: adjust comment describing `edit` action for clarity Differential Revision: https://phab.mercurial-scm.org/D9561

histedit: tweak `edit` message to try and guide users to our workflow histedit predates evolve, so it drops you on an _uncommitted_ version of the commit you're amending/splitting, which is in contrast to git which expects you to use `git commit --amend` (I think - I'm basing this on internal bug reports). My hope is that this output will guide users a little more towards the expected workflow. Differential Revision: https://phab.mercurial-scm.org/D9560

procutil: don't assign stdin to None, use os.devnull instead It will be painful to take care of procutil.stdin being None everywhere. Thanks to Yuya who recommended it.

dispatch: move IOError handling and flushing of streams to `dispatch()` Instead of patching both dispatch code and commandserver code, we directly handle this in `dispatch.dispatch()`. Thanks to Yuya who recommended this.

simplemerge: write output only once it's complete `simplemerge()` can write either to `ui.fout` or to the file context (for in-memory merge). This patch simplifies the code a bit by making it build the output the same way regardless of where it's written, and then writes the whole output at once. I don't think it will be a problem that we don't output anything until the whole file is merged even if the file is large. Differential Revision: https://phab.mercurial-scm.org/D9550

simplemerge: avoid quadratic concatenation when building output text I haven't checked if the difference is measurable, but the new version is no less readable or idiomatic, so I don't think performance numbers are needed. Differential Revision: https://phab.mercurial-scm.org/D9549

simplemerge: work with opts as native strings instead of bytes There was little reason to use `pycompat.byteskwargs()` in `simplemerge()` as far as I could tell. Differential Revision: https://phab.mercurial-scm.org/D9548

hghave: update the check for virtualenv This started as `hghave --test-features` failing on Windows in `test-hghave.t`. IDK how this worked, as neither my Linux nor Windows machines have the old attribute with virtualenv 20.2.2, even on py2. I think this was noticed recently because 357d8415aa27 mentioned an AttributeError, and mitigated by making this py2 only. But as mentioned, this is also a problem on py2 (where the failure was observed). When I got this working by removing the attribute reference, the command in the test failed because the `--no-site-package` argument was removed some time ago. Therefore, this backs out 357d8415aa27 and references a known good attribute (which was done to suppress the warning about an unused import) that also ensures the command does not need the argument. Since there appears to be (minor) broken stuff on py3, manually apply the `no-py3` guard that was backed out of the check itself. Differential Revision: https://phab.mercurial-scm.org/D9547

singlehead: introduce option to restrict to public changes The new experimental.single-head-per-branch:public-changes-only option restricts the single-head-per-branch filter to public changesets. This is useful when serving one repository with different views as publishing and non-publishing repository. Differential Revision: https://phab.mercurial-scm.org/D9525

treemanifest: stop storing full path for each item in manifest._lazydirs This information is obtainable, if needed, based on the lazydirs key (which is the entry name) and the manifest's `dir()` method. ### Performance This is actually both a memory and a performance improvement, but it's likely to be a very small one in most situations. In the pathological repo I've been using for testing other performance work I've done recently, this reduced the time for a rebase operation (rebasing two commits across a public-phase change that touches a sibling of one of my tracked directories where the common parent is massive (>>10k entries)): #### Before ``` Time (mean ± σ): 4.059 s ± 0.121 s [User: 0.9 ms, System: 0.6 ms] Range (min … max): 3.941 s … 4.352 s 10 runs ``` #### After ``` Time (mean ± σ): 3.707 s ± 0.060 s [User: 0.8 ms, System: 0.8 ms] Range (min … max): 3.648 s … 3.818 s 10 runs ``` Differential Revision: https://phab.mercurial-scm.org/D9553

extensions: avoid including `__index__` in the disabled extension list This generated module contains a dictionary of all bundled extension names and their help for builds that cannot enumerate extensions in the filesystem. The disabled list gets displayed in `hg help extensions`, and is also used by `setup.py` to populate `__index__.py` when building. I haven't seen it sneak into either py2exe or PyOxidizer builds, but it does show up when running tests locally after having created an installer. Differential Revision: https://phab.mercurial-scm.org/D9544

windows: continue looking at `%HOME%` for user config files with py3.8+ The `%HOME%` variable is explicitly called out in `hg help config` as a location that is consulted when reading user files, but python stopped looking at it when expanding '~' in py3.8+.[1] Restore that old functionality by copying in the old implementation (and simplifying it to just use bytes). It could be simplfied further, since only '~' is passed, but I'm not sure yet if we need to make this a generic utility function on Windows. There are other uses of `os.path.expanduser()`, but this is the only case I know of that documents `%HOME%` usage. (The reason for removing it was that it typically isn't set, but it actually is set in MSYS and PowerShell, and `%HOME%` and `%USERPROFILE%` are different in MSYS. I could be convinced to just replace all uses with this as a general utility, so we don't have to think too hard about BC.) [1] https://bugs.python.org/issue36264 Differential Revision: https://phab.mercurial-scm.org/D9559

run-tests: configure the environment to expand `~` properly with Windows py38+ This was causing tests to point to the actual home path on the system, not the test defined one. Differential Revision: https://phab.mercurial-scm.org/D9558

run-tests: fix `HGTESTEXTRAEXTENSIONS` with py3 Since `extensions` was a str and `section` bytes, it never populated anything. If it had, it would have put bytes into the environment dictionary that is all str. As everything starts and ends as str, remove the incomplete attempt at byteification. It doesn't appear that we had any test coverage of this bit of code, so also add a non-extension config to make sure it is filtered out properly. Differential Revision: https://phab.mercurial-scm.org/D9557

rhg: use persistent nodemap when available … for node ID → revision number lookups, instead on linear scan in a revlog. Differential Revision: https://phab.mercurial-scm.org/D9520

persistent-nodemap: properly ignore non-existent `.nd` data file This code was meant to handle the case of a nodemap docket file pointing to a nodemap data file that doesn’t exist (anymore), but most likely caused an `UnboundLocalError` exception instead when `data` was used on the next line without being defined. This case is theoretically possible with a race condition between two hg processes, but is hard to reproduce or test: * Process A reads a docket file and finds a UID in it that points to a given data file name. * Process B decides that this same data file needs compacting. It writes a new one with a different UID, overwrites the docket file, then removes the old data file. * Only then process A tries to a open a file that doesn’t exist anymore. Differential Revision: https://phab.mercurial-scm.org/D9533

docs: prefer `hg diff --from/--to` over `-r` This patch includes updating away from the broken `hg diff -r 'date(...)'` (see not in previous patch). Differential Revision: https://phab.mercurial-scm.org/D9555

diff: add --from and --to flags as clearer alternative to -r -r I think it was mistake to let the `-r` flag accept two revisions in `hg diff` in 98633e60067c (Support for 0, 1, or 2 diff revs, 2005-05-07). The command clearly acts on two revisions and having a single flag to indicate which those are is unclear. It got worse when it started accepting revsets as input. This patch introduces `--from` and `--to` flags, each taking a single revision and each defaulting to the working copy. That means that `hg

commandserver: handle IOError related to flushing of streams After dispatch, without chg we have handling of flushing of streams and exception handling related to it. The exception handling part is important because there can be exceptions when flushing fout or ferr. One such case is in `test-basic.t` which was failing on python3+chg without this patch as this handling was missing from chg. Failure can be seen at https://foss.heptapod.net/octobus/mercurial-devel/-/jobs/128399 Honestly I am not sure which one of `chgserver.py` or `commandserver.py` the change should go in. Differential Revision: https://phab.mercurial-scm.org/D9517

tests: conditionalize output in test-ssh.t with chg+py3 Because of our wrapping around sys.std* and python3 internal buffering, the output order changes. The change in order seems like harmless because just few lines above the same command is run which results in same output. This makes `test-ssh.t` works with --chg on python 3. Differential Revision: https://phab.mercurial-scm.org/D9502

dispatch: disable line ending normalization on sys.stdin if its None Fixes test-chg.t on python 3 with chg. Differential Revision: https://phab.mercurial-scm.org/D9501