shelve: move method for creating backup to new shelf class Differential Revision: https://phab.mercurial-scm.org/D9712

shelve: make gennames() helper generate relative backup paths When I saw `gennames()`, I thought it was meant to take a relative filename as argument. Maybe it was or maybe it wasn't, but it seems simpler to pass it a relative path anyway, so that's what this patch does. That also makes the call to backupvfs.exists() more natural (I expect a relative path to be passed there too). Differential Revision: https://phab.mercurial-scm.org/D9711

shelve: use listshelves() in cleanup function The point of this patch is to make it so all the callers of `shelvedfile.movetobackup()` look the same, so I can move it over to the new `Shelf` class next. Differential Revision: https://phab.mercurial-scm.org/D9710

shelve: inline shelvedfile.filename() since there are no callers outside class Differential Revision: https://phab.mercurial-scm.org/D9709

shelve: make listshelves() return shelf names instead of filenames All three callers now prefer the shelf name over the filename (already before my recent patches, two out of three callers preferred the shelf name). Differential Revision: https://phab.mercurial-scm.org/D9708

shelve: move method for getting stat (mtime) to new shelf class Only the mtime was needed, so I made it restricted to that in the move. The new `Shelf` class expects its argument to be a shelf name (not a arbitrary filename like `shelvedfile` would accept), so only the shelf name is now passed in. Differential Revision: https://phab.mercurial-scm.org/D9707

shelve: open patch using new shelf class instead of open() For some reason the existing code didn't use `shelvedfile().opener()` so here we migrate to `shelf().open_patch()` from the `open()` system call instead. Differential Revision: https://phab.mercurial-scm.org/D9706

shelve: move function for opening .patch file to new shelf class The `opener()` method was used specifically for the `.patch` file, and the new `Shelf` class deals with all files involved in a shelf, so I renamed the function in the process. Differential Revision: https://phab.mercurial-scm.org/D9705

shelve: move method for reading .hg to new shelf class Differential Revision: https://phab.mercurial-scm.org/D9704

shelve: move method for writing bundle to new shelf class Differential Revision: https://phab.mercurial-scm.org/D9703

shelve: move method for reading .shelve file to new shelf class Differential Revision: https://phab.mercurial-scm.org/D9702

shelve: move method for writing .shelve to new shelf class Differential Revision: https://phab.mercurial-scm.org/D9701

shelve: introduce class representing a shelf I'm about to make phase-based shelve not write `.hg` and `.patch` files. Having a class that represents a single shelf, regardless of which files it uses will help. I'm starting small with just a `.exists()` function. I plan to eventually remove the `shelvedfile` class once all functionality has been moved to the new class. By the way, I know that things you shelve are not typically themselves shelves. I still picked `Shelf` for the class because it's short (compared to e.g. `ShelvedChange`). Differential Revision: https://phab.mercurial-scm.org/D9700

shelve: raise more specific errors Differential Revision: https://phab.mercurial-scm.org/D9699

shelve: trust caller of shelvedfile.opener() to check that the file exists The only place we call `shelvedfile.opener()` is when we're about to apply a bundle. The file should always exist. If it doesn't, the `.hg/` directory is corrupt and we don't provide any guarantees about supporting corrupt repos (besides, telling the user that the shelve doesn't exist when `hg shelve --list` lists it is not very helpful). Differential Revision: https://phab.mercurial-scm.org/D9698

shelve: rewrite check for unknown shelf to delete The code would try to delete the shelf's .patch file and if that raised an exception, it would convert it to an `error.Abort`. This patch rewrites it so the check is done upfront. I find it easier to read that way. It's now clear enough that I removed the comment explaining it as well. As Joerg pointed out during review, another differences is that the old code would move a `.hg` file without its `.patch` friend to backup before it realized that the `.patch` file was missing. The new code will error out earlier and not move the `.hg` file, which seems like an improvement. That should only matter on corrupt `.hg/shelved/` directories, however. Differential Revision: https://phab.mercurial-scm.org/D9697

shelve: remove a bundlerepo method It was added in 43816070284e (shelve: add a bundlerepo method, 2014-10-10), but I haven't been able to find a place it was used. Differential Revision: https://phab.mercurial-scm.org/D9696

tests: add tests for corrupt .hg/shelved/ directory I don't care much how we behave in these cases, except that we should provide a way for the user to get out of the broken state. Differential Revision: https://phab.mercurial-scm.org/D9718

ui: add a "config_default" method This allow code to access the expected value for a config. This is useful in the context of dynamic default value, and short term it will be useful to write dynamically "correct" code. Differential Revision: https://phab.mercurial-scm.org/D9759

test: split tests/test-merge-combination.t into multiple parts That test is quite slow, lets split it in smaller bits. Differential Revision: https://phab.mercurial-scm.org/D9768

test: extract the `genmerges` out of test-merge-combination.t This open the way to splitting this slow test in multiple ones. Differential Revision: https://phab.mercurial-scm.org/D9767

hghave: clarify `sqlite` requirements We need more than the python module, we also need the sqlite3 command line. Differential Revision: https://phab.mercurial-scm.org/D9787

localrepo: fix comment typo Differential Revision: https://phab.mercurial-scm.org/D9782

error: use detailed exit code 10 for command errors Command errors (unknown or ambiguous commands, or bad command arguments or options) are handled in the `dispatch` module. Most other errors are handled in the `scmutil` module. This patch therefore has to duplicate a little bit of code from the `scmutil` module. It's just a few lines, however, so it seems fine to me. It's a pretty common category of errors, so it's important to have them respect `ui.detailed-exit-code`. Differential Revision: https://phab.mercurial-scm.org/D9777

errors: raise InputError when non-existent help section requested Differential Revision: https://phab.mercurial-scm.org/D9776

revlog: migrate from PyEval_CallObject to PyObject_Call The former was deprecated in 3.9.0. Differential Revision: https://phab.mercurial-scm.org/D9791

fuzz: fix Makefile default PYTHON_CONFIG_FLAGS to be modern This is actually what we already do on oss-fuzz, so it's more correct as tests go. Differential Revision: https://phab.mercurial-scm.org/D9790

tests: wider work around matching in test-narrow-shallow.t Since issue6150 is still not fixed, we have to accommodate a larger array of possible results. Otherwise we get frequent flakiness of local and CI runs. Differential Revision: https://phab.mercurial-scm.org/D9766

fuzz: try and ensure fuzzer tests run against the right python-config Also only under python 3. Differential Revision: https://phab.mercurial-scm.org/D9752

contrib: remove testing for `dirstate-tree` Rust feature This feature will be replaced in a few months, and served more as a proof-of-concept. Keeping it in CI when no one is using it anymore is just wasteful. Differential Revision: https://phab.mercurial-scm.org/D9716

perf: don't turn byte to string when formatting perfbranchmap I am not sure why this `str` all is there is the first place. Differential Revision: https://phab.mercurial-scm.org/D9751

branchmap: avoid ancestor computations in absence of non-continous branches The branchhead computation is one of the more heavy operations for bigger repositories as it has to scan all changesets and potentially involves the expensive computation of the ancestor sets. Redo the computation to handle the common cases directly and use tighter conditions for when the ancestor scan is necessary. Most importantly, avoid it completely if the non-continous branches are processed in one update as seen in the initial computation after a clone. For the Mercurial repository, it gives a small 2-3% performance boost. For the NetBSD test repository, it cuts the time in half. Differential Revision: https://phab.mercurial-scm.org/D9631

persistent-nodemap: also list related file as part of the store This make sure they are will be selected during upgrade, and copy based clone. Differential Revision: https://phab.mercurial-scm.org/D9749

upgrade: explicitly test for revlog index We do not want to exclude `.d` we want to only include `.i`. We are about to add more extension type (for the persistent nodemap: `.n`, `.nd`) so lets make the list explicit instead. Differential Revision: https://phab.mercurial-scm.org/D9748

persistent-nodemap: highlight that node is not sent when streaming We have a local work-around, however having that data sent in the first place would be better. So we start with a test that monitor what is sent, and notice they are not. Differential Revision: https://phab.mercurial-scm.org/D9736

persistent-nodemap: test it (does not) exist after a stream clone This is currently buggy. We add a test before fixing the bug. Differential Revision: https://phab.mercurial-scm.org/D9734

persistent-nodemap: test it (does not) exist after a local clone This is currently buggy. We add a test before fixing the bug. Differential Revision: https://phab.mercurial-scm.org/D9733

persistent-nodemap: test that is it present after a clone The persistent nodemap is actually missing after local and stream clone. We start by adding a test for the case that works so that we can compare output after the fix. Differential Revision: https://phab.mercurial-scm.org/D9732

narrow: overwrite readfast in excludeddirmanifestctx The excludeddirmanifestctx does not have underlying storage (because it is excluded) so the implementation of the `readfast` trying to access it crash. This was reveled while running some cache warning code on narrow repositories. That code will be introduced further down in the series. Differential Revision: https://phab.mercurial-scm.org/D9731

patch: handle filenames with trailing spaces I have no idea if this is *actually* supported by the patch file format, but at least when reading from a patch file created by running `hg shelve`, it is written out such that there's a trailing space after the second (`b`) filename. When we read the patch file, we remove the space before parsing the filenames, so it doesn't end up matching the other sources of what files are in the shelve. We observed this internally due to a wrapper around unshelve that called into patch.changedfiles, but `hg patch` is able to reproduce the issue as well, so I've included both tests. Differential Revision: https://phab.mercurial-scm.org/D9729

rust: fix testing with $TMPDIR ≠ /tmp Differential Revision: https://phab.mercurial-scm.org/D9670

ci: avoid a global before_script definition This removes the implicit assumption that all jobs are test runs. Differential Revision: https://phab.mercurial-scm.org/D9723

setup: when possible, build and bundle man pages This makes it so the manual pages are built as part of the Python build, and includes them in any wheel generated. This should make Python wheels a much more useful and complete way of distributing Mercurial binaries. Differential Revision: https://phab.mercurial-scm.org/D9640

scmutil: improve documentation of writereporequirements() This makes it easier to understand the difference between `writerequires()` and `writereporequirements()`. Differential Revision: https://phab.mercurial-scm.org/D9568

command: automatically create alias for command using '-' in names As discussed during the "5.6 Sprint" ignoring dash in command name open the way to using them more. We can now move existing command to more readable (dash using) names without breaking any compatibility. Differential Revision: https://phab.mercurial-scm.org/D9515

worker: POSIX only supports workers from main thread (issue6460) The POSIX backend sets signal handlers for SIGINT (maybe avoidable) and SIGCHLD (necessary for waitpid). Python up to 3.9 only allow this from the main thread, so disable the worker feature otherwise. Differential Revision: https://phab.mercurial-scm.org/D9660

sharesafe: introduce config to disallow outdated shares if upgrade fails After this patch, we have config option to control all aspects of shares when share source is upgraded or downgraded. Differential Revision: https://phab.mercurial-scm.org/D9692

sharesafe: make warning about outdated share configurable If the source repository upgrades to use sharesafe mode, we show a warning in shares. This patch makes that warning configurable and some might not want their users see this warning. Differential Revision: https://phab.mercurial-scm.org/D9691

debuglock: rename flag names to better clarity `--force-lock` sounds as if we are taking the lock however in reality it's the opposite. Differential Revision: https://phab.mercurial-scm.org/D9690

sharesafe: add functionality to automatically downgrade shares Reasoning is same as previous patch which adds automatic upgrade support. Downgrade is required as if automatic upgrade is enabled, all shares upgrade and then source repository downgrades, shares won't work. We need to downgrade them. Differential Revision: https://phab.mercurial-scm.org/D9680

sharesafe: introduce functionality to automatically upgrade shares In past few months, we have developed a `share-safe` mode for sharing repository in which share source requirements and config values are shared with the shares. To get it rolling, an important task is to get these shares automatically upgraded. We are focusing on an installation where shares are created by scripts and test jobs. It will be difficult to manually upgrade these and we need some functionality to do so automatically. This patch introduces a config option to deal with it. If all of the following conditions are met, we upgrade the share repository automatically: * If the config option is enabled * Share source repository is share-safe enabled * Share is not share-safe enabled * Any command is run in the share Upgrading the share is pretty easy as it involves only editing the requirements file. Differential Revision: https://phab.mercurial-scm.org/D9679

localrepo: move storevfs calculation out of if statement In next patch, we will need this variable in else statement too. So, let's take it out. Differential Revision: https://phab.mercurial-scm.org/D9681

setup: don't import distutils prior to checking FORCE_SETUPTOOLS I've seen warnings about importing distutils before setuptools, although I can't reproduce them at the moment. Differential Revision: https://phab.mercurial-scm.org/D9722

largefiles: remove unused imports This fixes test-check-pyflakes.t Differential Revision: https://phab.mercurial-scm.org/D9747

upgrade: don't perform anything if nothing to do Before this patch, upgrade will process everything, re-clone all revlogs, write requirements file again even there is no change to be made. This patch makes it exit earlier. Differential Revision: https://phab.mercurial-scm.org/D9695

downgrade: if a compression is removed, consider that too For compression format variant, the result of `fromrepo()` and `fromconfig()` is not a boolean and we have to actually equate those to find change. Differential Revision: https://phab.mercurial-scm.org/D9693

engine: prevent a function call for each store file Python function calls are not cheap. Instead of calling the function once for each file in store, we use a dedicated function which filters and yields the required files. Differential Revision: https://phab.mercurial-scm.org/D9673

rhg: use a release-mode executable in tests This allows the rhg build for test-rhg.t to share compiled dependencies such as hg-core with the hg-cpython build for other tests. For context, my wrapper script for the typical edit-compile-test cycle now looks like this: (cd rust && cargo +nightly-2020-10-04 fmt) (cd rust && cargo build --release -p rhg) make --silent local PURE=--rust python test/run-tests.py --local "$@" Differential Revision: https://phab.mercurial-scm.org/D9728

rust: fix file folding map The file folding map, frequently used on macOS, had two issues: * the means for converting it to Python didn't work * a minor typo when copying the python code, where `!=` became `==` With this, the rust code passes all tests on macOS. Test Plan: I'm currently doing a full test run on a case-insensitive file system. If it passes, perhaps we can change the platform check from an error to a warning? Differential Revision: https://phab.mercurial-scm.org/D9671

test: replace a many occurence of `python` with `$PYTHON` Otherwise this can use the wrong python version, or worse, not find any python at all. Differential Revision: https://phab.mercurial-scm.org/D9730

tests: make test-subrepo-git.t compatible with git's master->main rename Git is about to change the default branch from "master" to "main". Recent versions has started warning about that, which makes tests fail. I assume the tests would fail in a different way once the default has changed. To make us compatible with that name change, let's set configure the default to be "master". That value makes the tests still work on older Git version (those where the default branch name is not configurable). Differential Revision: https://phab.mercurial-scm.org/D9746

revlog: use size_t for nodetree capacity This allows handling revlog containing more than 33554432 (INT_MAX / sizeof(nodetreenode)) revisions on x64 platforms. Differential Revision: https://phab.mercurial-scm.org/D9745

upgrade: demonstrate that a no-op upgrade still performs everything An upgrade operation which is not adding or removing anything should ideally error out. However, it does the whole cloning and everything. Next patch will fix it. Differential Revision: https://phab.mercurial-scm.org/D9694

upgrade: migrated -> upgraded in ui messages Differential Revision: https://phab.mercurial-scm.org/D9676

upgrade: remove unnecessary `is None` check `upgrade_engine.upgrade()` always return the `backuppath` value and there are not early returns. Hence I don't see how `backuppath` can be None. Adding extra unncessary safe checks hides unknown bugs. Hence removing it. Differential Revision: https://phab.mercurial-scm.org/D9675

engine: refactor code to replace stores in separate function In not all upgrades, we need to change the whole store. For example, when upgrading repository to share-safe mode, we don't touch revlogs at all hence store cloning and copying is not required. The store replacing code needs to be made aware about what all has changed and hence only copy/rename those things. To kickstart that, this patch moves existing logic into a separate function. Differential Revision: https://phab.mercurial-scm.org/D9674

engine: make hook point for extension a public function Well there are no private public functions in Python, but we generally treat functions and variables starting with `_` as private ones. A function which needs to be overrided in extension should be a public one. Differential Revision: https://phab.mercurial-scm.org/D9672

engine: prevent multiple checking of re-delta-multibase The _perform_clone function is called for each revlog cloned, hence we should prevent this function call overhead. Differential Revision: https://phab.mercurial-scm.org/D9669

engine: pass upgrade operation inside `_perform_clone()` Same as previous patch. Differential Revision: https://phab.mercurial-scm.org/D9668

engine: pass upgrade operation inside _clonerevlogs() Better to pass the operation instead of passing three of it's members (one of the them is a function call) separately. This will also be useful in future when we will like to control which things are upgraded. Differential Revision: https://phab.mercurial-scm.org/D9667

actions: store deltareuse mode of whole operation in UpgradeOperation UpgradeOperation should provide easy access to all the things related to the current operation. Clients should not need to compute them. Differential Revision: https://phab.mercurial-scm.org/D9666

engine: refactor how total dstsize is calculated Instead of increasing it with each revlog, we just get the sum of total destination changelog, manifest and filelogs sizes. Differential Revision: https://phab.mercurial-scm.org/D9665

upgrade: introduce post upgrade and downgrade message for improvements For certain imporvements, we will like to show a message after the operation completed. This patch introduces that functionality. Right now it's only used by share-safe feature. Differential Revision: https://phab.mercurial-scm.org/D9619

actions: introduce function to calculate downgrades An upgrade operation can also downgrade/remove some format variants. Before this patch there was no clean way to find out all such variants which will be removed. This patch adds a function for that. It will be used in next patch. Differential Revision: https://phab.mercurial-scm.org/D9618

debugupgraderepo: minor documentation fix When we specify `--no-changelog --no-manifest --no-filelog` we skip all revlog optimization instead of all filelog optimization. Also while I was here, for consistency, I did `optimisation` -> `optimization` to make it consistent with rest of occurrences. Note: I am not native speaker and I only changed it because of consistency. I don't know which one is correct. Differential Revision: https://phab.mercurial-scm.org/D9617

upgrade: rename actions to upgrade_actions The `actions` were a list of optimizations and format upgrades which will be upgraded. This does not include things which will be downgraded. Let's rename the variable for clarity. It now makes obvious that we don't have any concrete information on what things are downgraded. Differential Revision: https://phab.mercurial-scm.org/D9616

upgrade: move optimization addition to determineactions() The documentation of `determineactions()` mention that it is given a list returned from `findoptimizations()` however it was not true before this patch. The code extending actions with optimizations also mentioned about it that this should be in determineactions. So let's do what comments at couple of places say. Differential Revision: https://phab.mercurial-scm.org/D9615

upgrade: drop support for old style optimization names Old style optimization names like `redeltaparent` were converted into `re-delta-parent` more than two years ago. The old names were kept around for sometime because of BC reasons. Refer 5608b5a6c3231c4ec771171cc3079142c7672be6. The commit states the map is there for a while and we can drop them as the underlying command is a debug command. Differential Revision: https://phab.mercurial-scm.org/D9614

upgrade: add a missing space in status message Found while reading the code to refactor. Differential Revision: https://phab.mercurial-scm.org/D9583

actions: rename DEFICIENCY constant to FORMAT_VARIANT It was not obvious what does deficieny means and every format change can't be a deficiency. There are some format changes like compression levels, share-safe which can't be understood at deficiencies. This patch renames the constant to make things clearer. Differential Revision: https://phab.mercurial-scm.org/D9664

upgrade: rename finddeficiences() to find_format_upgrades() It was not obvious what does deficieny means and every format upgrade can't be a deficiency. There are some format upgrades like compression levels, share-safe which can't be understood at deficiencies. A change can be an upgrade or downgrade, however this `finddeficiences()` only used to find upgrades. This patch renames the function and related variables to make things more clearer. The ui message also got improved which is a good thing. Next patch will rename deficiency in general across the upgrade code. Differential Revision: https://phab.mercurial-scm.org/D9582

beautifygraph: change the current commit symbol The existing "circle with vertical fill" character renders as full width in many terminals making the beautified symbols have uneven size. Additionally, the proposed "fisheye" character is the logic 'active' version of the current merge symbol, "bullseye." Differential Revision: https://phab.mercurial-scm.org/D9678

merge with stable

statichttprepo: explicitly convert error message to str (issue6247) For Python 2.7, the implicit conversion of the HTTPError instance to str was good enough. For Python 3.x, this fails later when hitting the str to bytes conversion logic. Differential Revision: https://phab.mercurial-scm.org/D9661

debugsetparents: add various warning in the help message I am tired to see people shooting themself in the foot with this. So lets add more warning. At that point we should probably rename it or add extra confirmation flag. This is a debug command anyway we can break BC on it. Differential Revision: https://phab.mercurial-scm.org/D9534

largefiles: redo heads interception The largefiles extension replaces the "heads" wire command and tries to redirect all uses towards the custom "lheads" wire command. As seen in issue6384, this doesn't currently work for ssh. Instead of hooking into the _callstream interface, properly register the command for the peer instance and monkeypatch the executor to do the redirection. This works transparently for both all kinds of peers and both for the batch and non-batch case. Differential Revision: https://phab.mercurial-scm.org/D9663

nodemap: match comment to actual code REV_OFFSET constant is 2, not 10. Differential Revision: https://phab.mercurial-scm.org/D9688

clone: update to active bookmark, if set This cannot happen during a normal Mercurial clone, but is useful for extensions like hg-git where we know what to check out — the Git HEAD — but do not wish to track it later on using the `@` bookmark. Test Plan: I have not included an explicit test, as this is much more easily tested within the `hg-git` test suite. Differential Revision: https://phab.mercurial-scm.org/D9638

branchmap: micro-optimize branchinfo changelogrevision() is supposed to be used if not all data of changelog.read is used. This is the case here as only the extra field is used. This also improves extensibility as at least hgext.git doesn't implement changelog.read. Differential Revision: https://phab.mercurial-scm.org/D9626

contrib: py3 compat for perfnodemap Differential Revision: https://phab.mercurial-scm.org/D9687

comments: fix typos Differential Revision: https://phab.mercurial-scm.org/D9689

engine: unwrap a hard to understand for loop The loop was iterating over all the datafiles and maintaining a set to check whether filelogs have been processed, manifests have been processed or not. The code was hard to understand and it assumed that `alldatafiles` are ordered in a certain way. This refactors the for loop in separate parts for each manifests, changelog and filelogs. This will also help in future work where we will like more better handling on whether we want to upgrade filelogs or not. Differential Revision: https://phab.mercurial-scm.org/D9580

engine: refactor actual cloning code into separate function The `for ...` under which this cloning code exists is too complicated and based on certain assumptions. I am going to refactor it in next patches and make it bit saner. Differential Revision: https://phab.mercurial-scm.org/D9579

upgrade: move printing of unused optimizations to UpgradeOperation class Differential Revision: https://phab.mercurial-scm.org/D9578

upgrade: move `printrequirements()` to UpgradeOperation class Part of refactor where we make things more arranged and integrated into single `UpgradeOperation` class. Differential Revision: https://phab.mercurial-scm.org/D9577

upgrade: move `printoptimisations() to UpgradeOperation class Part of refactor where we make things more arranged and integrated into single `UpgradeOperation` class. Differential Revision: https://phab.mercurial-scm.org/D9576

upgrade: move `printupgradeactions()` to UpgradeOperation class Part of refactor where we make things more arranged and integrated into single `UpgradeOperation` class. Differential Revision: https://phab.mercurial-scm.org/D9575

upgrade: move `print_affected_revlogs()` to UpgradeOperation class Part of refactor where we make things more arranged and integrated into single `UpgradeOperation` class. Differential Revision: https://phab.mercurial-scm.org/D9574

hg-core: add basic config module The config module exposes a `Config` struct, unused for now. It only reads the config file local to the repository, but handles all valid patterns and includes/unsets. It is structured in layers instead of erasing by reverse order of precedence, allowing us to transparently know more about the config for debugging purposes, and potentially other things I haven't thought about yet. This change also introduces `format_bytes!` to `hg-core`. Differential Revision: https://phab.mercurial-scm.org/D9408

copies-tests: update to null in test-copies-chain-merge.t This avoid some unrelated output changeset when adding more cases. Differential Revision: https://phab.mercurial-scm.org/D9589

copies-tests: add a summary of all cases created in test-copies-chain-merge.t This helps to keep track of existing branch when adding new cases. Differential Revision: https://phab.mercurial-scm.org/D9588

copies: stop attempt to avoid extra dict copies around branching In the python code, we attempt to avoid unnecessary dict copies when gathering copy information. However that logic is wobbly and I keep running into case where independent branches affects each others. With the current code we can't ensure we are the only "user" of dict when dealing with merge. This caused havoc in the next series on tests I am about to introduce. So for now I am disabling the faulty optimisation. I believe we will need a dedicated overlay to deal with the "copy on write logic" to have something correct. I am also hoping to find time to build dedicated test case for this category of problem instead of relying on side effect in other tests. However for now I am focussing on another issue. Differential Revision: https://phab.mercurial-scm.org/D9608

copies: deal with the "same revision" special case earlier This can happens a lot in case of deletion so we better deal with it early. Differential Revision: https://phab.mercurial-scm.org/D9592

tags: describe all abnormal tag types in `hg tags -v` In particular, this affects `git` and `git-remote` tags when using hg-git. Test Plan: I have not included an explicit test, as this is much more easily tested within the `hg-git` test suite. Differential Revision: https://phab.mercurial-scm.org/D9639

hg-core: add format-bytes dependency This will be used in the next patch to make error messages that require bytestring concatenation clearer. Differential Revision: https://phab.mercurial-scm.org/D9409

rebase: handle the case when nothing to rebase (dry-run) In dry-run mode, even when there was no rebase in progress it tried to abort (for context, at the end of dry-run mode we abort the in-memory performed rebase) because we were not early checking if there was any rebase started. Changes in test file reflect the fixed behavior. Differential Revision: https://phab.mercurial-scm.org/D9659

rebase: add test to demonstrate an issue in dry-run In dry-run mode, the case when there is nothing to rebase is not handled correctly. Added test show that it try to abort a rebase while there is no rebase in progress. This will be fixed in next patch. Differential Revision: https://phab.mercurial-scm.org/D9658

pycompat: fix typos Differential Revision: https://phab.mercurial-scm.org/D9662

chg: format code by clang-format version 11.0.1-+rc1-1 test-check-clang-format.t started failing on my Debian sid environment, and new style looks slightly better. So let's bump the required clang-format version to 11.

test-check-interface: do not expect bare "python" executable exists The test would crash if python executable had version suffix.

procutil: assign pseudo file object if sys.stdout/stderr is missing This basically simulates the Python 2 behavior. If libc stdio were used, these file objects would be available and raise EBADF. There is subtle difference between py2 and py3, but I think py3 behavior (i.e. exit 255) is more correct. "if" conditions are adjust so that they look similar to dispatch.initstdio().

procutil: introduce pseudo file object that just raises EBADF This should be safer than closing underlying fd as the fd may be reused. On Python 2, closed sys.stdin could be redirected to a random file having fd=0, but we'd be better not copying this behavior. Only readinto() and write() are implemented according to the following ABC table. fileno() is not implemented since fd=0/1/2 may be assigned later to other files. https://docs.python.org/3/library/io.html#class-hierarchy

dispatch: gate against missing stdout/stderr We do need procutil.stdin/stdout/stderr, but we don't care much for sys.std*. Let's leave them be None as it is the Python 3 way.

dispatch: remove stale comment about fdopen()-ed stdio On Python 3, stdout is just wrapped by LineBufferedWrapper.

mergetools: add BeyondCompare 4 for Windows This is a copy of the TortoiseHg configuration, but dropping the 3-way diff and dirdiff settings (since those aren't supported in core Mercurial), and swapping the 'parent1', 'parent2', and 'base' literals for `$labellocal`, `$labelother, and `$labelbase` respectively. (That functionality was apparently never ported to TortoiseHg.) Additionally, the single quotes were removed from around these arguments, since none of the other configs have them. Differential Revision: https://phab.mercurial-scm.org/D9635

mergetools: add support for 32-bit BeyondCompare 3 on 64-bit Windows Again, marginal usefulness, but other tools have this config and it eliminates a diff from the TortoiseHg file. Differential Revision: https://phab.mercurial-scm.org/D9634

mergetools: enable the `checkconflicts` option for Araxis Merge This must have been a typo. This matches the config read in filemerge, as well as the TortoiseHg config file. Differential Revision: https://phab.mercurial-scm.org/D9633

mergetools: sync up comments with the TortoiseHg copy of the config file It's of limited value, but a step towards making the diff between the two less noisy. Differential Revision: https://phab.mercurial-scm.org/D9632

rust: introduce Repo and Vfs types for filesystem abstraction This is similar to the corresponding Python classes. Repo represents a repository and knows the path to the `.hg` directory, the `store` directory, and the working directory. Separating these will enable supporting the share extension. A Vfs is created from a Repo for one of these three directories. It has filesystem access APIs that take a relative std::path::Path as a parameter. Differential Revision: https://phab.mercurial-scm.org/D9596

bundle2: drop some outdated comment This commend trace back to a very early bundle2 changeset c7ceae0faf69. And the code moved past this warning over 5 years ago. Differential Revision: https://phab.mercurial-scm.org/D9637