py3: use fsencode for vcr recording paths and strings for custom_patches args This fixes phabricator.py's vcrcommand under py3 Differential Revision: https://phab.mercurial-scm.org/D6102

phabricator: convert conduit response JSON unicode to bytes inside callconduit Previously the byte conversion was happening piecemeal in callers, and in the case of createdifferentialrevision not at all, leading to UnicodeEncodeErrors when trying to phabsend a commit with a description containing characters not representable in ascii. (issue6040) Remove all the scattered encoding.unitolocal calls and perform it once, inside callconduit, on the entire response dict recursively before returning it, in keeping with the strategy of converting at the earliest opportunity. Convert all keys used on returned object to bytes. Modify the phabsend tests to test this by adding a € to the commit message of alpha. Differential Revision: https://phab.mercurial-scm.org/D6044

transaction: include txnname in the hookargs dictionary There is no reason to not include the txnname alongside the txnid in all case. The python hooks already have them, so aligning the the shell hooks seems it could be useful in the future. (I don't have a strong opinion about this, we can also decide to never align the python and shell hooks and this and I'll drop this patch).

discovery-helper: reflect argument value in the name of the results It is common to create multiple pairs of repositories using different argument values. Recording the argument value in the results names has two main advantages: * It is easy to remember the value used to create a pair, * It get simpler to create multiple pair at the same time from the same source. Previously, running: `./discovery-helper.sh pypy 50 10` would create a `pypy-left` and `pypy-right` repository. Now it will create `pypy-50h-10d-left` and `pypy-50h-10d-right`.

discovery-helper: echo the stripped revsets early Having them printed early make it easy for a user to just grab the generated revset and directly uses them

contrib: move the `discovery-helper.sh` script in`perf-utils` directory The script appeared before the directory. However the directory exists for this kind of script. We move it there.

tests: stabilize test-split.t for Windows It looks like there will be additional problems beyond this trivial fix, but this should make the bot green again.

tests: stabilize test-share.t on Windows PYTHON was not getting mangled for MSYS style paths, and remote was spitting out remote: 'C' is not recognized as an internal or external command, remote: operable program or batch file. (once -q was removed). Additionally, this should fix a failure with py3 because of spaces in the path.

split: add tests which demonstrate the issue5864 Differential Revision: https://phab.mercurial-scm.org/D6057

discovery: clarify why the caching of children is valid Yuya Nishihara pointed out that the code looks wrong without this clarification. (And, unsurprisingly, Yuya is right)

tests: clarify test setup test in test-uncommit.t I assume the "hg uncommit b" is there to prove that the working copy is dirty before we try "hg uncommit --allow-dirty-working-copy b". It seems clearer to put that check just before we run the actual test. Differential Revision: https://phab.mercurial-scm.org/D6078

tests: fix a stale reference to experimental.uncommitondirtywdir These tests no longer test the config option, they test the command line flag. Differential Revision: https://phab.mercurial-scm.org/D6077

discovery: explicitly use `undecided` for the children mapping Recent performance achievements makes the assumption that the `undecided` set is used for sampling. That assumption is always true in practice. We stop pretending that taking anything else would make sense and we directly use the `undecided` set from the object. This provides a more honest API.

discovery: cache the children mapping used during each discovery During discovery, the `undecided` set keep shrinking. Therefore, the map computed for an iteration N will be valid for iteration N+1. Instead of computing the same data over and over we cache it the first time. Our private pathological case speed up from about 7.5 seconds to about 6.3 seconds. (starting from over 70s at the start of the full series)

discovery: move children computation in its own method This clarifies the main logic and starts to pave the way to some caching.

discovery: simplify the building of the children mapping Since we only care about the revisions inside the set we are sampling, we can use simpler code (and probably sightly faster).

discovery: simply walk the undecided revs when building the children mapping The sampling only care about revisions in the undecided set, so building children relationship within this set is sufficient. The set of undecided changesets can be much smaller than the full span from its smallest item to the tip of the repository. This restriction can significantly speed up operations in some cases. For example, on our private pathological case, this speeds things up from about 53 seconds to about 7.5 seconds.

discovery: use a lower level but faster way to retrieve parents We already know that no revision in the undecided set are filtered, so we can skip multiple checks and directly access lower level data. In a private pathological case, this improves the timing from about 70 seconds to about 50 seconds. There are other actions to be taken to improve that case, however this gives an idea of the general overhead.

discovery: avoid computing identical sets of heads twice The very same set of heads is computed in the previous statement, it seems more efficient to just copy that result.

discovery: moved sampling functions inside discovery object In this patch, we transform the sampling functions into methods of the `partialdiscovery` class in the Python case. This will provide multiple benefit. For example we can keep some cache from one sampling to another. In addition this will help the Oxidation work as all graph traversal related logic will be contained in a single object.

discovery: rename `srvheads` to `knownsrvheads` The `srvheads` variable only contains the known set of remove heads. Renaming the variable make it clearer.

verify: small refactoring and documentation in `_verifymanifest` Small changes to make this area of code clearer.

verify: document the `_verifymanifest` method

verify: document `_verifychangelog` We document the method input, output and checks.

verify: rename the `checklog` to `_checkrevlog` The method is for internal use only. In addition we make the method name explicitly contains `revlog` to make it clearer it is checking higher level revlog properties.

verify: document the `checklog` method Let us add details about what the function is expected to do.

revlog: add some documentation to the `checksize` method I had to look at it, so I figured I would leave some documentation for the next person seeking information.

verify: make `checkentry` a private method This method is for internal use only.

verify: document the `checkentry` method This method checks various core propertes of a revision. We document inputs, outputs and the checks performed.

verify: add some inline documentation to the top level `verify` method The goal is to clarify each section goal.