stack: implement __bool__ and __nonzero__

stack: get stack data directly from stack and remove stackdata() stackdata function began its life in 137f8b04901e as a proto-stack: it computed stack revs on its own and only had one property to return, "changesetcount". Later it started to prepare and return more properties, but since b933a8068c17 it was computing revs using a getstack function. And then finally in 17749d9d3968 it started to rely on stack class entirely. It was a good function, but now, when all the logic it provided was factored into stack class, I'd say it's finally time for it to be put to rest.

stack: use stack._revs instead of stack.revs[1:] in external children revset The revset in question excludes all revs that are part of the stack. Using stack.revs[1:] works (rev #0 is stack base, which is not a part of the stack), but using stack._revs is technically more correct, because this variable is specifically designed to hold only revisions that are part of the stack.

test: update output to match the parent changesets This amend was forgotten.

topic: add a simple option to reject publishing The option is pretty basic but it can be used as base to build larger feature. The main target for going in this direction is to be able to distinct between user that are "simple contributors" pushing topic for review and the "maintainers" or "automation" that can publish changesets.

compat: adjust `wrapadd` for upstream Mercurial core updated the API in f385ba70e4af.

debian: override default value for SPHINXBUILD in docs/makefile This is the recommended Debian approach. As suggested by Debian Developer Stephen Kitt, use the approach recommended by Debian for building Sphinx documentation. See https://wiki.debian.org/Python/LibraryStyleGuide#Sphinx_documentation Also belated credit to Zash on the #mercurial channel on the Freenode IRC network, who suggested the Make variable approach in the first place.

obshashtree: move obshashtree in its own module The code no longer serve a core purpose. We just keep it because the command might be useful. We move it in a dedicated module so that it does not get in the way of other work.

obsdiscovery: drop `obshash` discovery protocol (issue6136) The protocol has been superseeded by stablerange for a long time. It is untested and more and more buggy. Since this is deprecated experimental code in an experimental code, we drop it. We keep the underlying computation and debug command around for now. They might still be useful to looks at repositories

cmdrewrite: use context manager for some locks and transactions These were the trivial cases where I didn't even need to extend the scope of a transaction or change indentation to fix it.

evolve: mention that --all is default, in list of options

touch: use util.acceptintervention() for closing the transaction It will close the transaction on InterventionRequired.

touch: use context manager for locks

touch: extract the logic of touching rev's to its own function This refactoring will also help us in using the context manager for locks in next patches and also help reducing the nested depth.

changelog: mention user merging in the changelog

evolve: consider using three way merge to get the user for div resolution This patch adds the logic to merge the users from two divergent csets considering the base (i.e three way merge). The case when all the three are different, we concatenate the two authors of divergent csets.

evolve: add tests for the case when div csets has different users

branching: merge with stable

evolve: move status msg to verbose mode in content-divergence resolution As suggested by Pierre-Yves, lets move these too verbose message for the user to verbose mode to decrease some noise.

debian: Override default value for SPHINXBUILD in docs/makefile Sphinx now defaults to Python 3 in Debian Buster, so we need to explicitly select the Python 2 version of sphinx-build for building docs.

docs: add SPHINXBUILD make variable This defaults to sphinx-build. The current use case is for the Evolve Debian package build.

topic: add test to increase code coverage in case of multiple topics This patch adds a test which cover the part that when we have one topic on top of other topic, this make sure that when evolving it's boundary are the current active topic (i.e hg stack)

changelog: --no-update is the default, recommend --update instead

topic: drop support for accessing csets in branch stack using bxx (issue6119) When topic extension is enabled and we have some cset whose hash is `b1234`, topic extension thinks that we are accessing 1234 cset in current branch stack. However that's not the case generally. Also I am not sure many people use this bxxx thing. Since we have a generic sxxx way to access csets, let's drop support for accessing csets using bxx which leads to bad behavior. Looking at the tests, we don't show bxxx in hg stack output anymore. I update the test to use sxxx instead of bxxxx.

legacy: drop the check for `obsolete._enabled` This looks like an ancient version check, and presumably `minimumhgversion` will do the same thing.

docs: drop references to the old temporary commit that was created with amend The sharing.rst page also mentions amend, but the diagrams aren't showing, so I'm not sure if they're in some other repo and needing to be updated.

templatekw: add `instabilities` alias for `troubles` Per https://www.mercurial-scm.org/wiki/CEDVocabulary

revset: switch internal uses and tests to `predecessors` from legacy name