rebase: remove experimental option from 'rebase' config section
Changeset
f0e9f38d250f introduced a guard against case where obsolete changesets
are included in the rebase in a way this will result in divergence (because
rebase create new successors for changeset which already have successors). In
the same go a 'rebase.allowdivergence' option was introduced to control that
behavior.
We rename this config option to 'experimental.allowdivergence' for multiple
reasons:
* First this behavior is attached to changeset evolution, a feature still
experimental.
* Second, there was no 'rebase' section in config before we introduced this
option. I would like to avoid proliferation of micro config section and
therefore would like to avoid the creation of this new section just for an
experimental feature.
* Third, this guard (warning the user about a history rewriting operation that
will create divergence) will very likely be generalised to all history
rewriting operations, making this not rebase specific.
* Finally, because this will likely be a general guard present a bit everywhere
in the UI we'll likely end up with something better than a config option to
control this behavior, so having the current config option living in
experimental will allow us make it disappear in the future.
So we banish this config option back to the experimental section where it
belongs, killing the newly born 'rebase' config section in the process.
testing: allow Hypothesis tests to disable extensions
Doing this required the introduction of a mechanism for keeping
track of more general config in the test. At present this is only
used for extensions but it could be used more widely (e.g. to
control specific extension behaviour)
This greatly simplifies the extension management logic by introducing
a general notion of config, which we maintain ourselves and pass to
HG on every invocation.
This results in significantly less error prone test generation, and
also allows us to turn extensions off as well as on.
The logic that used an environment variable to rerun the tests with
an extension disabled now just edits the test file (in a fresh copy)
to remove these --config command line flags.