This is done so config.py can import other python files in the config
directory. For example, config.py can 'import theme' which would load
a theme.py.
The previous path is restored at the end of this function, to avoid
tainting qutebrowser's path
There are just way too many gotchas related to valid modes, aliases, and
circular dependencies when validating aliases/bindings in the config.
Let's just remove this and let invalid commands fail late, when they're actually
used.
I considered introducing another list of deleted options (or a "deleted: True"
in configdata.yml), similar to what we had with the old config.
However, let's take the easier route and just delete everything we don't know
from configdata.yml. If someone edits it by hand, it's their fault :P
See #2772, #2847
Includes a test for persistence of intermediate mutations in a
configuration file (i.e. more than one update) and a switch of the
_mutable attribute in configurations to a dictionary of (old, new)
values rather than (name, old, new). get_obj() now checks for an
existing mutable value and returns a reference to that value, only
making an initial copy; this preserves changes between update_mutables()
We were only rendering .html files before, so the old _guess_autoescape function
had the effect of always autoescaping .render() (from a file) but never
autoescaping .from_string(). However, most places using .from_string() actually
render (Qt-)HTML via jinja, so they should escape stuff!
Now, we always autoescape, except when the caller uses the
jinja.environment.no_autoescape() context manager, which places rendering
stylesheets now do.
This impacted:
- Confirm quit texts (no HTML here)
- config.py loading errors
(where this was found because of an error containing - a <keybinding>)
- Certificate error prompts
(should be fine from what I can tell, as the only user-controllable output is
the hostname, which cannot contain HTML)
