Currently the editor deletes its temp file whenever editing is finished.
With this patch, the file will not be deleted if the editor callback
encounters an exception.
One example is if the tab containing the edited element is closed. The
editor errors with "Edited element vanished", but with this patch it
will also print "Backup at ..." so the user does not lose their work.
Resolves#1596.
Supersedes #3641, using the cleaner approach started in #1677.
With QtWebKit it's probably okay to still use it (*cough* Hyperbola
GNU/Linux-libre^tm *cough*), and only blacklisting it with QtWebEngine would be
quite some effort.
Fixes#3608
After reading https://pyyaml.org/wiki/PyYAMLDocumentation again, turns out
Loader.add_constructor and .add_implicit_resolver are actually *class* methods.
In other words, we've been adding dozens of constructors/resolvers to the
default YAML loader object, causing it to slow down massively in other tests
which call configdata.init().
Instead, create our own loader class and only add them once there.
I'm still not sure why this caused the duration to increase with every YAML load
though - that might still be some kind of bug in PyYAML.
Fixes#2777
The test above this one loads hello.txt, but we don't wait for the "load
finished" message, so it can arrive after the previous test already finished and
make this test not wait properly.
However, we also can't easily wait for the load finished message in the
previous test as it only appears with QtWebEngine, not QtWebKit.
As a workaround, we simply load another file in that test, to circumvent this
kind of cross-interaction.
