BUG: Allow extensions to pass Sphinx errors during init

[larsoner]

In sphinx-gallery #7683 causes some problems for us because we used to check that things like ValueError were raised during builder init, but now it's always ExtensionError with the message "Handler <function generate_gallery_rst at 0x7f88327f69d0> for event 'builder-inited' threw an exception", and the useful error message higher up.

One solution is that we can switch to emitting ExtensionError and ConfigError as appropriate (I have tested this and it works). Then Sphinx needs the change here, and things work as expected.

Let me know if there is some other solution. It's possible that there are other events that get emitted that might need similar changes.

[larsoner]

... another option would be to add a new config value allowed_exceptions where you specify which exceptions to pass through, and then each self.emit or self.events.emit would use allowed_exceptions=self.allowed_exceptions or so. But again I'm not sure if this makes much sense.

[eric-wieser]

Is #7658 related in any way here?

[tk0miya]

Sorry for bothering you. I don't know your extension raises a ValueError on the handler.

BTW, I think current implementation accept SphinxError without allowed_exceptions. So it would go well with replacing ValueError with SphinxError family now.

[larsoner]

Indeed it does! Sorry for the noise