Let beet config -e work even when the configuration file can't be parsed

[azrdev]

Under some circumstances, beets and/or the config command fail, which can be fixed by changing the config file - thus, the user has to find & edit that by hand, since the command fails. Examples:

1. Upon upgrade to v1.3.9, the discogs plugin wanted an auth token from me, which it requested on beets startup. Since I didn't supply one, beets failed, until I removed the plugins activation from the configuration
2. Make a syntax error in the config file, e.g. a yaml "collection" without any value in it, and watch all beets commands fail since it cannot read the file. This works even when editing "through" beets.

[sampsyo]

Good point, although neither of these will be easy to solve.

Can you elaborate on how beets "failed" when discogs was broken? Was there a traceback?

[azrdev]

$ beet version
To authenticate with Discogs, visit:
http://www.discogs.com/oauth/authorize?oauth_token=dLTKUZxKWdAbABnORoErTjorzZwEZpijPbzjLZXp
Enter the code: 
error: Discogs authorization failed
$ echo $?                                                                                                                                :(
1

Dunno if this counts as broken, I just didn't supply a code (since the link asks to log in with an account, which I don't have)

[sampsyo]

Aha, thanks for clarifying! I'm pushing a fix now that makes the plugin only ask for authentication when running an import, so that should solve that half.

The other component here will be somewhat trickier. We need to parse the configuration file before dispatching commands (for plugins' sake), so parse errors can get in the way. I think the best way to make config -e still work, which is a good idea, would be to hard-code that particular invocation. This would happen in beets.ui._raw_main after the global options are parsed but before we call _setup. I'll leave this open to remind us to do that.