Add support for using LicenseRef- when initialising

[sgaist]

When initializing a new project that will use a custom license, the first step will fail because it currently handles only the list of supported license.

This pull request implements the handling for LicenseRef- so that it can also be used from the start.

The implementation will request a path to the license file so it can be copied over to the project.

Fixes #677

[nicorikken]

Thanks for the pull-request! It is great to accept other LicenseRef's this way.
I added a suggestion to make the regex more strict, which improves validation.
I think the input for a LicenseRef file can be improved by accepting a file instead of a directory too.
Tab completion on the file input would be nice, but I didn't find an easy way from the standard library to get that functionality.

[nicorikken]

Wow, you're acting quickly. Just let me know when you think it is ready for another review.

[sgaist]

You're catching me at a good time :-)

I think I have implemented or added all of your suggestions so you can go on for a new round.

[nicorikken]

I gave it another test, much better now, thanks! I have two main remarks having tested it:

• No warning or error if you don't provide anything.
• No option to retry if a path if it failed to copy.

Maybe this is acceptable for now, as it mimics the behavior of other prompts.
Perhaps the error can be improved to hint to the user where to put it?
Could not copy LicenseRef-mylicense. Please add it manually as LicenseRef-mylicense.txt in the LICENCES/ directory.

Not sure about this. I'll ping @carmenbianca @mxmehl @linozen to hear what they think, before asking more work.

[mxmehl]

Thanks for the work @sgaist and the thorough review @nicorikken!

I gave it another test, much better now, thanks! I have two main remarks having tested it:

• No warning or error if you don't provide anything.
• No option to retry if a path if it failed to copy.

Maybe this is acceptable for now, as it mimics the behavior of other prompts. Perhaps the error can be improved to hint to the user where to put it? Could not copy LicenseRef-mylicense. Please add it manually as LicenseRef-mylicense.txt in the LICENCES/ directory.

I think it's acceptable. I would avoid to overengineer this as the number of users is probably quite small. How it's implemented now is a great improvement already, retaining the service init provides with custom licenses.

I'd appreciate Nico proposed error message to be added to this PR though as it directly provides users with concrete next steps when they see an error.

[sgaist]

@mxmehl Sorry for the late reply, I missed your feedback.

I have simplified the code and added the error message as requested.

[mxmehl]

Just one grammar mistake found, otherwise LGTM. Thanks!

[floriansnow]

Just a minor issue, but should this be defined here or rather in _licenses.py to keep everything in the same central place?

[mxmehl]

I don't have a strong opinion, but it might make sense to put it there. In the rest of the code base we don't use a regex for LicenseRef yet but just .startswith("LicenseRef-"), but it may well be that this will change for some reason someday.

[nicorikken]

@floriansnow can we merge this as is or do you want this changed?

[floriansnow]

@nicorikken I can live with both, but if we merge it as is, let's create an issue to clean this up a bit at a later date, together with the instances Max mentioned.

[sgaist]

No need to create an issue, I moved the regexp and updated the LicenseRef- check occurrences.

[carmenbianca]

Slightly refactored this and added some tests. Thanks for the PR @sgaist !