docs: tag mutability adr

[jesperhodge]

Description

This is an ADR addressing an ambiguity on what identifiers of a Tag in a Taxonomy should be editable.

For further details, see the Files changed, as well as the conversations in this PR.

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[bradenmacdonald]

I think this is a good summary of our conversation.

As for how to handle external_id, I think a compromise might be:

• The taxonomy editor UI displays external IDs, but doesn't allow changing them. It may allow specifying them when creating a tag, and/or generate one based on the value if none is specified.
• In the rare case where an external ID needs to be changed, that can be easily done by an administrator using the Django admin UI.

[jesperhodge]

I think this is a good summary of our conversation.

As for how to handle external_id, I think a compromise might be:

• The taxonomy editor UI displays external IDs, but doesn't allow changing them. It may allow specifying them when creating a tag, and/or generate one based on the value if none is specified.
• In the rare case where an external ID needs to be changed, that can be easily done by an administrator using the Django admin UI.

Sounds good to me. Do you agree with this solution @mgwozdz-unicon ? In that case I'll put that in the ADR decision block and mark this as ready for review

[mgwozdz-unicon]

I think this is a good summary of our conversation.
As for how to handle external_id, I think a compromise might be:

• The taxonomy editor UI displays external IDs, but doesn't allow changing them. It may allow specifying them when creating a tag, and/or generate one based on the value if none is specified.
• In the rare case where an external ID needs to be changed, that can be easily done by an administrator using the Django admin UI.

Sounds good to me. Do you agree with this solution @mgwozdz-unicon ? In that case I'll put that in the ADR decision block and mark this as ready for review

Yes, I think this sounds good.

[jesperhodge]

@bradenmacdonald ready for review

[mphilbrick211]

@bradenmacdonald are you able to allow checks to run on this?

[bradenmacdonald]

Before we merge this, I think we should decide what to do about the current import/export format.

Currently, if you go into a course and choose "Tools > Export Tags" or "Tools > Export Course", the result will include a CSV that only has Values, not external_ids. I'm not sure if we should change this, nor if it's even possible without breaking backwards compatibility. But there is likely a way to achieve it, if we think it would be a good idea.

[mgwozdz-unicon]

@bradenmacdonald

Before we merge this, I think we should decide what to do about the current import/export format.

Currently, if you go into a course and choose "Tools > Export Tags" or "Tools > Export Course", the result will include a CSV that only has Values, not external_ids. I'm not sure if we should change this, nor if it's even possible without breaking backwards compatibility. But there is likely a way to achieve it, if we think it would be a good idea.

When Dave and I tested this towards the end of last year, I think we concluded that the way tags are exported doesn't currently allow for them to import usefully, so it might be the case that it's currently a bug that the external_id isn't included in the export CSV files and that the code doesn't check for the existing Taxonomy to make updates or creations on import. I think that addressing this is outside of our current scope to implement the existing backlog of editing features, but we can raise it as something for us to address if we have time.

If we want to add something to this ADR about that, then I think we might want to just say that the intention is for there to be enough data in the Tag and Course export files to be able to validate if the taxonomy currently exists in the system and if so, update it if needed, and if not, then create it. I think that will mean that the external_id needs to be included as well as some way to identify the Taxonomy itself. Should the taxonomies themselves also have an external_id? Adding one for it would require backwards compatibility considerations. It looks like maybe the Taxonomy's export_id is intended to be used for this situation?

[bradenmacdonald]

Should the taxonomies themselves also have an external_id? Adding one for it would require backwards compatibility considerations. It looks like maybe the Taxonomy's export_id is intended to be used for this situation?

Yes, that's it's purpose - a cross-system identifier for each taxonomy.

[bradenmacdonald]

I think we might want to just say that the intention is for there to be enough data in the Tag and Course export files to be able to validate if the taxonomy currently exists in the system and if so, update it if needed, and if not, then create it.

The intention was for there to be enough data in the Tag and Course export file to associate all tagged objects in the course with tagged objects in their taxonomies if the taxonomy already exists on the system, or if the taxonomy is imported into the system at a later date. (So you can import a course, see it has no tags in it, import the corresponding taxonomy, and suddenly tags will show up on all the objects in the course.)

It wasn't the intention to be able to re-create the taxonomy from the Tag and Course export files, although that's interesting.