DM-42637: Keep copies of old dimension universes

[dhirving]

Store the dimensions.yaml configuration for universes 5 and 6.

This will be used by daf_butler_migrate to verify that the dimension universe stored in the DB is as expected before performing the migration.

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.91%. Comparing base (2967610) to head (6c3cf4d).

Additional details and impacted files

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  Lines       42330    42330           
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  Hits        37639    37639           
  Misses       3441     3441           
  Partials     1250     1250           

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[andy-slac]

In general for daf_butler_migrate I try to avoid depending on daf_butler interfaces. daf_butler_migrate is very special in that it may need to work with different daf_butler versions, not just most recent (would be better to avoid this dependency completely, but some things are too expensive to reimplement).

[dhirving]

So would you prefer that I put the historical dimension universe YAMLs in daf_butler_migrate instead then? (I actually slightly prefer that but Tim wanted them in daf_butler.)

[timj]

My argument for putting them in daf_butler is that I have been asked by people in the past about old universes and it seems easier to point them at a file in daf_butler than try to explain to them what daf_butler_migrate is. If the consensus is that people want them in daf_butler_migrate I will go along with that (and we have to remember to add them there when we create new ones.

[andy-slac]

I think I like them better in daf_butler, but the code that reads them can go to daf_butler_migrate. I'm not sure that load_historical_dimension_universe_json is even generally useful in daf_butler.

[dhirving]

I thought it would be a good idea to have a stable function that daf_butler_migrate could call to insulate it from changes in daf_butler's package structure, and to make it obvious to readers in daf_butler that there is code elsewhere using these files, but I don't feel that strongly about it -- I'll put the code in daf_butler_migrate and the YAMLs in daf_butler.

[timj]

As a general comment, I think I'd like the file name to include the namespace and the version number for completeness. I realize that daf_butler won't really have universes in it other than for daf_butler namespace but it would make it more explicit for people looking in from the outside if both were included.

[timj]

This looks okay. I'll see about copying in earlier ones at some point.

[timj]

Maybe add a note here that the naming convention is <namespace>_universe<version>.yaml ?

[timj]

Also consider adding a new PR check list item to remind people to copy universes in here whenever there is a new universe.