Refactors how/when rebuilds are required

[jasonb5]

• Refactors check_lockedfiles
• Updates xmlchange to use check_lockedfiles
• Adds ability for components to define when a rebuild is required
  • Define custom component triggers by adding REBUILD_TRIGGER_{comp} with comma separated list of variables to config_component.xml, e.g. REBUILD_TRIGGER_CPL=NTASKS would require a rebuild if NTASKS changes for the cpl component
• Removes warning/error when pelayout is changed
  • To add old behavior define REBUILD_TRIGGER_CPL with a value NTASKS,NTHRDS,NINST to couplers config_component.xml

Test suite: n/a
Test baseline: n/a
Test namelist changes: n/a
Test status: n/a

Fixes n/a
User interface changes? n/a
Update gh-pages html (Y/N)?:

[jasonb5]

TODO

• Add documentation
• Finish adding tests

[github-actions]

You can preview documentation at https://esmci.github.io/cime/branch/fix-model-rebuild/html/index.html

[jgfouca]

LGTM

[jgfouca]

@jedwards4b , you want to review or should I just merge?

[rljacob]

Does this mean I can: change NTASKS for a component that doesn't need a rebuild, run case.setup, immediately run case.submit without running case.build ? Do I still have to run case.setup?

[jasonb5]

@rljacob Yes you would still have to run ./case.setup to regenerate the batch script files, but ./case.build can be skipped.
It's possible we could automatically run ./case.setup after running ./xmlchange on a variable or make it an option to do it with a single command e.g. ./xmlchange NTASKS=8 --reset or something similar.

[jgfouca]

@jedwards4b , last chance to review before I merge.

[jasonb5]

@jgfouca What are your thoughts on adding a --reset argument to ./xmlchange to skip the call to ./case.setup --reset? I can address this in another PR if it's a worth while addition.

[jgfouca]

@jasonb5 , that sounds fine to me.

[jasonb5]

@jgfouca Sounds good, I'll make a separate PR for it.

[jedwards4b]

I was on vacation. Sorry you couldn't find another cesm person to review, I'll bring that up in our team meeting tomorrow.