Zero diff changes

Submitters responsibilities for submitting a PR

1. Build on discover
   1. baseline from head of develop branch
   2. evaluation version from your feature branch
2. Perform a 1 day run (Q: do we want to specify which options are selected in gcm_setup?)
   1. baseline
   2. evaluation
3. Verify results are identical

cdo <baseline-exp>/scratch/...   <feature-exp>/scratch/...

4. Create a PR and check that there are no merge conflicts.
   • If there are merge conflicts, fix them on the feature branch and repeat 1.ii, 2.ii, and 3 until there are none.
   • If the PR corresponds to an open issue #xxx, please start the PR subject with

   Fixes #xxx

5. Add the label "0-diff" in the PR

Approval & Merge process

1. CODEOWNERs teams will inspect all code changes to ensure that the changes appear sensible and that implementation quality is acceptable. CODEOWNERs may request changes. If nontrivial changes are required, the verifications above will need to be repeated.
2. Gatekeeper will verify the zero-diff nature of the change by repeating the steps above.
3. Gatekeeper approves the PR
   1. Click merge button
   2. Click confirm button
   3. Click delete branch button

Note: The head of the develop branch may have changed by the time the gatekeepers get to your PR. Usually this will not affect zero-diff changes, but they may ask you to merge the latest develop into your feature branch and repeat the verification steps above.