core#1688 - false positive on missing custom field check

[MegaphoneJon]

https://lab.civicrm.org/dev/core/-/issues/1688

Overview

Any custom field that can take multiple values (multi-select, checkboxes, etc) will return a false positive for missing custom fields on the API call System.check.

Before

False positives

After

No false positives

Technical Details

The current code assumes that any saved search that has a form value starting with custom_ will end with an integer (e.g. custom_18). However, multi-select fields' form values have an operator - e.g. custom_18_operator). The check grabs 18_operator and compares it to a list of existing custom field IDs, and of course comes up empty.

Comments

I confirmed that deleting this field will still correctly trigger a warning. I gave detailed replicated steps on the Gitlab ticket.

[civibot]

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[MegaphoneJon]

Note that this is the rc version of #16960, which already had an r-run from Kevin C.

[seamuslee001]

Merging as per review by Kevin on the other PR