CRM-21773 Fix merging multi-value custom fields

[JKingsnorth]

Overview

Multi-value custom fields are ignored during the merge process, when they should be merged provided we tick the box to move them during the process.

Before

Multi-value fields not migrated.

After

Multi-value fields are migrated if required.

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• CRM-21773: CRM-20858 breaks merging multi-value custom groups

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• CRM-20858: Custom fields migrated even when not asked during merge

[JKingsnorth]

The test should FAIL - proving the issue.

[JKingsnorth]

It failed, good: not ok 988 - Error: CRM_Dedupe_MergerTest::testMigrationOfSomeCustomDataOnEmptyCustomRecord

[JKingsnorth]

Now, with the fix, it should pass.

[JKingsnorth]

@eileenmcnaughton I think this is failing because \CRM_Dedupe_Merger::relTables is being cached in a static variable (https://github.com/JKingsnorth/civicrm-core/blob/06f4969c149039c74940604b75d5f44e44de7bfc/CRM/Dedupe/Merger.php#L42), so it's not loading up the new group I'm creating during the test. Can you advise me on how to clear that static variable cache? I'm not sure it's even possible since the scope of the static variable is limited to the function itself? How do other unit tests get around these issues?

[eileenmcnaughton]

@JKingsnorth search for Civi::statics - that is a static var that is cleared between test runs & can be cleared from outside the function

[JKingsnorth]

Thanks @eileenmcnaughton - I'll try that out.

[JKingsnorth]

@eileenmcnaughton @systopia This is ready for review now! I had to refactor the static variable caching to get the tests to work. Thanks for the tip Eileen.

I confirm that I have reviewed @systopia 's patch, and it resolves the issue. If someone could check my unit test then this should be good to merge.

[eileenmcnaughton]

(CiviCRM Review Template WORD-1.1)

• (r-explain) Pass
• (r-test) Pass - added by John
• (r-code) Pass, actual change is simple. Caching change is positive
• (r-doc) Pass - not required
• (r-maint) Pass - mild code improvement
• (r-run)Pass - John tested:
• (r-user) Pass:
• (r-tech) Pass - trivial change:

[eileenmcnaughton]

thanks @JKingsnorth & @systopia

[JKingsnorth]

Thanks all.

[bjendres]

Thanks @eileenmcnaughton and @JKingsnorth !