dbDelta Case Sensitive Key Names Duplicates Indexes

[charlestonsw]

Reference ticket #10404.

This is to decompose the original ticket into components. May be fixed in 4.4. Needs testing.

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Using an uppercase index name will create duplicate indexes:

  KEY MY_KEY ( SLUG ),

This works:

 KEY my_key ( slug ),

[jdgrimes]

I can confirm that this bug is still present in trunk.

From the ​MySQL reference:

Column, index, stored routine, and event names are not case sensitive on any platform, nor are column aliases.

So this ticket is correct that we shouldn't be treating indexes as if they are case sensitive.

[pento]

In 38591:

Database: Normalise index names in dbDelta().

When comparing index definitions, normalise the index names to lower case, as they are not case sensitive within MySQL.

Fixes #34874.