[WIP] Polymorphic through

[kbrock]

Fix queries that have virtual attributes and polymorphic queries

This gets away from references().includes() and uses preload for those models we want to reference from ruby and left_joins for those models we want to have in our where and select clauses

• Probably caused by Improve references #19127
• Fixes [Bug] Cannot eagerly load the polymorphic association :resource in performance report #19664

[miq-bot]

Checked commits kbrock/manageiq@eeb8c62~...d7cf4fd with ruby 2.5.5, rubocop 0.69.0, haml-lint 0.20.0, and yamllint 1.10.0
12 files checked, 4 offenses detected

lib/rbac/filterer.rb

• ⚠️ - Line 370, Col 29 - Lint/UnusedMethodArgument - Unused method argument - klass. If it's necessary, use _ or _klass as an argument name to indicate that it won't be used.

spec/models/miq_report_spec.rb

• ❗ - Line 780, Col 13 - Layout/IndentFirstArgument - Indent the first argument one step more than the start of the previous line.
• ❗ - Line 782, Col 27 - Style/PercentLiteralDelimiters - %w-literals should be delimited by [ and ].
• ❗ - Line 783, Col 80 - Layout/MultilineMethodCallBraceLayout - Closing method call brace must be on the line after the last argument when opening brace is on a separate line from the first argument.

[kbrock]

defering to #19778

[kbrock]

Actually think it was actually fixed by #19804

(still wish we could use join instead of references though)

[kbrock]

commenting to explain why this was closed:

everything worked with this except for includes and counts

You would think that calling a count would not deal with the includes. It is a preload. And since we are not bringing back the model to then use the preload, it would be pointless to bring them back. So it seems right to ignore the includes statement.

But for counts, the includes are automatically converted to references, which is not what we want and sometimes creates syntax errors. To make this work we would need to add special logic around our counts to ensure that the includes (that do not have references) are removed.

I thought we would also need to add logic to make sure that we don't have a references to a table that is in a joins. But it turned out to remove all the code that used references and includes. Of course I don't totally rule out that there is a problem, hence I am adding this note.

still wish we could use left joins instead of references.