Support contains, exists, forall for optional embedded case classes with optional fields.

[mxl]

Fixes #785

Solution

• flatten option operations recursively to support optional embedded case classes with optional fields
• parse embedded.forall(...) as OptionExists AST

Notes

embedded.forall(...) currently generates invalid query like (t.embedded IS NULL) || ....
One option is to generate instead - ((t.a IS NULL) && (t.b IS NULL)) || ... where a, b is embedded fields, but it's too hard because on FlattenOptionOperation stage there is no info about embedded case classes and their fields. Also this behavior will be too complex and unexpected (especially if there will be nested embedded case classes). Without this behavior embedded.forall(...) is equivalent to embedded.exists(...). I thought about adding warning on parsing stage to motivate developers use exists() instead of forall() with embedded case classes but I do not think that someone will expect from forall() the behavior that I described above (with generating ((t.a IS NULL) && (t.b IS NULL)) || ...).

Checklist

• Unit test all changes
• Update README.md if applicable
• Add [WIP] to the pull request title if it's work in progress
• Squash commits that aren't meaningful changes
• Run sbt scalariformFormat test:scalariformFormat to make sure that the source files are formatted

@getquill/maintainers

[fwbrasil]

I think it'd be better to fail if forall is used with an embedded value. The parsed AST should mirror the original code.

[mxl]

@fwbrasil I fixed that 👍

[fwbrasil]

Thanks! :)