ensure the LEFT JOIN behaves as expected

[bwdmr]

The WHERE clause will filter out these rows because NULL values do not satisfy either the IS NULL or the greater than conditions, effectively excluding them from the result set.

Turning the LEFT JOIN into an INNER JOIN for rows where NULL values would have been expected.

• move includeDeleted checks from query to join, where the filter will be applied
• copy filters over and add filter as necessary, on case deleted in not included
• keep includeDeleted checks within query aswell, as null checks now can exists in where clause aswell.
• adjust tests to reflect changes in code.

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 24.48%. Comparing base (260eff9) to head (13e26ac).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
Sources/FluentKit/Model/AnyModel.swift	0.00%	1 Missing ⚠️
...es/FluentKit/Query/Builder/QueryBuilder+Join.swift	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #623      +/-   ##
==========================================
+ Coverage   24.28%   24.48%   +0.19%     
==========================================
  Files         149      149              
  Lines        9349     9375      +26     
==========================================
+ Hits         2270     2295      +25     
- Misses       7079     7080       +1     

Files with missing lines	Coverage Δ
Sources/FluentKit/Properties/CompositeID.swift	88.46% <100.00%> (+0.46%)	⬆️
Sources/FluentKit/Properties/Timestamp.swift	87.37% <100.00%> (+2.49%)	⬆️
Sources/FluentKit/Query/Builder/QueryBuilder.swift	73.51% <100.00%> (ø)
Sources/FluentKit/Model/AnyModel.swift	42.30% <0.00%> (ø)
...es/FluentKit/Query/Builder/QueryBuilder+Join.swift	56.81% <88.88%> (+3.06%)	⬆️

[gwynne]

It appears that the Mongo driver (or Mongo itself) can't handle this. @Joannis, can you provide any insight?

[gwynne]

Excess whitespace change, please remove

[bwdmr]

support for complex joins with filters is not implemented yet.

https://github.com/vapor/fluent-mongo-driver/blob/79bf35430e72e4290b3d08ac1eb8784d4e389c32/Sources/FluentMongoDriver/MongoDB%2BJoin.swift#L114

joins with filter would require a pipeline as in the following example

db.orders.aggregate([
  { $lookup: {
    from: "customers",
    let: { 
      orderId: "$customerId",
      orderDate: "$orderDate" 
    },
    pipeline: [
      { $match: {
        $expr: {
          $and: [
            { $eq: ["$_id", "$$orderId"] },
            { $gt: ["$memberSince", "$$orderDate"] },
            { $eq: ["$isVerified", true] }
          ]
        }
      }}
    ],
    as: "customerInfo"
  }}
])

[gwynne]

A solution for the Mongo driver is being worked on (though not by me, as I neither have nor want any knowledge of Mongo 😅)