Support expressions in selectattr/rejectattr

[mattcoley]

Previous PR allowed nested properties in selectattr and rejectattr #238.

This is great however is still limiting because you cannot execute filters. For example you may have a list of objects you would like to map to a value before executing the filter: |selectattr("optionList|map('id')", "containing", 1) or perhaps you would like to trim the values |selectattr("name|trim|lower", "equalto", "matt").

This resolves the first argument as an expression and then applies the test case. The solution is hacky as it stores a temporary variable to resolve the expression against. I have not thought of a way to get around this.

Motivation: This makes it easier to filter many HubL/HubSpot objects that have properties that are lists of other objects. Previously this required a for loop.

[codecov-io]

Codecov Report

Merging #249 into master will increase coverage by 0.02%.
The diff coverage is 77.77%.

@@             Coverage Diff              @@
##             master     #249      +/-   ##
============================================
+ Coverage     71.84%   71.87%   +0.02%     
- Complexity     1402     1405       +3     
============================================
  Files           220      220              
  Lines          4412     4420       +8     
  Branches        700      701       +1     
============================================
+ Hits           3170     3177       +7     
  Misses         1002     1002              
- Partials        240      241       +1

Impacted Files	Coverage Δ	Complexity Δ
...m/hubspot/jinjava/lib/filter/SelectAttrFilter.java	71.42% <77.77%> (+1.05%)	10 <2> (+2)	⬆️
...c/main/java/com/hubspot/jinjava/util/ScopeMap.java	79.03% <0%> (+1.61%)	23% <0%> (+1%)	⬆️

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[TheWebTech]

Understand the performance issues. Perhaps there's a way to allow some of the functionality without allowing everything.
Change:
|selectattr("name|trim|lower", "equalto", "matt")
to
|selectattr("name", "equalto", "matt",["trim","lower"])

The 4th parameter being permitted filters to apply to the value of the attribute. You could then restrict which filters were applied.
While not super sophisticated you could simply have a bunch of if statements to make it work
{%if "trim" in permittedFilters %} {%set attribute = attribute|trim %}