fix: add deep compare to update dropdown items

[deandreamatias]

Connection with issue(s)

Close #1252

Connected to #687
Connected to #1239

Solution description

Add a deep compare to reset dropdown only when items are really different.

I considered remove the verification and transfer it responsibility to reset dropdown to developer users (like @danvick says on this comment), but I thinks that this behavior is a important to have embedded on package because is a feature that able implement related fields with minor effort.

Screenshots or Videos

Test behavior of original issue (#1252)

Screencast.from.15-07-23.14.23.59.webm

Test behavior of related issue (#687)

Screencast.from.15-07-23.14.25.01.webm

To Do

• Read contributing guide
• Check the original issue to confirm it is fully satisfied
• Add solution description to help guide reviewers
• Add unit test to verify new or fixed behaviour
• If apply, add documentation to code properties and package readme

[codecov]

Codecov Report

Merging #1272 (3487bfb) into main (7541ae5) will decrease coverage by 0.05%.
The diff coverage is 42.10%.

@@            Coverage Diff             @@
##             main    #1272      +/-   ##
==========================================
- Coverage   84.98%   84.94%   -0.05%     
==========================================
  Files          20       21       +1     
  Lines         706      724      +18     
==========================================
+ Hits          600      615      +15     
- Misses        106      109       +3     

Impacted Files	Coverage Δ
lib/src/extensions/generic_validator.dart	0.00% <0.00%> (ø)
lib/src/fields/form_builder_dropdown.dart	83.33% <61.53%> (+5.55%)	⬆️

... and 1 file with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[danvick]

Hi @deandreamatias, please check the suggested changes.

[danvick]

Other than the highlighted error, I think the code is well done.

HOWEVER, there is still a loophole to this condition currentlyValues.contains(initialValue).
As I had indicated in point number 2 of my original comment, if the List contains objects of a class that doesn't override the equality operator (==), the condition will still return false.

Example:

main(){
  print([
    Continent(id: 1, name: 'Africa'), 
    Continent(id: 2, name: 'Asia'), 
    Continent(id: 3, name: 'Europe'),
  ].contains(Continent(id: 1, name: 'Africa'))); // PRINTS `true` because the Continent class is 'equatable'

  // WHILE

  print([
    Country(id: 2, name: 'India', continentId: 2),
    Country(id: 3, name: 'Spain', continentId: 3),
    Country(id: 3, name: 'France', continentId: 3),
  ].contains(Country(id: 2, name: 'India', continentId: 2))); // PRINTS `false` because the Country class is NOT 'equatable'

}
class Continent {
  final int id;
  final String name;

  Continent({required this.id, required this.name});

  @override
  operator ==(Object other){
    return other is Continent && other.id == id;
  }

  @override
  int get hashCode => id.hashCode;
}

class Country {
  final int id;
  final String name;
  final int continentId;

  Country({required this.id, required this.name, required this.continentId});
}

It is therefore up to the user to make sure that that's the case.

For example, in the example of the original issue that we're solving, if the Line class was "equatable", the issue wouldn't have occurred in the first place.

Since there's nothing more we could do about that, I applaud @deandreamatias's efforts to prevent the user of the library from shooting themselves in the foot. Good work!

You can resolve the reviews then go ahead and merge. Thanks.