$isDirty not using correct equality semantics on DateTime values

[juni0r]

Two DateTime values that represent the same time in different time zones aren't considered equal by BaseModel.$isDirty. It uses === to compare DateTime values which is not the proper semantics since both equals() as well as strict equality === for the respective valueOf() two DateTimes would be true:

const d1 = DateTime.fromISO("2000-01-01T12:00:00+02:00")
const d2 = DateTime.fromISO("2000-01-01T10:00:00Z")

d1 === d2  // => false :-o
d1.equals(d2) // => true
d1.valueOf() === d2.valueOf() // => true

https://github.com/adonisjs/lucid/blob/98644992cbd55cd1fdaa4b1fcf40d38540440083/src/Orm/BaseModel/index.ts#L1244-L1253

[thetutlage]

Nice catch. We should be using value.equals(originalValue) here. Can you please send a PR for the same?

[juni0r]

Upon closer inspection I realized that DateTime's concept of equality is … well … eccentric

Two DateTimes are equal iff they represent the same millisecond, have the same zone and location, and are both valid. To compare just the millisecond values, use +dt1 === +dt2.

I don't want to argue with this, but in my view a date represents a moment in time which is the same, no matter if you're in India, Germany or on the Moon. I just think you should be aware since there might be other parts of the codebase where this becomes an issue.

In terms of an ORM I believe it's the most sensible choice to consider two dates equal if their timestamp is equal, hence valueOf() which is precisely what fast-deep-equal uses. So that would boil down to this:

-      if (DateTime.isDateTime(value) || DateTime.isDateTime(originalValue)) {
-        isEqual = value === originalValue
-      } else if (isObject(value) && 'isDirty' in value) {
+      if (isObject(value) && 'isDirty' in value) {
         isEqual = !value.isDirty
       } else {
         isEqual = equal(originalValue, value)

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