systemfw / dynosaur Goto Github PK

We should be able to provide a cats.Defer instance - this would enable usage of Defer[Schema].fix, which would be convenient for recursion (no lazy val, a little harder to mess up).

Edit: of course I didn't check it all the way through, recursive is exactly like fix. Still think the instance might be helpful, though.

Also, Invariant[Schema].

It would be great to be able to better communicate why a deserialization has failed via an error message.

I have a use case with dynamo where in a large dataset, we sometimes modify the schema by adding an attribute to support a new feature, but our process for adding the attribute is eventual so over the course of 24 hours, the old records get updated. The field is nullable by design of the feature, but because our update is eventual, there is a period when I need the field to be optional and nullable.

The documentation here seems to indicate this is not possible. Can this be changed?

The installing page at https://systemfw.org/dynosaur/#/installing shows libraryDependencies += "org.systemfw" %% "dynosaur" % "0.2.0" but the source shows the corrected dynosaur-core (and would presumably also update to show the current 0.3.0 version).

Maybe we can find a way to fail on compilation if user provided non-exhaustive ADT legs

sealed trait Foo
case class A extends Foo
case class B extends Foo
case class C extends Foo

val schema : Schema[Foo] = Schema.oneOf[Foo]{alt =>
val schemaA : Schema[A] = ???
val schemaB : Schema[B] = ???

alt(schemaA) |+| alt(schemaB) // fail to compile here, because missing schemaC
}

I like the simplicity of the current error model (just a string is sometimes exactly what you want), but currently if a union fails to decode, you get virtually no information.

Combining the errors somehow would be great to have. Some ideas:

• Either -> EitherNel (probably the most intrusive change)
• ReadError as an ADT
• just combining the strings to a larger string in the decoding logic for alternatives

Hi,

I noticed when calling DynamoValue.toString the resulting JSON is missing the leading { resulting in invalid JSON

See this test case for an example: https://github.com/SystemFw/dynosaur/blame/main/modules/core/shared/src/test/scala/DynamoValueSuite.scala#L169