Go Optional Function Argument Support #2442
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MrArnoldPalmer
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MrArnoldPalmer
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Go Sprint Jan 20 - Feb 10 2021,
Go Sprint Feb 11 - Feb 24 2020
MrArnoldPalmer
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Go Sprint Feb 11 - Mar 3 2020,
Go Sprint March 4 - Mar 17 2020
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Mar 18, 2021
Adds support for passing `nil` to jsii nullable types in generated go code. Changes go code generation to always use "pointer types" for all struct fields, method arguments, and method return values. Update runtime type conversion to correctly handle serializing and deserializing to these pointer types where necessary. Removes unnecessary functionality for resolving scoped interface names for generated go types as each generated type now has only one public name. Adds support for resolving `scopedReferenceName` to easily generate "pointer types" for complex data structures from a type reference. [RFC](aws/aws-cdk-rfcs#297) fix: #2442 fix: #2671 --- By submitting this pull request, I confirm that my contribution is made under the terms of the [Apache 2.0 license]. [Apache 2.0 license]: https://www.apache.org/licenses/LICENSE-2.0
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The Go runtime and code generation don't currently support TS functions with optional arguments. In JSII libraries currently, most methods that accept complex data structures use interfaces with optional properties. These are currently handled "correctly" implicitly because when these are "zero values" in go, they are serialized as undefined and therefore not passed over the wire.
A more explicit approach will likely have to be taken here. A couple of options that have been discussed previously.
Wrapper types. This would cause us to wrap all optional types in some wrapper type. This however has the huge downside of when a type goes from required to optional in TS, a breaking change would occur in the generated Go code. This is likely untenable.
Pointers everywhere. All types in all public APIs would be converted from
Tto*T. This would allow users to pass null pointers for optional values. This also has some huge downsides. The first being, users can also pass null pointers to non-optional types and the go compiler wouldn't complain, these would manifest as a runtime crash. Additionally, increased verbosity is an issue. In Go you cannot pass a pointer to a primitive type anonymously. iecallThing(&"MyString"). Instead the user would have to allocate a variable with"MyString"and specify a pointer to that. This however could be mitigated by creating wrapper types from "pointer to a thing".The text was updated successfully, but these errors were encountered: