Implement a first version of try in PCL
#18454
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This was referenced Feb 5, 2025
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try in PCL
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This was referenced Feb 10, 2025
Frassle
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Feb 10, 2025
pkg/codegen/pcl/functions.go
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| "try": model.NewFunction(model.StaticFunctionSignature{ | ||
| Parameters: []model.Parameter{{ | ||
| Name: "values", | ||
| Type: model.NewListType(model.DynamicType), | ||
| }}, | ||
| ReturnType: model.NewOutputType(model.DynamicType), | ||
| }), |
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Can't we do better here? If all the args are the same type we know the output type. For mixed types it might be better to use a union output rather than dynamic?
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I think if you use GenericFunctionSignature you can even make the arg count variadic?
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but we don't know (at this time) all the call sites of try and we are only generating one instance (now). We can do better in the future but I think for v1 we should keep it simple and try to bring types back in special cases after that
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Discussed and it's now variadic, with a slightly better inferred type signature 👍
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[Terraform's `try` function](https://developer.hashicorp.com/terraform/language/functions/try) accepts a variable number of arguments (of variable types) and returns the first that does not throw an error when evaluated. This change takes a first pass at adding `try` to PCL, in an effort to support better conversion from Terraform to Pulumi programs. It makes the following contributions: * PCL gets a new `try` function, which is variadic like its Terraform equivalent. An expression of the form `try(e1, e2, ..., en)` will be typed as `(t1, t2, ..., tn) -> dynamic`, where `ti` is the type of `ei`. * Code generation for NodeJS and Python has been extended to support a naive first implementation of `try`. Both implementations rely on these languages being dynamic under the hood. A Go implementation is not currently provided and its omission is tracked by #18506. * A conformance test, `l1-builtin-try`, has been added to exercise the NodeJS and Python implementations. It is skipped in Go with a reference to the aforementioned tracking issue. When this has merged, we can look at extending `pulumi-converter-terraform` to generate applications of `try`, which should enable us to make progress converting a number of popular Terraform modules and programs. Part of #18350 Co-authored-by: Brandon Pollack <brandonpollack23@gmail.com>
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This was referenced Feb 11, 2025
Frassle
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Feb 11, 2025
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Terraform's
tryfunction accepts a variable number of arguments (of variable types) and returns the first that does not throw an error when evaluated. This change takes a first pass at addingtryto PCL, in an effort to support better conversion from Terraform to Pulumi programs. It makes the following contributions:PCL gets a new
tryfunction, which takes a single argument which is a list/tuple of expressions to be tried.Code generation for NodeJS and Python has been extended to support a naive first implementation of
try. Both implementations rely on these languages being dynamic under the hood. A Go implementation is not currently provided and its omission is tracked by Supporttryin Go program generation #18506.A conformance test,
l1-builtin-try, has been added to exercise the NodeJS and Python implementations. It is skipped in Go with a reference to the aforementioned tracking issue.When this has merged, we can look at extending
pulumi-converter-terraformto generate applications oftry, which should enable us to make progress converting a number of popular Terraform modules and programs.Part of #18350