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263821ac25
cty's new "refinements" concept allows us to reduce the range of unknown values from our functions. This initial changeset focuses only on declaring which functions are guaranteed to return a non-null result, which is a helpful baseline refinement because it allows "== null" and "!= null" tests to produce known results even when the given value is otherwise unknown. This commit also includes some updates to test results that are now refined based on cty's own built-in refinement behaviors, just as a result of us having updated cty in the previous commit.
63 lines
2 KiB
Go
63 lines
2 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: BUSL-1.1
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package function
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import (
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"errors"
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"github.com/zclconf/go-cty/cty"
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"github.com/zclconf/go-cty/cty/function"
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"github.com/zclconf/go-cty/cty/function/stdlib"
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)
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var LengthFunc = function.New(&function.Spec{
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Params: []function.Parameter{
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{
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Name: "value",
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Type: cty.DynamicPseudoType,
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AllowDynamicType: true,
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AllowUnknown: true,
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},
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},
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Type: func(args []cty.Value) (cty.Type, error) {
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collTy := args[0].Type()
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switch {
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case collTy == cty.String || collTy.IsTupleType() || collTy.IsObjectType() || collTy.IsListType() || collTy.IsMapType() || collTy.IsSetType() || collTy == cty.DynamicPseudoType:
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return cty.Number, nil
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default:
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return cty.Number, errors.New("argument must be a string, a collection type, or a structural type")
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}
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},
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RefineResult: refineNotNull,
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Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
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coll := args[0]
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collTy := args[0].Type()
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switch {
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case collTy == cty.DynamicPseudoType:
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return cty.UnknownVal(cty.Number), nil
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case collTy.IsTupleType():
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l := len(collTy.TupleElementTypes())
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return cty.NumberIntVal(int64(l)), nil
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case collTy.IsObjectType():
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l := len(collTy.AttributeTypes())
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return cty.NumberIntVal(int64(l)), nil
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case collTy == cty.String:
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// We'll delegate to the cty stdlib strlen function here, because
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// it deals with all of the complexities of tokenizing unicode
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// grapheme clusters.
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return stdlib.Strlen(coll)
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case collTy.IsListType() || collTy.IsSetType() || collTy.IsMapType():
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return coll.Length(), nil
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default:
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// Should never happen, because of the checks in our Type func above
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return cty.UnknownVal(cty.Number), errors.New("impossible value type for length(...)")
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}
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},
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})
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// Length returns the number of elements in the given collection or number of
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// Unicode characters in the given string.
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func Length(collection cty.Value) (cty.Value, error) {
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return LengthFunc.Call([]cty.Value{collection})
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}
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