terraform/configs/version_constraint.go

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package configs
import (
"fmt"
version "github.com/hashicorp/go-version"
"github.com/hashicorp/hcl2/hcl"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/convert"
)
// VersionConstraint represents a version constraint on some resource
// (e.g. Terraform Core, a provider, a module, ...) that carries with it
// a source range so that a helpful diagnostic can be printed in the event
// that a particular constraint does not match.
type VersionConstraint struct {
Required version.Constraints
DeclRange hcl.Range
}
func decodeVersionConstraint(attr *hcl.Attribute) (VersionConstraint, hcl.Diagnostics) {
ret := VersionConstraint{
DeclRange: attr.Range,
}
val, diags := attr.Expr.Value(nil)
if diags.HasErrors() {
return ret, diags
}
var err error
val, err = convert.Convert(val, cty.String)
if err != nil {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid version constraint",
Detail: fmt.Sprintf("A string value is required for %s.", attr.Name),
Subject: attr.Expr.Range().Ptr(),
})
return ret, diags
}
if val.IsNull() {
// A null version constraint is strange, but we'll just treat it
// like an empty constraint set.
return ret, diags
}
if !val.IsWhollyKnown() {
// If there is a syntax error, HCL sets the value of the given attribute
// to cty.DynamicVal. A diagnostic for the syntax error will already
// bubble up, so we will move forward gracefully here.
return ret, diags
}
constraintStr := val.AsString()
constraints, err := version.NewConstraint(constraintStr)
if err != nil {
// NewConstraint doesn't return user-friendly errors, so we'll just
// ignore the provided error and produce our own generic one.
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid version constraint",
Detail: "This string does not use correct version constraint syntax.", // Not very actionable :(
Subject: attr.Expr.Range().Ptr(),
})
return ret, diags
}
ret.Required = constraints
return ret, diags
}