From 8c41a1e036052cabd87c06a1c27c125b653bb70b Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Thu, 21 Dec 2023 13:40:10 -0500
Subject: [PATCH] MarshalProviderFunctions

---
 internal/command/jsonfunction/function.go  | 38 ++++++++++++++++++++++
 internal/command/jsonfunction/parameter.go | 18 ++++++++++
 2 files changed, 56 insertions(+)

diff --git a/internal/command/jsonfunction/function.go b/internal/command/jsonfunction/function.go
index 31ceddb546..22c9522838 100644
--- a/internal/command/jsonfunction/function.go
+++ b/internal/command/jsonfunction/function.go
@@ -7,6 +7,7 @@ import (
 	"encoding/json"
 	"fmt"
 
+	"github.com/hashicorp/terraform/internal/providers"
 	"github.com/hashicorp/terraform/internal/tfdiags"
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/function"
@@ -50,6 +51,24 @@ func newFunctions() *functions {
 	}
 }
 
+func MarshalProviderFunctions(f map[string]providers.FunctionDecl) ([]byte, error) {
+	if len(f) == 0 {
+		return nil, nil
+	}
+
+	signatures := newFunctions()
+
+	for name, v := range f {
+		signatures.Signatures[name] = marshalProviderFunction(v)
+	}
+
+	ret, err := json.Marshal(signatures)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to serialize provider functions: %w", err)
+	}
+	return ret, nil
+}
+
 func Marshal(f map[string]function.Function) ([]byte, tfdiags.Diagnostics) {
 	var diags tfdiags.Diagnostics
 	signatures := newFunctions()
@@ -113,6 +132,25 @@ func marshalFunction(f function.Function) (*FunctionSignature, error) {
 	}, nil
 }
 
+func marshalProviderFunction(f providers.FunctionDecl) *FunctionSignature {
+	var vp *parameter
+	if f.VariadicParameter != nil {
+		vp = marshalProviderParameter(*f.VariadicParameter)
+	}
+
+	var p []*parameter
+	if len(f.Parameters) > 0 {
+		p = marshalProviderParameters(f.Parameters)
+	}
+
+	return &FunctionSignature{
+		Description:       f.Description,
+		ReturnType:        f.ReturnType,
+		Parameters:        p,
+		VariadicParameter: vp,
+	}
+}
+
 // marshalTry returns a static function signature for the try function.
 // We need this exception because the function implementation uses capsule
 // types that we can't marshal.
diff --git a/internal/command/jsonfunction/parameter.go b/internal/command/jsonfunction/parameter.go
index 0037460dc2..147f20a4e0 100644
--- a/internal/command/jsonfunction/parameter.go
+++ b/internal/command/jsonfunction/parameter.go
@@ -4,6 +4,7 @@
 package jsonfunction
 
 import (
+	"github.com/hashicorp/terraform/internal/providers"
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/function"
 )
@@ -44,3 +45,20 @@ func marshalParameters(parameters []function.Parameter) []*parameter {
 	}
 	return ret
 }
+
+func marshalProviderParameter(p providers.FunctionParam) *parameter {
+	return &parameter{
+		Name:        p.Name,
+		Description: p.Description,
+		IsNullable:  p.AllowNullValue,
+		Type:        p.Type,
+	}
+}
+
+func marshalProviderParameters(parameters []providers.FunctionParam) []*parameter {
+	ret := make([]*parameter, len(parameters))
+	for k, p := range parameters {
+		ret[k] = marshalProviderParameter(p)
+	}
+	return ret
+}