wrap JSON strings as jsonencode calls on generate-config-out (#1595)

Signed-off-by: ollevche <ollevche@gmail.com>
Signed-off-by: Oleksandr Levchenkov  <ollevche@gmail.com>

CHANGELOG.md

@@ -6,6 +6,7 @@ NEW FEATURES:
 
 ENHANCEMENTS:
 * Added `tofu test -json` types to website Machine-Readable UI documentation ([1408](https://github.com/opentofu/opentofu/issues/1408))
+* Made `tofu plan` with `generate-config-out` flag replace JSON strings with `jsonencode` functions calls. ([#1595](https://github.com/opentofu/opentofu/pull/1595))
 
 BUG FIXES:
 * Fixed crash in gcs backend when using certain commands ([#1618](https://github.com/opentofu/opentofu/pull/1618))

internal/genconfig/generate_config.go

@@ -6,6 +6,7 @@
 package genconfig
 
 import (
+	"errors"
 	"fmt"
 	"sort"
 	"strings"
@@ -13,6 +14,7 @@ import (
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/hclwrite"
 	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/json"
 
 	"github.com/opentofu/opentofu/internal/addrs"
 	"github.com/opentofu/opentofu/internal/configs/configschema"
@@ -160,7 +162,7 @@ func writeConfigAttributesFromExisting(addr addrs.AbsResourceInstance, buf *stri
 			if attrS.Sensitive || val.IsMarked() {
 				buf.WriteString("null # sensitive")
 			} else {
-				tok := hclwrite.TokensForValue(val)
+				tok := tryWrapAsJsonEncodeFunctionCall(val)
 				if _, err := tok.WriteTo(buf); err != nil {
 					diags = diags.Append(&hcl.Diagnostic{
 						Severity: hcl.DiagWarning,
@@ -592,3 +594,40 @@ func omitUnknowns(val cty.Value) cty.Value {
 		panic(fmt.Sprintf("omitUnknowns cannot handle %#v", val))
 	}
 }
+
+func tryWrapAsJsonEncodeFunctionCall(v cty.Value) hclwrite.Tokens {
+	tokens, err := wrapAsJSONEncodeFunctionCall(v)
+	if err != nil {
+		return hclwrite.TokensForValue(v)
+	}
+	return tokens
+}
+
+func wrapAsJSONEncodeFunctionCall(v cty.Value) (hclwrite.Tokens, error) {
+	if v.IsNull() || v.Type() != cty.String || !v.IsKnown() {
+		return nil, errors.New("value cannot be treated as JSON string")
+	}
+
+	s := []byte(strings.TrimSpace(v.AsString()))
+	if len(s) == 0 {
+		return nil, errors.New("empty value")
+	}
+
+	if s[0] != '{' && s[0] != '[' {
+		return nil, errors.New("value is not a JSON object, nor a JSON array")
+	}
+
+	t, err := json.ImpliedType(s)
+	if err != nil {
+		return nil, fmt.Errorf("cannot define implied cty type (possibly not a JSON string): %w", err)
+	}
+
+	v, err = json.Unmarshal(s, t)
+	if err != nil {
+		return nil, fmt.Errorf("cannot unmarshal using implied type (possible not a JSON string): %w", err)
+	}
+
+	tokens := hclwrite.TokensForFunctionCall("jsonencode", hclwrite.TokensForValue(v))
+
+	return tokens, nil
+}

internal/genconfig/generate_config_test.go

@@ -423,6 +423,73 @@ resource "tfcoremock_simple_resource" "empty" {
   list   = null
   map    = null
   single = null
+}`,
+		},
+		"jsonencode_wrapping": {
+			schema: &configschema.Block{
+				Attributes: map[string]*configschema.Attribute{
+					"juststr": {
+						Type:     cty.String,
+						Optional: true,
+					},
+					"jsonobj": {
+						Type:     cty.String,
+						Optional: true,
+					},
+					"jsonarr": {
+						Type:     cty.String,
+						Optional: true,
+					},
+					"sensitivejsonobj": {
+						Type:      cty.String,
+						Optional:  true,
+						Sensitive: true,
+					},
+					"secrets": {
+						Type: cty.Object(map[string]cty.Type{
+							"main":      cty.String,
+							"secondary": cty.String,
+						}),
+						Optional:  true,
+						Sensitive: true,
+					},
+				},
+			},
+			addr: addrs.AbsResourceInstance{
+				Module: nil,
+				Resource: addrs.ResourceInstance{
+					Resource: addrs.Resource{
+						Mode: addrs.ManagedResourceMode,
+						Type: "tfcoremock_simple_resource",
+						Name: "example",
+					},
+					Key: nil,
+				},
+			},
+			provider: addrs.LocalProviderConfig{
+				LocalName: "tfcoremock",
+			},
+			value: cty.ObjectVal(map[string]cty.Value{
+				"juststr":          cty.StringVal("{a=b}"),
+				"jsonobj":          cty.StringVal(`{"SomeDate":"2012-10-17"}`),
+				"jsonarr":          cty.StringVal(`[{"a": 1}]`),
+				"sensitivejsonobj": cty.StringVal(`{"SomePassword":"dontstealplease"}`),
+				"secrets": cty.ObjectVal(map[string]cty.Value{
+					"main":      cty.StringVal(`{"v":"mypass"}`),
+					"secondary": cty.StringVal(`{"v":"mybackup"}`),
+				}),
+			}),
+			expected: `
+resource "tfcoremock_simple_resource" "example" {
+  jsonarr = jsonencode([{
+    a = 1
+  }])
+  jsonobj = jsonencode({
+    SomeDate = "2012-10-17"
+  })
+  juststr          = "{a=b}"
+  secrets          = null # sensitive
+  sensitivejsonobj = null # sensitive
 }`,
 		},
 	}