From bd9d579589226f9c119cc8fc13ffd6d8cedb78ee Mon Sep 17 00:00:00 2001
From: Igor Tsiglyar <igor_tsiglyar@outlook.com>
Date: Wed, 15 Mar 2023 07:34:46 +0300
Subject: [PATCH] use_allof_for_refs: extend to example field (#3240)

---
 .../internal/genopenapi/template.go             | 11 +++++++----
 .../internal/genopenapi/template_test.go        | 17 +++++++++++++++++
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/protoc-gen-openapiv2/internal/genopenapi/template.go b/protoc-gen-openapiv2/internal/genopenapi/template.go
index 3a3f539561a..09a3be23560 100644
--- a/protoc-gen-openapiv2/internal/genopenapi/template.go
+++ b/protoc-gen-openapiv2/internal/genopenapi/template.go
@@ -522,13 +522,16 @@ func renderMessageAsDefinition(msg *descriptor.Message, reg *descriptor.Registry
 			if fieldSchema.Ref != "" {
 				// Per the JSON Reference syntax: Any members other than "$ref" in a JSON Reference object SHALL be ignored.
 				// https://tools.ietf.org/html/draft-pbryan-zyp-json-ref-03#section-3
-				// However, use allOf to specify Title/Description/readOnly fields.
-				if fieldSchema.Title != "" || fieldSchema.Description != "" || fieldSchema.ReadOnly {
+				// However, use allOf to specify Title/Description/Example/readOnly fields.
+				if fieldSchema.Title != "" || fieldSchema.Description != "" || len(fieldSchema.Example) > 0 || fieldSchema.ReadOnly {
 					fieldSchema = openapiSchemaObject{
 						Title:       fieldSchema.Title,
 						Description: fieldSchema.Description,
-						ReadOnly:    fieldSchema.ReadOnly,
-						AllOf:       []allOfEntry{{Ref: fieldSchema.Ref}},
+						schemaCore: schemaCore{
+							Example: fieldSchema.Example,
+						},
+						ReadOnly: fieldSchema.ReadOnly,
+						AllOf:    []allOfEntry{{Ref: fieldSchema.Ref}},
 					}
 				} else {
 					fieldSchema = openapiSchemaObject{schemaCore: schemaCore{Ref: fieldSchema.Ref}}
diff --git a/protoc-gen-openapiv2/internal/genopenapi/template_test.go b/protoc-gen-openapiv2/internal/genopenapi/template_test.go
index 165f7d305c1..1427236b47b 100644
--- a/protoc-gen-openapiv2/internal/genopenapi/template_test.go
+++ b/protoc-gen-openapiv2/internal/genopenapi/template_test.go
@@ -5372,6 +5372,18 @@ func TestRenderMessagesAsDefinition(t *testing.T) {
 					},
 				},
 			},
+			openAPIOptions: &openapiconfig.OpenAPIOptions{
+				Field: []*openapiconfig.OpenAPIFieldOption{
+					{
+						Field: "example.Message.nested",
+						Option: &openapi_options.JSONSchema{
+							Title:       "nested field title",
+							Description: "nested field desc",
+							Example:     `"ok":"TRUE"`,
+						},
+					},
+				},
+			},
 			defs: map[string]openapiSchemaObject{
 				"exampleMessage": {
 					schemaCore: schemaCore{
@@ -5386,6 +5398,11 @@ func TestRenderMessagesAsDefinition(t *testing.T) {
 							Value: openapiSchemaObject{
 								AllOf:    []allOfEntry{{Ref: "#/definitions/MessageNested"}},
 								ReadOnly: true,
+								schemaCore: schemaCore{
+									Example: RawExample(`"ok":"TRUE"`),
+								},
+								Title:       "nested field title",
+								Description: "nested field desc",
 							},
 						},
 					},