From 8eae9cacdf7d34123d2895e022621406908d2e60 Mon Sep 17 00:00:00 2001
From: Ihar Hrachyshka <ihrachyshka@nvidia.com>
Date: Mon, 22 Sep 2025 22:26:18 -0400
Subject: [PATCH] go: Fix missing imports for optional body params.

Previous mustache template was using #isBodyParam outside of #operation
context, so it was not effective.

Even if we'd add the proper context, we'd then risk generating duplicate
imports for multiple matching parameters.

For this reason, this patch implements detection of an optional body
parameter in code, making sure the corresponding import is added just
once.

Fixes #19237
---
 .../java/org/openapitools/codegen/CodegenOperation.java  | 9 +++++++++
 .../openapitools/codegen/languages/GoServerCodegen.java  | 5 +++++
 .../src/main/resources/go-server/controller-api.mustache | 6 ++----
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenOperation.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenOperation.java
index d204fe4246af..9dca0e0e048e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenOperation.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenOperation.java
@@ -115,6 +115,15 @@ public boolean getHasBodyParam() {
         return nonEmpty(bodyParams);
     }
 
+    /**
+     * Check if there's at least one optional body parameter
+     *
+     * @return true if optional body parameter exists, false otherwise
+     */
+    public boolean getHasOptionalBodyParam() {
+        return nonEmpty(bodyParams) && nonEmpty(optionalParams) && bodyParams.stream().anyMatch(optionalParams::contains);
+    }
+
     /**
      * Check if there's at least one query parameter
      *
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoServerCodegen.java
index 54b0292fc309..fbec59327245 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoServerCodegen.java
@@ -410,6 +410,7 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
     private void addConditionalImportInformation(OperationsMap operations) {
         boolean hasPathParams = false;
         boolean hasBodyParams = false;
+        boolean hasOptionalBodyParams = false;
 
         for (CodegenOperation op : operations.getOperations().getOperation()) {
             if (op.getHasPathParams()) {
@@ -418,10 +419,14 @@ private void addConditionalImportInformation(OperationsMap operations) {
             if (op.getHasBodyParam()) {
                 hasBodyParams = true;
             }
+            if (op.getHasOptionalBodyParam()) {
+                hasOptionalBodyParams = true;
+            }
         }
 
         additionalProperties.put("hasPathParams", hasPathParams);
         additionalProperties.put("hasBodyParams", hasBodyParams);
+        additionalProperties.put("hasOptionalBodyParams", hasOptionalBodyParams);
     }
 
 
diff --git a/modules/openapi-generator/src/main/resources/go-server/controller-api.mustache b/modules/openapi-generator/src/main/resources/go-server/controller-api.mustache
index 309405baab60..b390633971a7 100644
--- a/modules/openapi-generator/src/main/resources/go-server/controller-api.mustache
+++ b/modules/openapi-generator/src/main/resources/go-server/controller-api.mustache
@@ -6,12 +6,10 @@ import (
 	{{#hasBodyParams}}
 	"encoding/json"
 	{{/hasBodyParams}}
-	{{#isBodyParam}}
-	    {{^required}}
+	{{#hasOptionalBodyParams}}
 	"errors"
 	"io"
-	    {{/required}}
-	{{/isBodyParam}}
+	{{/hasOptionalBodyParams}}
 	"net/http"
 	"strings"
 {{#imports}}	"{{import}}"