[scala-http4s] Preserve underscores in enum names (#23842)

* fix(scala-http4s): preserve underscores in enum names

* Fix scala-http4s enum underscore formatting

Author: anupamchaubey

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaHttp4sClientCodegen.java

@@ -624,11 +624,24 @@ public String toDefaultValue(Schema p) {
         }
     }
 
+    @Override
+    public String toEnumVarName(String value, String datatype) {
+        String sanitized = sanitizeName(value);
+
+        // Preserve SCREAMING_SNAKE_CASE values
+        if (sanitized.matches("^[A-Z][A-Z0-9_]*$")
+                && !isReservedWord(sanitized)) {
+            return sanitized;
+        }
+
+        return super.formatIdentifier(sanitized, true);
+
+    }
 
     private class EnumEntryLambda extends CustomLambda {
         @Override
         public String formatFragment(String fragment) {
-            return formatIdentifier(fragment, true);
+            return toEnumVarName(fragment, "string");
         }
     }
 

modules/openapi-generator/src/test/java/org/openapitools/codegen/scala/ScalaHttp4sClientCodegenTest.java

@@ -144,6 +144,42 @@ public void convertVarNameCamelCase() {
         assertEquals(codegen.toVarName("1AAaa"), "`1aAaa`");
     }
 
+    @Test
+    public void preserveScreamingSnakeCaseEnumNames() {
+        ScalaHttp4sClientCodegen codegen = new ScalaHttp4sClientCodegen();
+
+        assertEquals(
+                codegen.toEnumVarName("ACTIVE_STATUS", "string"),
+                "ACTIVE_STATUS"
+        );
+
+        assertEquals(
+                codegen.toEnumVarName("INACTIVE_STATUS", "string"),
+                "INACTIVE_STATUS"
+        );
+
+        assertEquals(
+                codegen.toEnumVarName("USER_123_STATUS", "string"),
+                "USER_123_STATUS"
+        );
+    }
+
+    @Test
+    public void formatRegularEnumNames() {
+        ScalaHttp4sClientCodegen codegen = new ScalaHttp4sClientCodegen();
+
+        assertEquals(
+                codegen.toEnumVarName("available", "string"),
+                "Available"
+        );
+
+        assertEquals(
+                codegen.toEnumVarName("pending_status", "string"),
+                "PendingStatus"
+        );
+
+    }
+
     @Test
     public void encodePath() {
         ScalaHttp4sClientCodegen codegen = new ScalaHttp4sClientCodegen();