[BUG][C++] Avoid using plain underscore when escaping reserved words (#5269)

* Don't use plain underscore when escaping reserved words

* Regenerate petstore output

* Add CLI option for reserved word prefix

* Ensure CLI option isn't cleared in cpprest client codegen

* Regenerate docs

docs/generators/cpp-qt5-client.md

@@ -12,6 +12,7 @@ sidebar_label: cpp-qt5-client
 |modelNamePrefix|Prefix that will be prepended to all model names.| |OAI|
 |optionalProjectFile|Generate client.pri.| |true|
 |prependFormOrBodyParameters|Add form or body parameters to the beginning of the parameter list.| |false|
+|reservedWordPrefix|Prefix to prepend to reserved words in order to avoid conflicts| |r_|
 |sortModelPropertiesByRequiredFlag|Sort model properties to place required parameters before optional parameters.| |true|
 |sortParamsByRequiredFlag|Sort method arguments to place required parameters before optional parameters.| |true|
 

docs/generators/cpp-qt5-qhttpengine-server.md

@@ -11,6 +11,7 @@ sidebar_label: cpp-qt5-qhttpengine-server
 |ensureUniqueParams|Whether to ensure parameter names are unique in an operation (rename parameters that are not).| |true|
 |modelNamePrefix|Prefix that will be prepended to all model names.| |OAI|
 |prependFormOrBodyParameters|Add form or body parameters to the beginning of the parameter list.| |false|
+|reservedWordPrefix|Prefix to prepend to reserved words in order to avoid conflicts| |r_|
 |sortModelPropertiesByRequiredFlag|Sort model properties to place required parameters before optional parameters.| |true|
 |sortParamsByRequiredFlag|Sort method arguments to place required parameters before optional parameters.| |true|
 

docs/generators/cpp-restsdk.md

@@ -11,6 +11,7 @@ sidebar_label: cpp-restsdk
 |generateGMocksForApis|Generate Google Mock classes for APIs.| |null|
 |modelPackage|C++ namespace for models (convention: name.space.model).| |org.openapitools.client.model|
 |packageVersion|C++ package version.| |1.0.0|
+|reservedWordPrefix|Prefix to prepend to reserved words in order to avoid conflicts| |r_|
 
 ## IMPORT MAPPING
 

docs/generators/cpp-tizen.md

@@ -8,6 +8,7 @@ sidebar_label: cpp-tizen
 |allowUnicodeIdentifiers|boolean, toggles whether unicode identifiers are allowed in names or not, default is false| |false|
 |ensureUniqueParams|Whether to ensure parameter names are unique in an operation (rename parameters that are not).| |true|
 |prependFormOrBodyParameters|Add form or body parameters to the beginning of the parameter list.| |false|
+|reservedWordPrefix|Prefix to prepend to reserved words in order to avoid conflicts| |r_|
 |sortModelPropertiesByRequiredFlag|Sort model properties to place required parameters before optional parameters.| |true|
 |sortParamsByRequiredFlag|Sort method arguments to place required parameters before optional parameters.| |true|
 

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

@@ -39,6 +39,10 @@ import java.util.Map;
 abstract public class AbstractCppCodegen extends DefaultCodegen implements CodegenConfig {
     private static final Logger LOGGER = LoggerFactory.getLogger(AbstractCppCodegen.class);
 
+    protected static final String RESERVED_WORD_PREFIX_OPTION = "reservedWordPrefix";
+    protected static final String RESERVED_WORD_PREFIX_DESC = "Prefix to prepend to reserved words in order to avoid conflicts";
+    protected String reservedWordPrefix = "r_";
+
     public AbstractCppCodegen() {
         super();
 
@@ -135,6 +139,10 @@ abstract public class AbstractCppCodegen extends DefaultCodegen implements Codeg
                         "xor",
                         "xor_eq")
         );
+
+        addOption(RESERVED_WORD_PREFIX_OPTION,
+                RESERVED_WORD_PREFIX_DESC,
+                this.reservedWordPrefix);
     }
 
     @Override
@@ -200,7 +208,7 @@ abstract public class AbstractCppCodegen extends DefaultCodegen implements Codeg
         if (this.reservedWordsMappings().containsKey(name)) {
             return this.reservedWordsMappings().get(name);
         }
-        return sanitizeName("_" + name);
+        return sanitizeName(reservedWordPrefix + name);
     }
 
     @Override
@@ -259,6 +267,12 @@ abstract public class AbstractCppCodegen extends DefaultCodegen implements Codeg
             LOGGER.info("Environment variable CPP_POST_PROCESS_FILE not defined so the C++ code may not be properly formatted. To define it, try 'export CPP_POST_PROCESS_FILE=\"/usr/local/bin/clang-format -i\"' (Linux/Mac)");
             LOGGER.info("NOTE: To enable file post-processing, 'enablePostProcessFile' must be set to `true` (--enable-post-process-file for CLI).");
         }
+
+        if (additionalProperties.containsKey(RESERVED_WORD_PREFIX_OPTION)) {
+            reservedWordPrefix = (String) additionalProperties.get(RESERVED_WORD_PREFIX_OPTION);
+        }
+
+        additionalProperties.put(RESERVED_WORD_PREFIX_OPTION, reservedWordPrefix);
     }
 
     @Override

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

@@ -129,6 +129,9 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
         addOption(GENERATE_GMOCKS_FOR_APIS,
                 "Generate Google Mock classes for APIs.",
                 null);
+        addOption(RESERVED_WORD_PREFIX_OPTION,
+                RESERVED_WORD_PREFIX_DESC,
+                this.reservedWordPrefix);
 
         supportingFiles.add(new SupportingFile("modelbase-header.mustache", "", "ModelBase.h"));
         supportingFiles.add(new SupportingFile("modelbase-source.mustache", "", "ModelBase.cpp"));
@@ -194,6 +197,10 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
             defaultInclude = additionalProperties.get(DEFAULT_INCLUDE).toString();
         }
 
+        if (additionalProperties.containsKey(RESERVED_WORD_PREFIX_OPTION)) {
+            reservedWordPrefix = (String) additionalProperties.get(RESERVED_WORD_PREFIX_OPTION);
+        }
+
         if (convertPropertyToBoolean(GENERATE_GMOCKS_FOR_APIS)) {
             apiTemplateFiles.put("api-gmock.mustache", "GMock.h");
             additionalProperties.put("gmockApis", "true");
@@ -207,6 +214,7 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
         additionalProperties.put("apiHeaderGuardPrefix", apiPackage.replaceAll("\\.", "_").toUpperCase(Locale.ROOT));
         additionalProperties.put("declspec", declspec);
         additionalProperties.put("defaultInclude", defaultInclude);
+        additionalProperties.put(RESERVED_WORD_PREFIX_OPTION, reservedWordPrefix);
     }
 
     /**