Fixes invalid Kotlin client variable names for reserved words (#3993)

The Kotlin Multiplatform client introduced an bug that rendered variable
names that were also Kotlin reserved words incorrectly. This change reverts
the template to use the previous mechanism for rendering variable names.

#3992

Author: andrewemery

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

@@ -19,25 +19,17 @@
 
 import org.openapitools.codegen.CliOption;
 import org.openapitools.codegen.CodegenConstants;
-import org.openapitools.codegen.CodegenModel;
 import org.openapitools.codegen.CodegenOperation;
-import org.openapitools.codegen.CodegenProperty;
 import org.openapitools.codegen.CodegenType;
 import org.openapitools.codegen.SupportingFile;
 
 import java.io.File;
 import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
-import java.util.regex.Pattern;
 
 public class KotlinClientCodegen extends AbstractKotlinCodegen {
 
-    protected static final String VENDOR_EXTENSION_ESCAPED_NAME = "x-escapedName";
-
     protected static final String JVM = "jvm";
     protected static final String MULTIPLATFORM = "multiplatform";
 
@@ -47,14 +39,6 @@ public class KotlinClientCodegen extends AbstractKotlinCodegen {
     protected String dateLibrary = DateLibrary.JAVA8.value;
     protected String collectionType = CollectionType.ARRAY.value;
 
-    // https://kotlinlang.org/docs/reference/grammar.html#Identifier
-    protected static final Pattern IDENTIFIER_PATTERN =
-            Pattern.compile("[\\p{Ll}\\p{Lm}\\p{Lo}\\p{Lt}\\p{Lu}\\p{Nl}_][\\p{Ll}\\p{Lm}\\p{Lo}\\p{Lt}\\p{Lu}\\p{Nl}\\p{Nd}_]*");
-
-    // https://kotlinlang.org/docs/reference/grammar.html#Identifier
-    protected static final String IDENTIFIER_REPLACEMENTS =
-            "[.;:/\\[\\]<>]";
-
     public enum DateLibrary {
         STRING("string"),
         THREETENBP("threetenbp"),
@@ -212,7 +196,6 @@ public void processOpts() {
             supportingFiles.add(new SupportingFile("infrastructure/HttpResponse.kt.mustache", infrastructureFolder, "HttpResponse.kt"));
 
             // multiplatform specific testing files
-            final String testFolder = (sourceFolder + File.separator + packageName + File.separator + "infrastructure").replace(".", "/");
             supportingFiles.add(new SupportingFile("commonTest/coroutine.mustache", "src/commonTest/kotlin/util", "Coroutine.kt"));
             supportingFiles.add(new SupportingFile("iosTest/coroutine.mustache", "src/iosTest/kotlin/util", "Coroutine.kt"));
             supportingFiles.add(new SupportingFile("jvmTest/coroutine.mustache", "src/jvmTest/kotlin/util", "Coroutine.kt"));
@@ -253,58 +236,6 @@ public void processOpts() {
         }
     }
 
-    @Override
-    public Map<String, Object> postProcessModels(Map<String, Object> objs) {
-        objs = super.postProcessModels(objs);
-        return postProcessModelsEscapeNames(objs);
-    }
-
-    @SuppressWarnings("unchecked")
-    private static Map<String, Object> postProcessModelsEscapeNames(Map<String, Object> objs) {
-        List<Object> models = (List<Object>) objs.get("models");
-        for (Object _mo : models) {
-            Map<String, Object> mo = (Map<String, Object>) _mo;
-            CodegenModel cm = (CodegenModel) mo.get("model");
-
-            if (cm.vars != null) {
-                for (CodegenProperty var : cm.vars) {
-                    var.vendorExtensions.put(VENDOR_EXTENSION_ESCAPED_NAME, escapeIdentifier(var.name));
-                }
-            }
-            if (cm.requiredVars != null) {
-                for (CodegenProperty var : cm.requiredVars) {
-                    var.vendorExtensions.put(VENDOR_EXTENSION_ESCAPED_NAME, escapeIdentifier(var.name));
-                }
-            }
-            if (cm.optionalVars != null) {
-                for (CodegenProperty var : cm.optionalVars) {
-                    var.vendorExtensions.put(VENDOR_EXTENSION_ESCAPED_NAME, escapeIdentifier(var.name));
-                }
-            }
-        }
-        return objs;
-    }
-
-    private static String escapeIdentifier(String identifier) {
-
-        // the kotlin grammar permits a wider set of characters in their identifiers that all target
-        // platforms permit (namely jvm). in order to remain compatible with target platforms, we
-        // initially replace all illegal target characters before escaping the identifier if required.
-        identifier = identifier.replaceAll(IDENTIFIER_REPLACEMENTS, "_");
-        if (IDENTIFIER_PATTERN.matcher(identifier).matches()) return identifier;
-        return '`' + identifier + '`';
-    }
-
-    private static void removeDuplicates(List<CodegenProperty> list) {
-        Set<String> set = new HashSet<>();
-        Iterator<CodegenProperty> iterator = list.iterator();
-        while (iterator.hasNext()) {
-            CodegenProperty item = iterator.next();
-            if (set.contains(item.name)) iterator.remove();
-            else set.add(item.name);
-        }
-    }
-
     @Override
     @SuppressWarnings("unchecked")
     public Map<String, Object> postProcessOperationsWithModels(Map<String, Object> objs, List<Object> allModels) {

modules/openapi-generator/src/main/resources/kotlin-client/data_class.mustache

@@ -18,7 +18,7 @@ import kotlinx.serialization.internal.CommonEnumSerializer
 /**
  * {{{description}}}
 {{#vars}}
- * @param {{{vendorExtensions.x-escapedName}}} {{{description}}}
+ * @param {{{name}}} {{{description}}}
 {{/vars}}
  */
 {{#parcelizeModels}}

modules/openapi-generator/src/main/resources/kotlin-client/data_class_opt_var.mustache

@@ -9,4 +9,4 @@
     @SerializedName("{{name}}")
     {{/gson}}
     {{/jvm}}
-    {{#multiplatform}}@SerialName(value = "{{name}}") {{/multiplatform}}val {{{vendorExtensions.x-escapedName}}}: {{#isEnum}}{{#isListContainer}}{{#isList}}kotlin.collections.List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{classname}}.{{{nameInCamelCase}}}>{{/isListContainer}}{{^isListContainer}}{{classname}}.{{{nameInCamelCase}}}{{/isListContainer}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{/isEnum}}? = {{#defaultvalue}}{{defaultvalue}}{{/defaultvalue}}{{^defaultvalue}}null{{/defaultvalue}}
+    {{#multiplatform}}@SerialName(value = "{{baseName}}") {{/multiplatform}}val {{{name}}}: {{#isEnum}}{{#isListContainer}}{{#isList}}kotlin.collections.List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{classname}}.{{{nameInCamelCase}}}>{{/isListContainer}}{{^isListContainer}}{{classname}}.{{{nameInCamelCase}}}{{/isListContainer}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{/isEnum}}? = {{#defaultvalue}}{{defaultvalue}}{{/defaultvalue}}{{^defaultvalue}}null{{/defaultvalue}}

modules/openapi-generator/src/main/resources/kotlin-client/data_class_req_var.mustache

@@ -9,4 +9,4 @@
     @SerializedName("{{name}}")
     {{/gson}}
     {{/jvm}}
-    {{#multiplatform}}@SerialName(value = "{{name}}") @Required {{/multiplatform}}val {{{vendorExtensions.x-escapedName}}}: {{#isEnum}}{{#isListContainer}}{{#isList}}kotlin.collections.List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{classname}}.{{{nameInCamelCase}}}>{{/isListContainer}}{{^isListContainer}}{{classname}}.{{{nameInCamelCase}}}{{/isListContainer}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{/isEnum}}
+    {{#multiplatform}}@SerialName(value = "{{baseName}}") @Required {{/multiplatform}}val {{{name}}}: {{#isEnum}}{{#isListContainer}}{{#isList}}kotlin.collections.List{{/isList}}{{^isList}}kotlin.Array{{/isList}}<{{classname}}.{{{nameInCamelCase}}}>{{/isListContainer}}{{^isListContainer}}{{classname}}.{{{nameInCamelCase}}}{{/isListContainer}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{/isEnum}}