Fix #9083 #14577: Parse JsonSchema for type in OpenAPI 3.1

Created by: GuillaumeSmaha

Since swagger-core 2.2.0 for OpenAPI 3.1, a set of type can be used instead of an unique type: https://github.com/swagger-api/swagger-core/blob/v2.2.8/modules/swagger-models/src/main/java/io/swagger/v3/oas/models/media/Schema.java#L107-L111

In the case of an array, the schema is not an ArraySchema but an JsonSchema with a set of types defined to [array]. Example of usage of JsonSchema if OpenAPI is 3.1: https://github.com/swagger-api/swagger-parser/blob/v2.1.8/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/util/ResolverFully.java#L383-L390

See https://github.com/OpenAPITools/openapi-generator/issues/14577#issuecomment-1418778197 for example of the JsonSchema in getPrimitiveType(Schema).

To solve that, ModelUtils.isArraySchema(schema) is now returning true if the schema is an instance of ArraySchema or JsonSchema with only one type and this type need to be equal to array.

The function getSchemaItems(schema) is moved to ModelUtils.getArrayItems(schema) to be used in ModelUtils and it is now used everywhere to get items in a schema whatever the type of the schema (ArraySchema or JsonSchema)

Add test testOpenAPI310ResponsesJsonSchemaIsArray to validate JsonSchema is correctly translate to an array

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modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/ExampleGenerator.java

@@ -19,7 +19,6 @@ package org.openapitools.codegen.examples;
 
 import io.swagger.v3.core.util.Json;
 import io.swagger.v3.oas.models.OpenAPI;
-import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.Schema;
 import org.apache.commons.lang3.StringUtils;
 import org.openapitools.codegen.utils.ModelUtils;
@@ -79,10 +78,9 @@ public class ExampleGenerator {
         }
 
         if (ModelUtils.isArraySchema(responseSchema)) { // array of schema
-            ArraySchema as = (ArraySchema) responseSchema;
-            if (as.getItems() != null) { // array of primitive types
+            if (ModelUtils.getArrayItems(responseSchema) != null) { // array of primitive types
                 return generate((Map<String, Object>) responseSchema.getExample(),
-                        new ArrayList<>(producesInfo), as);
+                        new ArrayList<>(producesInfo), responseSchema);
             } else {
                 // TODO log warning message as such case is not handled at the moment
                 return null;
@@ -229,9 +227,9 @@ public class ExampleGenerator {
             }
             return Boolean.TRUE;
         } else if (ModelUtils.isArraySchema(property)) {
-            Schema innerType = ((ArraySchema) property).getItems();
+            Schema innerType = ModelUtils.getArrayItems(property);
             if (innerType != null) {
-                int arrayLength = null == ((ArraySchema) property).getMaxItems() ? 2 : ((ArraySchema) property).getMaxItems();
+                int arrayLength = null == property.getMaxItems() ? 2 : property.getMaxItems();
                 // avoid memory issues by limiting to max. 5 items
                 arrayLength = Math.min(arrayLength, 5);
                 Object[] objectProperties = new Object[arrayLength];

modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/XmlExampleGenerator.java

@@ -17,7 +17,6 @@
 
 package org.openapitools.codegen.examples;
 
-import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.oas.models.media.XML;
 import org.apache.commons.lang3.StringUtils;
@@ -128,8 +127,7 @@ public class XmlExampleGenerator {
         StringBuilder sb = new StringBuilder();
 
         if (ModelUtils.isArraySchema(schema)) {
-            ArraySchema as = (ArraySchema) schema;
-            Schema inner = as.getItems();
+            Schema inner = ModelUtils.getArrayItems(schema);
             boolean wrapped = false;
             if (schema.getXml() != null && schema.getXml().getWrapped() != null && schema.getXml().getWrapped()) {
                 wrapped = true;

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

@@ -451,8 +451,7 @@ abstract public class AbstractAdaCodegen extends DefaultCodegen implements Codeg
         }
 
         if (ModelUtils.isArraySchema(p)) {
-            ArraySchema ap = (ArraySchema) p;
-            Schema inner = ap.getItems();
+            Schema inner = ModelUtils.getArrayItems(p);
             return getTypeDeclaration(inner) + "_Vectors.Vector";
         }
         if (ModelUtils.isMapSchema(p)) {

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

@@ -188,10 +188,9 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
     @Override
     public String getTypeDeclaration(Schema p) {
         if (ModelUtils.isArraySchema(p)) {
-            ArraySchema ap = (ArraySchema) p;
-            Schema inner = ap.getItems();
+            Schema inner = ModelUtils.getArrayItems(p);
             if (inner == null) {
-                LOGGER.warn("{}(array property) does not have a proper inner type defined", ap.getName());
+                LOGGER.warn("{}(array property) does not have a proper inner type defined", p.getName());
                 // TODO maybe better defaulting to StringProperty than returning null
                 return null;
             }
@@ -318,7 +317,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
 
         if (ModelUtils.isArraySchema(p)) {
             example = "new " + getTypeDeclaration(p) + "{" + toExampleValue(
-                    ((ArraySchema) p).getItems()) + "}";
+                    ModelUtils.getArrayItems(p)) + "}";
         } else if (ModelUtils.isBooleanSchema(p)) {
             example = String.valueOf(!"false".equals(example));
         } else if (ModelUtils.isByteArraySchema(p)) {

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

@@ -493,7 +493,7 @@ public abstract class AbstractDartCodegen extends DefaultCodegen {
         Schema<?> schema = unaliasSchema(p);
         Schema<?> target = ModelUtils.isGenerateAliasAsModel() ? p : schema;
         if (ModelUtils.isArraySchema(target)) {
-            Schema<?> items = getSchemaItems((ArraySchema) schema);
+            Schema<?> items = ModelUtils.getArrayItems(schema);
             return getSchemaType(target) + "<" + getTypeDeclaration(items) + ">";
         }
         if (ModelUtils.isMapSchema(target)) {
@@ -558,7 +558,7 @@ public abstract class AbstractDartCodegen extends DefaultCodegen {
 
         // Handle composed properties
         if (ModelUtils.isComposedSchema(p)) {
-            ComposedSchema composed = (ComposedSchema) p;
+            Schema<?> composed = p;
 
             // Count the occurrences of allOf/anyOf/oneOf with exactly one child element
             long count = Stream.of(composed.getAllOf(), composed.getAnyOf(), composed.getOneOf())