Fix $ref to allOf in properties

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

@@ -3861,8 +3861,29 @@ public CodegenProperty fromProperty(String name, Schema p, boolean required, boo
         }
 
         Schema original = null;
+        // process the dereference schema if it's a ref to allOf with a single item
+        // and certain field(s) (e.g. description, readyOnly, etc) is set
+        if (p.get$ref() != null) {
+            Schema derefSchema = ModelUtils.getReferencedSchema(openAPI, p);
+            if (ModelUtils.isAllOfWithSingleItem(derefSchema) && (
+                    derefSchema.getReadOnly() != null ||
+                            derefSchema.getWriteOnly() != null ||
+                            derefSchema.getDeprecated() != null ||
+                            derefSchema.getDescription() != null ||
+                            derefSchema.getMaxLength() != null ||
+                            derefSchema.getMinLength() != null ||
+                            derefSchema.getMinimum() != null ||
+                            derefSchema.getMaximum() != null ||
+                            derefSchema.getMaximum() != null ||
+                            derefSchema.getMinItems() != null ||
+                            derefSchema.getTitle() != null
+                    )) {
+                p = ModelUtils.getReferencedSchema(openAPI, p);
+            }
+        }
+
         // check if it's allOf (only 1 sub schema) with or without default/nullable/etc set in the top level
-        if (ModelUtils.isAllOf(p) && p.getAllOf().size() == 1) {
+        if (ModelUtils.isAllOfWithSingleItem(p)) {
             if (p.getAllOf().get(0) instanceof Schema) {
                 original = p;
                 p = (Schema) p.getAllOf().get(0);

modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java

@@ -2031,6 +2031,18 @@ public static boolean isAllOf(Schema schema) {
         return false;
     }
 
+
+    /**
+     * Returns true if the schema contains allOf with a single item but
+     * no properties/oneOf/anyOf defined
+     *
+     * @param schema the schema
+     * @return true if the schema contains allOf but no properties/oneOf/anyOf defined.
+     */
+    public static boolean isAllOfWithSingleItem(Schema schema) {
+        return (isAllOf(schema) && schema.getAllOf().size() == 1);
+    }
+
     /**
      * Returns true if the schema contains allOf and may or may not have
      * properties/oneOf/anyOf defined.

modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml

@@ -2610,6 +2610,10 @@ components:
       minItems: 1
       items:
         $ref: '#/components/schemas/Scalar'
+    AllOfRefToString:
+      allOf:
+        - $ref: '#/components/schemas/OuterString'
+      description: testing allOf with a ref to string
     NewPet:
       type: object
       required:
@@ -2620,6 +2624,12 @@ components:
           type: integer
           format: int64
           x-is-unique: true
+        category_ref_to_inline_allof_string:
+          $ref: '#/components/schemas/AllOfRefToString'
+        category_inline_allof_string:
+          allOf:
+            - $ref: '#/components/schemas/OuterString'
+          description: testing allOf with a ref to string
         category_inline_allof:
           allOf:
             - type: object

samples/client/petstore/java/okhttp-gson/api/openapi.yaml

@@ -2689,12 +2689,22 @@ components:
         $ref: '#/components/schemas/Scalar'
       minItems: 1
       type: array
+    AllOfRefToString:
+      allOf:
+      - $ref: '#/components/schemas/OuterString'
+      description: testing allOf with a ref to string
     NewPet:
       properties:
         id:
           format: int64
           type: integer
           x-is-unique: true
+        category_ref_to_inline_allof_string:
+          $ref: '#/components/schemas/AllOfRefToString'
+        category_inline_allof_string:
+          allOf:
+          - $ref: '#/components/schemas/OuterString'
+          description: testing allOf with a ref to string
         category_inline_allof:
           $ref: '#/components/schemas/NewPet_category_inline_allof'
         category_allOf_ref:

samples/client/petstore/java/okhttp-gson/docs/NewPet.md

@@ -8,6 +8,8 @@
 | Name | Type | Description | Notes |
 |------------ | ------------- | ------------- | -------------|
 |**id** | **Long** |  |  [optional] |
+|**categoryRefToInlineAllofString** | **String** | testing allOf with a ref to string |  [optional] |
+|**categoryInlineAllofString** | **String** | testing allOf with a ref to string |  [optional] |
 |**categoryInlineAllof** | [**NewPetCategoryInlineAllof**](NewPetCategoryInlineAllof.md) |  |  [optional] |
 |**categoryAllOfRef** | [**Category**](Category.md) |  |  [optional] |
 |**categoryAllOfRefDescription** | [**Category**](Category.md) | Adding description to property using allOf  |  [optional] |

samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/model/NewPet.java

@@ -60,6 +60,16 @@ public class NewPet {
   @javax.annotation.Nullable
   private Long id;
 
+  public static final String SERIALIZED_NAME_CATEGORY_REF_TO_INLINE_ALLOF_STRING = "category_ref_to_inline_allof_string";
+  @SerializedName(SERIALIZED_NAME_CATEGORY_REF_TO_INLINE_ALLOF_STRING)
+  @javax.annotation.Nullable
+  private String categoryRefToInlineAllofString;
+
+  public static final String SERIALIZED_NAME_CATEGORY_INLINE_ALLOF_STRING = "category_inline_allof_string";
+  @SerializedName(SERIALIZED_NAME_CATEGORY_INLINE_ALLOF_STRING)
+  @javax.annotation.Nullable
+  private String categoryInlineAllofString;
+
   public static final String SERIALIZED_NAME_CATEGORY_INLINE_ALLOF = "category_inline_allof";
   @SerializedName(SERIALIZED_NAME_CATEGORY_INLINE_ALLOF)
   @javax.annotation.Nullable
@@ -183,6 +193,44 @@ public void setId(@javax.annotation.Nullable Long id) {
   }
 
 
+  public NewPet categoryRefToInlineAllofString(@javax.annotation.Nullable String categoryRefToInlineAllofString) {
+    this.categoryRefToInlineAllofString = categoryRefToInlineAllofString;
+    return this;
+  }
+
+  /**
+   * testing allOf with a ref to string
+   * @return categoryRefToInlineAllofString
+   */
+  @javax.annotation.Nullable
+  public String getCategoryRefToInlineAllofString() {
+    return categoryRefToInlineAllofString;
+  }
+
+  public void setCategoryRefToInlineAllofString(@javax.annotation.Nullable String categoryRefToInlineAllofString) {
+    this.categoryRefToInlineAllofString = categoryRefToInlineAllofString;
+  }
+
+
+  public NewPet categoryInlineAllofString(@javax.annotation.Nullable String categoryInlineAllofString) {
+    this.categoryInlineAllofString = categoryInlineAllofString;
+    return this;
+  }
+
+  /**
+   * testing allOf with a ref to string
+   * @return categoryInlineAllofString
+   */
+  @javax.annotation.Nullable
+  public String getCategoryInlineAllofString() {
+    return categoryInlineAllofString;
+  }
+
+  public void setCategoryInlineAllofString(@javax.annotation.Nullable String categoryInlineAllofString) {
+    this.categoryInlineAllofString = categoryInlineAllofString;
+  }
+
+
   public NewPet categoryInlineAllof(@javax.annotation.Nullable NewPetCategoryInlineAllof categoryInlineAllof) {
     this.categoryInlineAllof = categoryInlineAllof;
     return this;
@@ -398,6 +446,8 @@ public boolean equals(Object o) {
     }
     NewPet newPet = (NewPet) o;
     return Objects.equals(this.id, newPet.id) &&
+        Objects.equals(this.categoryRefToInlineAllofString, newPet.categoryRefToInlineAllofString) &&
+        Objects.equals(this.categoryInlineAllofString, newPet.categoryInlineAllofString) &&
         Objects.equals(this.categoryInlineAllof, newPet.categoryInlineAllof) &&
         Objects.equals(this.categoryAllOfRef, newPet.categoryAllOfRef) &&
         Objects.equals(this.categoryAllOfRefDescription, newPet.categoryAllOfRefDescription) &&
@@ -411,14 +461,16 @@ public boolean equals(Object o) {
 
   @Override
   public int hashCode() {
-    return Objects.hash(id, categoryInlineAllof, categoryAllOfRef, categoryAllOfRefDescription, categoryAllOfRefDescriptionReadonly, name, photoUrls, tags, status, additionalProperties);
+    return Objects.hash(id, categoryRefToInlineAllofString, categoryInlineAllofString, categoryInlineAllof, categoryAllOfRef, categoryAllOfRefDescription, categoryAllOfRefDescriptionReadonly, name, photoUrls, tags, status, additionalProperties);
   }
 
   @Override
   public String toString() {
     StringBuilder sb = new StringBuilder();
     sb.append("class NewPet {\n");
     sb.append("    id: ").append(toIndentedString(id)).append("\n");
+    sb.append("    categoryRefToInlineAllofString: ").append(toIndentedString(categoryRefToInlineAllofString)).append("\n");
+    sb.append("    categoryInlineAllofString: ").append(toIndentedString(categoryInlineAllofString)).append("\n");
     sb.append("    categoryInlineAllof: ").append(toIndentedString(categoryInlineAllof)).append("\n");
     sb.append("    categoryAllOfRef: ").append(toIndentedString(categoryAllOfRef)).append("\n");
     sb.append("    categoryAllOfRefDescription: ").append(toIndentedString(categoryAllOfRefDescription)).append("\n");
@@ -451,6 +503,8 @@ private String toIndentedString(Object o) {
     // a set of all properties/fields (JSON key names)
     openapiFields = new HashSet<String>();
     openapiFields.add("id");
+    openapiFields.add("category_ref_to_inline_allof_string");
+    openapiFields.add("category_inline_allof_string");
     openapiFields.add("category_inline_allof");
     openapiFields.add("category_allOf_ref");
     openapiFields.add("category_allOf_ref_description");
@@ -486,6 +540,12 @@ public static void validateJsonElement(JsonElement jsonElement) throws IOExcepti
         }
       }
         JsonObject jsonObj = jsonElement.getAsJsonObject();
+      if ((jsonObj.get("category_ref_to_inline_allof_string") != null && !jsonObj.get("category_ref_to_inline_allof_string").isJsonNull()) && !jsonObj.get("category_ref_to_inline_allof_string").isJsonPrimitive()) {
+        throw new IllegalArgumentException(String.format("Expected the field `category_ref_to_inline_allof_string` to be a primitive type in the JSON string but got `%s`", jsonObj.get("category_ref_to_inline_allof_string").toString()));
+      }
+      if ((jsonObj.get("category_inline_allof_string") != null && !jsonObj.get("category_inline_allof_string").isJsonNull()) && !jsonObj.get("category_inline_allof_string").isJsonPrimitive()) {
+        throw new IllegalArgumentException(String.format("Expected the field `category_inline_allof_string` to be a primitive type in the JSON string but got `%s`", jsonObj.get("category_inline_allof_string").toString()));
+      }
       // validate the optional field `category_inline_allof`
       if (jsonObj.get("category_inline_allof") != null && !jsonObj.get("category_inline_allof").isJsonNull()) {
         NewPetCategoryInlineAllof.validateJsonElement(jsonObj.get("category_inline_allof"));