diff --git a/src/main/java/com/qdesrame/openapi/diff/compare/SchemaDiff.java b/src/main/java/com/qdesrame/openapi/diff/compare/SchemaDiff.java
index 9d8b774da..8642c91f6 100644
--- a/src/main/java/com/qdesrame/openapi/diff/compare/SchemaDiff.java
+++ b/src/main/java/com/qdesrame/openapi/diff/compare/SchemaDiff.java
@@ -10,10 +10,19 @@
 import com.qdesrame.openapi.diff.utils.RefPointer;
 import com.qdesrame.openapi.diff.utils.RefType;
 import io.swagger.v3.oas.models.Components;
+import io.swagger.v3.oas.models.ExternalDocumentation;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.ComposedSchema;
+import io.swagger.v3.oas.models.media.Discriminator;
 import io.swagger.v3.oas.models.media.Schema;
-import java.util.*;
+import io.swagger.v3.oas.models.media.XML;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
 
 public class SchemaDiff extends ReferenceDiffCache<Schema, ChangedSchema> {
 
@@ -87,10 +96,9 @@ protected static Schema resolveComposedSchema(Components components, Schema sche
   protected static Schema addSchema(Schema<?> schema, Schema<?> fromSchema) {
     if (fromSchema.getProperties() != null) {
       if (schema.getProperties() == null) {
-        schema.setProperties(fromSchema.getProperties());
-      } else {
-        schema.getProperties().putAll(fromSchema.getProperties());
+        schema.setProperties(new LinkedHashMap<>());
       }
+      schema.getProperties().putAll(fromSchema.getProperties());
     }
 
     if (fromSchema.getRequired() != null) {
@@ -100,7 +108,165 @@ protected static Schema addSchema(Schema<?> schema, Schema<?> fromSchema) {
         schema.getRequired().addAll(fromSchema.getRequired());
       }
     }
-    // TODO copy other things from fromSchema
+
+    if (fromSchema.getReadOnly() != null) {
+      schema.setReadOnly(fromSchema.getReadOnly());
+    }
+    if (fromSchema.getWriteOnly() != null) {
+      schema.setWriteOnly(fromSchema.getWriteOnly());
+    }
+    if (fromSchema.getDeprecated() != null) {
+      schema.setDeprecated(fromSchema.getDeprecated());
+    }
+    if (fromSchema.getExclusiveMaximum() != null) {
+      schema.setExclusiveMaximum(fromSchema.getExclusiveMaximum());
+    }
+    if (fromSchema.getExclusiveMinimum() != null) {
+      schema.setExclusiveMinimum(fromSchema.getExclusiveMinimum());
+    }
+    if (fromSchema.getNullable() != null) {
+      schema.setNullable(fromSchema.getNullable());
+    }
+    if (fromSchema.getUniqueItems() != null) {
+      schema.setUniqueItems(fromSchema.getUniqueItems());
+    }
+    if (fromSchema.getDescription() != null) {
+      schema.setDescription(fromSchema.getDescription());
+    }
+    if (fromSchema.getFormat() != null) {
+      schema.setFormat(fromSchema.getFormat());
+    }
+    if (fromSchema.getType() != null) {
+      schema.setType(fromSchema.getType());
+    }
+    if (fromSchema.getEnum() != null) {
+      if (schema.getEnum() == null) {
+        schema.setEnum(new ArrayList<>());
+      }
+      //noinspection unchecked
+      schema.getEnum().addAll((List) fromSchema.getEnum());
+    }
+    if (fromSchema.getExtensions() != null) {
+      if (schema.getExtensions() == null) {
+        schema.setExtensions(new LinkedHashMap<>());
+      }
+      schema.getExtensions().putAll(fromSchema.getExtensions());
+    }
+    if (fromSchema.getDiscriminator() != null) {
+      if (schema.getDiscriminator() == null) {
+        schema.setDiscriminator(new Discriminator());
+      }
+      final Discriminator discriminator = schema.getDiscriminator();
+      final Discriminator fromDiscriminator = fromSchema.getDiscriminator();
+      if (fromDiscriminator.getPropertyName() != null) {
+        discriminator.setPropertyName(fromDiscriminator.getPropertyName());
+      }
+      if (fromDiscriminator.getMapping() != null) {
+        if (discriminator.getMapping() == null) {
+          discriminator.setMapping(new LinkedHashMap<>());
+        }
+        discriminator.getMapping().putAll(fromDiscriminator.getMapping());
+      }
+    }
+    if (fromSchema.getTitle() != null) {
+      schema.setTitle(fromSchema.getTitle());
+    }
+    if (fromSchema.getName() != null) {
+      schema.setName(fromSchema.getName());
+    }
+    if (fromSchema.getAdditionalProperties() != null) {
+      schema.setAdditionalProperties(fromSchema.getAdditionalProperties());
+    }
+    if (fromSchema.getDefault() != null) {
+      schema.setDefault(fromSchema.getDefault());
+    }
+    if (fromSchema.getExample() != null) {
+      schema.setExample(fromSchema.getExample());
+    }
+    if (fromSchema.getExternalDocs() != null) {
+      if (schema.getExternalDocs() == null) {
+        schema.setExternalDocs(new ExternalDocumentation());
+      }
+      final ExternalDocumentation externalDocs = schema.getExternalDocs();
+      final ExternalDocumentation fromExternalDocs = fromSchema.getExternalDocs();
+      if (fromExternalDocs.getDescription() != null) {
+        externalDocs.setDescription(fromExternalDocs.getDescription());
+      }
+      if (fromExternalDocs.getExtensions() != null) {
+        if (externalDocs.getExtensions() == null) {
+          externalDocs.setExtensions(new LinkedHashMap<>());
+        }
+        externalDocs.getExtensions().putAll(fromExternalDocs.getExtensions());
+      }
+      if (fromExternalDocs.getUrl() != null) {
+        externalDocs.setUrl(fromExternalDocs.getUrl());
+      }
+    }
+    if (fromSchema.getMaximum() != null) {
+      schema.setMaximum(fromSchema.getMaximum());
+    }
+    if (fromSchema.getMinimum() != null) {
+      schema.setMinimum(fromSchema.getMinimum());
+    }
+    if (fromSchema.getMaxItems() != null) {
+      schema.setMaxItems(fromSchema.getMaxItems());
+    }
+    if (fromSchema.getMinItems() != null) {
+      schema.setMinItems(fromSchema.getMinItems());
+    }
+    if (fromSchema.getMaxProperties() != null) {
+      schema.setMaxProperties(fromSchema.getMaxProperties());
+    }
+    if (fromSchema.getMinProperties() != null) {
+      schema.setMinProperties(fromSchema.getMinProperties());
+    }
+    if (fromSchema.getMaxLength() != null) {
+      schema.setMaxLength(fromSchema.getMaxLength());
+    }
+    if (fromSchema.getMinLength() != null) {
+      schema.setMinLength(fromSchema.getMinLength());
+    }
+    if (fromSchema.getMultipleOf() != null) {
+      schema.setMultipleOf(fromSchema.getMultipleOf());
+    }
+    if (fromSchema.getNot() != null) {
+      if (schema.getNot() == null) {
+        schema.setNot(addSchema(new Schema(), fromSchema.getNot()));
+      } else {
+        addSchema(schema.getNot(), fromSchema.getNot());
+      }
+    }
+    if (fromSchema.getPattern() != null) {
+      schema.setPattern(fromSchema.getPattern());
+    }
+    if (fromSchema.getXml() != null) {
+      if (schema.getXml() == null) {
+        schema.setXml(new XML());
+      }
+      final XML xml = schema.getXml();
+      final XML fromXml = fromSchema.getXml();
+      if (fromXml.getAttribute() != null) {
+        xml.setAttribute(fromXml.getAttribute());
+      }
+      if (fromXml.getName() != null) {
+        xml.setName(fromXml.getName());
+      }
+      if (fromXml.getNamespace() != null) {
+        xml.setNamespace(fromXml.getNamespace());
+      }
+      if (fromXml.getExtensions() != null) {
+        if (xml.getExtensions() == null) {
+          xml.setExtensions(new LinkedHashMap<>());
+        }
+        xml.getExtensions().putAll(fromXml.getExtensions());
+      }
+      if (fromXml.getPrefix() != null) {
+        xml.setPrefix(fromXml.getPrefix());
+      }
+      if (fromXml.getWrapped() != null) {
+        xml.setWrapped(fromXml.getWrapped());
+      }
+    }
     return schema;
   }
 
diff --git a/src/test/java/com/qdesrame/openapi/test/AllOfDiffTest.java b/src/test/java/com/qdesrame/openapi/test/AllOfDiffTest.java
index b72e60dd2..5255f34d3 100644
--- a/src/test/java/com/qdesrame/openapi/test/AllOfDiffTest.java
+++ b/src/test/java/com/qdesrame/openapi/test/AllOfDiffTest.java
@@ -11,6 +11,7 @@ public class AllOfDiffTest {
   private final String OPENAPI_DOC1 = "allOf_diff_1.yaml";
   private final String OPENAPI_DOC2 = "allOf_diff_2.yaml";
   private final String OPENAPI_DOC3 = "allOf_diff_3.yaml";
+  private final String OPENAPI_DOC4 = "allOf_diff_4.yaml";
 
   @Test
   public void testDiffSame() {
@@ -23,7 +24,12 @@ public void testDiffSameWithAllOf() {
   }
 
   @Test
-  public void testDiffDifferent() {
+  public void testDiffDifferent1() {
     assertOpenApiChangedEndpoints(OPENAPI_DOC1, OPENAPI_DOC3);
   }
+
+  @Test
+  public void testDiffDifferent2() {
+    assertOpenApiChangedEndpoints(OPENAPI_DOC1, OPENAPI_DOC4);
+  }
 }
diff --git a/src/test/resources/allOf_diff_1.yaml b/src/test/resources/allOf_diff_1.yaml
index 522657e0e..2d1cc4060 100644
--- a/src/test/resources/allOf_diff_1.yaml
+++ b/src/test/resources/allOf_diff_1.yaml
@@ -108,7 +108,9 @@ components:
       - pet_type
       properties:
         pet_type:
-          type: string
+          nullable: false
+          allOf:
+          - type: string
     Cat:
       description: Cat class
       allOf:
diff --git a/src/test/resources/allOf_diff_2.yaml b/src/test/resources/allOf_diff_2.yaml
index a0d4cc933..fef87ee57 100644
--- a/src/test/resources/allOf_diff_2.yaml
+++ b/src/test/resources/allOf_diff_2.yaml
@@ -101,6 +101,7 @@ components:
       - pet_type
       properties:
         pet_type:
+          nullable: false
           type: string
     Cat:
       description: Cat class
diff --git a/src/test/resources/allOf_diff_3.yaml b/src/test/resources/allOf_diff_3.yaml
index da0ddc304..c5fd84803 100644
--- a/src/test/resources/allOf_diff_3.yaml
+++ b/src/test/resources/allOf_diff_3.yaml
@@ -105,7 +105,9 @@ components:
       - pet_type
       properties:
         pet_type:
-          type: string
+          nullable: false
+          allOf:
+          - type: string
     Cat:
       description: Cat class
       allOf:
diff --git a/src/test/resources/allOf_diff_4.yaml b/src/test/resources/allOf_diff_4.yaml
new file mode 100644
index 000000000..38fcbb1e8
--- /dev/null
+++ b/src/test/resources/allOf_diff_4.yaml
@@ -0,0 +1,129 @@
+openapi: 3.0.0
+servers:
+  - url: 'http://petstore.swagger.io/v2'
+info:
+  description: >-
+    This is a sample server Petstore server.  You can find out more about
+    Swagger at [http://swagger.io](http://swagger.io) or on [irc.freenode.net,
+    #swagger](http://swagger.io/irc/).  For this sample, you can use the api key
+    `special-key` to test the authorization filters.
+  version: 1.0.0
+  title: Swagger Petstore
+  termsOfService: 'http://swagger.io/terms/'
+  contact:
+    email: apiteam@swagger.io
+  license:
+    name: Apache 2.0
+    url: 'http://www.apache.org/licenses/LICENSE-2.0.html'
+tags:
+  - name: pet
+    description: Everything about your Pets
+    externalDocs:
+      description: Find out more
+      url: 'http://swagger.io'
+  - name: store
+    description: Access to Petstore orders
+  - name: user
+    description: Operations about user
+    externalDocs:
+      description: Find out more about our store
+      url: 'http://swagger.io'
+paths:
+  /pet/findByStatus:
+    get:
+      tags:
+        - pet
+      summary: Finds Pets by status
+      description: Multiple status values can be provided with comma separated strings
+      operationId: findPetsByStatus
+      parameters:
+        - name: status
+          in: query
+          description: Status values that need to be considered for filter
+          required: true
+          explode: true
+          schema:
+            type: array
+            items:
+              type: string
+              enum:
+                - available
+                - pending
+                - sold
+              default: available
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  pets:
+                    type: array
+                    items:
+                      $ref: '#/components/schemas/Cat'
+        '400':
+          description: Invalid status value
+      security:
+        - petstore_auth:
+            - 'write:pets'
+            - 'read:pets'
+externalDocs:
+  description: Find out more about Swagger
+  url: 'http://swagger.io'
+components:
+  requestBodies:
+    Pet:
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Pet'
+      description: Pet object that needs to be added to the store
+      required: true
+  securitySchemes:
+    petstore_auth:
+      type: oauth2
+      flows:
+        implicit:
+          authorizationUrl: 'http://petstore.swagger.io/oauth/dialog'
+          scopes:
+            'write:pets': modify pets in your account
+            'read:pets': read your pets
+    api_key:
+      type: apiKey
+      name: api_key
+      in: header
+  schemas:
+    BasePet:
+      type: object
+      properties:
+        pet_color:
+          type: string
+    Pet:
+      allOf:
+        - $ref: '#/components/schemas/BasePet'
+      type: object
+      required:
+        - pet_type
+      properties:
+        pet_type:
+          nullable: false
+          allOf:
+            - type: number
+    Cat:
+      description: Cat class
+      allOf:
+        - $ref: '#/components/schemas/Pet'
+      type: object
+      properties:
+        name:
+          type: string
+    Dog:
+      description: Dog class
+      allOf:
+        - $ref: '#/components/schemas/Pet'
+      type: object
+      properties:
+        bark:
+          type: string