Add a way to unset an input property

codegen/lib/graphql_java_gen/templates/APISchema.java.erb

@@ -286,6 +286,7 @@ public class <%= schema_name %> {
                       this.<%= escape_reserved_word(field.camelize_name) %> = <%= escape_reserved_word(field.camelize_name) %>;
                       return this;
                   }
+
                 <% end %>
                 <% type.optional_input_fields.each do |field| %>
                   <%= java_annotations(field) %>
@@ -298,6 +299,14 @@ public class <%= schema_name %> {
                       this.<%= field.camelize_name %>Seen = true;
                       return this;
                   }
+
+                  // Unsets the <%= escape_reserved_word(field.camelize_name) %> property so that it is not serialized.
+                  public <%= type.name %> unset<%= field.classify_name %>() {
+                      this.<%= escape_reserved_word(field.camelize_name) %> = null;
+                      this.<%= field.camelize_name %>Seen = false;
+                      return this;
+                  }
+
                 <% end %>
 
                 public void appendTo(StringBuilder _queryBuilder) {

support/src/test/java/com/shopify/graphql/support/Generated.java

@@ -1120,6 +1120,13 @@ public SetIntegerInput setTtl(@Nullable LocalDateTime ttl) {
             return this;
         }
 
+        // Unsets the ttl property so that it is not serialized.
+        public SetIntegerInput unsetTtl() {
+            this.ttl = null;
+            this.ttlSeen = false;
+            return this;
+        }
+
         @Nullable
         public Boolean getNegate() {
             return negate;
@@ -1131,6 +1138,13 @@ public SetIntegerInput setNegate(@Nullable Boolean negate) {
             return this;
         }
 
+        // Unsets the negate property so that it is not serialized.
+        public SetIntegerInput unsetNegate() {
+            this.negate = null;
+            this.negateSeen = false;
+            return this;
+        }
+
         @Nullable
         public String getApiClient() {
             return apiClient;
@@ -1142,6 +1156,13 @@ public SetIntegerInput setApiClient(@Nullable String apiClient) {
             return this;
         }
 
+        // Unsets the apiClient property so that it is not serialized.
+        public SetIntegerInput unsetApiClient() {
+            this.apiClient = null;
+            this.apiClientSeen = false;
+            return this;
+        }
+
         public void appendTo(StringBuilder _queryBuilder) {
             String separator = "";
             _queryBuilder.append('{');

support/src/test/java/com/shopify/graphql/support/IntegrationTest.java

@@ -164,4 +164,12 @@ public void testOptionalFieldOnInput() throws Exception {
         ).toString();
         assertEquals("mutation{set_integer(input:{key:\"answer\",value:42,ttl:null})}", queryString);
     }
+
+    @Test
+    public void testUnsetOptionalFieldOnInput() throws Exception {
+        String queryString = Generated.mutation(mutation -> mutation
+            .setInteger(new Generated.SetIntegerInput("answer", 42).setTtl(null).unsetTtl())
+        ).toString();
+        assertEquals("mutation{set_integer(input:{key:\"answer\",value:42})}", queryString);
+    }
 }