allow unrecognized outputs and cell types in notebooks from the future

in nbformat schema / validation

IPython/nbformat/tests/test4plus.ipynb

@@ -306,6 +306,41 b''
     "from IPython.display import Image\n",
     "Image(\"http://ipython.org/_static/IPy_header.png\")"
    ]
+  },
+  {
+   "cell_type": "future cell",
+   "metadata": {},
+   "key": "value"
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 99,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "hello\n"
+     ]
+    },
+    {
+     "output_type": "future output",
+     "some key": [
+      "some data"
+     ]
+    },
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "hello again\n"
+     ]
+    }
+   ],
+   "source": [
+    "future_output()"
+   ]
   }
  ],
  "metadata": {},

IPython/nbformat/v4/nbformat.v4.schema.json

@@ -54,18 +54,19 b''
         "cells": {
             "description": "Array of cells of the current notebook.",
             "type": "array",
-            "items": {
-                "type": "object",
-                "oneOf": [
-                    {"$ref": "#/definitions/raw_cell"},
-                    {"$ref": "#/definitions/markdown_cell"},
-                    {"$ref": "#/definitions/code_cell"}
-                ]
-            }
+            "items": {"$ref": "#/definitions/cell"}
         }
     },
 
     "definitions": {
+        "cell": {
+            "type": "object",
+            "oneOf": [
+                {"$ref": "#/definitions/raw_cell"},
+                {"$ref": "#/definitions/markdown_cell"},
+                {"$ref": "#/definitions/code_cell"}
+            ]
+        },
 
         "raw_cell": {
             "description": "Notebook raw nbconvert cell.",
@@ -157,6 +158,31 b''
                 }
             }
         },
+        
+        "unrecognized_cell": {
+            "description": "Unrecognized cell from a future minor-revision to the notebook format.",
+            "type": "object",
+            "additionalProperties": true,
+            "required": ["cell_type", "metadata"],
+            "properties": {
+                "cell_type": {
+                    "description": "String identifying the type of cell.",
+                    "not" : {
+                      "enum": ["markdown", "code", "raw"]
+                    }
+                },
+                "metadata": {
+                    "description": "Cell-level metadata.",
+                    "type": "object",
+                    "properties": {
+                        "name": {"$ref": "#/definitions/misc/metadata_name"},
+                        "tags": {"$ref": "#/definitions/misc/metadata_tags"}
+                    },
+                    "additionalProperties": true
+                }
+            }
+        },
+        
         "output": {
             "type": "object",
             "oneOf": [
@@ -249,6 +275,21 b''
             }
         },
 
+        "unrecognized_output": {
+            "description": "Unrecognized output from a future minor-revision to the notebook format.",
+            "type": "object",
+            "additionalProperties": true,
+            "required": ["output_type"],
+            "properties": {
+                "output_type": {
+                    "description": "Type of cell output.",
+                    "not": {
+                        "enum": ["execute_result", "display_data", "stream", "error"]
+                    }
+                }
+            }
+        },
+
         "misc": {
             "metadata_name": {
                 "description": "The cell's name. If present, must be a non-empty string.",

IPython/nbformat/validator.py

@@ -30,7 +30,6 b' def _relax_additional_properties(obj):'
     if isinstance(obj, dict):
         for key, value in obj.items():
             if key == 'additionalProperties':
-                print(obj)
                 value = True
             else:
                 value = _relax_additional_properties(value)
@@ -40,6 +39,15 b' def _relax_additional_properties(obj):'
             obj[i] = _relax_additional_properties(value)
     return obj
 
+def _allow_undefined(schema):
+    schema['definitions']['cell']['oneOf'].append(
+        {"$ref": "#/definitions/unrecognized_cell"}
+    )
+    schema['definitions']['output']['oneOf'].append(
+        {"$ref": "#/definitions/unrecognized_output"}
+    )
+    return schema
+
 def get_validator(version=None, version_minor=None):
     """Load the JSON schema into a Validator"""
     if version is None:
@@ -66,6 +74,8 b' def get_validator(version=None, version_minor=None):'
         if current_minor < version_minor:
             # notebook from the future, relax all `additionalProperties: False` requirements
             schema_json = _relax_additional_properties(schema_json)
+            # and allow undefined cell types and outputs
+            schema_json = _allow_undefined(schema_json)
 
         validators[version_tuple] = Validator(schema_json)
     return validators[version_tuple]