Repository: mozilla-services/react-jsonschema-form (js)

Issue:
Release 1.6.0 editor crashes when dependencies are used
### Prerequisites

- [x] I have read the [documentation](https://react-jsonschema-form.readthedocs.io/);
- [x] In the case of a bug report, I understand that providing a [SSCCE](http://sscce.org/) example is tremendously useful to the maintainers.
- [x] Ideally, I'm providing a [sample JSFiddle](https://jsfiddle.net/n1k0/f2y3fq7L/6/) or a [shared playground link](https://mozilla-services.github.io/react-jsonschema-form/) demonstrating the issue.

### Description

With the latest release 1.6.0 we now see an issue for all fields where we use dependencies. The issue causes the editor to not render at all. In our own build we see the console.log stating that the dependency-based fields are not defined.

Everything works in 1.5.0 - but we're eager to shift to 1.6.0 to enable default values in anyOf dependencies, as listed in issue #1293 

### Steps to Reproduce
For us, all fields that have dependencies now cause the editor to break - incl. the playground sample shared above (you can verify this by copying the Schema into a new playground and observe that it does not render):
[example (worked in 1.5.0, but not 1.6.0)
](https://mozilla-services.github.io/react-jsonschema-form/#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)

In contrast, the same example will still render if I completely remove the "dependencies" tab - but of course that's probably not the intention. I assume some issue has arisen during the implementation of a fix for default values.
[same example after removing dependencies (works in 1.5.0 and 1.6.0)](https://mozilla-services.github.io/react-jsonschema-form/#eyJmb3JtRGF0YSI6eyJydGMiOnsic3luYyI6MH19LCJzY2hlbWEiOnsidHlwZSI6Im9iamVjdCIsInByb3BlcnRpZXMiOnsicnRjIjp7InRpdGxlIjoiQ29uZmlndXJlIENsb2NrIiwidHlwZSI6Im9iamVjdCIsInByb3BlcnRpZXMiOnsic3luYyI6eyJ0aXRsZSI6IlRpbWUgU3luYyBUeXBlIiwidHlwZSI6ImludGVnZXIiLCJkZWZhdWx0IjowLCJhbnlPZiI6W3sidGl0bGUiOiJSZXRhaW4gdGltZSIsInR5cGUiOiJpbnRlZ2VyIiwiZW51bSI6WzBdfSx7InRpdGxlIjoiQXV0byB0aW1lIiwidHlwZSI6ImludGVnZXIiLCJlbnVtIjpbMV19XX19fX19LCJ1aVNjaGVtYSI6e319)

Martin

Pull request description:
fix: populate defaults for nested dependencies when formData is undefined
### Reasons for making this change

Fixes #1311. It looks like the problem is that formData is not defaulted to `{}` when populating defaults for dependencies, so then when formData is undefined / null, it crashes.

### Checklist

* [ ] **I'm updating documentation**
  - [ ] I've [checked the rendering](https://react-jsonschema-form.readthedocs.io/en/latest/#contributing) of the Markdown text I've added
* [x] **I'm adding or updating code**
  - [x] I've added and/or updated tests
  - [ ] I've updated [docs](https://react-jsonschema-form.readthedocs.io/) if needed
  - [ ] I've run `npm run cs-format` on my branch to conform my code to [prettier](https://github.com/prettier/prettier) coding style
* [ ] **I'm adding a new feature**
  - [ ] I've updated the playground with an example use of the feature


Patch:
diff --git a/src/utils.js b/src/utils.js
index 82fa1bbe0..5eef006af 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -144,7 +144,13 @@ export function hasWidget(schema, widget, registeredWidgets = {}) {
   }
 }
 
-function computeDefaults(schema, parentDefaults, definitions, formData) {
+function computeDefaults(
+  schema,
+  parentDefaults,
+  definitions,
+  rawFormData = {}
+) {
+  const formData = isObject(rawFormData) ? rawFormData : {};
   // Compute the defaults recursively: give highest priority to deepest nodes.
   let defaults = parentDefaults;
   if (isObject(defaults) && isObject(schema.default)) {


Test patch:
diff --git a/test/utils_test.js b/test/utils_test.js
index 73960dfb2..7a6eeac36 100644
--- a/test/utils_test.js
+++ b/test/utils_test.js
@@ -614,6 +614,96 @@ describe("utils", () => {
           },
         });
       });
+
+      it("should populate defaults for nested dependencies when formData passed to computeDefaults is undefined", () => {
+        const schema = {
+          type: "object",
+          properties: {
+            can_1: {
+              type: "object",
+              properties: {
+                phy: {
+                  title: "Physical",
+                  description: "XYZ",
+                  type: "object",
+                  properties: {
+                    bit_rate_cfg_mode: {
+                      title: "Sub title",
+                      description: "XYZ",
+                      type: "integer",
+                      default: 0,
+                    },
+                  },
+                  dependencies: {
+                    bit_rate_cfg_mode: {
+                      oneOf: [
+                        {
+                          properties: {
+                            bit_rate_cfg_mode: {
+                              enum: [0],
+                            },
+                          },
+                        },
+                      ],
+                    },
+                  },
+                },
+              },
+            },
+          },
+        };
+        expect(getDefaultFormState(schema, undefined)).eql({
+          can_1: {
+            phy: {
+              bit_rate_cfg_mode: 0,
+            },
+          },
+        });
+      });
+
+      it("should not crash for defaults for nested dependencies when formData passed to computeDefaults is null", () => {
+        const schema = {
+          type: "object",
+          properties: {
+            can_1: {
+              type: "object",
+              properties: {
+                phy: {
+                  title: "Physical",
+                  description: "XYZ",
+                  type: "object",
+                  properties: {
+                    bit_rate_cfg_mode: {
+                      title: "Sub title",
+                      description: "XYZ",
+                      type: "integer",
+                      default: 0,
+                    },
+                  },
+                  dependencies: {
+                    bit_rate_cfg_mode: {
+                      oneOf: [
+                        {
+                          properties: {
+                            bit_rate_cfg_mode: {
+                              enum: [0],
+                            },
+                          },
+                        },
+                      ],
+                    },
+                  },
+                },
+              },
+            },
+          },
+        };
+        expect(getDefaultFormState(schema, { can_1: { phy: null } })).eql({
+          can_1: {
+            phy: null,
+          },
+        });
+      });
     });
   });