Throw error when migration not defined in same plugin as mappings

src/legacy/ui/ui_exports/__tests__/collect_ui_exports.js

@@ -90,5 +90,48 @@ describe('plugin discovery', () => {
         },
       });
     });
+
+    it(`throws an error when migrations and mappings aren't defined in the same plugin`, () => {
+      const invalidSpecs = new PluginPack({
+        path: '/dev/null',
+        pkg: {
+          name: 'test',
+          version: 'kibana',
+        },
+        provider({ Plugin }) {
+          return [
+            new Plugin({
+              id: 'test',
+              uiExports: {
+                mappings: {
+                  'test-type': {
+                    properties: {},
+                  },
+                },
+              },
+            }),
+            new Plugin({
+              id: 'test2',
+              uiExports: {
+                migrations: {
+                  'test-type': {
+                    '1.2.3': (doc) => {
+                      return doc;
+                    },
+                  },
+                },
+              },
+            }),
+          ];
+        },
+      }).getPluginSpecs();
+      expect(
+        () => collectUiExports(invalidSpecs),
+      ).to.throwError((err) => {
+        expect(err).to.be.a(Error);
+        expect(err).to.have.property('message', 'Migrations and mappings must be defined together in the uiExports of a single plugin. ' +
+          'test2 defines migrations for types test-type but does not define their mappings.');
+      });
+    });
   });
 });

src/legacy/ui/ui_exports/ui_export_types/saved_object.js

@@ -30,10 +30,29 @@ export const mappings = wrap(
   flatConcatAtType
 );
 
+const pluginId = (pluginSpec) => pluginSpec.id ? pluginSpec.id() : pluginSpec.getId();
+
 // Combines the `migrations` property of each plugin,
-// ensuring that properties are unique across plugins.
+// ensuring that properties are unique across plugins
+// and has migrations defined where the mappings are defined.
 // See saved_objects/migrations for more details.
-export const migrations = wrap(alias('savedObjectMigrations'), uniqueKeys(), mergeAtType);
+export const migrations = wrap(
+  alias('savedObjectMigrations'),
+  (next) => (acc, spec, type, pluginSpec) => {
+    const mappings = pluginSpec.getExportSpecs().mappings || {};
+    const invalidMigrationTypes = Object.keys(spec)
+      .filter(type => !mappings[type]);
+    if (invalidMigrationTypes.length) {
+      throw new Error(
+        'Migrations and mappings must be defined together in the uiExports of a single plugin. ' +
+        `${pluginId(pluginSpec)} defines migrations for types ${invalidMigrationTypes.join(', ')} but does not define their mappings.`
+      );
+    }
+    return next(acc, spec, type, pluginSpec);
+  },
+  uniqueKeys(),
+  mergeAtType,
+);
 
 export const savedObjectSchemas = wrap(uniqueKeys(), mergeAtType);