Test error thrown when FragmentRegistry cannot resolve all fragments.

src/cache/inmemory/__tests__/fragmentRegistry.ts

@@ -114,6 +114,110 @@ describe("FragmentRegistry", () => {
     });
   });
 
+  it("throws an error when not all used fragments are defined", () => {
+    const cache = new InMemoryCache({
+      fragments: createFragmentRegistry(gql`
+        fragment IncompleteFragment on Person {
+          __typename
+          id
+          ...MustBeDefinedByQuery
+        }
+      `),
+    });
+
+    const queryWithoutFragment = gql`
+      query WithoutFragment {
+        me {
+          ...IncompleteFragment
+        }
+      }
+    `;
+
+    const queryWithFragment = gql`
+      query WithFragment {
+        me {
+          ...IncompleteFragment
+        }
+      }
+
+      fragment MustBeDefinedByQuery on Person {
+        name
+      }
+    `;
+
+    expect(() => {
+      cache.writeQuery({
+        query: queryWithoutFragment,
+        data: {
+          me: {
+            __typename: "Person",
+            id: 12345,
+            name: "Ben",
+          },
+        },
+      });
+    }).toThrow(
+      /No fragment named MustBeDefinedByQuery/
+    );
+
+    expect(cache.extract()).toEqual({
+      // Nothing written because the cache.writeQuery failed above.
+    });
+
+    cache.writeQuery({
+      query: queryWithFragment,
+      data: {
+        me: {
+          __typename: "Person",
+          id: 12345,
+          name: "Ben Newman",
+        },
+      },
+    });
+
+    expect(cache.extract()).toEqual({
+      ROOT_QUERY: {
+        __typename: "Query",
+        me: { __ref: "Person:12345" },
+      },
+      "Person:12345": {
+        __typename: "Person",
+        id: 12345,
+        name: "Ben Newman",
+      },
+    });
+
+    expect(() => {
+      cache.diff({
+        query: queryWithoutFragment,
+        returnPartialData: true,
+        optimistic: true,
+      });
+    }).toThrow(
+      /No fragment named MustBeDefinedByQuery/
+    );
+
+    expect(() => {
+      cache.readQuery({
+        query: queryWithoutFragment
+      });
+    }).toThrow(
+      /No fragment named MustBeDefinedByQuery/
+    );
+
+    expect(
+      cache.readQuery({
+        query: queryWithFragment,
+      }),
+    ).toEqual({
+      me: {
+        __typename: "Person",
+        id: 12345,
+        name: "Ben Newman",
+      },
+    });
+  });
+
   it("can register fragments with unbound ...spreads", () => {
     const cache = new InMemoryCache({
       fragments: createFragmentRegistry(gql`

src/cache/inmemory/fragmentRegistry.ts

@@ -133,8 +133,6 @@ class FragmentRegistry implements FragmentRegistryAPI {
         const def = map[name];
         if (def) {
           defsToAppend.push(def);
-        } else {
-          // TODO Warn? Error?
         }
       });
 

src/cache/inmemory/inMemoryCache.ts

@@ -181,11 +181,11 @@ export class InMemoryCache extends ApolloCache<NormalizedCacheObject> {
       }).result || null;
     } catch (e) {
       if (e instanceof MissingFieldError) {
-        // Swallow MissingFieldError and return null, so callers do not
-        // need to worry about catching "normal" exceptions resulting from
-        // incomplete cache data. Unexpected errors will be re-thrown. If
-        // you need more information about which fields were missing, use
-        // cache.diff instead, and examine diffResult.missing.
+        // Swallow MissingFieldError and return null, so callers do not need to
+        // worry about catching "normal" exceptions resulting from incomplete
+        // cache data. Unexpected errors will be re-thrown. If you need more
+        // information about which fields were missing, use cache.diff instead,
+        // and examine diffResult.missing.
         return null;
       }
       throw e;

src/cache/inmemory/readFromStore.ts

@@ -1,8 +1,9 @@
-import { invariant } from '../../utilities/globals';
+import { invariant, InvariantError } from '../../utilities/globals';
 
 import {
   DocumentNode,
   FieldNode,
+  Kind,
   SelectionSetNode,
 } from 'graphql';
 import { wrap, OptimisticWrapperFunction } from 'optimism';
@@ -406,6 +407,10 @@ export class StoreReader {
           context.lookupFragment,
         );
 
+        if (!fragment && selection.kind === Kind.FRAGMENT_SPREAD) {
+          throw new InvariantError(`No fragment named ${selection.name.value}`);
+        }
+
         if (fragment && policies.fragmentMatches(fragment, typename)) {
           fragment.selectionSet.selections.forEach(workSet.add, workSet);
         }

src/cache/inmemory/writeToStore.ts

@@ -4,6 +4,7 @@ import { Trie } from '@wry/trie';
 import {
   SelectionSetNode,
   FieldNode,
+  Kind,
 } from 'graphql';
 
 import {
@@ -566,6 +567,10 @@ export class StoreWriter {
             context.lookupFragment,
           );
 
+          if (!fragment && selection.kind === Kind.FRAGMENT_SPREAD) {
+            throw new InvariantError(`No fragment named ${selection.name.value}`);
+          }
+
           if (fragment &&
               policies.fragmentMatches(
                 fragment, typename, result, context.variables)) {