fix(github): Error messages for empty repository result (#17645)

Co-authored-by: Michael Kriese <michael.kriese@visualon.de>

lib/modules/datasource/github-releases/cache/cache-base.spec.ts

@@ -333,7 +333,7 @@ describe('modules/datasource/github-releases/cache/cache-base', () => {
       {
         statusCode: 200,
         headers: {},
-        body: { errors: [{ message: 'Ooops' }] },
+        body: { errors: [{} as never, { message: 'Ooops' }] },
       },
     ];
     const cache = new TestCache(http, { resetDeltaMinutes: 0 });
@@ -345,6 +345,50 @@ describe('modules/datasource/github-releases/cache/cache-base', () => {
     expect(packageCache.set).not.toHaveBeenCalled();
   });
 
+  it('throws for unknown graphql errors', async () => {
+    packageCache.get.mockResolvedValueOnce({
+      items: {},
+      createdAt: t3,
+      updatedAt: t3,
+    });
+    responses = [
+      {
+        statusCode: 200,
+        headers: {},
+        body: { errors: [] },
+      },
+    ];
+    const cache = new TestCache(http, { resetDeltaMinutes: 0 });
+
+    await expect(cache.getItems({ packageName: 'foo/bar' })).rejects.toThrow(
+      'GitHub datasource cache: unknown GraphQL error'
+    );
+    expect(packageCache.get).toHaveBeenCalled();
+    expect(packageCache.set).not.toHaveBeenCalled();
+  });
+
+  it('throws for empty payload', async () => {
+    packageCache.get.mockResolvedValueOnce({
+      items: {},
+      createdAt: t3,
+      updatedAt: t3,
+    });
+    responses = [
+      {
+        statusCode: 200,
+        headers: {},
+        body: { data: { repository: { payload: null as never } } },
+      },
+    ];
+    const cache = new TestCache(http, { resetDeltaMinutes: 0 });
+
+    await expect(cache.getItems({ packageName: 'foo/bar' })).rejects.toThrow(
+      'GitHub datasource cache: failed to obtain payload data'
+    );
+    expect(packageCache.get).toHaveBeenCalled();
+    expect(packageCache.set).not.toHaveBeenCalled();
+  });
+
   it('shrinks for some of graphql errors', async () => {
     packageCache.get.mockResolvedValueOnce({
       items: {},

lib/modules/datasource/github-releases/cache/cache-base.ts

@@ -1,3 +1,4 @@
+import is from '@sindresorhus/is';
 import { DateTime, DurationLikeObject } from 'luxon';
 import { logger } from '../../../../logger';
 import * as memCache from '../../../../util/cache/memory';
@@ -164,11 +165,11 @@ export abstract class AbstractGithubDatasourceCache<
    */
   abstract coerceFetched(fetchedItem: FetchedItem): StoredItem | null;
 
-  private async query(
+  private async queryPayload(
     baseUrl: string,
     variables: GithubQueryParams,
     options: GithubHttpOptions
-  ): Promise<QueryResponse<FetchedItem> | Error> {
+  ): Promise<QueryResponse<FetchedItem>['repository']['payload'] | Error> {
     try {
       const graphqlRes = await this.http.postJson<
         GithubGraphqlResponse<QueryResponse<FetchedItem>>
@@ -179,7 +180,22 @@ export abstract class AbstractGithubDatasourceCache<
       });
       const { body } = graphqlRes;
       const { data, errors } = body;
-      return data ?? new Error(errors?.[0]?.message);
+
+      if (errors) {
+        let [errorMessage] = errors
+          .map(({ message }) => message)
+          .filter(is.string);
+        errorMessage ??= 'GitHub datasource cache: unknown GraphQL error';
+        return new Error(errorMessage);
+      }
+
+      if (!data?.repository?.payload) {
+        return new Error(
+          'GitHub datasource cache: failed to obtain payload data'
+        );
+      }
+
+      return data.repository.payload;
     } catch (err) {
       return err;
     }
@@ -282,12 +298,12 @@ export abstract class AbstractGithubDatasourceCache<
           : this.maxPrefetchPages;
         let stopIteration = false;
         while (pagesRemained > 0 && !stopIteration) {
-          const res = await this.query(baseUrl, variables, {
+          const queryResult = await this.queryPayload(baseUrl, variables, {
             repository: packageName,
           });
-          if (res instanceof Error) {
+          if (queryResult instanceof Error) {
             if (
-              res.message.startsWith(
+              queryResult.message.startsWith(
                 'Something went wrong while executing your query.' // #16343
               ) &&
               variables.count > 30
@@ -299,15 +315,15 @@ export abstract class AbstractGithubDatasourceCache<
               variables.count = Math.floor(variables.count / 2);
               continue;
             }
-            throw res;
+            throw queryResult;
           }
 
           pagesRemained -= 1;
 
           const {
             nodes: fetchedItems,
             pageInfo: { hasNextPage, endCursor },
-          } = res.repository.payload;
+          } = queryResult;
 
           if (hasNextPage) {
             variables.cursor = endCursor;