fix(nuget): gracefully accept a lack of a PackageBaseAddress resource

lib/modules/datasource/nuget/index.spec.ts

@@ -243,6 +243,65 @@ describe('modules/datasource/nuget/index', () => {
       expect(res).toBeNull();
     });
 
+    // This is for coverage and to make sure we don't completely fall over--we
+    // don't have a way to test if we successfully replaced the TypeError.
+    it(`doesn't trigger a TypeError when PackageBaseAddress is missing from service index`, async () => {
+      const nugetIndex = `
+        {
+          "version": "3.0.0",
+          "resources": [
+            {
+              "@id": "https://api.nuget.org/v3/metadata",
+              "@type": "RegistrationsBaseUrl",
+              "comment": "Get package metadata."
+            },
+            {
+              "@id": "https://api.nuget.org/v3/metadata",
+              "@type": "RegistrationsBaseUrl/3.0.0-beta",
+              "comment": "Get package metadata."
+            }
+          ]
+        }
+      `;
+      const nunitRegistration = `
+        {
+          "count": 1,
+          "items": [
+            {
+              "@id": "https://api.nuget.org/v3/metadata/nunit/5.0.json",
+              "lower": "5.0",
+              "upper": "5.0",
+              "count": 1,
+              "items": [
+                {
+                  "@id": "foo",
+                  "packageContent": "foo",
+                  "catalogEntry": {
+                    "id": "nunit",
+                    "version": "5.0"
+                  }
+                }
+              ]
+            }
+          ]
+        }
+      `;
+
+      httpMock
+        .scope('https://api.nuget.org')
+        .get('/v3/index.json')
+        .reply(200, nugetIndex)
+        .get('/v3/metadata/nunit/index.json')
+        .reply(200, nunitRegistration)
+        .get('/v3/index.json')
+        .reply(200, nugetIndex);
+      const res = await getPkgReleases({
+        ...configV3,
+      });
+      expect(res).not.toBeNull();
+      expect(res!.releases).toHaveLength(1);
+    });
+
     it('returns null for non 200 (v3v2)', async () => {
       httpMock.scope('https://api.nuget.org').get('/v3/index.json').reply(500);
       httpMock

lib/modules/datasource/nuget/v3.ts

@@ -68,6 +68,15 @@ export async function getResourceUrl(
           ? semver.compare(x.version, y.version)
           : /* istanbul ignore next: hard to test */ 0
       );
+
+    if (services.length === 0) {
+      logger.debug(
+        { url, servicesIndexRaw },
+        `no ${resourceType} services found`
+      );
+      return null;
+    }
+
     const { serviceId, version } = services.pop()!;
 
     // istanbul ignore if