[GH Idx] Stop uploading empty blob when job crashes

src/NuGet.Jobs.GitHubIndexer/ReposIndexer.cs

@@ -85,7 +85,15 @@ await ProcessInParallel(inputBag, repo =>
                 .ThenBy(x => x.Id)
                 .ToList();
 
-            await WriteFinalBlobAsync(finalList);
+            if (finalList.Any())
+            {
+                await WriteFinalBlobAsync(finalList);
+            }
+            else
+            {
+                // TODO: Add telemetry for this (https://github.com/NuGet/NuGetGallery/issues/7359)
+                _logger.LogError("The final blob is empty!");
+            }
 
             // Delete the repos and cache directory
             Directory.Delete(RepositoriesDirectory, recursive: true);

tests/NuGet.Jobs.GitHubIndexer.Tests/ReposIndexerFacts.cs

@@ -112,7 +112,10 @@ public async Task TestNoDependenciesInFiles()
                     new GitFileInfo(configFileNames[3], 1)
                 };
 
-                var indexer = CreateIndexer(repo, repoFiles, onDisposeHandler: null);
+                var indexer = CreateIndexer(repo,
+                    repoFiles, 
+                    // This should not be called since there is no dependencies
+                    onDisposeHandler: (string serializedValue) => Assert.True(false));
                 await indexer.RunAsync();
 
                 var result = repo.ToRepositoryInformation();