[Hotfix] Set download count to Int32.MaxValue for V2 feed packages exceeding this threshold (#9199)

Author: shishirx34

src/NuGetGallery/OData/PackageExtensions.cs

@@ -88,7 +88,10 @@ internal static IQueryable<V2FeedPackage> ProjectV2FeedPackage(
                     Created = p.Created,
                     Dependencies = p.FlattenedDependencies,
                     Description = p.Description,
-                    DownloadCount = p.PackageRegistration.DownloadCount,
+                    // Some of the older clients and packages (eg: NuGet.Core) suffer from integer overflow when the download count
+                    // exceeds the MaxValue due to usage of Int32 for "DownloadCount" field. As such, for the V2 Feed restrict the download
+                    // count to Int32.MaxValue in order to allow older clients to successfully fetch these values.
+                    DownloadCount = p.PackageRegistration.DownloadCount > Int32.MaxValue ? (long)Int32.MaxValue : p.PackageRegistration.DownloadCount,
                     GalleryDetailsUrl = siteRoot + "packages/" + p.PackageRegistration.Id + "/" + p.NormalizedVersion,
                     IconUrl = p.IconUrl,
                     // We do not expose the internal IsLatestSemVer2 and IsLatestStableSemVer2 properties; 

tests/NuGetGallery.Facts/OData/Interceptors/PackageExtensionsFacts.cs

@@ -132,6 +132,29 @@ public void ReturnsNullLicenseReportInfoIfFeatureDisabled()
                 Assert.Null(actual.LicenseNames);
                 Assert.Null(actual.LicenseReportUrl);
             }
+
+            [Fact]
+            public void RestrictsExceedingDownloadCountsToInt32MaxValue()
+            {
+                // Arrange
+                var package = CreateFakeBasePackage();
+                package.PackageRegistration.DownloadCount = long.MaxValue;
+                var packages = new List<Package>
+                {
+                    package
+                }.AsQueryable();
+
+                // Act
+                var projected = PackageExtensions.ProjectV2FeedPackage(
+                    packages,
+                    siteRoot: "http://nuget.org",
+                    includeLicenseReport: false,
+                    semVerLevelKey: SemVerLevelKey.Unknown).ToList();
+
+                // Assert
+                var actual = projected.Single();
+                Assert.Equal(Int32.MaxValue, actual.DownloadCount);
+            }
         }
 
         /// <summary>