Initialize resource when GetInstalledVersions is called first (#7245)

Author: nkolev92

src/NuGet.Core/NuGet.Commands/RestoreCommand/SourceRepositoryDependencyProvider.cs

@@ -361,13 +361,13 @@ private async Task<LibraryDependencyInfo> GetDependenciesCoreAsync(
             FindPackageByIdDependencyInfo packageInfo = null;
             try
             {
-                await EnsureResource(cancellationToken);
-
                 if (_throttle != null)
                 {
                     await _throttle.WaitAsync(cancellationToken);
                 }
 
+                await EnsureResource(cancellationToken);
+
                 // Read package info, this will download the package if needed.
                 packageInfo = await _findPackagesByIdResource.GetDependencyInfoAsync(
                     match.Name,
@@ -459,13 +459,13 @@ public async Task<IPackageDownloader> GetPackageDownloaderAsync(
 
             try
             {
-                await EnsureResource(cancellationToken);
-
                 if (_throttle != null)
                 {
                     await _throttle.WaitAsync(cancellationToken);
                 }
 
+                await EnsureResource(cancellationToken);
+
                 cancellationToken.ThrowIfCancellationRequested();
 
                 var packageDownloader = await _findPackagesByIdResource.GetPackageDownloaderAsync(
@@ -634,10 +634,9 @@ internal async Task<IEnumerable<NuGetVersion>> GetAllVersionsInternalAsync(
                 {
                     await _throttle.WaitAsync(cancellationToken);
                 }
-                if (_findPackagesByIdResource == null)
-                {
-                    return null;
-                }
+
+                await EnsureResource(cancellationToken);
+
                 return await _findPackagesByIdResource.GetAllVersionsAsync(
                     id,
                     cacheContext,

test/NuGet.Core.Tests/NuGet.Commands.Test/SourceRepositoryDependencyProviderTests.cs

@@ -661,6 +661,56 @@ public async Task GetPackageDownloaderAsync_ReturnsPackageDownloader()
             }
         }
 
+        [Fact]
+        public async Task GetAllVersionsAsync_EnsuresResourceIsInitialized_ReturnsVersions()
+        {
+            // Arrange
+            // This test verifies that GetAllVersionsAsync properly calls EnsureResource
+            // to initialize _findPackagesByIdResource. Previously, EnsureResource was not called
+            // and GetAllVersionsInternalAsync would see _findPackagesByIdResource as null,
+            // silently returning null instead of the actual versions.
+            var testLogger = new TestLogger();
+            var cacheContext = new SourceCacheContext();
+            var expectedVersions = new[] { NuGetVersion.Parse("1.0.0"), NuGetVersion.Parse("2.0.0") };
+
+            var findResource = new Mock<FindPackageByIdResource>();
+            findResource.Setup(s => s.GetAllVersionsAsync(
+                    It.IsAny<string>(),
+                    It.IsAny<SourceCacheContext>(),
+                    It.IsAny<ILogger>(),
+                    It.IsAny<CancellationToken>()))
+                .ReturnsAsync(expectedVersions);
+
+            var source = new Mock<SourceRepository>();
+            source.Setup(s => s.GetResourceAsync<FindPackageByIdResource>(CancellationToken.None))
+                .ReturnsAsync(findResource.Object);
+            source.SetupGet(s => s.PackageSource)
+                .Returns(new PackageSource("http://test/index.json"));
+
+            var provider = new SourceRepositoryDependencyProvider(
+                source.Object,
+                testLogger,
+                cacheContext,
+                ignoreFailedSources: true,
+                ignoreWarning: true);
+
+            // Act
+            var versions = await provider.GetAllVersionsAsync(
+                "x",
+                cacheContext,
+                testLogger,
+                CancellationToken.None);
+
+            // Assert
+            versions.Should().BeEquivalentTo(expectedVersions);
+            source.Verify(s => s.GetResourceAsync<FindPackageByIdResource>(CancellationToken.None), Times.Once);
+            findResource.Verify(s => s.GetAllVersionsAsync(
+                "x",
+                It.IsAny<SourceCacheContext>(),
+                It.IsAny<ILogger>(),
+                It.IsAny<CancellationToken>()), Times.Once);
+        }
+
         [Fact]
         public async Task FindLibraryAsync_WhenASourceIsInaccessible_AndFailuresAreNotIgnored_EveryCallLogsAnErrorMessage()
         {