Rework support for @latest version

src/LibraryManager/ManifestConstants.cs

@@ -48,5 +48,10 @@ public static class ManifestConstants
         /// libman.json files element 
         /// </summary>
         public const string Files = "files";
+
+        /// <summary>
+        /// For providers that support versioned libraries, this represents the evergreen latest version
+        /// </summary>
+        public const string LatestVersion = "latest";
     }
 }

src/LibraryManager/Providers/BaseProvider.cs

@@ -98,6 +98,18 @@ public virtual async Task<ILibraryOperationResult> UpdateStateAsync(ILibraryInst
             try
             {
                 ILibraryCatalog catalog = GetCatalog();
+
+                if (string.Equals(desiredState.Version, ManifestConstants.LatestVersion, StringComparison.Ordinal))
+                {
+                    // replace the @latest version with the latest version from the catalog.  This redirect
+                    // ensures that as new versions are released, we will not reuse stale "latest" assets
+                    // from the cache.
+                    string latestVersion = await catalog.GetLatestVersion(libraryId, includePreReleases: false, cancellationToken).ConfigureAwait(false);
+                    LibraryInstallationState newState = LibraryInstallationState.FromInterface(desiredState);
+                    newState.Version = latestVersion;
+                    desiredState = newState;
+                }
+
                 ILibrary library = await catalog.GetLibraryAsync(desiredState.Name, desiredState.Version, cancellationToken).ConfigureAwait(false);
 
                 if (library == null)

src/LibraryManager/Providers/Cdnjs/CdnjsCatalog.cs

@@ -20,7 +20,7 @@ internal class CdnjsCatalog : ILibraryCatalog
         // TO DO: These should become Provider properties to be passed to CacheService
         private const string FileName = "cache.json";
         public const string CatalogUrl = "https://api.cdnjs.com/libraries?fields=name,description,version";
-        public const string MetaPackageUrlFormat =    "https://api.cdnjs.com/libraries/{0}?fields=filename,versions"; // {libraryName}
+        public const string MetaPackageUrlFormat = "https://api.cdnjs.com/libraries/{0}?fields=filename,versions"; // {libraryName}
         public const string PackageVersionUrlFormat = "https://api.cdnjs.com/libraries/{0}/{1}?fields=files";         // {libraryName}/{version}
 
         private readonly string _cacheFile;
@@ -150,7 +150,13 @@ public async Task<ILibrary> GetLibraryAsync(string libraryName, string version,
                 throw new InvalidLibraryException(libraryId, _provider.Id);
             }
 
-            if (!(await GetLibraryVersionsAsync(libraryName, cancellationToken)).Contains(version))
+            if (string.Equals(version, ManifestConstants.LatestVersion, StringComparison.Ordinal))
+            {
+                version = await GetLatestVersion(libraryName, includePreReleases: false, cancellationToken);
+            }
+
+            IEnumerable<string> enumerable = await GetLibraryVersionsAsync(libraryName, cancellationToken);
+            if (!enumerable.Contains(version))
             {
                 throw new InvalidLibraryException(libraryId, _provider.Id);
             }
@@ -160,7 +166,7 @@ public async Task<ILibrary> GetLibraryAsync(string libraryName, string version,
                 JObject groupMetadata = await GetLibraryGroupMetadataAsync(libraryName, cancellationToken);
                 string defaultFile = groupMetadata?["filename"].Value<string>() ?? string.Empty;
 
-                IEnumerable<string> libraryFiles= await GetLibraryFilesAsync(libraryName, version, cancellationToken).ConfigureAwait(false);
+                IEnumerable<string> libraryFiles = await GetLibraryFilesAsync(libraryName, version, cancellationToken).ConfigureAwait(false);
 
                 return new CdnjsLibrary
                 {

src/LibraryManager/Providers/Unpkg/UnpkgCatalog.cs

@@ -20,7 +20,6 @@ internal class UnpkgCatalog : ILibraryCatalog
         public const string CacheFileName = "cache.json";
         public const string LibraryFileListUrlFormat = "https://unpkg.com/{0}@{1}/?meta"; // e.g. https://unpkg.com/jquery@3.3.1/?meta
         public const string LatestLibraryVersonUrl = "https://unpkg.com/{0}/package.json"; // e.g. https://unpkg.com/jquery/package.json
-        public const string LatestVersionTag = "latest";
 
         private readonly INpmPackageInfoFactory _packageInfoFactory;
         private readonly INpmPackageSearch _packageSearch;
@@ -58,7 +57,7 @@ public async Task<string> GetLatestVersion(string libraryName, bool includePreRe
             try
             {
                 string latestLibraryVersionUrl = string.Format(LatestLibraryVersonUrl, libraryName);
-                string latestCacheFile = Path.Combine(_cacheFolder, libraryName, $"{LatestVersionTag}.json");
+                string latestCacheFile = Path.Combine(_cacheFolder, libraryName, $"{ManifestConstants.LatestVersion}.json");
 
                 string latestJson = await _cacheService.GetContentsFromUriWithCacheFallbackAsync(latestLibraryVersionUrl,
                                                                                                  latestCacheFile,
@@ -88,7 +87,7 @@ public async Task<ILibrary> GetLibraryAsync(string libraryName, string version,
             }
 
             string libraryId = _libraryNamingScheme.GetLibraryId(libraryName, version);
-            if (string.Equals(version, LatestVersionTag, StringComparison.Ordinal))
+            if (string.Equals(version, ManifestConstants.LatestVersion, StringComparison.Ordinal))
             {
                 string latestVersion = await GetLatestVersion(libraryId, includePreReleases: false, cancellationToken).ConfigureAwait(false);
                 libraryId = _libraryNamingScheme.GetLibraryId(libraryName, latestVersion);
@@ -263,8 +262,8 @@ public async Task<CompletionSet> GetLibraryCompletionSetAsync(string libraryName
                     // support @latest version
                     completions.Add(new CompletionItem
                     {
-                        DisplayText = LatestVersionTag,
-                        InsertionText = _libraryNamingScheme.GetLibraryId(name, LatestVersionTag),
+                        DisplayText = ManifestConstants.LatestVersion,
+                        InsertionText = _libraryNamingScheme.GetLibraryId(name, ManifestConstants.LatestVersion),
                     });
 
                     completionSet.CompletionType = CompletionSortOrder.Version;

src/LibraryManager/Providers/jsDelivr/JsDelivrCatalog.cs

@@ -23,7 +23,6 @@ internal class JsDelivrCatalog : ILibraryCatalog
         public const string LatestLibraryVersionUrl = "https://data.jsdelivr.com/v1/package/npm/{0}";
         public const string LibraryFileListUrlFormatGH = "https://data.jsdelivr.com/v1/package/gh/{0}/flat";
         public const string LatestLibraryVersionUrlGH = "https://data.jsdelivr.com/v1/package/gh/{0}";
-        public const string LatestVersionTag = "latest";
 
         private readonly INpmPackageInfoFactory _packageInfoFactory;
         private readonly INpmPackageSearch _packageSearch;
@@ -61,7 +60,7 @@ public async Task<string> GetLatestVersion(string libraryId, bool includePreRele
                 bool isGitHub = IsGitHub(libraryId);
                 string latestLibraryVersionUrl = string.Format(isGitHub ? LatestLibraryVersionUrlGH : LatestLibraryVersionUrl, name);
                 string cacheFileType = isGitHub ? "github" : "npm";
-                string latestLibraryVersionCacheFile = Path.Combine(_cacheFolder, name, $"{cacheFileType}-{LatestVersionTag}.json");
+                string latestLibraryVersionCacheFile = Path.Combine(_cacheFolder, name, $"{cacheFileType}-{ManifestConstants.LatestVersion}.json");
 
                 string latestVersionContent = await _cacheService.GetContentsFromUriWithCacheFallbackAsync(latestLibraryVersionUrl,
                                                                                                            latestLibraryVersionCacheFile,
@@ -116,7 +115,7 @@ public async Task<ILibrary> GetLibraryAsync(string name, string version, Cancell
             }
 
             string libraryId = _libraryNamingScheme.GetLibraryId(name, version);
-            if (string.Equals(version, LatestVersionTag, StringComparison.Ordinal))
+            if (string.Equals(version, ManifestConstants.LatestVersion, StringComparison.Ordinal))
             {
                 string latestVersion = await GetLatestVersion(libraryId, includePreReleases: false, cancellationToken).ConfigureAwait(false);
                 libraryId = _libraryNamingScheme.GetLibraryId(name, latestVersion);
@@ -288,8 +287,8 @@ public async Task<CompletionSet> GetLibraryCompletionSetAsync(string libraryName
                     // support @latest version
                     completions.Add(new CompletionItem
                     {
-                        DisplayText = LatestVersionTag,
-                        InsertionText = _libraryNamingScheme.GetLibraryId(name, LatestVersionTag),
+                        DisplayText = ManifestConstants.LatestVersion,
+                        InsertionText = _libraryNamingScheme.GetLibraryId(name, ManifestConstants.LatestVersion),
                     });
 
                     completionSet.CompletionType = CompletionSortOrder.Version;

test/LibraryManager.Test/Providers/Cdnjs/CdnjsCatalogTest.cs

@@ -134,6 +134,19 @@ public async Task GetLibraryAsync_Success()
             Assert.IsNotNull(library.Files);
         }
 
+        [TestMethod]
+        public async Task GetLibraryAsync_LatestVersion_Success()
+        {
+            CdnjsCatalog sut = SetupCatalog();
+
+            ILibrary library = await sut.GetLibraryAsync("sampleLibrary", "latest", CancellationToken.None);
+
+            Assert.IsNotNull(library);
+            Assert.AreEqual("sampleLibrary", library.Name);
+            Assert.AreEqual("3.1.4", library.Version);
+            Assert.IsNotNull(library.Files);
+        }
+
         [TestMethod]
         public async Task GetLibraryAsync_InvalidLibraryId()
         {