Remove usages of deprecated registry methods (#8335)

### Motivation:

Fix the warnings around using the sync versions of PackageRegistry
methods.

### Modifications:

Convert the remainder of the PackageRegistry code to be async first, and
move existing usages of the old sync methods in PackageRegistryCommand
over to the new async alternatives. Clean up unnecessary plumbing of
callbackQueues through the async methods.

### Result:

All asynchronous methods are `async` based inside
Sources/PackageRegistry, and warnings about using deprecated methods
have been fixed.

Author: plemarquand

Sources/PackageMetadata/PackageMetadata.swift

@@ -174,8 +174,8 @@ public struct PackageSearchClient {
             package: package,
             version: version,
             fileSystem: self.fileSystem,
-            observabilityScope: observabilityScope,
-            callbackQueue: DispatchQueue.sharedConcurrent)
+            observabilityScope: observabilityScope
+        )
 
         return Metadata(
             licenseURL: metadata.licenseURL,
@@ -285,7 +285,10 @@ public struct PackageSearchClient {
         }
         let metadata: RegistryClient.PackageMetadata
         do {
-            metadata = try await self.registryClient.getPackageMetadata(package: identity, observabilityScope: observabilityScope, callbackQueue: DispatchQueue.sharedConcurrent)
+            metadata = try await self.registryClient.getPackageMetadata(
+                package: identity,
+                observabilityScope: observabilityScope
+            )
         } catch {
             return try await fetchStandalonePackageByURL(error)
         }
@@ -403,7 +406,7 @@ extension Package.Author {
             url: author.url
         )
     }
-    
+
     fileprivate init(_ author: PackageCollectionsModel.Package.Author) {
         self.init(
             name: author.username,

Sources/PackageRegistry/ChecksumTOFU.swift

@@ -43,22 +43,26 @@ struct PackageVersionChecksumTOFU {
         version: Version,
         checksum: String,
         timeout: DispatchTimeInterval?,
-        observabilityScope: ObservabilityScope,
-        callbackQueue: DispatchQueue
+        observabilityScope: ObservabilityScope
     ) async throws {
-        try await withCheckedThrowingContinuation { continuation in
-            self.validateSourceArchive(
-                registry: registry,
-                package: package,
-                version: version,
-                checksum: checksum,
-                timeout: timeout,
-                observabilityScope: observabilityScope,
-                callbackQueue: callbackQueue,
-                completion: {
-                    continuation.resume(with: $0)
-                }
-            )
+        let expectedChecksum = try await self.getExpectedChecksum(
+            registry: registry,
+            package: package,
+            version: version,
+            timeout: timeout,
+            observabilityScope: observabilityScope
+        )
+
+        if checksum != expectedChecksum {
+            switch self.fingerprintCheckingMode {
+            case .strict:
+                throw RegistryError.invalidChecksum(expected: expectedChecksum, actual: checksum)
+            case .warn:
+                observabilityScope
+                    .emit(
+                        warning: "the checksum \(checksum) for source archive of \(package) \(version) does not match previously recorded value \(expectedChecksum)"
+                    )
+            }
         }
     }
 
@@ -73,28 +77,14 @@ struct PackageVersionChecksumTOFU {
         callbackQueue: DispatchQueue,
         completion: @escaping (Result<Void, Error>) -> Void
     ) {
-        self.getExpectedChecksum(
-            registry: registry,
-            package: package,
-            version: version,
-            timeout: timeout,
-            observabilityScope: observabilityScope,
-            callbackQueue: callbackQueue
-        ) { result in
-            completion(
-                result.tryMap { expectedChecksum in
-                    if checksum != expectedChecksum {
-                        switch self.fingerprintCheckingMode {
-                        case .strict:
-                            throw RegistryError.invalidChecksum(expected: expectedChecksum, actual: checksum)
-                        case .warn:
-                            observabilityScope
-                                .emit(
-                                    warning: "the checksum \(checksum) for source archive of \(package) \(version) does not match previously recorded value \(expectedChecksum)"
-                                )
-                        }
-                    }
-                }
+        callbackQueue.asyncResult(completion) {
+            try await self.validateSourceArchive(
+                registry: registry,
+                package: package,
+                version: version,
+                checksum: checksum,
+                timeout: timeout,
+                observabilityScope: observabilityScope
             )
         }
     }
@@ -104,54 +94,48 @@ struct PackageVersionChecksumTOFU {
         package: PackageIdentity.RegistryIdentity,
         version: Version,
         timeout: DispatchTimeInterval?,
-        observabilityScope: ObservabilityScope,
-        callbackQueue: DispatchQueue,
-        completion: @escaping (Result<String, Error>) -> Void
-    ) {
+        observabilityScope: ObservabilityScope
+    ) async throws -> String {
         // We either use a previously recorded checksum, or fetch it from the registry.
         if let savedChecksum = try? self.readFromStorage(package: package, version: version, contentType: .sourceCode, observabilityScope: observabilityScope) {
-            return completion(.success(savedChecksum))
+            return savedChecksum
         }
 
         // Try fetching checksum from registry if:
         //   - No storage available
         //   - Checksum not found in storage
         //   - Reading from storage resulted in error
-        Task {
-            do {
-                let versionMetadata = try await self.versionMetadataProvider(package, version)
-                guard let sourceArchiveResource = versionMetadata.sourceArchive else {
-                    throw RegistryError.missingSourceArchive
-                }
-                guard let checksum = sourceArchiveResource.checksum else {
-                    throw RegistryError.sourceArchiveMissingChecksum(
-                        registry: registry,
-                        package: package.underlying,
-                        version: version
-                    )
-                }
-                do {
-                    try self.writeToStorage(
-                        registry: registry,
-                        package: package,
-                        version: version,
-                        checksum: checksum,
-                        contentType: .sourceCode,
-                        observabilityScope: observabilityScope
-                    )
-                    completion(.success(checksum))
-                } catch {
-                    completion(.failure(error))
-                }
-            } catch {
-                completion(.failure(RegistryError.failedRetrievingReleaseChecksum(
+        var checksum: String
+        do {
+            let versionMetadata = try await self.versionMetadataProvider(package, version)
+            guard let sourceArchiveResource = versionMetadata.sourceArchive else {
+                throw RegistryError.missingSourceArchive
+            }
+            guard let archiveChecksum = sourceArchiveResource.checksum else {
+                throw RegistryError.sourceArchiveMissingChecksum(
                     registry: registry,
                     package: package.underlying,
-                    version: version,
-                    error: error
-                )))
+                    version: version
+                )
             }
+            checksum = archiveChecksum
+        } catch {
+            throw RegistryError.failedRetrievingReleaseChecksum(
+                registry: registry,
+                package: package.underlying,
+                version: version,
+                error: error
+            )
         }
+        try self.writeToStorage(
+            registry: registry,
+            package: package,
+            version: version,
+            checksum: checksum,
+            contentType: .sourceCode,
+            observabilityScope: observabilityScope
+        )
+        return checksum
     }
 
     func validateManifest(