chore: import upstream snapshot with attribution

Sources/ContainerCommands/HelpCommand.swift

@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+// Copyright © 2026 Apple Inc. and the container project authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//===----------------------------------------------------------------------===//
+
+import ArgumentParser
+import ContainerAPIClient
+
+struct HelpCommand: AsyncLoggableCommand {
+    public static let configuration = CommandConfiguration(
+        commandName: "help",
+        shouldDisplay: false
+    )
+
+    @OptionGroup(visibility: .hidden)
+    public var logOptions: Flags.Logging
+
+    @Argument(parsing: .captureForPassthrough)
+    var subcommandPath: [String] = []
+
+    func run() async throws {
+        if subcommandPath.isEmpty {
+            let pluginLoader = try? await Application.createPluginLoader()
+            await Application.printModifiedHelpText(pluginLoader: pluginLoader)
+            return
+        }
+        guard let target = Self.resolveSubcommand(path: subcommandPath) else {
+            throw ValidationError("unknown command '\(subcommandPath.joined(separator: " "))'")
+        }
+        print(Application.helpMessage(for: target))
+    }
+
+    static func resolveSubcommand(path: [String]) -> ParsableCommand.Type? {
+        var current: ParsableCommand.Type = Application.self
+        for name in path {
+            guard let next = childSubcommands(of: current).first(where: { matches($0, name: name) }) else {
+                return nil
+            }
+            current = next
+        }
+        return current
+    }
+
+    private static func childSubcommands(of command: ParsableCommand.Type) -> [ParsableCommand.Type] {
+        var all = command.configuration.subcommands
+        for group in command.configuration.groupedSubcommands {
+            all.append(contentsOf: group.subcommands)
+        }
+        return all
+    }
+
+    private static func matches(_ command: ParsableCommand.Type, name: String) -> Bool {
+        let cfg = command.configuration
+        if cfg.commandName == name { return true }
+        return cfg.aliases.contains(name)
+    }
+}