Package command plugins should have the same initial working directory as the invocation (#4014)

Motivation:  This allows relative paths passed as parameters to work.  For build tool plugins we pass in the package directory so that relative paths in configuration files work there as well.  This also matches the behavior of many build systems.  The proposal didn't specify the initial working directory and usually all paths are absolute, but having predictable initial working directories follows the principle of least surprise.

rdar://86831942

Author: abertelrud

Sources/Commands/SwiftPackageTool.swift

@@ -1050,6 +1050,7 @@ extension SwiftPackageTool {
                 package: package,
                 buildEnvironment: buildEnvironment,
                 scriptRunner: pluginScriptRunner,
+                workingDirectory: swiftTool.originalWorkingDirectory,
                 outputDirectory: outputDir,
                 toolSearchDirectories: toolSearchDirs,
                 toolNamesToPaths: toolNamesToPaths,

Sources/SPMBuildCore/PluginInvocation.swift

@@ -40,6 +40,7 @@ extension PluginTarget {
     ///   - action: The plugin action (i.e. entry point) to invoke, possibly containing parameters.
     ///   - package: The root of the package graph to pass down to the plugin.
     ///   - scriptRunner: Entity responsible for actually running the code of the plugin.
+    ///   - workingDirectory: The initial working directory of the invoked plugin.
     ///   - outputDirectory: A directory under which the plugin can write anything it wants to.
     ///   - toolNamesToPaths: A mapping from name of tools available to the plugin to the corresponding absolute paths.
     ///   - fileSystem: The file system to which all of the paths refers.
@@ -50,6 +51,7 @@ extension PluginTarget {
         package: ResolvedPackage,
         buildEnvironment: BuildEnvironment,
         scriptRunner: PluginScriptRunner,
+        workingDirectory: AbsolutePath,
         outputDirectory: AbsolutePath,
         toolSearchDirectories: [AbsolutePath],
         toolNamesToPaths: [String: AbsolutePath],
@@ -90,6 +92,7 @@ extension PluginTarget {
             sources: sources,
             input: inputStruct,
             toolsVersion: self.apiVersion,
+            workingDirectory: workingDirectory,
             writableDirectories: writableDirectories,
             readOnlyDirectories: readOnlyDirectories,
             fileSystem: fileSystem,
@@ -242,6 +245,7 @@ extension PackageGraph {
                     package: package,
                     buildEnvironment: buildEnvironment,
                     scriptRunner: pluginScriptRunner,
+                    workingDirectory: package.path,
                     outputDirectory: pluginOutputDir,
                     toolSearchDirectories: toolSearchDirectories,
                     toolNamesToPaths: toolNamesToPaths,
@@ -390,6 +394,7 @@ public protocol PluginScriptRunner {
         sources: Sources,
         input: PluginScriptRunnerInput,
         toolsVersion: ToolsVersion,
+        workingDirectory: AbsolutePath,
         writableDirectories: [AbsolutePath],
         readOnlyDirectories: [AbsolutePath],
         fileSystem: FileSystem,

Sources/Workspace/DefaultPluginScriptRunner.swift

@@ -70,6 +70,7 @@ public struct DefaultPluginScriptRunner: PluginScriptRunner {
         sources: Sources,
         input: PluginScriptRunnerInput,
         toolsVersion: ToolsVersion,
+        workingDirectory: AbsolutePath,
         writableDirectories: [AbsolutePath],
         readOnlyDirectories: [AbsolutePath],
         fileSystem: FileSystem,
@@ -93,6 +94,7 @@ public struct DefaultPluginScriptRunner: PluginScriptRunner {
                     // Compilation succeeded, so run the executable. We are already running on an asynchronous queue.
                     self.invoke(
                         compiledExec: result.compiledExecutable,
+                        workingDirectory: workingDirectory,
                         writableDirectories: writableDirectories,
                         readOnlyDirectories: readOnlyDirectories,
                         input: input,
@@ -343,6 +345,7 @@ public struct DefaultPluginScriptRunner: PluginScriptRunner {
     /// Private function that invokes a compiled plugin executable and communicates with it until it finishes.
     fileprivate func invoke(
         compiledExec: AbsolutePath,
+        workingDirectory: AbsolutePath,
         writableDirectories: [AbsolutePath],
         readOnlyDirectories: [AbsolutePath],
         input: PluginScriptRunnerInput,
@@ -369,7 +372,7 @@ public struct DefaultPluginScriptRunner: PluginScriptRunner {
         process.executableURL = Foundation.URL(fileURLWithPath: command[0])
         process.arguments = Array(command.dropFirst())
         process.environment = ProcessInfo.processInfo.environment
-        process.currentDirectoryURL = self.cacheDir.asURL
+        process.currentDirectoryURL = workingDirectory.asURL
 
         // Set up a pipe for sending structured messages to the plugin on its stdin.
         let stdinPipe = Pipe()

Tests/CommandsTests/PackageToolTests.swift

@@ -1083,17 +1083,23 @@ final class PackageToolTests: CommandsTestCase {
             try localFileSystem.writeFileContents(packageDir.appending(components: "Plugins", "MyPlugin", "plugin.swift")) {
                 $0 <<< """
                     import PackagePlugin
-                    
+                    import Foundation
                     @main
                     struct MyBuildToolPlugin: BuildToolPlugin {
                         func createBuildCommands(
                             context: PluginContext,
                             target: Target
                         ) throws -> [Command] {
+                            // Expect the initial working directory for build tool plugins is the package directory.
+                            guard FileManager.default.currentDirectoryPath == context.package.directory.string else {
+                                throw "expected initial working directory ‘\\(FileManager.default.currentDirectoryPath)’"
+                            }
+
                             // Check that the package display name is what we expect.
                             guard context.package.displayName == "MyPackage" else {
                                 throw "expected display name to be ‘MyPackage’ but found ‘\\(context.package.displayName)’"
                             }
+
                             // Create and return a build command that uses all the `.foo` files in the target as inputs, so they get counted as having been handled.
                             let fooFiles = (target as? SourceModuleTarget)?.sourceFiles.compactMap{ $0.path.extension == "foo" ? $0.path : nil } ?? []
                             return [ .buildCommand(displayName: "A command", executable: "/bin/echo", arguments: ["Hello"], inputFiles: fooFiles) ]
@@ -1106,8 +1112,9 @@ final class PackageToolTests: CommandsTestCase {
 
             // Invoke it, and check the results.
             let result = try SwiftPMProduct.SwiftBuild.executeProcess([], packagePath: packageDir)
-            XCTAssertEqual(result.exitStatus, .terminated(code: 0))
-            XCTAssert(try result.utf8Output().contains("Build complete!"))
+            let output = try result.utf8Output() + result.utf8stderrOutput()
+            XCTAssertEqual(result.exitStatus, .terminated(code: 0), "output: \(output)")
+            XCTAssert(output.contains("Build complete!"))
 
             // We expect a warning about `library.bar` but not about `library.foo`.
             let stderrOutput = try result.utf8stderrOutput()
@@ -1270,7 +1277,7 @@ final class PackageToolTests: CommandsTestCase {
             try localFileSystem.writeFileContents(packageDir.appending(components: "Plugins", "MyPlugin", "plugin.swift")) {
                 $0 <<< """
                 import PackagePlugin
-
+                import Foundation
                 @main
                 struct MyCommandPlugin: CommandPlugin {
                     func performCommand(
@@ -1280,6 +1287,9 @@ final class PackageToolTests: CommandsTestCase {
                     ) throws {
                         print("This is MyCommandPlugin.")
 
+                        // Print out the initial working directory so we can check it in the test.
+                        print("Initial working directory: \\(FileManager.default.currentDirectoryPath)")
+
                         // Check that we can find a binary-provided tool in the same package.
                         print("Looking for LocalBinaryTool...")
                         let localBinaryTool = try context.tool(named: "LocalBinaryTool")
@@ -1395,6 +1405,15 @@ final class PackageToolTests: CommandsTestCase {
                 XCTAssertMatch(output, .contains("Sources/MyLibrary/library.swift: source"))
                 XCTAssertMatch(output, .contains("Sources/MyLibrary/test.docc: unknown"))
             }
+
+            // Check that the initial working directory is what we expected.
+            do {
+                let workingDirectory = FileManager.default.currentDirectoryPath
+                let result = try SwiftPMProduct.SwiftPackage.executeProcess(["mycmd"], packagePath: packageDir)
+                let output = try result.utf8Output() + result.utf8stderrOutput()
+                XCTAssertEqual(result.exitStatus, .terminated(code: 0), "output: \(output)")
+                XCTAssertMatch(output, .contains("Initial working directory: \(workingDirectory)"))
+            }
         }
     }
 

Tests/FunctionalTests/PluginTests.swift

@@ -425,6 +425,7 @@ class PluginTests: XCTestCase {
                         package: package,
                         buildEnvironment: BuildEnvironment(platform: .macOS, configuration: .debug),
                         scriptRunner: scriptRunner,
+                        workingDirectory: package.path,
                         outputDirectory: pluginDir.appending(component: "output"),
                         toolSearchDirectories: [UserToolchain.default.swiftCompilerPath.parentDirectory],
                         toolNamesToPaths: [:],

Tests/SPMBuildCoreTests/PluginInvocationTests.swift

@@ -92,6 +92,7 @@ class PluginInvocationTests: XCTestCase {
                 sources: Sources,
                 input: PluginScriptRunnerInput,
                 toolsVersion: ToolsVersion,
+                workingDirectory: AbsolutePath,
                 writableDirectories: [AbsolutePath],
                 readOnlyDirectories: [AbsolutePath],
                 fileSystem: FileSystem,