Add Snippet support with SwiftBuild

bkhouri · bkhouri · commit 6eb953ca834c · 2025-09-08T16:56:20.000-04:00
Snippets are treated as executable targets with the native build system. This change updates the PIF Builder to support snippet, giving Snippet support with the Swift Build build system. Depends on: swiftlang/swift-build#775 Fixes: swiftlang#9040 issue: rdar://158630024 issue: rdar://147705448
diff --git a/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Package.swift b/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Package.swift
@@ -8,7 +8,13 @@ let package = Package(
             name: "PluginScriptProduct",
             targets: [
                 "PluginScriptTarget"
-            ]
+            ],
+        ),
+        .library(
+            name: "MyLib",
+            targets: [
+                "MyLib",
+            ],
         ),
     ],
     targets: [
@@ -17,9 +23,10 @@ let package = Package(
             capability: .command(
                 intent: .custom(
                     verb: "do-something",
-                    description: "Do something"
-                )
-            )
+                    description: "Do something",
+                ),
+            ),
         ),
+        .target(name: "MyLib"),
     ]
 )
diff --git a/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/ContainsMain.swift b/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/ContainsMain.swift
@@ -0,0 +1,9 @@
+// The Swift Programming Language
+// https://docs.swift.org/swift-book
+
+@main
+struct foo {
+    static func main() {
+        print("hello, snippets. File: \(#file)")
+    }
+}
diff --git a/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/ImportsProductTarget.swift b/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/ImportsProductTarget.swift
@@ -0,0 +1,3 @@
+import MyLib
+
+libraryCall()
diff --git a/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/MySnippet.swift b/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/MySnippet.swift
@@ -0,0 +1 @@
+print("hello, snippets. File: \(#file)")
diff --git a/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/SubDirectory/main.swift b/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Snippets/SubDirectory/main.swift
@@ -0,0 +1 @@
+print("hello, snippets! File: \(#file)")
diff --git a/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Sources/MyLib/MyLib.swift b/Fixtures/Miscellaneous/Plugins/PluginsAndSnippets/Sources/MyLib/MyLib.swift
@@ -0,0 +1,3 @@
+public func libraryCall() {
+    print("From library")
+}
diff --git a/Package.swift b/Package.swift
@@ -535,6 +535,7 @@ let package = Package(
         .target(
             name: "SwiftBuildSupport",
             dependencies: [
+                "Build",
                 "SPMBuildCore",
                 "PackageGraph",
             ],
diff --git a/Sources/Basics/FileSystem/InMemoryFileSystem.swift b/Sources/Basics/FileSystem/InMemoryFileSystem.swift
@@ -226,12 +226,24 @@ public final class InMemoryFileSystem: FileSystem {
     }
 
     /// Virtualized current working directory.
+    private var _currentWorkingDirectory: TSCBasic.AbsolutePath = try! .init(validating: "/")
+
     public var currentWorkingDirectory: TSCBasic.AbsolutePath? {
-        return try? .init(validating: "/")
+        return _currentWorkingDirectory
     }
 
     public func changeCurrentWorkingDirectory(to path: TSCBasic.AbsolutePath) throws {
-        throw FileSystemError(.unsupported, path)
+        return try lock.withLock {
+            // Verify the path exists and is a directory
+            guard let node = try getNode(path) else {
+                throw FileSystemError(.noEntry, path)
+            }
+
+            guard case .directory = node.contents else {
+                throw FileSystemError(.notDirectory, path)
+            }
+            _currentWorkingDirectory = path
+        }
     }
 
     public var homeDirectory: TSCBasic.AbsolutePath {
diff --git a/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift b/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift
@@ -34,6 +34,34 @@ import struct TSCBasic.ByteString
 @available(*, deprecated, renamed: "SwiftModuleBuildDescription")
 public typealias SwiftTargetBuildDescription = SwiftModuleBuildDescription
 
+// looking into the file content to see if it is using the @main annotation
+// this is not bullet-proof since theoretically the file can contain the @main string for other reasons
+// but it is the closest to accurate we can do at this point
+package func containsAtMain(fileSystem: FileSystem, path: AbsolutePath) throws -> Bool {
+    let content: String = try fileSystem.readFileContents(path)
+    let lines = content.split(whereSeparator: { $0.isNewline }).map { $0.trimmingCharacters(in: .whitespaces) }
+
+    var multilineComment = false
+    for line in lines {
+        if line.hasPrefix("//") {
+            continue
+        }
+        if line.hasPrefix("/*") {
+            multilineComment = true
+        }
+        if line.hasSuffix("*/") {
+            multilineComment = false
+        }
+        if multilineComment {
+            continue
+        }
+        if line.hasPrefix("@main") {
+            return true
+        }
+    }
+    return false
+}
+
 /// Build description for a Swift module.
 public final class SwiftModuleBuildDescription {
     /// The package this target belongs to.
@@ -216,40 +244,12 @@ public final class SwiftModuleBuildDescription {
                 return false
             }
             // looking into the file content to see if it is using the @main annotation which requires parse-as-library
-            return (try? self.containsAtMain(fileSystem: self.fileSystem, path: self.sources[0])) ?? false
+            return (try? containsAtMain(fileSystem: self.fileSystem, path: self.sources[0])) ?? false
         default:
             return false
         }
     }
 
-    // looking into the file content to see if it is using the @main annotation
-    // this is not bullet-proof since theoretically the file can contain the @main string for other reasons
-    // but it is the closest to accurate we can do at this point
-    func containsAtMain(fileSystem: FileSystem, path: AbsolutePath) throws -> Bool {
-        let content: String = try self.fileSystem.readFileContents(path)
-        let lines = content.split(whereSeparator: { $0.isNewline }).map { $0.trimmingCharacters(in: .whitespaces) }
-
-        var multilineComment = false
-        for line in lines {
-            if line.hasPrefix("//") {
-                continue
-            }
-            if line.hasPrefix("/*") {
-                multilineComment = true
-            }
-            if line.hasSuffix("*/") {
-                multilineComment = false
-            }
-            if multilineComment {
-                continue
-            }
-            if line.hasPrefix("@main") {
-                return true
-            }
-        }
-        return false
-    }
-
     /// The filesystem to operate on.
     let fileSystem: FileSystem
 
diff --git a/Sources/Commands/PackageCommands/CompletionCommand.swift b/Sources/Commands/PackageCommands/CompletionCommand.swift
@@ -79,18 +79,18 @@ extension SwiftPackageCommand {
             case .listExecutables:
                 let graph = try await swiftCommandState.loadPackageGraph()
                 let package = graph.rootPackages[graph.rootPackages.startIndex].underlying
-                let executables = package.products.filter { $0.type == .executable }
+                let executables = package.products.filter { $0.type == .executable }.sorted()
                 for executable in executables {
                     print(executable.name)
                 }
             case .listSnippets:
                 let graph = try await swiftCommandState.loadPackageGraph()
                 let package = graph.rootPackages[graph.rootPackages.startIndex].underlying
-                let executables = package.modules.filter { $0.type == .snippet }
+                let executables = package.modules.filter { $0.type == .snippet }.sorted()
                 for executable in executables {
                     print(executable.name)
                 }
             }
         }
     }
-}
+}
diff --git a/Sources/PackageModel/Module/Module.swift b/Sources/PackageModel/Module/Module.swift
@@ -292,6 +292,12 @@ extension Module: Hashable {
     }
 }
 
+extension Module: Comparable {
+    public static func < (lhs: Module, rhs: Module) -> Bool {
+        return lhs.name < rhs.name
+    }
+}
+
 extension Module: CustomStringConvertible {
     public var description: String {
         return "<\(Swift.type(of: self)): \(name)>"
diff --git a/Sources/PackageModel/Product.swift b/Sources/PackageModel/Product.swift
@@ -68,6 +68,12 @@ extension Product: Hashable {
     }
 }
 
+extension Product: Comparable {
+    public static func < (lhs: Product, rhs: Product) -> Bool {
+        lhs.name < rhs.name
+    }
+}
+
 /// The type of product.
 public enum ProductType: Equatable, Hashable, Sendable {
 
diff --git a/Sources/SwiftBuildSupport/PackagePIFBuilder.swift b/Sources/SwiftBuildSupport/PackagePIFBuilder.swift
@@ -451,13 +451,13 @@ public final class PackagePIFBuilder {
                     try projectBuilder.makeLibraryProduct(product, type: libraryType)
                 }
 
-            case .executable, .test:
+            case .executable, .test, .snippet:
                 try projectBuilder.makeMainModuleProduct(product)
 
             case .plugin:
                 try projectBuilder.makePluginProduct(product)
 
-            case .snippet, .macro:
+            case .macro:
                 break // TODO: Double-check what's going on here as we skip snippet modules too (rdar://147705448)
             }
         }
diff --git a/Sources/SwiftBuildSupport/PackagePIFProjectBuilder+Products.swift b/Sources/SwiftBuildSupport/PackagePIFProjectBuilder+Products.swift
@@ -17,6 +17,7 @@ import TSCUtility
 import struct Basics.AbsolutePath
 import class Basics.ObservabilitySystem
 import struct Basics.SourceControlURL
+import func Build.containsAtMain
 
 import class PackageModel.BinaryModule
 import class PackageModel.Manifest
@@ -55,7 +56,7 @@ extension PackagePIFProjectBuilder {
         let synthesizedResourceGeneratingPluginInvocationResults: [PackagePIFBuilder.BuildToolPluginInvocationResult] =
             []
 
-        if product.type == .executable {
+        if [.executable, .snippet].contains(product.type) {
             if let customPIFProductType = pifBuilder.delegate.customProductType(forExecutable: product.underlying) {
                 pifProductType = customPIFProductType
                 moduleOrProductType = PackagePIFBuilder.ModuleOrProductType(from: customPIFProductType)
@@ -138,6 +139,17 @@ extension PackagePIFProjectBuilder {
                 settings[.INSTALL_PATH] = "/usr/local/bin"
                 settings[.LD_RUNPATH_SEARCH_PATHS] = ["$(inherited)", "@executable_path/../lib"]
             }
+        } else if mainModule.type == .snippet {
+            let hasMainModule: Bool
+            if let mainModule = product.mainModule {
+                // Check if any source file in the main module contains @main
+                hasMainModule = mainModule.sources.paths.contains { (sourcePath: AbsolutePath) in
+                    (try? containsAtMain(fileSystem: pifBuilder.fileSystem, path: sourcePath)) ?? false
+                }
+            } else {
+                hasMainModule = false
+            }
+            settings[.SWIFT_DISABLE_PARSE_AS_LIBRARY] = hasMainModule ? "NO" : "YES"
         }
 
         let mainTargetDeploymentTargets = mainModule.deploymentTargets(using: pifBuilder.delegate)
diff --git a/Sources/_InternalTestSupport/FileSystemHelpers.swift b/Sources/_InternalTestSupport/FileSystemHelpers.swift
@@ -0,0 +1,118 @@
+import Foundation
+import Basics
+
+func getFiles(atPath path: String, matchingExtension fileExtension: String) -> [URL] {
+    let fileManager = FileManager.default
+    var matchingFiles: [URL] = []
+
+    guard
+        let enumerator = fileManager.enumerator(
+            at: URL(fileURLWithPath: path),
+            includingPropertiesForKeys: [.isRegularFileKey],
+            options: [.skipsHiddenFiles, .skipsPackageDescendants]
+        )
+    else {
+        print("Error: Could not create enumerator for path: \(path)")
+        return []
+    }
+
+    for case let fileURL as URL in enumerator {
+        do {
+            let resourceValues = try fileURL.resourceValues(forKeys: [.isRegularFileKey])
+            if let isRegularFile = resourceValues.isRegularFile, isRegularFile {
+                if fileURL.pathExtension.lowercased() == fileExtension.lowercased() {
+                    matchingFiles.append(fileURL)
+                }
+            }
+        } catch {
+            print("Error retrieving resource values for \(fileURL.lastPathComponent): \(error.localizedDescription)")
+        }
+    }
+    return matchingFiles
+}
+
+/// Returns all files that match the given extension in the specified directory.
+///
+/// - Parameters:
+///   - directory: The directory to search in (AbsolutePath)
+///   - extension: The file extension to match (without the leading dot)
+///   - recursive: Whether to search subdirectories recursively (default: true)
+///   - fileSystem: The file system to use for operations (defaults to localFileSystem)
+/// - Returns: An array of AbsolutePath objects
+/// - Throws: FileSystemError if the directory cannot be accessed or enumerated
+public func getFiles(
+    in directory: AbsolutePath,
+    matchingExtension extension: String,
+    recursive: Bool = true,
+    fileSystem: FileSystem = localFileSystem
+) throws -> [AbsolutePath] {
+    var matchingFiles: [AbsolutePath] = []
+    let normalizedExtension = `extension`.lowercased()
+    
+    guard fileSystem.exists(directory) else {
+        throw StringError("Directory does not exist: \(directory)")
+    }
+    
+    guard fileSystem.isDirectory(directory) else {
+        throw StringError("Path is not a directory: \(directory)")
+    }
+    
+    if recursive {
+        try fileSystem.enumerate(directory: directory) { filePath in
+            if fileSystem.isFile(filePath) {
+                if let fileExtension = filePath.extension?.lowercased(),
+                   fileExtension == normalizedExtension {
+                    matchingFiles.append(filePath)
+                }
+            }
+        }
+    } else {
+        // Non-recursive: only check direct children
+        let contents = try fileSystem.getDirectoryContents(directory)
+        for item in contents {
+            let itemPath = directory.appending(component: item)
+            if fileSystem.isFile(itemPath) {
+                if let fileExtension = itemPath.extension?.lowercased(),
+                   fileExtension == normalizedExtension {
+                    matchingFiles.append(itemPath)
+                }
+            }
+        }
+    }
+    
+    return matchingFiles
+}
+
+/// Returns all files that match the given extension in the specified directory.
+///
+/// - Parameters:
+///   - directory: The directory to search in (RelativePath)
+///   - extension: The file extension to match (without the leading dot)
+///   - recursive: Whether to search subdirectories recursively (default: true)
+///   - fileSystem: The file system to use for operations (defaults to localFileSystem)
+/// - Returns: An array of RelativePath objects
+/// - Throws: FileSystemError if the directory cannot be accessed or enumerated
+public func getFiles(
+    in directory: RelativePath,
+    matchingExtension extension: String,
+    recursive: Bool = true,
+    fileSystem: FileSystem = localFileSystem
+) throws -> [RelativePath] {
+    // Convert RelativePath to AbsolutePath for enumeration
+    guard let currentWorkingDirectory = fileSystem.currentWorkingDirectory else {
+        throw StringError("Cannot determine current working directory")
+    }
+    
+    let absoluteDirectory = currentWorkingDirectory.appending(directory)
+    let absoluteResults = try getFiles(
+        in: absoluteDirectory,
+        matchingExtension: `extension`,
+        recursive: recursive,
+        fileSystem: fileSystem
+    )
+    
+    // Convert results back to RelativePath
+    return absoluteResults.map { absolutePath in
+        absolutePath.relative(to: currentWorkingDirectory)
+    }
+}
diff --git a/Sources/_InternalTestSupport/SwiftTesting+Tags.swift b/Sources/_InternalTestSupport/SwiftTesting+Tags.swift
@@ -33,6 +33,7 @@ extension Tag.Feature {
     @Tag public static var NetRc: Tag
     @Tag public static var Resource: Tag
     @Tag public static var SpecialCharacters: Tag
+    @Tag public static var Snippets: Tag
     @Tag public static var Traits: Tag
 
 }
diff --git a/Tests/BasicsTests/FileSystem/InMemoryFilesSystemTests.swift b/Tests/BasicsTests/FileSystem/InMemoryFilesSystemTests.swift
diff --git a/Tests/BuildTests/BuildDescriptionTests.swift b/Tests/BuildTests/BuildDescriptionTests.swift
diff --git a/Tests/CommandsTests/PackageCommandTests.swift b/Tests/CommandsTests/PackageCommandTests.swift
diff --git a/Tests/FunctionalTests/PluginTests.swift b/Tests/FunctionalTests/PluginTests.swift
diff --git a/Tests/PackageLoadingTests/PackageBuilderTests.swift b/Tests/PackageLoadingTests/PackageBuilderTests.swift
diff --git a/Tests/PackageModelTests/SnippetTests.swift b/Tests/PackageModelTests/SnippetTests.swift
diff --git a/Tests/_InternalTestSupportTests/FileSystemHelpersTests.swift b/Tests/_InternalTestSupportTests/FileSystemHelpersTests.swift

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+import MyLib`
	`2`	`+`
	`3`	`+libraryCall()`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+print("hello, snippets. File: \(#file)")`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+print("hello, snippets! File: \(#file)")`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+public func libraryCall() {`
	`2`	`+ print("From library")`
	`3`	`+}`
Original file line number	Diff line number	Diff line change
`@@ -79,18 +79,18 @@ extension SwiftPackageCommand {`
`79`	`79`	`case .listExecutables:`
`80`	`80`	`let graph = try await swiftCommandState.loadPackageGraph()`
`81`	`81`	`let package = graph.rootPackages[graph.rootPackages.startIndex].underlying`
`82`		`- let executables = package.products.filter { $0.type == .executable }`
	`82`	`+ let executables = package.products.filter { $0.type == .executable }.sorted()`
`83`	`83`	`for executable in executables {`
`84`	`84`	`print(executable.name)`
`85`	`85`	`}`
`86`	`86`	`case .listSnippets:`
`87`	`87`	`let graph = try await swiftCommandState.loadPackageGraph()`
`88`	`88`	`let package = graph.rootPackages[graph.rootPackages.startIndex].underlying`
`89`		`- let executables = package.modules.filter { $0.type == .snippet }`
	`89`	`+ let executables = package.modules.filter { $0.type == .snippet }.sorted()`
`90`	`90`	`for executable in executables {`
`91`	`91`	`print(executable.name)`
`92`	`92`	`}`
`93`	`93`	`}`
`94`	`94`	`}`
`95`	`95`	`}`
`96`		`-}`
	`96`	`+}`