feat: Add support for buildable folder exceptions

Sources/XcodeGraph/Models/BuildableFolder.swift

@@ -1,16 +1,47 @@
 import Path
 
-/// A buildable folder maps to an PBXFileSystemSynchronizedRootGroup in Xcode projects.
+/// Represents a file inside a buildable folder, along with any compiler flags to apply to it.
+public struct BuildableFolderFile: Sendable, Codable, Equatable, Hashable {
+    /// The absolute path to the file within the buildable folder.
+    public let path: AbsolutePath
+
+    /// Compiler flags to apply when building this file. An empty string means no extra flags.
+    public let compilerFlags: String?
+
+    /// Initializes a buildable folder file.
+    /// - Parameters:
+    ///   - path: The absolute path to the file within the buildable folder.
+    ///   - compilerFlags: Compiler flags to apply when building this file. An empty string means no extra flags.
+    public init(path: AbsolutePath, compilerFlags: String?) {
+        self.path = path
+        self.compilerFlags = compilerFlags
+    }
+}
+
+/// A buildable folder maps to a PBXFileSystemSynchronizedRootGroup in Xcode projects.
 /// Synchronized groups were introduced in Xcode 16 to reduce git conflicts by having a reference
 /// to a folder whose content is "synchronized" by Xcode itself. Think of it as Xcode resolving
 /// the globs.
+///
+/// This struct describes a buildable folder, the exception rules for files within it, and the resolved file list.
 public struct BuildableFolder: Sendable, Codable, Equatable, Hashable {
     /// The absolute path to the buildable folder.
     public var path: AbsolutePath
 
-    /// Creates an instance of buildable folder.
-    /// - Parameter path: Absolute path to the buildable folder.
-    public init(path: AbsolutePath) {
+    /// Exceptions associated with this buildable folder, describing files to exclude or per-file build configuration overrides.
+    public var exceptions: BuildableFolderExceptions
+
+    /// The files resolved from this buildable folder, each with any per-file compiler flags.
+    public var resolvedFiles: [BuildableFolderFile]
+
+    /// Creates a new `BuildableFolder` instance.
+    /// - Parameters:
+    ///   - path: The absolute path to the buildable folder.
+    ///   - exceptions: The set of exceptions (such as excluded files or custom compiler flags) for the folder.
+    ///   - resolvedFiles: The list of files resolved from the folder, each file optionally having compiler flags.
+    public init(path: AbsolutePath, exceptions: BuildableFolderExceptions, resolvedFiles: [BuildableFolderFile]) {
         self.path = path
+        self.exceptions = exceptions
+        self.resolvedFiles = resolvedFiles
     }
 }

Sources/XcodeGraph/Models/BuildableFolderException.swift

@@ -0,0 +1,19 @@
+import Path
+
+/// Represents exceptions for a buildable folder, such as files to exclude or specific compiler flags to apply.
+public struct BuildableFolderException: Sendable, Codable, Equatable, Hashable {
+    /// A list of absolute paths to files excluded from the buildable folder.
+    public var excluded: [AbsolutePath]
+
+    /// A dictionary mapping files (referenced by their absolute path) to the compiler flags to apply.
+    public var compilerFlags: [AbsolutePath: String]
+
+    /// Creates a new exception for a buildable folder.
+    /// - Parameters:
+    ///   - excluded: An array of absolute paths to files that should be excluded from the buildable folder.
+    ///   - compilerFlags: A dictionary mapping absolute file paths to specific compiler flags to apply to those files.
+    public init(excluded: [AbsolutePath], compilerFlags: [AbsolutePath: String]) {
+        self.excluded = excluded
+        self.compilerFlags = compilerFlags
+    }
+}

Sources/XcodeGraph/Models/BuildableFolderExceptions.swift

@@ -0,0 +1,24 @@
+import Path
+
+/// PBXFileSystemSynchronizedRootGroup have a one-to-many relationship with PBXFileSystemSynchronizedBuildFileExceptionSet
+/// through .exceptions. Exceptions are used to exclude files and override conffigurations.
+public struct BuildableFolderExceptions: Sendable, Codable, Equatable, Hashable, ExpressibleByArrayLiteral, Sequence {
+    /// A list with all the exceptions.
+    public var exceptions: [BuildableFolderException]
+
+    /// Create a group of exceptions to exclude files from your group or change the configuration of some of them.
+    /// - Parameter exceptions: The list of exceptions.
+    /// - Returns: An instance containing all the exceptions.
+    public init(arrayLiteral elements: BuildableFolderException...) {
+        exceptions = elements
+    }
+
+    public init(exceptions: [BuildableFolderException]) {
+        self.exceptions = exceptions
+    }
+
+    /// Returns an iterator over the contained exceptions.
+    public func makeIterator() -> [BuildableFolderException].Iterator {
+        exceptions.makeIterator()
+    }
+}