Use VirtualPaths To Write Module Dependency Graph

Author: CodaFi

Sources/SwiftDriver/Driver/Driver.swift

@@ -206,15 +206,15 @@ public struct Driver {
   ///
   /// FIXME: This is a little ridiculous. We could probably just replace the
   /// build record outright with a serialized format.
-  var driverDependencyGraphPath: AbsolutePath? {
-    guard
-      let recordInfo = self.buildRecordInfo,
-      let recordPath = recordInfo.buildRecordPath.absolutePath
-    else {
+  var driverDependencyGraphPath: VirtualPath? {
+    guard let recordInfo = self.buildRecordInfo else {
       return nil
     }
-    let filename = recordPath.basenameWithoutExt
-    return recordPath.parentDirectory.appending(component: filename + ".priors")
+    let filename = recordInfo.buildRecordPath.basenameWithoutExt
+    return recordInfo
+      .buildRecordPath
+      .parentDirectory
+      .appending(component: filename + ".priors")
   }
 
   /// Code & data for incremental compilation. Nil if not running in incremental mode.

Sources/SwiftDriver/IncrementalCompilation/ModuleDependencyGraph.swift

@@ -457,7 +457,7 @@ extension ModuleDependencyGraph {
   /// - Throws: An error describing any failures to read the graph from the given file.
   /// - Returns: A fully deserialized ModuleDependencyGraph.
   static func read(
-    from path: AbsolutePath,
+    from path: VirtualPath,
     on fileSystem: FileSystem,
     diagnosticEngine: DiagnosticsEngine,
     reporter: IncrementalCompilationState.Reporter?,
@@ -648,7 +648,7 @@ extension ModuleDependencyGraph {
   ///   - compilerVersion: A string containing version information for the
   ///                      driver used to create this file.
   func write(
-    to path: AbsolutePath,
+    to path: VirtualPath,
     on fileSystem: FileSystem,
     compilerVersion: String
   ) {
@@ -1038,7 +1038,7 @@ fileprivate extension DependencyKey.Designator {
 
 extension Diagnostic.Message {
   fileprivate static func error_could_not_write_dep_graph(
-    to path: AbsolutePath
+    to path: VirtualPath
   ) -> Diagnostic.Message {
     .error("could not write driver dependency graph to \(path)")
   }

Sources/SwiftDriver/Utilities/VirtualPath.swift

@@ -410,6 +410,13 @@ extension TSCBasic.FileSystem {
     try resolvingVirtualPath(path, apply: readFileContents)
   }
 
+  func writeFileContents(_ path: VirtualPath, bytes: ByteString, atomically: Bool) throws {
+    try resolvingVirtualPath(path) { absolutePath in
+      try self.writeFileContents(absolutePath, bytes: bytes, atomically: atomically)
+    }
+  }
+
+
   func getFileInfo(_ path: VirtualPath) throws -> TSCBasic.FileInfo {
     try resolvingVirtualPath(path, apply: getFileInfo)
   }

Tests/SwiftDriverTests/DependencyGraphSerializationTests.swift

@@ -16,7 +16,7 @@ import TSCBasic
 
 class DependencyGraphSerializationTests: XCTestCase {
   func roundTrip(_ graph: ModuleDependencyGraph) throws {
-    let mockPath = AbsolutePath("/module-dependency-graph")
+    let mockPath = VirtualPath.absolute(AbsolutePath("/module-dependency-graph"))
     let de = DiagnosticsEngine()
     let fs = InMemoryFileSystem()
     graph.write(to: mockPath, on: fs, compilerVersion: "Swift 99")