Add a test.

Author: David Ungar

Tests/SwiftDriverTests/Helpers/AssertDiagnostics.swift

@@ -15,17 +15,18 @@ import SwiftDriver
 import TSCBasic
 import TestUtilities
 
-func assertDriverDiagnostics(
+@discardableResult
+func assertDriverDiagnostics<Result> (
   args: [String],
   env: [String: String] = ProcessEnv.vars,
   file: StaticString = #file, line: UInt = #line,
-  do body: (inout Driver, DiagnosticVerifier) throws -> Void
-) throws {
+  do body: (inout Driver, DiagnosticVerifier) throws -> Result
+) throws -> Result {
   let matcher = DiagnosticVerifier()
   defer { matcher.verify(file: file, line: line) }
 
   var driver = try Driver(args: args, env: env, diagnosticsEngine: DiagnosticsEngine(handlers: [matcher.emit(_:)]))
-  try body(&driver, matcher)
+  return try body(&driver, matcher)
 }
 
 /// Asserts that the `Driver` it instantiates will only emit warnings and errors

Tests/SwiftDriverTests/IncrementalCompilationTests.swift

@@ -407,11 +407,13 @@ final class IncrementalCompilationTests: XCTestCase {
 }
 
 extension IncrementalCompilationTests {
+  @discardableResult
   func doABuild(_ message: String,
                 checkDiagnostics: Bool,
                 extraArguments: [String],
                 expectingRemarks texts: [String],
-                whenAutolinking: [String]) throws {
+                whenAutolinking: [String]
+  ) throws -> Driver? {
     try doABuild(
       message,
       checkDiagnostics: checkDiagnostics,
@@ -420,14 +422,16 @@ extension IncrementalCompilationTests {
       expectingWhenAutolinking: whenAutolinking.map {.remark($0)})
   }
 
+  @discardableResult
   func doABuild(_ message: String,
                 checkDiagnostics: Bool,
                 extraArguments: [String],
                 expecting expectations: [Diagnostic.Message],
-                expectingWhenAutolinking autolinkExpectations: [Diagnostic.Message]) throws {
+                expectingWhenAutolinking autolinkExpectations: [Diagnostic.Message]
+  ) throws -> Driver? {
     print("*** starting build \(message) ***", to: &stderrStream); stderrStream.flush()
 
-    func doIt(_ driver: inout Driver) {
+    func doTheCompile(_ driver: inout Driver) {
       let jobs = try! driver.planBuild()
       try? driver.run(jobs: jobs)
     }
@@ -437,14 +441,16 @@ extension IncrementalCompilationTests {
       throw XCTSkip("Cannot perform this test on this host")
     }
     let allArgs = commonArgs + extraArguments + sdkArgumentsForTesting
+    let postMortemDriver: Driver?
     if checkDiagnostics {
-      try assertDriverDiagnostics(args: allArgs) {driver, verifier in
+      postMortemDriver = try assertDriverDiagnostics(args: allArgs) {driver, verifier in
         verifier.forbidUnexpected(.error, .warning, .note, .remark, .ignored)
         expectations.forEach {verifier.expect($0)}
         if driver.isAutolinkExtractJobNeeded {
           autolinkExpectations.forEach {verifier.expect($0)}
         }
-        doIt(&driver)
+        doTheCompile(&driver)
+        return driver
       }
     }
     else {
@@ -454,9 +460,11 @@ extension IncrementalCompilationTests {
       var driver = try Driver(args: allArgs, env: ProcessEnv.vars,
                               diagnosticsEngine: diagnosticEngine,
                               fileSystem: localFileSystem)
-      doIt(&driver)
+      doTheCompile(&driver)
+      postMortemDriver = driver
     }
     print("", to: &stderrStream); stderrStream.flush()
+    return postMortemDriver
   }
 }
 
@@ -587,6 +595,22 @@ extension IncrementalCompilationTests {
     }
   }
 
+  /// Ensure that if an output of post-compile job is missing, the job gets rerun.
+  func testIncrementalPostCompileJob() throws {
+    let driver = try XCTUnwrap(tryInitial(checkDiagnostics: true))
+    for postCompileOutput in try driver.postCompileOutputs() {
+      let absPostCompileOutput = try XCTUnwrap(postCompileOutput.file.absolutePath)
+      try localFileSystem.removeFileTree(absPostCompileOutput)
+      XCTAssertFalse(localFileSystem.exists(absPostCompileOutput))
+      tryNoChange()
+      XCTAssertTrue(localFileSystem.exists(absPostCompileOutput))
+    }
+  }
+
+  private func postCompileOutputs() -> [AbsolutePath] {
+    abort()
+  }
+
   func testIncremental(checkDiagnostics: Bool) throws {
     try tryInitial(checkDiagnostics: checkDiagnostics)
     #if true // sometimes want to skip for debugging
@@ -597,10 +621,10 @@ extension IncrementalCompilationTests {
     tryReplacingMain(checkDiagnostics: checkDiagnostics)
   }
 
-
+  @discardableResult
   func tryInitial(checkDiagnostics: Bool = false,
                   extraArguments: [String] = []
-  ) throws {
+  ) throws -> Driver? {
     try doABuild(
       "initial",
       checkDiagnostics: checkDiagnostics,
@@ -919,3 +943,8 @@ class CrossModuleIncrementalBuildTests: XCTestCase {
   }
 }
 
+fileprivate extension Driver {
+  func postCompileOutputs() throws -> [TypedVirtualPath] {
+    try XCTUnwrap(incrementalCompilationState).jobsAfterCompiles.flatMap {$0.outputs}
+  }
+}