From cec27947dacf3e24fb6afa95ff8c81889404a066 Mon Sep 17 00:00:00 2001
From: Jonathan Grynspan <jgrynspan@apple.com>
Date: Wed, 28 Aug 2024 15:29:14 -0400
Subject: [PATCH] Plumb through the testing library version into a function
 instead of a macro.

This PR moves the consumption of the testing library version (via C++ macro
`SWT_TESTING_LIBRARY_VERSION`) to a C++ function. It seems that defining it
in CMake for C++ targets doesn't trigger for the Swift side when it imports
symbols from C headers.

Will verify with a toolchain build.
---
 Sources/Testing/Support/Versions.swift       |  2 +-
 Sources/_TestingInternals/CMakeLists.txt     |  1 +
 Sources/_TestingInternals/Versions.cpp       | 20 ++++++++++++++
 Sources/_TestingInternals/include/Defines.h  | 11 --------
 Sources/_TestingInternals/include/Versions.h | 28 ++++++++++++++++++++
 5 files changed, 50 insertions(+), 12 deletions(-)
 create mode 100644 Sources/_TestingInternals/Versions.cpp
 create mode 100644 Sources/_TestingInternals/include/Versions.h

diff --git a/Sources/Testing/Support/Versions.swift b/Sources/Testing/Support/Versions.swift
index 0218aa185..75bb4b88f 100644
--- a/Sources/Testing/Support/Versions.swift
+++ b/Sources/Testing/Support/Versions.swift
@@ -125,7 +125,7 @@ let simulatorVersion: String = {
 ///
 /// This value is not part of the public interface of the testing library.
 var testingLibraryVersion: String {
-  SWT_TESTING_LIBRARY_VERSION
+  swt_getTestingLibraryVersion().flatMap(String.init(validatingCString:)) ?? "unknown"
 }
 
 /// A human-readable string describing the Swift Standard Library's version.
diff --git a/Sources/_TestingInternals/CMakeLists.txt b/Sources/_TestingInternals/CMakeLists.txt
index 42c27932e..128b0aa48 100644
--- a/Sources/_TestingInternals/CMakeLists.txt
+++ b/Sources/_TestingInternals/CMakeLists.txt
@@ -11,6 +11,7 @@ set(CMAKE_CXX_SCAN_FOR_MODULES 0)
 include(LibraryVersion)
 add_library(_TestingInternals STATIC
   Discovery.cpp
+  Versions.cpp
   WillThrow.cpp)
 target_include_directories(_TestingInternals PUBLIC
   ${CMAKE_CURRENT_SOURCE_DIR}/include)
diff --git a/Sources/_TestingInternals/Versions.cpp b/Sources/_TestingInternals/Versions.cpp
new file mode 100644
index 000000000..e9f0db698
--- /dev/null
+++ b/Sources/_TestingInternals/Versions.cpp
@@ -0,0 +1,20 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+#include "Versions.h"
+
+const char *swt_getTestingLibraryVersion(void) {
+#if defined(_SWT_TESTING_LIBRARY_VERSION)
+  return _SWT_TESTING_LIBRARY_VERSION;
+#else
+#warning _SWT_TESTING_LIBRARY_VERSION not defined: testing library version is unavailable
+  return nullptr;
+#endif
+}
diff --git a/Sources/_TestingInternals/include/Defines.h b/Sources/_TestingInternals/include/Defines.h
index 9af70b384..a93d3f8b2 100644
--- a/Sources/_TestingInternals/include/Defines.h
+++ b/Sources/_TestingInternals/include/Defines.h
@@ -32,15 +32,4 @@
 /// An attribute that renames a C symbol in Swift.
 #define SWT_SWIFT_NAME(name) __attribute__((swift_name(#name)))
 
-/// The testing library version from the package manifest.
-///
-/// - Bug: The value provided to the compiler (`_SWT_TESTING_LIBRARY_VERSION`)
-///   is not visible in Swift, so this second macro is needed.
-///   ((#43521)[https://github.com/swiftlang/swift/issues/43521])
-#if defined(_SWT_TESTING_LIBRARY_VERSION)
-#define SWT_TESTING_LIBRARY_VERSION _SWT_TESTING_LIBRARY_VERSION
-#else
-#define SWT_TESTING_LIBRARY_VERSION "unknown"
-#endif
-
 #endif // SWT_DEFINES_H
diff --git a/Sources/_TestingInternals/include/Versions.h b/Sources/_TestingInternals/include/Versions.h
new file mode 100644
index 000000000..e30aec043
--- /dev/null
+++ b/Sources/_TestingInternals/include/Versions.h
@@ -0,0 +1,28 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+#if !defined(SWT_VERSIONS_H)
+#define SWT_VERSIONS_H
+
+#include "Defines.h"
+
+SWT_ASSUME_NONNULL_BEGIN
+
+/// Get the human-readable version of the testing library.
+///
+/// - Returns: A human-readable string describing the version of the testing
+///   library, or `nullptr` if no version information is available. This
+///   string's value and format may vary between platforms, releases, or any
+///   other conditions. Do not attempt to parse it.
+SWT_EXTERN const char *_Nullable swt_getTestingLibraryVersion(void);
+
+SWT_ASSUME_NONNULL_END
+
+#endif