Move the package version to version.txt.

This change moves the definition of Swift Testing's version to a new file,
version.txt. This file doesn't represent a standard, _per se_, but it is common
for open-source projects to list their version info in such a file. And by
putting our version info in this file, we can share it between package builds
and CMake builds.

Author: grynspan

Package.swift

@@ -470,14 +470,10 @@ extension Array where Element == PackageDescription.CXXSetting {
 
     // Capture the testing library's version as a C++ string constant.
     if let git {
-      let testingLibraryVersion = if let tag = git.currentTag {
-        tag
-      } else if git.hasUncommittedChanges {
-        "\(git.currentCommit) (modified)"
-      } else {
-        git.currentCommit
+      result.append(.define("SWT_TESTING_LIBRARY_COMMIT_HASH", to: #""\#(git.currentCommit)""#))
+      if git.hasUncommittedChanges {
+        result.append(.define("SWT_TESTING_LIBRARY_COMMIT_MODIFIED", to: "1"))
       }
-      result.append(.define("SWT_TESTING_LIBRARY_VERSION", to: #""\#(testingLibraryVersion)""#))
     }
 
     return result

Sources/Testing/Support/Versions.swift

@@ -129,9 +129,28 @@ let simulatorVersion: String = {
 /// an event writer.
 ///
 /// This value is not part of the public interface of the testing library.
-var testingLibraryVersion: String {
-  swt_getTestingLibraryVersion().flatMap(String.init(validatingCString:)) ?? "unknown"
-}
+let testingLibraryVersion: String = {
+  guard var result = swt_getTestingLibraryVersion().flatMap(String.init(validatingCString:)) else {
+    return "unknown"
+  }
+
+  // Get details of the git commit used when compiling the testing library.
+  var commitHash: UnsafePointer<CChar>?
+  var commitModified = CBool(false)
+  swt_getTestingLibraryCommit(&commitHash, &commitModified)
+
+  if let commitHash = commitHash.flatMap(String.init(validatingCString:)) {
+    // Truncate to 15 characters of the hash to match `swift --version`.
+    let commitHash = commitHash.prefix(15)
+    if commitModified {
+      result = "\(result) (\(commitHash) - modified)"
+    } else {
+      result = "\(result) (\(commitHash))"
+    }
+  }
+
+  return result
+}()
 
 /// Get the LLVM target triple used to build the testing library, if available.
 ///

Sources/_TestingInternals/CMakeLists.txt

@@ -8,7 +8,7 @@
 
 set(CMAKE_CXX_SCAN_FOR_MODULES 0)
 
-include(LibraryVersion)
+include(GitCommit)
 include(TargetTriple)
 add_library(_TestingInternals STATIC
   Discovery.cpp

Sources/_TestingInternals/Versions.cpp

@@ -10,15 +10,50 @@
 
 #include "Versions.h"
 
+#include <mutex>
+
 const char *swt_getTestingLibraryVersion(void) {
 #if defined(SWT_TESTING_LIBRARY_VERSION)
+  // The current environment explicitly specifies a version string to return.
   return SWT_TESTING_LIBRARY_VERSION;
+#elif __has_embed("../../version.txt")
+  // Read the version from version.txt at the root of the package's repository.
+  static char version[] = {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc23-extensions"
+#embed "../../version.txt" suffix(, '\0')
+#pragma clang diagnostic pop
+  };
+
+  // Trim any trailing whitespace.
+  static std::once_flag once;
+  std::call_once(once, [] {
+    auto i = std::find_if(std::begin(version), std::end(version), std::isspace);
+    if (i != std::end(version)) {
+      *i = '\0';
+    }
+  });
+
+  return version;
 #else
-#warning SWT_TESTING_LIBRARY_VERSION not defined: testing library version is unavailable
+#warning SWT_TESTING_LIBRARY_VERSION not defined and version.txt not found: testing library version is unavailable
   return nullptr;
 #endif
 }
 
+void swt_getTestingLibraryCommit(const char *_Nullable *_Nonnull outHash, bool *outModified) {
+#if defined(SWT_TESTING_LIBRARY_COMMIT_HASH)
+  *outHash = SWT_TESTING_LIBRARY_COMMIT_HASH;
+#else
+  *outHash = nullptr;
+#endif
+#if defined(SWT_TESTING_LIBRARY_COMMIT_MODIFIED)
+  *outModified = (SWT_TESTING_LIBRARY_COMMIT_MODIFIED != 0);
+#else
+  *outModified = false;
+#endif
+}
+
 const char *swt_getTargetTriple(void) {
 #if defined(SWT_TARGET_TRIPLE)
   return SWT_TARGET_TRIPLE;

Sources/_TestingInternals/include/Versions.h

@@ -38,6 +38,15 @@ static inline uint64_t swt_getSwiftCompilerVersion(void) {
 ///   other conditions. Do not attempt to parse it.
 SWT_EXTERN const char *_Nullable swt_getTestingLibraryVersion(void);
 
+/// Get details of the source control (git) commit from which the testing
+/// library was built.
+///
+/// - Parameters:
+///   - outHash: On return, set to a pointer to a string containing the commit
+///     hash from which the testing library was built.
+///   - outModified: On return, whether or not there were uncommitted changes.
+SWT_EXTERN void swt_getTestingLibraryCommit(const char *_Nullable *_Nonnull outHash, bool *outModified);
+
 /// Get the LLVM target triple used to build the testing library.
 ///
 /// - Returns: A string containing the LLVM target triple used to build the

cmake/modules/GitCommit.cmake

@@ -0,0 +1,34 @@
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See http://swift.org/LICENSE.txt for license information
+# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+
+find_package(Git QUIET)
+if(Git_FOUND)
+  # Get the commit hash corresponding to the current build.
+  execute_process(
+    COMMAND ${GIT_EXECUTABLE} rev-parse --verify HEAD
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+    OUTPUT_VARIABLE SWT_TESTING_LIBRARY_COMMIT_HASH
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    ERROR_QUIET)
+
+  # Check if there are local changes.
+  execute_process(
+    COMMAND ${GIT_EXECUTABLE} status -s
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+    OUTPUT_VARIABLE SWT_TESTING_LIBRARY_COMMIT_MODIFIED
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+endif()
+
+if(SWT_TESTING_LIBRARY_COMMIT_HASH)
+  add_compile_definitions(
+    "$<$<COMPILE_LANGUAGE:CXX>:SWT_TESTING_LIBRARY_COMMIT_HASH=\"${SWT_TESTING_LIBRARY_COMMIT_HASH}\">")
+  if(SWT_TESTING_LIBRARY_COMMIT_MODIFIED)
+    add_compile_definitions(
+      "$<$<COMPILE_LANGUAGE:CXX>:SWT_TESTING_LIBRARY_COMMIT_MODIFIED=1>")
+  endif()
+endif()

cmake/modules/LibraryVersion.cmake

@@ -1,43 +1,10 @@
 # This source file is part of the Swift.org open source project
 #
-# Copyright (c) 2024 Apple Inc. and the Swift project authors
+# Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
-# The current version of the Swift Testing release. For release branches,
-# remember to remove -dev.
-set(SWT_TESTING_LIBRARY_VERSION "6.3-dev")
-
-find_package(Git QUIET)
-if(Git_FOUND)
-  # Get the commit hash corresponding to the current build. Limit length to 15
-  # to match `swift --version` output format.
-  execute_process(
-    COMMAND ${GIT_EXECUTABLE} rev-parse --short=15 --verify HEAD
-    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    OUTPUT_VARIABLE GIT_VERSION
-    OUTPUT_STRIP_TRAILING_WHITESPACE
-    ERROR_QUIET)
-
-  # Check if there are local changes.
-  execute_process(
-    COMMAND ${GIT_EXECUTABLE} status -s
-    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    OUTPUT_VARIABLE GIT_STATUS
-    OUTPUT_STRIP_TRAILING_WHITESPACE)
-  if(GIT_STATUS)
-    set(GIT_VERSION "${GIT_VERSION} - modified")
-  endif()
-endif()
-
-# Combine the hard-coded Swift version with available Git information.
-if(GIT_VERSION)
-set(SWT_TESTING_LIBRARY_VERSION "${SWT_TESTING_LIBRARY_VERSION} (${GIT_VERSION})")
-endif()
-
-# All done!
-message(STATUS "Swift Testing version: ${SWT_TESTING_LIBRARY_VERSION}")
-add_compile_definitions(
-  "$<$<COMPILE_LANGUAGE:CXX>:SWT_TESTING_LIBRARY_VERSION=\"${SWT_TESTING_LIBRARY_VERSION}\">")
+# The library version is now tracked in version.txt at the root directory of the
+# repository. This file will be removed in a future commit.

version.txt

@@ -0,0 +1,9 @@
+6.3-dev
+
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2025 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See http://swift.org/LICENSE.txt for license information
+# See http://swift.org/CONTRIBUTORS.txt for Swift project authors