Add workflow to verify CMakeLists.txt files

.github/workflows/pull_request.yml

@@ -108,3 +108,160 @@ jobs:
             ${{ runner.temp }}/${{ env.BASELINE_FILE }}
             ${{ runner.temp }}/${{ env.COMPARE_FILE }}
             ${{ runner.temp }}/${{ env.COMPARE_OUT_FILE }}
+  crossrepo:
+    name: Cross-Repo Validation
+    runs-on: ubuntu-latest
+    container:
+      image: swift:6.3-jammy
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v7
+      - name: Install apt dependencies
+        run: apt-get -qq update && apt-get -qq -y install curl ninja-build
+      - name: Install CMake 3.30.2
+        run: |
+          ARCH=`uname -m`
+          curl -sL https://github.com/Kitware/CMake/releases/download/v3.30.2/cmake-3.30.2-linux-$ARCH.tar.gz -O
+          tar xzf cmake-3.30.2-linux-$ARCH.tar.gz
+          export PATH="`pwd`/cmake-3.30.2-linux-$ARCH/bin:$PATH"
+          echo "PATH=$PATH" >> $GITHUB_ENV
+          cmake --version
+      - name: Compare CMakeLists.txt against swiftlang/swift/Runtimes/Supplemental
+        id: compare
+        env:
+          UPSTREAM_DIR: https://raw.githubusercontent.com/swiftlang/swift/refs/heads/main/Runtimes/Supplemental/StringProcessing
+          MODULES: _StringProcessing _RegexParser
+        shell: bash
+        run: |
+          set -u
+
+          # `-f` so a file moving upstream reports a fetch error rather than
+          # diffing against a 404 page.
+          for module in $MODULES; do
+            if ! curl -fsSL "$UPSTREAM_DIR/$module/CMakeLists.txt" \
+                 -o "upstream-$module-CMakeLists.txt"; then
+              echo "result=fetch-failed" >> "$GITHUB_OUTPUT"
+              echo "Could not fetch $module/CMakeLists.txt from swiftlang/swift."
+              exit 1
+            fi
+          done
+
+          : > "$RUNNER_TEMP/cmake-diff.txt"
+          status=0
+          for module in $MODULES; do
+            if ! diff -u \
+                 --label "swiftlang/swift: Runtimes/Supplemental/StringProcessing/$module/CMakeLists.txt" \
+                 --label "this repo:       Sources/$module/CMakeLists.txt" \
+                 "upstream-$module-CMakeLists.txt" \
+                 "Sources/$module/CMakeLists.txt" \
+                 >> "$RUNNER_TEMP/cmake-diff.txt"; then
+              status=1
+            fi
+          done
+
+          if [ "$status" -eq 0 ]; then
+            echo "result=match" >> "$GITHUB_OUTPUT"
+            echo "Both CMakeLists.txt files match swiftlang/swift."
+          else
+            echo "result=differs" >> "$GITHUB_OUTPUT"
+            cat "$RUNNER_TEMP/cmake-diff.txt"
+          fi
+          exit "$status"
+      - name: Configure CMake
+        id: configure
+        if: ${{ !cancelled() }}
+        run: cmake -G Ninja -S Sources -B build -DCMAKE_BUILD_TYPE=Release
+      - name: Build
+        id: build
+        if: ${{ !cancelled() }}
+        run: cmake --build build
+      - name: Verdict
+        if: ${{ always() }}
+        env:
+          COMPARE_OUTCOME: ${{ steps.compare.outcome }}
+          COMPARE_RESULT: ${{ steps.compare.outputs.result }}
+          CONFIGURE_OUTCOME: ${{ steps.configure.outcome }}
+          BUILD_OUTCOME: ${{ steps.build.outcome }}
+        shell: bash
+        run: |
+          set -u
+
+          # Report to the step log and to the job summary page.
+          emit() { printf '%s\n' "$@" | tee -a "$GITHUB_STEP_SUMMARY"; }
+
+          failed=0
+
+          # --- the CMake build ---
+          if [ "$CONFIGURE_OUTCOME" = failure ] || [ "$BUILD_OUTCOME" = failure ]; then
+            failed=1
+            if [ "$CONFIGURE_OUTCOME" = failure ]; then
+              stage='CMake configuration'
+            else
+              stage='CMake build'
+            fi
+            emit \
+              "## :x: $stage failed" \
+              '' \
+              'The CMake build of `_RegexParser` and `_StringProcessing` is broken.' \
+              "See the \"$stage\" step above for the output." \
+              ''
+          fi
+
+          # --- the comparison against swiftlang/swift ---
+          case "${COMPARE_RESULT:-}" in
+            match)
+              ;;
+            differs)
+              failed=1
+              emit \
+                '## :warning: `CMakeLists.txt` differs from swiftlang/swift' \
+                '' \
+                '<details><summary>Diff to apply upstream</summary>' \
+                '' \
+                '```diff'
+              tee -a "$GITHUB_STEP_SUMMARY" < "$RUNNER_TEMP/cmake-diff.txt"
+              emit '```' '' '</details>' ''
+              ;;
+            fetch-failed)
+              failed=1
+              emit \
+                '## :x: Could not fetch the upstream `CMakeLists.txt` files'
+              ;;
+            *)
+              failed=1
+              emit \
+                "## :x: Comparison did not complete (outcome: ${COMPARE_OUTCOME:-unknown})"
+              ;;
+          esac
+
+          # --- all clear ---
+          if [ "$failed" -eq 0 ]; then
+            emit \
+              '## :white_check_mark: Cross-repo validation passed'
+          fi
+
+          exit "$failed"
+  required:
+    name: Required
+    runs-on: ubuntu-latest
+    needs:
+      - tests
+      - soundness
+      - bench
+    if: always()  # Runs even if previous jobs fail so it can evaluate them
+    steps:
+      - name: Install required tools
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y --no-install-recommends coreutils jq
+      - name: Check upstream job statuses
+        env:
+          NEEDS_JSON: ${{ toJSON(needs) }}
+        run: |
+          failed=$(printf '%s' "$NEEDS_JSON" | jq -r 'to_entries | map(select(.value.result != "success")) | .[] | "\(.key): \(.value.result)"')
+          if [ -n "$failed" ]; then
+            echo "The following required jobs did not succeed:"
+            printf '%s\n' "$failed"
+            exit 1
+          fi
+          echo "All required jobs succeeded."

Package.swift

@@ -1,6 +1,4 @@
 // swift-tools-version:6.0
-// The swift-tools-version declares the minimum version of Swift required to build this package.
-
 import PackageDescription
 
 let availabilityDefinition = PackageDescription.SwiftSetting.unsafeFlags([
@@ -46,7 +44,6 @@ let publicStdlibSettings: [PackageDescription.SwiftSetting] = [
 let package = Package(
     name: "swift-experimental-string-processing",
     products: [
-        // Products define the executables and libraries produced by a package, and make them visible to other packages.
         .library(
             name: "_StringProcessing",
             targets: ["_StringProcessing"]),
@@ -69,11 +66,10 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-argument-parser", from: "1.0.0"),
     ],
     targets: [
-        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
-        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
         .target(
             name: "_RegexParser",
             dependencies: [],
+            exclude: ["CMakeLists.txt"],
             packageAccess: false,
             swiftSettings: privateStdlibSettings),
         .testTarget(
@@ -90,6 +86,7 @@ let package = Package(
               "_RegexParser",
               "_CUnicode",
             ],
+            exclude: ["CMakeLists.txt", "_CUnicode"],
             packageAccess: false,
             swiftSettings: publicStdlibSettings),
         .target(

Sources/CMakeLists.txt

@@ -0,0 +1,92 @@
+#===-----------------------------------------------------------------------===#
+#
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2026 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
+#
+#===-----------------------------------------------------------------------===#
+
+# NOTE: This build configuration is only to validate that the settings
+# match between the swiftlang/swift project and this one, not for
+# producing installable libraries.
+
+cmake_minimum_required(VERSION 3.26)
+
+project(SwiftStringProcessing
+  VERSION 1.0.0
+  LANGUAGES C Swift)
+
+include(GNUInstallDirs)
+
+set(CMAKE_Swift_LANGUAGE_VERSION 5)
+set(CMAKE_C_STANDARD 99)
+
+option(BUILD_SHARED_LIBS "Build shared libraries" YES)
+
+set(SwiftStringProcessing_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/swift"
+  CACHE STRING "Destination for the built libraries")
+
+#===-----------------------------------------------------------------------===#
+# Compiler flags
+#===-----------------------------------------------------------------------===#
+
+add_compile_options(
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-concurrency-module-import>"
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>")
+
+foreach(definition
+    "SwiftStdlib 5.7:macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0"
+    "SwiftStdlib 5.8:macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4"
+    "SwiftStdlib 5.9:macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0"
+    "SwiftStdlib 6.0:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0"
+    "SwiftStdlib 6.1:macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4"
+    "SwiftStdlib 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0"
+    "SwiftStdlib 6.3:macOS 26.4, iOS 26.4, watchOS 26.4, tvOS 26.4, visionOS 26.4"
+    "SwiftStdlib 6.4:macOS 27.0, iOS 27.0, watchOS 27.0, tvOS 27.0, visionOS 27.0"
+    "SwiftStdlib 6.5:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999")
+  add_compile_options(
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -define-availability -Xfrontend \"${definition}\">")
+endforeach()
+
+add_compile_options(
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-upcoming-feature MemberImportVisibility>")
+
+#===-----------------------------------------------------------------------===#
+# Shims for the runtime build
+#===-----------------------------------------------------------------------===#
+#
+# The module files call into helpers that only exist in the Swift runtime's
+# build. Define just enough here for them to resolve. Each shim below is a no-op,
+# so this configuration builds and links the two modules but does *not* produce
+# an installable stdlib component.
+
+# In the runtime build `swiftCore` is a real target. Standalone, the stdlib
+# comes from the toolchain and needs no explicit link.
+if(NOT TARGET swiftCore)
+  add_library(swiftCore INTERFACE)
+endif()
+
+# Library evolution and `.swiftinterface` emission.
+function(emit_swift_interface target)
+endfunction()
+
+function(install_swift_interface target)
+endfunction()
+
+# Darwin packaging metadata, irrelevant to a standalone build.
+function(generate_plist name version target)
+endfunction()
+
+function(embed_manifest target)
+endfunction()
+
+#===-----------------------------------------------------------------------===#
+# Modules
+#===-----------------------------------------------------------------------===#
+
+# Order matters: _StringProcessing links _RegexParser.
+add_subdirectory(_RegexParser)
+add_subdirectory(_StringProcessing)

Sources/_RegexParser/CMakeLists.txt

@@ -0,0 +1,49 @@
+add_library(swift_RegexParser
+  Regex/TreeProtocols.swift
+  Regex/Parse/DelimiterLexing.swift
+  Regex/Parse/Source.swift
+  Regex/Parse/CharacterPropertyClassification.swift
+  Regex/Parse/LexicalAnalysis.swift
+  Regex/Parse/SyntaxOptions.swift
+  Regex/Parse/CaptureList.swift
+  Regex/Parse/CompilerInterface.swift
+  Regex/Parse/CaptureStructure.swift
+  Regex/Parse/Parse.swift
+  Regex/Parse/SourceLocation.swift
+  Regex/Parse/Diagnostics.swift
+  Regex/Parse/Sema.swift
+  Regex/Printing/RenderRanges.swift
+  Regex/Printing/PrettyPrinter.swift
+  Regex/Printing/PrintAsCanonical.swift
+  Regex/Printing/DumpAST.swift
+  Regex/AST/ASTAction.swift
+  Regex/AST/AST.swift
+  Regex/AST/CustomCharClass.swift
+  Regex/AST/Quantification.swift
+  Regex/AST/Conditional.swift
+  Regex/AST/MatchingOptions.swift
+  Regex/AST/ASTProtocols.swift
+  Regex/AST/Group.swift
+  Regex/AST/Atom.swift
+  Utility/TypeConstruction.swift
+  Utility/Misc.swift
+  Utility/AllScalars.swift
+  Utility/Errors.swift
+  Utility/MissingUnicode.swift)
+
+target_link_libraries(swift_RegexParser PRIVATE
+  swiftCore
+  $<$<BOOL:${SwiftSwiftDirectRuntime_FOUND}>:swiftSwiftDirectRuntime>)
+
+set_target_properties(swift_RegexParser PROPERTIES
+  Swift_MODULE_NAME _RegexParser)
+
+install(TARGETS swift_RegexParser
+  ARCHIVE DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${SwiftStringProcessing_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+emit_swift_interface(swift_RegexParser)
+install_swift_interface(swift_RegexParser)
+
+generate_plist(swiftRegexParser "${CMAKE_PROJECT_VERSION}" swift_RegexParser)
+embed_manifest(swift_RegexParser)