feat(concurrency)!: finalize parallel triangulation support

.clang-format

@@ -137,9 +137,9 @@ QualifierAlignment: Custom
 QualifierOrder:
   - static
   - inline
+  - constexpr
   - type
   - const
-  - constexpr
   - volatile
   - restrict
 RawStringFormats:

.github/CONTRIBUTING.md

@@ -45,14 +45,20 @@ substantial implementation so its maintenance value and scope can be agreed upon
    just fix
    just check
    just ci
+   just build-parallel
    ```
 
    `just check` is the fast, non-mutating source and tooling gate, including the repository-owned Semgrep policy and
-   its fixtures. `just ci` adds the supported build and complete 22-entry CTest suite: all 103 doctest unit scenarios
-   and 21 CLI integration tests. When changing C++ behavior, also run
+   its fixtures. `just ci` adds the supported build and complete 24-entry CTest suite: all 103 doctest unit scenarios
+   and 23 CLI integration tests. `just build-parallel` builds the distinct
+   CGAL/oneTBB configuration and runs the same scientific suite plus the
+   replayable parallel stress launcher, for 25 entries. When changing C++ behavior, also run
    `just clang-tidy` with the pinned LLVM 22 toolchain and review its advisory diagnostics.
-   GitHub Actions runs the same `just ci` contract in its Ubuntu GCC, Ubuntu Clang, macOS AppleClang, and Windows
-   MSVC jobs. The Windows job continues to compile with native MSVC; LLVM tooling is used only for source formatting.
+   GitHub Actions runs `just ci` in its Ubuntu GCC, Ubuntu Clang, macOS AppleClang, and Windows MSVC jobs. The two
+   Ubuntu jobs also run `just build-parallel` to exercise the opt-in CGAL/oneTBB contract. The Windows job continues
+   to compile with native MSVC; LLVM tooling is used only for source formatting. Toolchain setup is pkgx-first;
+   because pkgx does not currently publish its CMake and Ninja packages for Windows, that job uses the exact Justfile
+   pins available as PyPI wheels through `uv tool install --no-build`.
 
 6. Run the relevant Linux sanitizer configuration for changes involving memory, lifetime, undefined behavior, or
    concurrency:

.github/actions/setup-just/action.yml

@@ -36,6 +36,6 @@ runs:
         echo "version=$version" >> "$GITHUB_OUTPUT"
 
     - name: Install Just
-      uses: taiki-e/install-action@43aecc8d72668fbcfe75c31400bc4f890f1c5853  # v2.83.2
+      uses: taiki-e/install-action@7572810d7dd469b651bb7793945692cf78da5dd7  # v2.85.0
       with:
         tool: just@${{ steps.resolve.outputs.version }}

.github/workflows/ci.yml

@@ -31,21 +31,25 @@ jobs:
             compiler_package: gnu.org/gcc@16
             cc: gcc
             cxx: g++
+            run_parallel_contract: true
           - name: Ubuntu Clang
             os: ubuntu-latest
             compiler_package: llvm.org@22
             cc: clang
             cxx: clang++
+            run_parallel_contract: true
           - name: macOS AppleClang
             os: macos-latest
             compiler_package: ""
             cc: clang
             cxx: clang++
+            run_parallel_contract: false
           - name: Windows MSVC
             os: windows-latest
             compiler_package: ""
             cc: cl
             cxx: cl
+            run_parallel_contract: false
 
     steps:
       - name: Disable Git autocrlf on Windows
@@ -76,16 +80,35 @@ jobs:
         shell: bash
         run: |
           {
+            echo "cmake=$(just --evaluate cmake_version)"
             echo "llvm=$(just --evaluate llvm_version)"
+            echo "ninja=$(just --evaluate ninja_version)"
+            echo "ninja-windows-wheel=$(just --evaluate ninja_windows_wheel_version)"
             echo "uv=$(just --evaluate uv_version)"
-            echo "zizmor=$(just --evaluate zizmor_version)"
           } >> "$GITHUB_OUTPUT"
 
       - name: Set up canonical CI environment with pkgx
         if: runner.os != 'Windows'
         uses: pkgxdev/setup@4d4ae97af87ccb39ab8be4e073dea697fef2c6f7  # v5.0.0
         with:
-          +: llvm.org@${{ steps.tool-versions.outputs.llvm }}
+          +: >-
+            llvm.org@${{ steps.tool-versions.outputs.llvm }}
+            cmake.org@${{ steps.tool-versions.outputs.cmake }}
+            ninja-build.org@${{ steps.tool-versions.outputs.ninja }}
+
+      - name: Resolve pkgx certificate bundle
+        if: runner.os != 'Windows'
+        shell: bash
+        run: |
+          ssl_cert_file="$(
+            env -u SSL_CERT_FILE pkgx +curl.se/ca-certs env |
+              sed -n 's/^SSL_CERT_FILE=//p'
+          )"
+          if [[ -z "$ssl_cert_file" || ! -r "$ssl_cert_file" ]]; then
+            echo "pkgx CA bundle is missing or unreadable: $ssl_cert_file" >&2
+            exit 1
+          fi
+          echo "SSL_CERT_FILE=$ssl_cert_file" >> "$GITHUB_ENV"
 
       - name: Set up Python
         uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1  # v6.3.0
@@ -97,13 +120,17 @@ jobs:
         with:
           version: ${{ steps.tool-versions.outputs.uv }}
 
-      - name: Synchronize Python development dependencies
-        run: uv sync --locked --group dev
-
-      - name: Install zizmor
-        uses: taiki-e/install-action@07b4745e0c39a41822af610387492e3e53aa222b  # v2.83.4
-        with:
-          tool: zizmor@${{ steps.tool-versions.outputs.zizmor }}
+      # pkgx's CMake and Ninja packages do not currently support Windows.
+      - name: Set up pinned Windows wheel toolchain
+        if: runner.os == 'Windows'
+        shell: pwsh
+        env:
+          CMAKE_VERSION: ${{ steps.tool-versions.outputs.cmake }}
+          NINJA_VERSION: ${{ steps.tool-versions.outputs.ninja-windows-wheel }}
+        run: |
+          uv tool install --no-build "cmake==$env:CMAKE_VERSION"
+          uv tool install --no-build "ninja==$env:NINJA_VERSION"
+          uv tool dir --bin | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
 
       - name: Install pinact on Windows
         if: runner.os == 'Windows'
@@ -133,6 +160,14 @@ jobs:
           CXX: ${{ matrix.cxx }}
         run: just ci
 
+      - name: Run the opt-in CGAL/oneTBB contract
+        if: matrix.run_parallel_contract
+        env:
+          CC: ${{ matrix.cc }}
+          CDT_PKGX_COMPILER_PACKAGE: ${{ matrix.compiler_package }}
+          CXX: ${{ matrix.cxx }}
+        run: just build-parallel
+
   build:
     name: build
     if: ${{ always() }}

.github/workflows/codecov-upload.yml

@@ -54,12 +54,40 @@ jobs:
       - name: Set up Just
         uses: ./.github/actions/setup-just
 
-      - name: Setup GCC
+      - name: Resolve coverage tool versions
+        id: tool-versions
+        run: |
+          {
+            echo "cmake=$(just --evaluate cmake_version)"
+            echo "ninja=$(just --evaluate ninja_version)"
+          } >> "$GITHUB_OUTPUT"
+
+      - name: Set up coverage toolchain
         uses: pkgxdev/setup@4d4ae97af87ccb39ab8be4e073dea697fef2c6f7  # v5.0.0
         with:
-          +: gnu.org/gcc@16
+          +: >-
+            gnu.org/gcc@16
+            cmake.org@${{ steps.tool-versions.outputs.cmake }}
+            ninja-build.org@${{ steps.tool-versions.outputs.ninja }}
 
-      - run: gcc --version
+      - name: Resolve pkgx certificate bundle
+        shell: bash
+        run: |
+          ssl_cert_file="$(
+            env -u SSL_CERT_FILE pkgx +curl.se/ca-certs env |
+              sed -n 's/^SSL_CERT_FILE=//p'
+          )"
+          if [[ -z "$ssl_cert_file" || ! -r "$ssl_cert_file" ]]; then
+            echo "pkgx CA bundle is missing or unreadable: $ssl_cert_file" >&2
+            exit 1
+          fi
+          echo "SSL_CERT_FILE=$ssl_cert_file" >> "$GITHUB_ENV"
+
+      - name: Report coverage toolchain
+        run: |
+          cmake --version
+          ninja --version
+          gcc --version
 
       - name: Restore artifacts or setup vcpkg
         uses: lukka/run-vcpkg@b1a0dd252f06b9e25b3c022a9a03bd7a427fb6a2  # v11.6

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.21)
+cmake_minimum_required(VERSION 4.4.0)
 
 # vcpkg settings must be set before project()
 if(DEFINED ENV{VCPKG_ROOT} AND NOT DEFINED CMAKE_TOOLCHAIN_FILE)
@@ -26,10 +26,48 @@ project(
   DESCRIPTION "Fast Causal Dynamical Triangulations in C++"
   LANGUAGES CXX)
 
+# CDT++ does not use C++ modules, so avoid unnecessary dependency scanning.
+set(CMAKE_CXX_SCAN_FOR_MODULES OFF)
+
 # CMake project versions are numeric, so keep the release-candidate suffix in
 # the product version used by executables and release metadata.
 set(CDT_VERSION_SUFFIX "-rc2")
 set(CDT_VERSION "${PROJECT_VERSION}${CDT_VERSION_SUFFIX}")
+set(CDT_SOURCE_REVISION "unknown")
+find_package(Git QUIET)
+if(GIT_FOUND)
+  if(IS_DIRECTORY "${PROJECT_SOURCE_DIR}/.git")
+    set_property(
+      DIRECTORY APPEND
+      PROPERTY CMAKE_CONFIGURE_DEPENDS
+               "${PROJECT_SOURCE_DIR}/.git/HEAD"
+               "${PROJECT_SOURCE_DIR}/.git/index")
+  endif()
+  execute_process(
+    COMMAND "${GIT_EXECUTABLE}" rev-parse HEAD
+    WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}"
+    RESULT_VARIABLE _git_revision_result
+    OUTPUT_VARIABLE _git_revision
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    ERROR_QUIET)
+  if(_git_revision_result EQUAL 0)
+    set(CDT_SOURCE_REVISION "${_git_revision}")
+    execute_process(
+      COMMAND "${GIT_EXECUTABLE}" status --porcelain --untracked-files=no
+      WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}"
+      RESULT_VARIABLE _git_status_result
+      OUTPUT_VARIABLE _git_status
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+      ERROR_QUIET)
+    if(_git_status_result EQUAL 0 AND NOT _git_status STREQUAL "")
+      string(APPEND CDT_SOURCE_REVISION "-dirty")
+    endif()
+  endif()
+  unset(_git_revision)
+  unset(_git_revision_result)
+  unset(_git_status)
+  unset(_git_status_result)
+endif()
 
 # Project settings
 include(cmake/StandardProjectSettings.cmake)
@@ -79,6 +117,13 @@ option(ENABLE_PARALLEL_TRIANGULATION
 option(ENABLE_DEPRECATION_ERRORS
        "Treat deprecated C++ and CGAL API use in project targets as an error" ON)
 
+if(ENABLE_PARALLEL_TRIANGULATION AND ENABLE_SANITIZER_THREAD)
+  message(
+    FATAL_ERROR
+      "The pinned CGAL/oneTBB parallel path is not a supported ThreadSanitizer combination. Use the sequential tsan preset and the parallel asan preset."
+  )
+endif()
+
 target_compile_definitions(
   project_options
   INTERFACE CDT_ENABLE_PARALLEL_TRIANGULATION=$<BOOL:${ENABLE_PARALLEL_TRIANGULATION}>)

CMakePresets.json

@@ -1,20 +1,40 @@
 {
-  "version": 3,
+  "$schema": "https://raw.githubusercontent.com/Kitware/CMake/v4.4.0/Help/manual/presets/schema.json",
+  "version": 12,
   "cmakeMinimumRequired": {
-    "major": 3,
-    "minor": 21,
+    "major": 4,
+    "minor": 4,
     "patch": 0
   },
   "configurePresets": [
     {
       "name": "common",
       "hidden": true,
+      "$comment": "Uninitialized-variable diagnostics are disabled because vcpkg and imported package configurations probe optional variables before defining them.",
       "generator": "Ninja",
       "binaryDir": "${sourceDir}/build",
       "cacheVariables": {
         "CMAKE_CXX_EXTENSIONS": false,
         "CMAKE_CXX_STANDARD": "23",
         "CMAKE_CXX_STANDARD_REQUIRED": true
+      },
+      "warnings": {
+        "author": true,
+        "deprecated": true,
+        "experimental": true,
+        "installAbsoluteDestination": true,
+        "policy": true,
+        "uninitialized": false,
+        "unusedCli": true
+      },
+      "errors": {
+        "author": true,
+        "deprecated": true,
+        "experimental": true,
+        "installAbsoluteDestination": true,
+        "policy": true,
+        "uninitialized": false,
+        "unusedCli": true
       }
     },
     {
@@ -27,7 +47,6 @@
         "rhs": "Linux"
       },
       "cacheVariables": {
-        "CMAKE_C_COMPILER": "clang",
         "CMAKE_CXX_COMPILER": "clang++",
         "CMAKE_BUILD_TYPE": "RelWithDebInfo",
         "CMAKE_CXX_FLAGS": "-Wall -Wextra -Wpedantic -Wconversion -Wsign-conversion -Wcast-qual -Wformat=2 -Werror=float-equal -Wshadow -Wcast-align -Wunused -Wnull-dereference -Wdouble-promotion -Wimplicit-fallthrough -Wextra-semi -Woverloaded-virtual -Wnon-virtual-dtor -Wold-style-cast",
@@ -47,6 +66,16 @@
         "ENABLE_TESTING": true
       }
     },
+    {
+      "name": "parallel",
+      "displayName": "Supported CGAL/oneTBB build",
+      "description": "Configure the opt-in CGAL parallel insertion and removal path with tests",
+      "inherits": "reference",
+      "binaryDir": "${sourceDir}/out/build/parallel",
+      "cacheVariables": {
+        "ENABLE_PARALLEL_TRIANGULATION": true
+      }
+    },
     {
       "name": "debug",
       "displayName": "Local debug build",
@@ -98,6 +127,11 @@
       "name": "reference",
       "displayName": "Build the supported headless reference targets",
       "configurePreset": "reference"
+    },
+    {
+      "name": "parallel",
+      "displayName": "Build the supported CGAL/oneTBB targets",
+      "configurePreset": "parallel"
     }
   ],
   "testPresets": [
@@ -113,6 +147,19 @@
         "noTestsAction": "error",
         "stopOnFailure": false
       }
+    },
+    {
+      "name": "parallel-smoke",
+      "displayName": "Run the CGAL/oneTBB invariant and stress suite",
+      "description": "Run the complete suite with the parallel TDS plus the replayable stress contract",
+      "configurePreset": "parallel",
+      "output": {
+        "outputOnFailure": true
+      },
+      "execution": {
+        "noTestsAction": "error",
+        "stopOnFailure": false
+      }
     }
   ]
 }