Use clang 21 in CI.

Author: insertinterestingnamehere

.circleci/config.yml

@@ -51,8 +51,8 @@ jobs:
       - image: ubuntu:25.04
     resource_class: arm.medium
     environment:
-      CC: clang-20
-      CXX: clang++-20
+      CC: clang-21
+      CXX: clang++-21
     steps:
       - run: |
           apt-get update --quiet=2 || apt-get update --quiet=2 || apt-get update --quiet=2
@@ -66,10 +66,12 @@ jobs:
           sudo apt-get install -y gcc-15 g++-15
           sudo apt-get install -y cmake
           sudo apt-get install -y hwloc libhwloc-dev
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          sudo apt-add-repository -y 'deb https://apt.llvm.org/plucky/ llvm-toolchain-plucky-21 main'
           # tzdata is required by clang and has to be installed carefully to avoid user prompts stalling the script.
           ln -fs /usr/share/zoneinfo/America/New_York /etc/localtime
           DEBIAN_FRONTEND=noninteractive sudo apt-get install -y --no-install-recommends tzdata
-          sudo apt-get install -y clang-20
+          sudo apt-get install -y clang-21
       - run: |
           mkdir build
           cd build
@@ -92,11 +94,11 @@ jobs:
     #machine:
     #  image: ubuntu-2504:edge
     docker:
-      - image: ubuntu:25.04
+      - image: ubuntu:25.10
     resource_class: arm.medium
     environment:
-      CC: clang-20
-      CXX: clang++-20
+      CC: clang-21
+      CXX: clang++-21
       CFLAGS: "-fsanitize=<< parameters.sanitizer >> -fno-sanitize-recover=all"
       CXXFLAGS: "-fsanitize=<< parameters.sanitizer >> -fno-sanitize-recover=all"
       LDFLAGS: "-fsanitize=<< parameters.sanitizer >> -fno-sanitize-recover=all"
@@ -115,10 +117,12 @@ jobs:
           sudo apt-get install -y gcc-15 g++-15
           sudo apt-get install -y cmake
           sudo apt-get install -y hwloc libhwloc-dev
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+          sudo apt-add-repository -y 'deb https://apt.llvm.org/plucky/ llvm-toolchain-plucky-21 main'
           # tzdata is required by clang and has to be installed carefully to avoid user prompts stalling the script.
           ln -fs /usr/share/zoneinfo/America/New_York /etc/localtime
           DEBIAN_FRONTEND=noninteractive sudo apt-get install -y --no-install-recommends tzdata
-          sudo apt-get install -y clang-20
+          sudo apt-get install -y clang-21
       - run: |
           mkdir build
           cd build

.github/workflows/CI.yml

@@ -44,10 +44,11 @@ jobs:
 
   linux-clang:
     runs-on: ubuntu-24.04
+    container: ubuntu:25.04
     continue-on-error: true
     strategy:
       matrix:
-        clang_version: [14, 15, 16, 17, 18, 19]
+        clang_version: [14, 15, 16, 17, 18, 19, 20]
         scheduler: [nemesis, sherwood, distrib]
         topology: [hwloc, binders, no]
         include:
@@ -63,11 +64,19 @@ jobs:
             gcc_version: 13
           - clang_version: 19
             gcc_version: 14
+          - clang_version: 20
+            gcc_version: 15
     env:
       CC: clang-${{ matrix.clang_version }}
       CXX: clang++-${{ matrix.clang_version }}
     steps:
     - uses: actions/checkout@v4
+    - name: container prerequisites
+      run: |
+        # some additional setup steps are only needed when running in a container.
+        # These end up being no-ops in the github actions images.
+        apt-get update
+        apt-get install -y sudo wget software-properties-common cmake
     - name: install gcc
       run: sudo apt-get install gcc-${{ matrix.gcc_version }} g++-${{ matrix.gcc_version }}
     - name: install clang
@@ -281,30 +290,31 @@ jobs:
           - sanitizer: thread
             topology: binders
     env:
-      CC: clang-20
-      CXX: clang++-20
+      CC: clang-21
+      CXX: clang++-21
       CFLAGS: "-fsanitize=${{ matrix.sanitizer }} -fno-sanitize-recover=all"
       CXXFLAGS: ${{ matrix.use_libcxx && format('-stdlib=libc++ -fsanitize={0} -fno-sanitize-recover=all', matrix.sanitizer) || format('-fsanitize={0} -fno-sanitize-recover=all', matrix.sanitizer) }}
       LDFLAGS: "-fsanitize=${{ matrix.sanitizer }} -fno-sanitize-recover=all"
       QTHREAD_STACK_SIZE: 2097152
       ASAN_OPTIONS: "check_initialization_order=1"
     steps:
     - uses: actions/checkout@v4
-    - if:  ${{ ! matrix.use_libcxx }}
+    - name: container prerequisites
       run: |
+        # some additional setup steps are only needed when running in a container.
+        # These end up being no-ops in the github actions images.
         apt-get update
-        apt-get install -y sudo # Updating and installing sudo is only neccesary in a container.
-        # Installing sudo is just so that the later commands using sudo can be the same whether in a container or not.
+        apt-get install -y sudo wget software-properties-common cmake
+    - if:  ${{ ! matrix.use_libcxx }}
+      run: |
         sudo apt-get install -y gcc-15 g++-15
-        sudo apt-get install -y cmake # Only needed in a container. Cmake is installed by default on VM images.
     - name: install compiler
       run: |
-        sudo apt-get install -y software-properties-common # Only needed in container.
-        wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add - && break || sleep 1
-        sudo apt-add-repository 'deb https://apt.llvm.org/oracular/ llvm-toolchain-oracular-20 main' && break || sleep 1
-        sudo apt-get install -y clang-20
+        wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+        sudo apt-add-repository 'deb https://apt.llvm.org/plucky/ llvm-toolchain-plucky-21 main' && break || sleep 1
+        sudo apt-get install -y clang-21
     - if: ${{ matrix.use_libcxx }}
-      run: sudo apt-get install -y libc++-20-dev libc++abi-20-dev
+      run: sudo apt-get install -y libc++-21-dev libc++abi-21-dev
     - if: ${{ matrix.topology != 'no' }}
       run: |
         sudo apt-get install -y hwloc libhwloc-dev
@@ -337,26 +347,27 @@ jobs:
           - compiler: gcc
             use_libcxx: true
     env:
-      CC: ${{ matrix.compiler == 'gcc' && 'gcc-15' || 'clang-20' }}
-      CXX: ${{ matrix.compiler == 'gcc' && 'g++-15' || 'clang++-20' }}
+      CC: ${{ matrix.compiler == 'gcc' && 'gcc-15' || 'clang-21' }}
+      CXX: ${{ matrix.compiler == 'gcc' && 'g++-15' || 'clang++-21' }}
       CXXFLAGS: ${{ matrix.use_libcxx && '-stdlib=libc++' || '' }}
       QTHREADS_ENABLE_ASSERTS: ${{ matrix.use_asserts && '--enable-asserts' || '' }}
     steps:
     - uses: actions/checkout@v4
-    - run: |
+    - name: container prerequisites
+      run: |
+        # some additional setup steps are only needed when running in a container.
+        # These end up being no-ops in the github actions images.
         apt-get update
-        apt-get install -y sudo # Updating and installing sudo is only neccesary in a container.
-        # Installing sudo is just so that the later commands using sudo can be the same whether in a container or not.
+        apt-get install -y sudo wget software-properties-common cmake
+    - run: |
         sudo apt-get install -y gcc-15 g++-15
-        sudo apt-get install -y cmake # Only needed in a container. Cmake is installed by default on VM images.
     - if: ${{ matrix.compiler == 'clang' }}
       run: |
-        sudo apt-get install -y software-properties-common # Only needed in container.
-        wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add - && break || sleep 1
-        sudo apt-add-repository 'deb https://apt.llvm.org/oracular/ llvm-toolchain-oracular-20 main' && break || sleep 1
-        sudo apt-get install -y clang-20
+        wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
+        sudo apt-add-repository 'deb https://apt.llvm.org/plucky/ llvm-toolchain-plucky-21 main' && break || sleep 1
+        sudo apt-get install -y clang-21
     - if: ${{ matrix.use_libcxx }}
-      run: sudo apt-get install -y libc++-20-dev libc++abi-20-dev
+      run: sudo apt-get install -y libc++-21-dev libc++abi-21-dev
     - if: ${{ matrix.topology != 'no' }}
       run: |
         sudo apt-get install -y hwloc libhwloc-dev
@@ -377,14 +388,20 @@ jobs:
     runs-on: ubuntu-24.04
     continue-on-error: true
     env:
-      CC: 'clang-20'
-      CXX: 'clang++-20'
+      CC: 'clang-21'
+      CXX: 'clang++-21'
     steps:
     - uses: actions/checkout@v4
+    - name: container prerequisites
+      run: |
+        # some additional setup steps are only needed when running in a container.
+        # These end up being no-ops in the github actions images.
+        apt-get update
+        apt-get install -y sudo wget software-properties-common cmake
     - run: |
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add - && break || sleep 1
-        sudo apt-add-repository 'deb https://apt.llvm.org/noble/ llvm-toolchain-noble-20 main' && break || sleep 1
-        sudo apt-get install clang-format-20
+        sudo apt-add-repository 'deb https://apt.llvm.org/noble/ llvm-toolchain-noble-21 main' && break || sleep 1
+        sudo apt-get install clang-format-21
     - name: check formatting
       run: |
         clang-format --version

clang-format.sh

@@ -1 +1 @@
-find -iname *.h -or -iname *.c -or -iname *.hpp -or -iname *.cpp | xargs clang-format-20 -i
+find -iname *.h -or -iname *.c -or -iname *.hpp -or -iname *.cpp | xargs clang-format-21 -i