name: '🧵 ThreadSanitizer'

# Reusable workflow: builds the channel stress suite with ThreadSanitizer and
# runs it. This is the dynamic half of verifying the lock-free SPSC Channel<T>
# (the static half is the CDSChecker model-check harness in verify/).
#
# Triggering and path filtering are owned by ci.yaml (the orchestrator), which
# calls this only when code changed. workflow_dispatch is kept for manual runs.
#
# Runs in the prebuilt builder image (gcc:14), which already ships libtsan — no
# package installs at job time.
on:
  workflow_call:
  workflow_dispatch:

jobs:
  tsan:
    runs-on: linux/amd64
    container:
      image: gitea.tourolle.paris/dtourolle/kpnpp-builder:latest
      # This runner is Docker nested in an unprivileged LXC container, whose
      # kernel randomizes mmap addresses beyond the range TSan's fixed shadow
      # mapping expects, so TSan aborts at init with "unexpected memory
      # mapping". The fix is to disable ASLR per-process with `setarch -R`
      # (below), which needs the personality(2) syscall that Docker's default
      # seccomp profile blocks. seccomp=unconfined permits it. Verified on the
      # runner: setarch -R alone gets EPERM, seccomp alone still aborts, both
      # together run clean. Scoped to this job, which runs only our own tests.
      options: --security-opt seccomp=unconfined
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          path: tsan-${{ github.run_id }}

      - name: Cache FetchContent dependencies
        uses: actions/cache@v3
        with:
          path: ~/.cmake/fetchcontent
          key: cmake-fetchcontent-${{ hashFiles('**/CMakeLists.txt') }}
          restore-keys: cmake-fetchcontent-

      - name: Configure (TSan)
        working-directory: tsan-${{ github.run_id }}
        run: |
          cmake -S . -B build \
            -G Ninja \
            -DCMAKE_BUILD_TYPE=Debug \
            -DKPN_SANITIZER=thread \
            -DKPN_BUILD_TESTS=ON \
            -DKPN_BUILD_EXAMPLES=OFF \
            -DKPN_BUILD_PYTHON=OFF \
            -DFETCHCONTENT_BASE_DIR=$HOME/.cmake/fetchcontent

      - name: Build (TSan)
        working-directory: tsan-${{ github.run_id }}
        run: cmake --build build --parallel --target kpn_tests kpn_tests_stress

      - name: Run stress suite under TSan
        working-directory: tsan-${{ github.run_id }}
        # halt_on_error=1 makes the first detected race fail the job; the report
        # (with both stacks) is printed to the log. second_deadlock_stack gives
        # the full picture for lock-order issues.
        env:
          TSAN_OPTIONS: "halt_on_error=1 second_deadlock_stack=1"
        # setarch -R disables ASLR for this process; see the container comment.
        run: setarch -R ./build/tests/kpn_tests_stress

      - name: Run unit tests under TSan
        working-directory: tsan-${{ github.run_id }}
        env:
          TSAN_OPTIONS: "halt_on_error=1 second_deadlock_stack=1"
        run: setarch -R ./build/tests/kpn_tests

      - name: Cleanup
        if: always()
        run: rm -rf tsan-${{ github.run_id }}