ci-linux.yml

name: ci-linux

# Self-host CI on Linux: mcpp builds mcpp. The bootstrap mcpp comes from
# `xlings install mcpp` (xim:mcpp in the xlings package index), so this
# workflow no longer depends on a previous-release tarball — the
# chicken-and-egg now lives upstream in the xlings index.
#
# Paired workflows: ci-macos.yml, ci-windows.yml.

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]
  workflow_dispatch:

concurrency:
  group: ci-${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  build-and-test:
    name: build + test (linux x86_64, self-host)
    runs-on: ubuntu-24.04
    timeout-minutes: 60
    env:
      # MCPP_HOME pinned so the cache key below restores into the
      # same path mcpp resolves at runtime.
      MCPP_HOME: /home/runner/.mcpp
    steps:
      - uses: actions/checkout@v4

      # Cache mcpp's sandbox: the toolchain (musl-gcc + binutils +
      # glibc + linux-headers + patchelf + ninja) takes minutes to
      # install on a cold runner. Key on the workspace manifest so a
      # toolchain change in mcpp.toml refreshes the cache; restore-keys
      # provide a layered fallback so near-misses still skip the slow
      # toolchain installs.
      - name: Cache mcpp sandbox
        uses: actions/cache@v4
        with:
          path: ~/.mcpp
          key: mcpp-sandbox-${{ runner.os }}-${{ hashFiles('mcpp.toml', '.xlings.json') }}
          restore-keys: |
            mcpp-sandbox-${{ runner.os }}-

      # Cache xlings + its locally installed packages (xim:mcpp etc.).
      # Saves the xlings bootstrap roundtrip + the mcpp xpkg download
      # on hot runs.
      - name: Cache xlings
        uses: actions/cache@v4
        with:
          path: ~/.xlings
          key: xlings-${{ runner.os }}-v2-${{ hashFiles('.xlings.json') }}
          restore-keys: |
            xlings-${{ runner.os }}-v2-

      - name: Bootstrap mcpp via xlings
        env:
          XLINGS_NON_INTERACTIVE: '1'
          XLINGS_VERSION: '0.4.30'
        run: |
          # Always install the pinned version — cache may hold an older
          # xlings whose sysroot/packages are incompatible.
          tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
          curl -fsSL -o "/tmp/${tarball}" \
            "https://github.com/d2learn/xlings/releases/download/v${XLINGS_VERSION}/${tarball}"
          tar -xzf "/tmp/${tarball}" -C /tmp
          "/tmp/xlings-${XLINGS_VERSION}-linux-x86_64/subos/default/bin/xlings" self install
          export PATH="$HOME/.xlings/subos/default/bin:$PATH"
          xlings --version
          # xim:mcpp — `xlings install` is idempotent so cache hits skip
          # the download.
          xlings install mcpp -y
          MCPP="$HOME/.xlings/subos/default/bin/mcpp"
          test -x "$MCPP"
          "$MCPP" --version
          echo "MCPP=$MCPP" >> "$GITHUB_ENV"
          echo "XLINGS_BIN=$HOME/.xlings/subos/default/bin/xlings" >> "$GITHUB_ENV"

      # Cache the build directory: precise key on src/ + manifest
      # so a no-source-change run lands on a full hit. Layered
      # restore-keys let mid-run partial hits keep BMI/dyndep state
      # for proper incremental builds.
      - name: Cache target/ (build artifacts + BMIs)
        uses: actions/cache@v4
        with:
          path: target
          key: mcpp-target-${{ runner.os }}-${{ hashFiles('src/**', 'tests/**', 'mcpp.toml', 'mcpp.lock') }}
          restore-keys: |
            mcpp-target-${{ runner.os }}-

      - name: Configure mirror + Build mcpp from source (self-host)
        run: |
          export MCPP_VENDORED_XLINGS="$XLINGS_BIN"
          # Set GLOBAL mirror via xlings directly (bootstrap mcpp may lack --mirror flag)
          "$XLINGS_BIN" config --mirror GLOBAL 2>/dev/null || true
          "$MCPP" self config --mirror GLOBAL 2>/dev/null || true
          "$MCPP" build

      - name: Unit + integration tests via `mcpp test`
        run: |
          # Use freshly-built mcpp for test (it has --mirror support)
          MCPP_FRESH=$(realpath "$(find target -type f -name mcpp -printf '%T@ %p\n' | sort -rn | head -1 | cut -d' ' -f2)")
          "$MCPP_FRESH" self config --mirror GLOBAL
          "$MCPP_FRESH" test

      - name: E2E suite
        # Step-level guard: a single hung test (historically 10_env_command.sh
        # on slow xlings/network) used to eat the full 60-min job budget.
        # Cap the suite at 25 min so a hang fails fast and we still have room
        # for the downstream toolchain steps. Per-test 600s timeout lives in
        # tests/e2e/run_all.sh and identifies WHICH test hung.
        timeout-minutes: 25
        run: |
          # Point the e2e runner at the freshly-built binary, not the
          # bootstrap one. Tests cd into mktemp -d, so $MCPP must be
          # absolute or the relative path breaks under the temp cwd.
          MCPP=$(realpath "$(find target -type f -name mcpp -printf '%T@ %p\n' | sort -rn | head -1 | cut -d' ' -f2)")
          test -x "$MCPP"
          export MCPP
          # Tests that set MCPP_HOME to a fresh tmpdir need an xlings
          # to bootstrap from; surface the xlings binary installed
          # above so they don't have to reinstall the sandbox.
          export MCPP_VENDORED_XLINGS="$XLINGS_BIN"
          test -x "$MCPP_VENDORED_XLINGS"
          # GitHub-hosted runners are outside CN; keep CI toolchain downloads on
          # the global mirror while mcpp's default remains CN for fresh local
          # sandboxes. E2E tests with their own MCPP_HOME read this variable.
          export MCPP_E2E_TOOLCHAIN_MIRROR=GLOBAL
          "$MCPP" self config --mirror "$MCPP_E2E_TOOLCHAIN_MIRROR"
          "$MCPP" self config
          # Pin the global default so test 28 (which exercises the
          # default-toolchain path) gets a deterministic GNU answer
          # instead of whatever auto-install picks on a fresh sandbox.
          "$MCPP" toolchain default gcc@16.1.0
          bash tests/e2e/run_all.sh

      - name: Save freshly-built mcpp for toolchain tests
        run: |
          MCPP=$(realpath "$(find target -type f -name mcpp -printf '%T@ %p\n' | sort -rn | head -1 | cut -d' ' -f2)")
          cp "$MCPP" /tmp/mcpp-fresh
          echo "MCPP=/tmp/mcpp-fresh" >> "$GITHUB_ENV"

      - name: "Toolchain: GCC — build mcpp + test"
        run: |
          "$MCPP" clean
          "$MCPP" build 2>&1 | tee build.log; grep -q "Resolved gcc@16.1.0" build.log
          "$MCPP" test

      - name: "Toolchain: musl-gcc — build mcpp (--target)"
        run: |
          "$MCPP" clean
          "$MCPP" build --target x86_64-linux-musl 2>&1 | tee build.log; grep -q "Resolved gcc@15.1.0-musl" build.log

      - name: "Toolchain: LLVM — build mcpp"
        run: |
          "$MCPP" toolchain install llvm 20.1.7
          # Override project toolchain to use LLVM for this build
          sed -i 's/^default = "gcc@16.1.0"/default = "llvm@20.1.7"/' mcpp.toml
          "$MCPP" clean
          "$MCPP" build 2>&1 | tee build.log; grep -q "Resolved llvm@20.1.7" build.log
          # Restore
          sed -i 's/^default = "llvm@20.1.7"/default = "gcc@16.1.0"/' mcpp.toml