cmakeFetchContentVersusGitSubmodule.yml

# SPDX-FileCopyrightText: 2026 Marcel Petrick
#
# SPDX-License-Identifier: GPL-3.0-or-later

# -----------------------------------------------------------------------------
# cmakeFetchContentVersusGitSubmodule CI
#
# Proves the project's claim on a clean runner: a normal checkout without
# submodules is enough, CMake fetches LVGL itself during configure, the demo
# links against it, and changing LVGL_GIT_TAG in the same build directory makes
# FetchContent switch the checkout. Git is only used read-only, to inspect
# which revision CMake checked out.
#
# No build/ or _deps/ cache on purpose: a warm cache would hide the first fetch.
# The job only runs when this project or this workflow changes, so the other
# projects in this repository do not trigger it.
# -----------------------------------------------------------------------------
name: cmakeFetchContentVersusGitSubmodule

on:
  push:
    paths:
      - "cmakeFetchContentVersusGitSubmodule/**"
      - ".github/workflows/cmakeFetchContentVersusGitSubmodule.yml"
  pull_request:
    paths:
      - "cmakeFetchContentVersusGitSubmodule/**"
      - ".github/workflows/cmakeFetchContentVersusGitSubmodule.yml"
  workflow_dispatch:

permissions:
  contents: read

concurrency:
  group: cmake-fetchcontent-lvgl-${{ github.ref }}
  cancel-in-progress: true

defaults:
  run:
    shell: bash
    working-directory: cmakeFetchContentVersusGitSubmodule

env:
  # Second LVGL release used to prove the revision switch.
  SWITCH_TAG: v9.4.0

jobs:
  fetchcontent:
    name: FetchContent fetch, build and tag switch
    runs-on: ubuntu-latest
    timeout-minutes: 30
    steps:
      - name: Check out this repository only (submodules disabled)
        uses: actions/checkout@v7.0.1
        with:
          submodules: false

      - name: Confirm there are no submodules and no vendored LVGL
        run: |
          test ! -e "$GITHUB_WORKSPACE/.gitmodules"
          test ! -e .gitmodules
          test -z "$(git -C "$GITHUB_WORKSPACE" ls-files -- '*lvgl.h' '*lv_obj.c')"
          echo "No .gitmodules and no LVGL sources tracked by this repository."

      - name: Install host prerequisites (SDL2, Ninja) - LVGL is not installed
        run: |
          sudo apt-get update
          sudo apt-get install -y libsdl2-dev ninja-build
          cmake --version
          ninja --version

      - name: Read the default LVGL tag from CMakeLists.txt
        run: |
          default_tag=$(sed -n 's/^ *set(LVGL_GIT_TAG "\(.*\)")$/\1/p' CMakeLists.txt)
          echo "Default LVGL_GIT_TAG: $default_tag"
          test -n "$default_tag"
          test "$default_tag" != "$SWITCH_TAG"
          echo "DEFAULT_TAG=$default_tag" >> "$GITHUB_ENV"
          {
            echo '### LVGL checkout in build/_deps/lvgl-src'
            echo
            echo '| Step | Requested tag | Checked-out commit |'
            echo '| --- | --- | --- |'
          } >> "$GITHUB_STEP_SUMMARY"

      - name: Configure with default LVGL tag (CMake FetchContent clones LVGL into build/_deps)
        run: |
          test ! -e build
          cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DFETCHCONTENT_QUIET=OFF

      - name: Verify FetchContent checked out the default tag
        run: |
          head=$(git -C build/_deps/lvgl-src rev-parse HEAD)
          want=$(git -C build/_deps/lvgl-src rev-parse "$DEFAULT_TAG^{commit}")
          echo "build/_deps/lvgl-src is at $head ($(git -C build/_deps/lvgl-src describe --tags))"
          test "$head" = "$want"
          echo "| Configure (default) | \`$DEFAULT_TAG\` | \`$head\` |" >> "$GITHUB_STEP_SUMMARY"

      - name: Build the demo against the fetched LVGL
        run: |
          cmake --build build
          test -x build/hello_lvgl

      - name: Reconfigure same build directory with another LVGL tag
        run: cmake -S . -B build -DLVGL_GIT_TAG="$SWITCH_TAG"

      - name: Verify FetchContent changed the LVGL checkout
        run: |
          head=$(git -C build/_deps/lvgl-src rev-parse HEAD)
          want=$(git -C build/_deps/lvgl-src rev-parse "$SWITCH_TAG^{commit}")
          echo "build/_deps/lvgl-src is at $head ($(git -C build/_deps/lvgl-src describe --tags))"
          test "$head" = "$want"
          echo "| Reconfigure with \`-DLVGL_GIT_TAG=$SWITCH_TAG\` | \`$SWITCH_TAG\` | \`$head\` |" >> "$GITHUB_STEP_SUMMARY"

      - name: Build the demo against the switched LVGL release
        run: cmake --build build

      - name: Remove the cached tag override with -U and reconfigure
        run: cmake -S . -B build -U LVGL_GIT_TAG

      - name: Verify FetchContent returned to the default tag
        run: |
          head=$(git -C build/_deps/lvgl-src rev-parse HEAD)
          want=$(git -C build/_deps/lvgl-src rev-parse "$DEFAULT_TAG^{commit}")
          echo "build/_deps/lvgl-src is at $head ($(git -C build/_deps/lvgl-src describe --tags))"
          test "$head" = "$want"
          echo "| Reconfigure with \`-U LVGL_GIT_TAG\` | \`$DEFAULT_TAG\` | \`$head\` |" >> "$GITHUB_STEP_SUMMARY"