feat: new FindPython support (#2370)

* feat: FindPython support

* refactor: rename to PYBIND11_FINDPYTHON

* docs: Caps fixes

* feat: NOPYTHON mode

* test: check simple call

* docs: add changelog/upgrade guide

* feat: Support Python3 and Python2

* refactor: Use targets in tests

* fix: support CMake 3.4+

* feat: classic search also finds virtual environments

* docs: some updates from @wjakob's review

* fix: wrong name for QUIET mode variable, reported by @skoslowski

* refactor: cleaner output messaging

* fix: support debug Python's in FindPython mode too

* fixup! refactor: cleaner output messaging

* fix: missing pybind11_FOUND and pybind11_INCLUDE_DIR restored to subdir mode

* fix: nicer reporting of Python / PyPy

* fix: out-of-order variable fix

* docs: minor last-minute cleanup

.github/workflows/ci.yml

@@ -31,11 +31,13 @@ jobs:
             arch: x64
             max-cxx-std: 17
             dev: false
+            args: "-DPYBIND11_FINDPYTHON=ON"
           - runs-on: macos-latest
             python: 3.7
             arch: x64
             max-cxx-std: 17
             dev: false
+            args: "-DPYBIND11_FINDPYTHON=ON"
           - runs-on: windows-2016
             python: 3.7
             arch: x86
@@ -46,6 +48,7 @@ jobs:
             arch: x64
             max-cxx-std: 17
             dev: false
+            args: "-DPYBIND11_FINDPYTHON=ON"
           - runs-on: windows-latest
             python: 3.7
             arch: x64
@@ -89,7 +92,7 @@ jobs:
             dev: false
 
 
-    name: "🐍 ${{ matrix.python }} • ${{ matrix.runs-on }} • ${{ matrix.arch }}"
+    name: "🐍 ${{ matrix.python }} • ${{ matrix.runs-on }} • ${{ matrix.arch }} ${{ matrix.args }}"
     runs-on: ${{ matrix.runs-on }}
     continue-on-error: ${{ matrix.dev }}
 
@@ -106,6 +109,9 @@ jobs:
       if: runner.os != 'macOS'
       run: echo "::set-env name=BOOST_ROOT::$BOOST_ROOT_1_72_0"
 
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v1.3
+
     - name: Cache wheels
       if: runner.os == 'macOS'
       uses: actions/cache@v2
@@ -120,7 +126,7 @@ jobs:
     - name: Prepare env
       run: python -m pip install -r tests/requirements.txt
 
-    - name: Configure C++11
+    - name: Configure C++11 ${{ matrix.args }}
       shell: bash
       run: >
         cmake -S . -B build
@@ -128,7 +134,7 @@ jobs:
         -DDOWNLOAD_CATCH=ON
         -DDOWNLOAD_EIGEN=ON
         -DCMAKE_CXX_STANDARD=11
-        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
+        ${{ matrix.args }}
 
     - name: Build C++11
       run: cmake --build build -j 2
@@ -140,9 +146,9 @@ jobs:
       run: cmake --build build --target cpptest -j 2
 
     - name: Interface test C++11
-      run: cmake --build build --target test_cmake_build
+      run: cmake --build build --target test_cmake_build -v
 
-    - name: Configure C++${{ matrix.max-cxx-std }}
+    - name: Configure C++${{ matrix.max-cxx-std }} ${{ matrix.args }}
       shell: bash
       run: >
         cmake -S . -B build2
@@ -150,7 +156,7 @@ jobs:
         -DDOWNLOAD_CATCH=ON
         -DDOWNLOAD_EIGEN=ON
         -DCMAKE_CXX_STANDARD=${{ matrix.max-cxx-std }}
-        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
+        ${{ matrix.args }}
 
     - name: Build C++${{ matrix.max-cxx-std }}
       run: cmake --build build2 -j 2
@@ -350,14 +356,14 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
-    - name: Install requirements
+    - name: Install system requirements
       run: apk add doxygen python3-dev
 
     - name: Ensure pip
       run: python3 -m ensurepip
 
-    - name: Install python docs requirements
-      run: python3 -m pip install "sphinx<3" sphinx_rtd_theme breathe==4.13.1 pytest setuptools
+    - name: Install docs & setup requirements
+      run: python3 -m pip install -r docs/requirements.txt pytest setuptools
 
     - name: Build docs
       run: python3 -m sphinx -W -b html docs docs/.build

.github/workflows/configure.yml

@@ -14,19 +14,22 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        runs-on: [ubuntu-latest, macos-latest]
+        runs-on: [ubuntu-latest, macos-latest, windows-latest]
         arch: [x64]
-        cmake: [3.7, 3.18]
+        cmake: [3.18]
 
         include:
-        - runs-on: windows-latest
+        - runs-on: ubuntu-latest
           arch: x64
-          cmake: 3.18
+          cmake: 3.4
+
+        - runs-on: macos-latest
+          arch: x64
+          cmake: 3.7
 
-        # TODO: 3.8
         - runs-on: windows-2016
           arch: x86
-          cmake: 3.11
+          cmake: 3.8
 
         - runs-on: windows-2016
           arch: x86
@@ -63,3 +66,13 @@ jobs:
         -DPYBIND11_WERROR=ON
         -DDOWNLOAD_CATCH=ON
         -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
+
+    - name: Build
+      working-directory: build dir
+      if: github.event_name == 'workflow_dispatch'
+      run: cmake --build . --config Release
+
+    - name: Test
+      working-directory: build dir
+      if: github.event_name == 'workflow_dispatch'
+      run: cmake --build . --config Release --target check