Invoke pip using Python

.appveyor.yml

@@ -33,7 +33,7 @@ install:
         c:\pillow\winbuild\build\build_dep_all.cmd
         $host.SetShouldExit(0)
 - path C:\pillow\winbuild\build\bin;%PATH%
-- '%PYTHON%\%PIP_DIR%\pip.exe install -U "setuptools>=49.3.2"'
+- '%PYTHON%\%EXECUTABLE% -m pip install -U "setuptools>=49.3.2"'
 
 build_script:
 - ps: |
@@ -44,13 +44,13 @@ build_script:
 
 test_script:
 - cd c:\pillow
-- '%PYTHON%\%PIP_DIR%\pip.exe install pytest pytest-cov'
+- '%PYTHON%\%EXECUTABLE% -m pip install pytest pytest-cov'
 - c:\"Program Files (x86)"\"Windows Kits"\10\Debuggers\x86\gflags.exe /p /enable %PYTHON%\%EXECUTABLE%
 - '%PYTHON%\%EXECUTABLE% -m pytest -vx --cov PIL --cov Tests --cov-report term --cov-report xml Tests'
 #- '%PYTHON%\%EXECUTABLE% test-installed.py -v -s %TEST_OPTIONS%' TODO TEST_OPTIONS with pytest?
 
 after_test:
-- pip install codecov
+- python -m pip install codecov
 - codecov --file coverage.xml --name %PYTHON% --flags AppVeyor
 
 matrix:
@@ -67,7 +67,7 @@ artifacts:
 
 before_deploy:
   - cd c:\pillow
-  - '%PYTHON%\%PIP_DIR%\pip.exe install wheel'
+  - '%PYTHON%\%EXECUTABLE% -m pip install wheel'
   - cd c:\pillow\winbuild\
   - c:\pillow\winbuild\build\build_pillow.cmd bdist_wheel
   - cd c:\pillow

.ci/install.sh

@@ -23,32 +23,32 @@ sudo apt-get -qq install libfreetype6-dev liblcms2-dev python3-tk\
 
 if [[ $TRAVIS_CPU_ARCH == "s390x" ]]; then sudo chown $USER ~/.cache/pip/wheels ; fi
 
-pip install --upgrade pip
-PYTHONOPTIMIZE=0 pip install cffi
-pip install coverage
-pip install olefile
-pip install -U pytest
-pip install -U pytest-cov
-pip install pyroma
-pip install test-image-results
-pip install numpy
+python3 -m pip install --upgrade pip
+PYTHONOPTIMIZE=0 python3 -m pip install cffi
+python3 -m pip install coverage
+python3 -m pip install olefile
+python3 -m pip install -U pytest
+python3 -m pip install -U pytest-cov
+python3 -m pip install pyroma
+python3 -m pip install test-image-results
+python3 -m pip install numpy
 
 # TODO Remove when 3.8 / 3.9 / PyPy3 includes setuptools 49.3.2+:
-if [ "$GHA_PYTHON_VERSION" == "3.8" ]; then pip install -U "setuptools>=49.3.2" ; fi
-if [ "$GHA_PYTHON_VERSION" == "3.9" ]; then pip install -U "setuptools>=49.3.2" ; fi
-if [ "$TRAVIS_PYTHON_VERSION" == "pypy3.6-7.3.1" ]; then pip install -U "setuptools>=49.3.2" ; fi
+if [ "$GHA_PYTHON_VERSION" == "3.8" ]; then python3 -m pip install -U "setuptools>=49.3.2" ; fi
+if [ "$GHA_PYTHON_VERSION" == "3.9" ]; then python3 -m pip install -U "setuptools>=49.3.2" ; fi
+if [ "$TRAVIS_PYTHON_VERSION" == "pypy3.6-7.3.1" ]; then python3 -m pip install -U "setuptools>=49.3.2" ; fi
 
 if [[ $TRAVIS_PYTHON_VERSION == 3.* ]]; then
   # arm64, ppc64le, s390x CPUs:
   # "ERROR: Could not find a version that satisfies the requirement pyqt5"
   if [[ $TRAVIS_CPU_ARCH == "amd64" ]]; then
     sudo apt-get -qq install libxcb-xinerama0 pyqt5-dev-tools
-    pip install pyqt5
+    python3 -m pip install pyqt5
   fi
 fi
 
 # docs only on Python 3.8
-if [ "$TRAVIS_PYTHON_VERSION" == "3.8" ]; then pip install -r requirements.txt ; fi
+if [ "$TRAVIS_PYTHON_VERSION" == "3.8" ]; then python3 -m pip install -r requirements.txt ; fi
 
 # webp
 pushd depends && ./install_webp.sh && popd

.github/workflows/macos-install.sh

@@ -4,20 +4,20 @@ set -e
 
 brew install libtiff libjpeg openjpeg libimagequant webp little-cms2 freetype openblas
 
-PYTHONOPTIMIZE=0 pip install cffi
-pip install coverage
-pip install olefile
-pip install -U pytest
-pip install -U pytest-cov
-pip install pyroma
-pip install test-image-results
+PYTHONOPTIMIZE=0 python3 -m pip install cffi
+python3 -m pip install coverage
+python3 -m pip install olefile
+python3 -m pip install -U pytest
+python3 -m pip install -U pytest-cov
+python3 -m pip install pyroma
+python3 -m pip install test-image-results
 
 echo -e "[openblas]\nlibraries = openblas\nlibrary_dirs = /usr/local/opt/openblas/lib" >> ~/.numpy-site.cfg
-pip install numpy
+python3 -m pip install numpy
 
 # TODO Remove when 3.8 / 3.9 includes setuptools 49.3.2+:
-if [ "$GHA_PYTHON_VERSION" == "3.8" ]; then pip install -U "setuptools>=49.3.2" ; fi
-if [ "$GHA_PYTHON_VERSION" == "3.9" ]; then pip install -U "setuptools>=49.3.2" ; fi
+if [ "$GHA_PYTHON_VERSION" == "3.8" ]; then python3 -m pip install -U "setuptools>=49.3.2" ; fi
+if [ "$GHA_PYTHON_VERSION" == "3.9" ]; then python3 -m pip install -U "setuptools>=49.3.2" ; fi
 
 # extra test images
 pushd depends && ./install_extra_test_images.sh && popd

.github/workflows/test-windows.yml

@@ -55,7 +55,7 @@ jobs:
     - name: Print build system information
       run: python .github/workflows/system-info.py
 
-    - name: pip install wheel pytest pytest-cov
+    - name: python -m pip install wheel pytest pytest-cov
       run: python -m pip install wheel pytest pytest-cov
 
     # TODO Remove when 3.8 / 3.9 includes setuptools 49.3.2+:

.github/workflows/test.yml

@@ -44,7 +44,7 @@ jobs:
     - name: Get pip cache dir
       id: pip-cache
       run: |
-        echo "::set-output name=dir::$(pip cache dir)"
+        echo "::set-output name=dir::$(python3 -m pip cache dir)"
 
     - name: pip cache
       uses: actions/cache@v2
@@ -96,7 +96,7 @@ jobs:
     - name: Docs
       if: startsWith(matrix.os, 'ubuntu') && matrix.python-version == 3.8
       run: |
-        pip install sphinx-removed-in sphinx-rtd-theme
+        python3 -m pip install sphinx-removed-in sphinx-rtd-theme
         make doccheck
 
     - name: After success

.travis.yml

@@ -46,7 +46,7 @@ matrix:
 install:
   - |
     if [ "$LINT" == "true" ]; then
-      pip install tox
+      python3 -m pip install tox
     else
       .ci/install.sh;
     fi

depends/diffcover-install.sh

@@ -5,4 +5,4 @@ git fetch origin master:refs/remotes/origin/master
 
 # CFLAGS=-O0 means build with no optimisation.
 # Makes build much quicker for lxml and other dependencies.
-time CFLAGS=-O0 pip install diff_cover
+time CFLAGS=-O0 python3 -m pip install diff_cover

docs/releasenotes/6.0.0.rst

@@ -17,7 +17,7 @@ Removed deprecated PIL.OleFileIO
 PIL.OleFileIO was removed as a vendored file and in Pillow 4.0.0 (2017-01) in favour of
 the upstream olefile Python package, and replaced with an ``ImportError``. The
 deprecated file has now been removed from Pillow. If needed, install from PyPI (eg.
-``pip install olefile``).
+``python3 -m pip install olefile``).
 
 Removed deprecated ImageOps functions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

tox.ini

@@ -1,7 +1,7 @@
 # Tox (https://tox.readthedocs.io/en/latest/) is a tool for running tests
 # in multiple virtualenvs. This configuration file will run the
-# test suite on all supported python versions. To use it, "pip install tox"
-# and then run "tox" from this directory.
+# test suite on all supported python versions. To use it,
+# "python3 -m pip install tox" and then run "tox" from this directory.
 
 [tox]
 envlist =

winbuild/build.rst

@@ -82,7 +82,7 @@ Pillow for the selected version of Python.
 instead of installing Pillow.
 
 You can also use ``winbuild\build\build_pillow.cmd --inplace develop`` to build
-and install Pillow in develop mode (instead of ``pip install --editable``).
+and install Pillow in develop mode (instead of ``python3 -m pip install --editable``).
 
 Testing Pillow
 --------------