Fix #910: Use python venv for macOS build

With this commit macOS build starts using Python virtual environment so
that our build steps can comply with PEP 668 [1].

This is only about the build procedure. There must be no behavior change
in the build artifacts.

#codehealth

 [1]: https://peps.python.org/pep-0668/

PiperOrigin-RevId: 621123606

.github/workflows/macos.yaml

@@ -11,6 +11,9 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
   cancel-in-progress: true
 
+env:
+  PYTHON_VENV_ROOT: ${{ github.workspace }}/src/python-venv
+
 jobs:
   build_arm64:
     # https://github.com/actions/virtual-environments/blob/main/images/macos/macos-14-Readme.md
@@ -23,9 +26,10 @@ jobs:
         with:
           submodules: 'recursive'
 
-      - name: Install pip dependencies
-        working-directory: ./src
+      - name: Setup Python
         run: |
+          python3 -m venv ${PYTHON_VENV_ROOT}
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 -m pip install requests
 
       - name: Try to restore update_deps cache
@@ -38,11 +42,13 @@ jobs:
         working-directory: ./src
         # This command uses src/third_party_cache as the download cache.
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/update_deps.py
 
       - name: Build Qt
         working-directory: ./src
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/build_qt.py --release --confirm_license --macos_cpus=arm64
           echo "MOZC_QT_PATH=${PWD}/third_party/qt" >> $GITHUB_ENV
 
@@ -69,9 +75,10 @@ jobs:
         with:
           submodules: 'recursive'
 
-      - name: Install pip dependencies
-        working-directory: ./src
+      - name: Setup Python
         run: |
+          python3 -m venv ${PYTHON_VENV_ROOT}
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 -m pip install requests
 
       - name: Try to restore update_deps cache
@@ -84,11 +91,13 @@ jobs:
         working-directory: ./src
         # This command uses src/third_party_cache as the download cache.
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/update_deps.py
 
       - name: Build Qt
         working-directory: ./src
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/build_qt.py --release --confirm_license --macos_cpus=x86_64
           echo "MOZC_QT_PATH=${PWD}/third_party/qt" >> $GITHUB_ENV
 
@@ -115,9 +124,10 @@ jobs:
         with:
           submodules: 'recursive'
 
-      - name: Install pip dependencies
-        working-directory: ./src
+      - name: Setup Python
         run: |
+          python3 -m venv ${PYTHON_VENV_ROOT}
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 -m pip install requests
 
       - name: Try to restore update_deps cache
@@ -130,11 +140,13 @@ jobs:
         working-directory: ./src
         # This command uses src/third_party_cache as the download cache.
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/update_deps.py
 
       - name: Build Qt
         working-directory: ./src
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/build_qt.py --release --confirm_license --macos_cpus=x86_64,arm64
           echo "MOZC_QT_PATH=${PWD}/third_party/qt" >> $GITHUB_ENV
 
@@ -161,9 +173,10 @@ jobs:
         with:
           submodules: 'recursive'
 
-      - name: Install pip dependencies
-        working-directory: ./src
+      - name: Setup Python
         run: |
+          python3 -m venv ${PYTHON_VENV_ROOT}
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 -m pip install requests
 
       - name: Try to restore update_deps cache
@@ -176,11 +189,13 @@ jobs:
         working-directory: ./src
         # This command uses src/third_party_cache as the download cache.
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/update_deps.py
 
       - name: Build Qt
         working-directory: ./src
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/build_qt.py --release --confirm_license
           echo "MOZC_QT_PATH=${PWD}/third_party/qt" >> $GITHUB_ENV
 
@@ -201,9 +216,10 @@ jobs:
       - name: checkout
         uses: actions/checkout@v4
 
-      - name: Install pip dependencies
-        working-directory: ./src
+      - name: Setup Python
         run: |
+          python3 -m venv ${PYTHON_VENV_ROOT}
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 -m pip install requests
 
       - name: Try to restore update_deps cache
@@ -216,4 +232,5 @@ jobs:
         working-directory: ./src
         # This command uses src/third_party_cache as the download cache.
         run: |
+          source ${PYTHON_VENV_ROOT}/bin/activate
           python3 build_tools/update_deps.py --cache_only