deps: Raise the Python requirement to 3.10 (#31088)

This will allow us to use the pip's new dependency resolver.

.github/workflows/docs.yml

@@ -10,7 +10,7 @@ jobs:
     # This job is only useful when run on upstream servo.
     if: github.repository == 'servo/servo' || github.event_name == 'workflow_dispatch'
     name: Upload docs to GitHub Pages
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v3
         with:

.github/workflows/linux.yml

@@ -87,6 +87,9 @@ jobs:
       - name: Set LIBCLANG_PATH env # needed for bindgen in mozangle
         if: ${{ !inputs.upload  }} # not needed on ubuntu 20.04 used for nightly
         run: echo "LIBCLANG_PATH=/usr/lib/llvm-14/lib" >> $GITHUB_ENV
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.10'
       - name: Install taplo
         uses: baptiste0928/cargo-install@v2
         with:

.github/workflows/nightly-rust.yml

@@ -22,6 +22,9 @@ jobs:
           fetch-depth: 2
       - name: Update rustc
         run: echo nightly > rust-toolchain
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.10'
       - name: Bootstrap
         run: |
           python3 -m pip install --upgrade pip

.github/workflows/windows.yml

@@ -70,6 +70,9 @@ jobs:
         run: |
           choco install wixtoolset
           echo "C:\\Program Files (x86)\\WiX Toolset v3.11\\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.10'
       - name: Bootstrap
         run: |
           python -m pip install --upgrade pip

README.md

@@ -22,6 +22,7 @@ manually, try the [manual build setup][manual-build].
 
 ### macOS
 
+- Ensure that the version showed by `python --version` is >= 3.10:
 - Install [Xcode](https://developer.apple.com/xcode/)
 - Install [Homebrew](https://brew.sh/)
 - Run `curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh`
@@ -31,7 +32,7 @@ manually, try the [manual build setup][manual-build].
 ### Linux
 
 - Run `curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh`
-- Install Python
+- Install Python (version >= 3.10):
     - **Debian-like:** Run `sudo apt install python3-pip python3-venv`
     - **Fedora:** Run `sudo dnf install python3 python3-pip python3-devel`
     - **Arch:** Run `sudo pacman -S --needed python python-pip`

python/mach_bootstrap.py

@@ -209,10 +209,10 @@ def bootstrap(topdir):
         print('Current path:', topdir)
         sys.exit(1)
 
-    # Ensure we are running Python 3.5+. We put this check here so we generate a
+    # Ensure we are running Python 3.10+. We put this check here so we generate a
     # user-friendly error message rather than a cryptic stack trace on module import.
-    if sys.version_info < (3, 5):
-        print('Python3 (>=3.5) is required to run mach.')
+    if sys.version_info < (3, 10):
+        print('Python3 (>=3.10) is required to run mach.')
         print('You are running Python', platform.python_version())
         sys.exit(1)