[3.14] gh-136234: Fix SelectorSocketTransport.writelines to be robust to connection loss (GH-136743)

.editorconfig

@@ -1,11 +1,11 @@
 root = true
 
-[*.{py,c,cpp,h,js,rst,md,yml,yaml}]
+[*.{py,c,cpp,h,js,rst,md,yml,yaml,gram}]
 trim_trailing_whitespace = true
 insert_final_newline = true
 indent_style = space
 
-[*.{py,c,cpp,h}]
+[*.{py,c,cpp,h,gram}]
 indent_size = 4
 
 [*.rst]

.github/CODEOWNERS

@@ -8,7 +8,7 @@
 .github/**                    @ezio-melotti @hugovk @AA-Turner
 
 # pre-commit
-.pre-commit-config.yaml       @hugovk @AlexWaygood
+.pre-commit-config.yaml       @hugovk
 .ruff.toml                    @hugovk @AlexWaygood @AA-Turner
 
 # Build system

.github/workflows/build.yml

@@ -177,7 +177,7 @@ jobs:
       - name: Build CPython
         run: |
           make -j4 regen-all
-          make regen-stdlib-module-names regen-sbom regen-unicodedata
+          make regen-stdlib-module-names regen-sbom
       - name: Check for changes
         run: |
           git add -u
@@ -225,8 +225,8 @@ jobs:
       free-threading: ${{ matrix.free-threading }}
 
   build-windows-msi:
-    name: >-  # ${{ '' } is a hack to nest jobs under the same sidebar category
-      Windows MSI${{ '' }}
+    # ${{ '' } is a hack to nest jobs under the same sidebar category.
+    name: Windows MSI${{ '' }}  # zizmor: ignore[obfuscation]
     needs: build-context
     if: fromJSON(needs.build-context.outputs.run-windows-msi)
     strategy:
@@ -317,7 +317,10 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-24.04]
-        openssl_ver: [3.0.16, 3.1.8, 3.2.4, 3.3.3, 3.4.1]
+        # Keep 1.1.1w in our list despite it being upstream EOL and otherwise
+        # unsupported as it most resembles other 1.1.1-work-a-like ssl APIs
+        # supported by important vendors such as AWS-LC.
+        openssl_ver: [1.1.1w, 3.0.17, 3.2.5, 3.3.4, 3.4.2, 3.5.2]
         # See Tools/ssl/make_ssl_data.py for notes on adding a new version
     env:
       OPENSSL_VER: ${{ matrix.openssl_ver }}
@@ -369,6 +372,29 @@ jobs:
     - name: SSL tests
       run: ./python Lib/test/ssltests.py
 
+  build-android:
+    name: Android (${{ matrix.arch }})
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
+    timeout-minutes: 60
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Use the same runs-on configuration as build-macos and build-ubuntu.
+          - arch: aarch64
+            runs-on: ${{ github.repository_owner == 'python' && 'ghcr.io/cirruslabs/macos-runner:sonoma' || 'macos-14' }}
+          - arch: x86_64
+            runs-on: ubuntu-24.04
+
+    runs-on: ${{ matrix.runs-on }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Build and test
+        run: ./Android/android.py ci ${{ matrix.arch }}-linux-android
+
   build-wasi:
     name: 'WASI'
     needs: build-context
@@ -557,20 +583,28 @@ jobs:
     - name: Tests
       run: xvfb-run make ci
 
-  build-tsan:
-    name: >-
-      Thread sanitizer
-      ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
+  build-san:
+    # ${{ '' } is a hack to nest jobs under the same sidebar category.
+    name: Sanitizers${{ '' }}  # zizmor: ignore[obfuscation]
     needs: build-context
     if: needs.build-context.outputs.run-tests == 'true'
     strategy:
       fail-fast: false
       matrix:
+        check-name:
+        - Thread
         free-threading:
         - false
         - true
-    uses: ./.github/workflows/reusable-tsan.yml
+        sanitizer:
+        - TSan
+        include:
+        - check-name: Undefined behavior
+          sanitizer: UBSan
+          free-threading: false
+    uses: ./.github/workflows/reusable-san.yml
     with:
+      sanitizer: ${{ matrix.sanitizer }}
       config_hash: ${{ needs.build-context.outputs.config-hash }}
       free-threading: ${{ matrix.free-threading }}
 
@@ -668,10 +702,11 @@ jobs:
     - build-macos
     - build-ubuntu
     - build-ubuntu-ssltests
+    - build-android
     - build-wasi
     - test-hypothesis
     - build-asan
-    - build-tsan
+    - build-san
     - cross-build-linux
     - cifuzz
     if: always()
@@ -701,10 +736,11 @@ jobs:
             build-macos,
             build-ubuntu,
             build-ubuntu-ssltests,
+            build-android,
             build-wasi,
             test-hypothesis,
             build-asan,
-            build-tsan,
+            build-san,
             cross-build-linux,
             '
             || ''

.github/workflows/jit.yml

@@ -113,6 +113,10 @@ jobs:
           find /usr/local/bin -lname '*/Library/Frameworks/Python.framework/*' -delete
           brew install llvm@${{ matrix.llvm }}
           export SDKROOT="$(xcrun --show-sdk-path)"
+          # Set MACOSX_DEPLOYMENT_TARGET and -Werror=unguarded-availability to
+          # make sure we don't break downstream distributors (like uv):
+          export CFLAGS_JIT='-Werror=unguarded-availability'
+          export MACOSX_DEPLOYMENT_TARGET=10.15
           ./configure --enable-experimental-jit --enable-universalsdk --with-universal-archs=universal2 ${{ matrix.debug && '--with-pydebug' || '' }}
           make all --jobs 4
           ./python.exe -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3

.github/workflows/mypy.yml

@@ -13,13 +13,17 @@ on:
       - "Lib/test/libregrtest/**"
       - "Lib/tomllib/**"
       - "Misc/mypy/**"
+      - "Tools/build/check_extension_modules.py"
+      - "Tools/build/check_warnings.py"
       - "Tools/build/compute-changes.py"
       - "Tools/build/deepfreeze.py"
-      - "Tools/build/generate_sbom.py"
       - "Tools/build/generate-build-details.py"
-      - "Tools/build/verify_ensurepip_wheels.py"
-      - "Tools/build/update_file.py"
+      - "Tools/build/generate_sbom.py"
+      - "Tools/build/generate_stdlib_module_names.py"
+      - "Tools/build/mypy.ini"
       - "Tools/build/umarshal.py"
+      - "Tools/build/update_file.py"
+      - "Tools/build/verify_ensurepip_wheels.py"
       - "Tools/cases_generator/**"
       - "Tools/clinic/**"
       - "Tools/jit/**"

.github/workflows/reusable-docs.yml

@@ -66,7 +66,7 @@ jobs:
       run: |
         set -Eeuo pipefail
         # Build docs with the nit-picky option; write warnings to file
-        make -C Doc/ PYTHON=../python SPHINXOPTS="--quiet --nitpicky --fail-on-warning --warning-file sphinx-warnings.txt" html
+        make -C Doc/ PYTHON=../python SPHINXOPTS="--quiet --nitpicky --warning-file sphinx-warnings.txt" html
     - name: 'Check warnings'
       if: github.event_name == 'pull_request'
       run: |
@@ -102,3 +102,30 @@ jobs:
     # Use "xvfb-run" since some doctest tests open GUI windows
     - name: 'Run documentation doctest'
       run: xvfb-run make -C Doc/ PYTHON=../python SPHINXERRORHANDLING="--fail-on-warning" doctest
+
+  check-epub:
+    name: 'Check EPUB'
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        persist-credentials: false
+    - name: 'Set up Python'
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3'
+        cache: 'pip'
+        cache-dependency-path: 'Doc/requirements.txt'
+    - name: 'Install build dependencies'
+      run: |
+        make -C Doc/ venv
+        python -m pip install epubcheck
+    - name: 'Build EPUB documentation'
+      run: make -C Doc/ PYTHON=../python epub
+    - name: 'Run epubcheck'
+      continue-on-error: true
+      run: epubcheck Doc/build/epub/Python.epub &> Doc/epubcheck.txt
+    - run: cat Doc/epubcheck.txt
+    - name: 'Check for fatal errors in EPUB'
+      run: python Doc/tools/check-epub.py

.github/workflows/reusable-san.yml

@@ -0,0 +1,124 @@
+name: Reusable Sanitizer
+
+on:
+  workflow_call:
+    inputs:
+      sanitizer:
+        required: true
+        type: string
+      config_hash:
+        required: true
+        type: string
+      free-threading:
+        description: Whether to use free-threaded mode
+        required: false
+        type: boolean
+        default: false
+
+env:
+  FORCE_COLOR: 1
+
+jobs:
+  build-san-reusable:
+    name: >-
+      ${{ inputs.sanitizer }}${{
+        inputs.free-threading
+        && ' (free-threading)'
+        || ''
+      }}
+    runs-on: ubuntu-24.04
+    timeout-minutes: 60
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        persist-credentials: false
+    - name: Runner image version
+      run: echo "IMAGE_OS_VERSION=${ImageOS}-${ImageVersion}" >> "$GITHUB_ENV"
+    - name: Restore config.cache
+      uses: actions/cache@v4
+      with:
+        path: config.cache
+        key: ${{ github.job }}-${{ env.IMAGE_OS_VERSION }}-${{ inputs.sanitizer }}-${{ inputs.config_hash }}
+    - name: Install dependencies
+      run: |
+        sudo ./.github/workflows/posix-deps-apt.sh
+        # Install clang
+        wget https://apt.llvm.org/llvm.sh
+        chmod +x llvm.sh
+
+        if [ "${SANITIZER}" = "TSan" ]; then
+          sudo ./llvm.sh 17  # gh-121946: llvm-18 package is temporarily broken
+          sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-17 100
+          sudo update-alternatives --set clang /usr/bin/clang-17
+          sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-17 100
+          sudo update-alternatives --set clang++ /usr/bin/clang++-17
+          # Reduce ASLR to avoid TSan crashing
+          sudo sysctl -w vm.mmap_rnd_bits=28
+        else
+          sudo ./llvm.sh 20
+        fi
+
+    - name: Sanitizer option setup
+      run: |
+        if [ "${SANITIZER}" = "TSan" ]; then
+          echo "TSAN_OPTIONS=${SAN_LOG_OPTION} suppressions=${GITHUB_WORKSPACE}/Tools/tsan/suppressions${{
+              fromJSON(inputs.free-threading)
+              && '_free_threading'
+              || ''
+            }}.txt handle_segv=0" >> "$GITHUB_ENV"
+        else
+          echo "UBSAN_OPTIONS=${SAN_LOG_OPTION}" >> "$GITHUB_ENV"
+        fi
+        echo "CC=clang" >> "$GITHUB_ENV"
+        echo "CXX=clang++" >> "$GITHUB_ENV"
+      env:
+        SANITIZER: ${{ inputs.sanitizer }}
+        SAN_LOG_OPTION: log_path=${{ github.workspace }}/san_log
+    - name: Add ccache to PATH
+      run: |
+        echo "PATH=/usr/lib/ccache:$PATH" >> "$GITHUB_ENV"
+    - name: Configure ccache action
+      uses: hendrikmuhs/[email protected]
+      with:
+        save: ${{ github.event_name == 'push' }}
+        max-size: "200M"
+    - name: Configure CPython
+      run: >-
+        ./configure
+        --config-cache
+        ${{
+          inputs.sanitizer == 'TSan'
+          && '--with-thread-sanitizer'
+          || '--with-undefined-behavior-sanitizer'
+        }}
+        --with-pydebug
+        ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
+    - name: Build CPython
+      run: make -j4
+    - name: Display build info
+      run: make pythoninfo
+    - name: Tests
+      run: >-
+        ./python -m test
+        ${{ inputs.sanitizer == 'TSan' && '--tsan' || '' }}
+        -j4
+    - name: Parallel tests
+      if: >-
+        inputs.sanitizer == 'TSan'
+        && fromJSON(inputs.free-threading)
+      run: ./python -m test --tsan-parallel --parallel-threads=4 -j4
+    - name: Display logs
+      if: always()
+      run: find "${GITHUB_WORKSPACE}" -name 'san_log.*' | xargs head -n 1000
+    - name: Archive logs
+      if: always()
+      uses: actions/upload-artifact@v4
+      with:
+        name: >-
+          ${{ inputs.sanitizer }}-logs-${{
+            fromJSON(inputs.free-threading)
+            && 'free-threading'
+            || 'default'
+          }}
+        path: san_log.*
+        if-no-files-found: ignore