[3.12] gh-87891: Add ABI check to CI

.github/workflows/build.yml

@@ -75,6 +75,36 @@ jobs:
             echo "run_hypothesis=true" >> $GITHUB_OUTPUT
           fi
 
+  check_abi:
+    name: 'Check if the ABI has changed'
+    runs-on: ubuntu-20.04
+    needs: check_source
+    if: needs.check_source.outputs.run_tests == 'true'
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+      - name: Install Dependencies
+        run: |
+            sudo ./.github/workflows/posix-deps-apt.sh
+            sudo apt-get install -yq abigail-tools
+      - name: Build CPython
+        env:
+          CFLAGS: -g3 -O0
+        run: |
+          # Build Python with the libpython dynamic library
+          ./configure --enable-shared
+          make -j4
+      - name: Check for changes in the ABI
+        run: |
+          if ! make check-abidump; then
+            echo "Generated ABI file is not up to date."
+            echo "Please, add the release manager of this branch as a reviewer of this PR."
+            echo ""
+            echo "To learn more about this check, please visit: https://devguide.python.org/setup/?highlight=abi#regenerate-the-abi-dump"
+            echo ""
+            exit 1
+          fi
+
   check_generated_files:
     name: 'Check if generated files are up to date'
     runs-on: ubuntu-latest

.gitignore

@@ -156,6 +156,3 @@ Python/frozen_modules/MANIFEST
 # Ignore ./python binary on Unix but still look into ./Python/ directory.
 /python
 !/Python/
-
-# main branch only: ABI files are not checked/maintained
-Doc/data/python*.abi