CI: Add job for pip check

.core_files.yaml

@@ -119,6 +119,12 @@ other: &other
   - .github/workflows/*
   - homeassistant/scripts/**
 
+requirements:
+  - .github/workflows/*
+  - homeassistant/package_constraints.txt
+  - requirements*.txt
+  - setup.py
+
 any:
   - *base_platforms
   - *components

.github/workflows/ci.yaml

@@ -17,6 +17,7 @@ env:
   PIP_CACHE: /tmp/pip-cache
   SQLALCHEMY_WARN_20: 1
   PYTHONASYNCIODEBUG: 1
+  DEPENDENCY_CONFLICTS: 14  # Update this one if a PR resolves a dependency conflict
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
@@ -36,6 +37,7 @@ jobs:
       tests_glob: ${{ steps.info.outputs.tests_glob }}
       test_groups: ${{ steps.info.outputs.test_groups }}
       test_group_count: ${{ steps.info.outputs.test_group_count }}
+      requirements: ${{ steps.core.outputs.requirements }}
     runs-on: ubuntu-latest
     steps:
       - name: Check out code from GitHub
@@ -671,6 +673,38 @@ jobs:
           python --version
           mypy homeassistant/components/${{ needs.changes.outputs.integrations_glob }}
 
+  pip-check:
+    runs-on: ubuntu-latest
+    if: needs.changes.outputs.requirements == 'true'
+    needs:
+      - changes
+      - prepare-tests
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: [3.9]
+    name: Run pip check ${{ matrix.python-version }}
+    container: homeassistant/ci-azure:${{ matrix.python-version }}
+    steps:
+      - name: Check out code from GitHub
+        uses: actions/[email protected]
+      - name: Restore full Python ${{ matrix.python-version }} virtual environment
+        id: cache-venv
+        uses: actions/[email protected]
+        with:
+          path: venv
+          key: ${{ runner.os }}-${{ matrix.python-version }}-${{
+            needs.prepare-tests.outputs.python-key }}
+      - name: Fail job if Python cache restore failed
+        if: steps.cache-venv.outputs.cache-hit != 'true'
+        run: |
+          echo "Failed to restore Python virtual environment from cache"
+          exit 1
+      - name: Run pip check
+        run: |
+          . venv/bin/activate
+          ./script/pip_check $PIP_CACHE $DEPENDENCY_CONFLICTS
+
   pytest:
     runs-on: ubuntu-latest
     if: needs.changes.outputs.test_full_suite == 'true' || needs.changes.outputs.tests_glob

script/pip_check

@@ -0,0 +1,24 @@
+#!/bin/bash
+PIP_CACHE=$1
+DEPENDENCY_CONFLICTS=$2
+
+PIP_CHECK=$(pip check --cache-dir=$PIP_CACHE)
+LINE_COUNT=$(echo "$PIP_CHECK" | wc -l)
+echo "$PIP_CHECK"
+
+if [[ $((LINE_COUNT)) -gt 15 ]]
+then
+    echo "------"
+    echo "Requirements change added another dependency conflict."
+    echo "Make sure to check the 'pip check' output above!"
+    exit 1
+elif [[ $((LINE_COUNT)) -lt 15 ]]
+then
+    echo "------"
+    echo "It seems like this PR resolves $((
+        15 - LINE_COUNT)) dependency conflicts."
+    echo "Please update the 'DEPENDENCY_CONFLICTS' environment variable "
+    echo "in '.github/workflows/ci.yaml' to help prevent regressions."
+    echo "Update it to: $((LINE_COUNT))"
+    exit 1
+fi