maintain stable versions of dependencies

.github/CODEOWNERS

@@ -0,0 +1 @@
+/.github/stable/ @PennyLaneAI/Core

.github/workflows/install_deps/action.yml

@@ -0,0 +1,113 @@
+name: Install Dependencies
+description: |
+  This workflow installs Python, PennyLane and all its dependencies. If a
+  requirements file is provided, it will upload the results of pip freeze
+  as well.
+inputs:
+  python_version:
+    description: The version of Python to use in order to run unit tests
+    required: false
+    default: '3.9'
+  install_jax:
+    description: Indicate if JAX should be installed or not
+    required: false
+    default: 'true'
+  jax_version:
+    description: The version of JAX to install for any job that requires JAX
+    required: false
+    default: 0.4.23
+  install_tensorflow:
+    description: Indicate if TensorFlow should be installed or not
+    required: false
+    default: 'true'
+  tensorflow_version:
+    description: The version of TensorFlow to install for any job that requires TensorFlow
+    required: false
+    default: 2.15.0
+  install_pytorch:
+    description: Indicate if PyTorch should be installed or not
+    required: false
+    default: 'true'
+  pytorch_version:
+    description: The version of PyTorch to install for any job that requires PyTorch
+    required: false
+    default: 2.2.0
+  install_pennylane_lightning_master:
+    description: Indicate if PennyLane-Lightning should be installed from the master branch
+    required: false
+    default: 'true'
+  additional_pip_packages:
+    description: Additional packages to install. Values will be passed to pip install {value}
+    required: false
+    default: ''
+  requirements_file:
+    description: File name to store stable version of requirements for a test group
+    required: false
+    default: ''
+
+runs:
+  using: composite
+  steps:
+    - name: Setup Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: '${{ inputs.python_version }}'
+
+    - name: Upgrade PIP
+      shell: bash
+      run: pip install --upgrade pip && pip install wheel --upgrade
+
+    - name: Install PennyLane dependencies
+      shell: bash
+      run: |
+        pip install -r requirements-ci.txt --upgrade
+        pip install -r requirements-dev.txt --upgrade
+
+    - name: Install PyTorch
+      shell: bash
+      if: inputs.install_pytorch == 'true'
+      env:
+        TORCH_VERSION: ${{ inputs.pytorch_version != '' && format('=={0}', inputs.pytorch_version) || '' }}
+      run: pip install "torch${{ env.TORCH_VERSION }}" -f https://download.pytorch.org/whl/torch_stable.html
+
+    - name: Install TensorFlow
+      shell: bash
+      if: inputs.install_tensorflow == 'true'
+      env:
+        TF_VERSION: ${{ inputs.tensorflow_version != '' && format('~={0}', inputs.tensorflow_version) || '' }}
+      run: pip install "tensorflow${{ env.TF_VERSION }}" "keras${{ env.TF_VERSION }}"
+
+    - name: Install JAX
+      shell: bash
+      if: inputs.install_jax == 'true'
+      env:
+        JAX_VERSION: ${{ inputs.jax_version != '' && format('=={0}', inputs.jax_version) || '' }}
+      run: pip install "jax${{ env.JAX_VERSION}}" "jaxlib${{ env.JAX_VERSION }}"
+
+    - name: Install additional PIP packages
+      shell: bash
+      if: inputs.additional_pip_packages != ''
+      run: pip install ${{ inputs.additional_pip_packages }}
+
+    - name: Install PennyLane
+      shell: bash
+      run: |
+        python setup.py bdist_wheel
+        pip install dist/PennyLane*.whl
+
+    - name: Install PennyLane-Lightning master
+      shell: bash
+      if: inputs.install_pennylane_lightning_master == 'true'
+      run: pip install -i https://test.pypi.org/simple/ PennyLane-Lightning --pre --upgrade
+
+    - name: Freeze dependencies
+      shell: bash
+      if: inputs.requirements_file != ''
+      run: pip freeze | grep -v "file:///" > ${{ inputs.requirements_file }}
+
+    - name: Upload frozen requirements
+      if: inputs.requirements_file != ''
+      uses: actions/upload-artifact@v4
+      with:
+        name: frozen-${{ inputs.requirements_file }}
+        path: ${{ inputs.requirements_file }}

.github/workflows/interface-unit-tests.yml

@@ -11,21 +11,6 @@ on:
           required: false
           type: string
           default: 'unit-tests'
-      jax_version:
-        description: The version of JAX to install for any job that requires JAX
-        required: false
-        type: string
-        default: 0.4.23
-      tensorflow_version:
-        description: The version of TensorFlow to install for any job that requires TensorFlow
-        required: false
-        type: string
-        default: 2.15.0
-      pytorch_version:
-        description: The version of PyTorch to install for any job that requires PyTorch
-        required: false
-        type: string
-        default: 2.2.0
       pytest_coverage_flags:
         description: PyTest Coverage flags to pass to all jobs
         required: false
@@ -162,10 +147,10 @@ jobs:
       install_jax: false
       install_tensorflow: false
       install_pytorch: true
-      pytorch_version: ${{ inputs.pytorch_version }}
       install_pennylane_lightning_master: true
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
       pytest_markers: torch and not qcut and not finite-diff and not param-shift
+      requirements_file: ${{ strategy.job-index == 0 && 'torch.txt' || '' }}
 
 
   autograd-tests:
@@ -225,13 +210,13 @@ jobs:
       pipeline_mode: ${{ inputs.pipeline_mode }}
       install_jax: false
       install_tensorflow: true
-      tensorflow_version: ${{ inputs.tensorflow_version }}
       install_pytorch: false
       install_pennylane_lightning_master: true
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
       pytest_markers: tf and not qcut and not finite-diff and not param-shift
       pytest_additional_args: --splits 3 --group ${{ matrix.group }} --durations-path='.github/workflows/tf_tests_durations.json'
       additional_pip_packages: pytest-split
+      requirements_file: ${{ strategy.job-index == 0 && 'tf.txt' || '' }}
 
 
   jax-tests:
@@ -259,14 +244,14 @@ jobs:
       python_version: ${{ matrix.python-version }}
       pipeline_mode: ${{ inputs.pipeline_mode }}
       install_jax: true
-      jax_version: ${{ inputs.jax_version }}
       install_tensorflow: false
       install_pytorch: false
       install_pennylane_lightning_master: true
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
       pytest_markers: jax and not qcut and not finite-diff and not param-shift
       pytest_additional_args: --splits 5 --group ${{ matrix.group }} --durations-path='.github/workflows/jax_tests_durations.json'
       additional_pip_packages: pytest-split
+      requirements_file: ${{ strategy.job-index == 0 && 'jax.txt' || '' }}
 
 
   core-tests:
@@ -303,6 +288,7 @@ jobs:
       pytest_markers: core and not qcut and not finite-diff and not param-shift
       pytest_additional_args: --splits 2 --group ${{ matrix.group }}
       additional_pip_packages: pytest-split
+      requirements_file: ${{ strategy.job-index == 0 && 'core.txt' || '' }}
 
 
   all-interfaces-tests:
@@ -329,14 +315,12 @@ jobs:
       python_version: ${{ matrix.python-version }}
       pipeline_mode: ${{ inputs.pipeline_mode }}
       install_jax: true
-      jax_version: ${{ inputs.jax_version }}
       install_tensorflow: true
-      tensorflow_version: ${{ inputs.tensorflow_version }}
       install_pytorch: true
-      pytorch_version: ${{ inputs.pytorch_version }}
       install_pennylane_lightning_master: false
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
       pytest_markers: all_interfaces
+      requirements_file: ${{ strategy.job-index == 0 && 'all_interfaces.txt' || '' }}
 
 
   external-libraries-tests:
@@ -363,14 +347,13 @@ jobs:
       python_version: ${{ matrix.python-version }}
       pipeline_mode: ${{ inputs.pipeline_mode }}
       install_jax: true
-      jax_version: ${{ inputs.jax_version }}
       install_tensorflow: true
-      tensorflow_version: ${{ inputs.tensorflow_version }}
       install_pytorch: false
       install_pennylane_lightning_master: false
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
       pytest_markers: external
-      additional_pip_packages: git+https://github.com/Quantomatic/pyzx.git@master pennylane-catalyst matplotlib stim
+      additional_pip_packages: pyzx pennylane-catalyst matplotlib stim
+      requirements_file: ${{ strategy.job-index == 0 && 'external.txt' || '' }}
 
 
   qcut-tests:
@@ -397,11 +380,8 @@ jobs:
       python_version: ${{ matrix.python-version }}
       pipeline_mode: ${{ inputs.pipeline_mode }}
       install_jax: true
-      jax_version: ${{ inputs.jax_version }}
       install_tensorflow: true
-      tensorflow_version: ${{ inputs.tensorflow_version }}
       install_pytorch: true
-      pytorch_version: ${{ inputs.pytorch_version }}
       install_pennylane_lightning_master: false
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
       pytest_markers: qcut
@@ -466,11 +446,8 @@ jobs:
       python_version: ${{ matrix.python-version }}
       pipeline_mode: ${{ inputs.pipeline_mode }}
       install_jax: true
-      jax_version: ${{ inputs.jax_version }}
       install_tensorflow: true
-      tensorflow_version: ${{ inputs.tensorflow_version }}
       install_pytorch: true
-      pytorch_version: ${{ inputs.pytorch_version }}
       install_pennylane_lightning_master: false
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
       pytest_markers: ${{ matrix.config.suite }}
@@ -543,11 +520,8 @@ jobs:
       python_version: ${{ matrix.python-version }}
       pipeline_mode: ${{ inputs.pipeline_mode }}
       install_jax: ${{ contains(matrix.config.device, 'jax') }}
-      jax_version: ${{ inputs.jax_version }}
       install_tensorflow: ${{ contains(matrix.config.device, 'tf') }}
-      tensorflow_version: ${{ inputs.tensorflow_version }}
       install_pytorch: ${{ contains(matrix.config.device, 'torch') }}
-      pytorch_version: ${{ inputs.pytorch_version }}
       install_pennylane_lightning_master: false
       pytest_test_directory: pennylane/devices/tests
       pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}

.github/workflows/tests.yml

@@ -9,6 +9,9 @@ concurrency:
   group: unit-tests-${{ github.ref }}
   cancel-in-progress: true
 
+env:
+  DEPS_BRANCH: bot/stable-deps-update
+
 jobs:
   tests:
     uses: ./.github/workflows/interface-unit-tests.yml
@@ -24,3 +27,61 @@ jobs:
           && !contains(github.event.pull_request.labels.*.name, 'ci:run-full-test-suite')
           || false
          }}
+
+  upload-stable-deps:
+    needs: tests
+    runs-on: ubuntu-latest
+    if: ${{ github.event_name == 'push' }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-tags: true
+          sparse-checkout: .github
+
+      - name: Prepare local repo
+        run: |
+          git fetch
+          git config user.name "GitHub Actions Bot"
+          git config user.email "<>"
+          if git ls-remote --exit-code origin "refs/heads/${{ env.DEPS_BRANCH }}"; then
+            git checkout "${{ env.DEPS_BRANCH }}"
+            git rebase origin/master
+          else
+            git checkout master
+            git checkout -b "${{ env.DEPS_BRANCH }}"
+          fi
+          rm -f .github/stable/*.txt
+
+      - name: Download artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: frozen-*
+          path: .github/stable/
+          merge-multiple: true
+
+      - name: Determine if changes have been made
+        id: changed
+        run: |
+          echo "has_changes=$(git status --porcelain | wc -l | awk '{print $1}')" >> $GITHUB_OUTPUT
+
+      - name: Stage changes
+        if: steps.changed.outputs.has_changes != '0'
+        run: |
+          git add .github/stable/
+          git commit -m "Update changed dependencies"
+          git push -f --set-upstream origin "${{ env.DEPS_BRANCH }}"
+
+      # Create PR to master
+      - name: Create pull request
+        if: steps.changed.outputs.has_changes != '0'
+        uses: repo-sync/pull-request@v2
+        with:
+          source_branch: "${{ env.DEPS_BRANCH }}"
+          destination_branch: "master"
+          github_token: "${{ secrets.GITHUB_TOKEN }}"
+          pr_title: "Update stable dependency files"
+          pr_body: "Automatic update of stable requirement files to snapshot valid python environments. Please push an empty commit using `git commit --allow-empty -m 'trigger ci'` as bots are not able to trigger CI on their own."
+          pr_allow_empty: false
+          pr_draft: false
+          pr_reviewer: "timmysilv"