releasing 2.5.3 [rebase & merge]

.actions/requirements.txt

@@ -1,3 +1,3 @@
-jsonargparse >=4.16.0, <=4.35.0
+jsonargparse
 requests
 packaging

.azure/gpu-benchmarks.yml

@@ -76,8 +76,13 @@ jobs:
         displayName: "Image info & NVIDIA"
 
       - bash: |
-          pip install -e .[dev] --find-links ${TORCH_URL}
-          pip install setuptools==75.6.0 jsonargparse==4.35.0
+          pip install -U -q -r .actions/requirements.txt
+          python .actions/assistant.py copy_replace_imports --source_dir="./tests" \
+            --source_import="lightning.fabric,lightning.pytorch" \
+            --target_import="lightning_fabric,pytorch_lightning"
+        displayName: "Adjust tests"
+
+      - bash: pip install -e .[dev] --find-links ${TORCH_URL}
         env:
           FREEZE_REQUIREMENTS: "1"
         displayName: "Install package"
@@ -88,17 +93,10 @@ jobs:
           python -c "import torch ; mgpu = torch.cuda.device_count() ; assert mgpu == 2, f'GPU: {mgpu}'"
         displayName: "Env details"
 
-      - bash: |
-          pip install -q -r .actions/requirements.txt
-          python .actions/assistant.py copy_replace_imports --source_dir="./tests" \
-            --source_import="lightning.fabric,lightning.pytorch" \
-            --target_import="lightning_fabric,pytorch_lightning"
-        displayName: "Adjust tests"
-
       - bash: python -m pytest parity_$(PACKAGE_NAME) -v --durations=0
         env:
           PL_RUNNING_BENCHMARKS: "1"
-          PL_RUN_CUDA_TESTS: "1"
+          RUN_ONLY_CUDA_TESTS: "1"
         workingDirectory: tests/
         displayName: "Testing: benchmarks"
 
@@ -107,7 +105,7 @@ jobs:
         # without succeeded this could run even if the job has already failed
         condition: and(succeeded(), eq(variables['PACKAGE_NAME'], 'fabric'))
         env:
-          PL_RUN_CUDA_TESTS: "1"
+          RUN_ONLY_CUDA_TESTS: "1"
           PL_RUN_STANDALONE_TESTS: "1"
         displayName: "Testing: fabric standalone tasks"
         timeoutInMinutes: "10"

.azure/gpu-tests-fabric.yml

@@ -48,7 +48,7 @@ jobs:
       DEVICES: $( python -c 'print("$(Agent.Name)".split("_")[-1])' )
       FREEZE_REQUIREMENTS: "1"
       PIP_CACHE_DIR: "/var/tmp/pip"
-      PL_RUN_CUDA_TESTS: "1"
+      RUN_ONLY_CUDA_TESTS: "1"
     container:
       image: $(image)
       # default shm size is 64m. Increase it to avoid:
@@ -60,13 +60,13 @@ jobs:
           image: "pytorchlightning/pytorch_lightning:base-cuda-py3.10-torch2.1-cuda12.1.1"
           PACKAGE_NAME: "fabric"
         "Fabric | latest":
-          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.7-cuda12.6.3"
+          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.8-cuda12.6.3"
           PACKAGE_NAME: "fabric"
         #"Fabric | future":
         #  image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.7-cuda12.6.3"
         #  PACKAGE_NAME: "fabric"
         "Lightning | latest":
-          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.7-cuda12.6.3"
+          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.8-cuda12.6.3"
           PACKAGE_NAME: "lightning"
     workspace:
       clean: all
@@ -78,8 +78,6 @@ jobs:
           echo "##vso[task.setvariable variable=TORCH_URL]https://download.pytorch.org/whl/cu${cuda_ver}/torch_stable.html"
           scope=$(python -c 'n = "$(PACKAGE_NAME)" ; print(dict(fabric="lightning_fabric").get(n, n))')
           echo "##vso[task.setvariable variable=COVERAGE_SOURCE]$scope"
-          python_ver=$(python -c "import sys; print(f'{sys.version_info.major}{sys.version_info.minor}')")
-          echo "##vso[task.setvariable variable=PYTHON_VERSION_MM]$python_ver"
         displayName: "set env. vars"
       - bash: |
           echo "##vso[task.setvariable variable=TORCH_URL]https://download.pytorch.org/whl/test/cu${CUDA_VERSION_MM}"
@@ -100,6 +98,12 @@ jobs:
           pip list
         displayName: "Image info & NVIDIA"
 
+      - bash: |
+          python .actions/assistant.py replace_oldest_ver
+          pip install "cython<3.0" wheel  # for compatibility
+        condition: contains(variables['Agent.JobName'], 'oldest')
+        displayName: "setting oldest dependencies"
+
       - bash: |
           PYTORCH_VERSION=$(python -c "import torch; print(torch.__version__.split('+')[0])")
           pip install -q wget packaging
@@ -109,11 +113,22 @@ jobs:
           done
         displayName: "Adjust dependencies"
 
+      - bash: |
+          pip install -U -q -r .actions/requirements.txt
+          python .actions/assistant.py copy_replace_imports --source_dir="./tests/tests_fabric" \
+            --source_import="lightning.fabric" \
+            --target_import="lightning_fabric"
+          python .actions/assistant.py copy_replace_imports --source_dir="./examples/fabric" \
+            --source_import="lightning.fabric" \
+            --target_import="lightning_fabric"
+        # without succeeded this could run even if the job has already failed
+        condition: and(succeeded(), eq(variables['PACKAGE_NAME'], 'fabric'))
+        displayName: "Adjust tests & examples"
+
       - bash: |
           set -e
           extra=$(python -c "print({'lightning': 'fabric-'}.get('$(PACKAGE_NAME)', ''))")
-          pip install -e ".[${extra}dev]" pytest-timeout -U --extra-index-url="${TORCH_URL}"
-          pip install setuptools==75.6.0 jsonargparse==4.35.0
+          pip install -e ".[${extra}dev]" -U --upgrade-strategy=eager --extra-index-url="${TORCH_URL}"
         displayName: "Install package & dependencies"
 
       - bash: |
@@ -130,18 +145,6 @@ jobs:
         condition: and(succeeded(), eq(variables['PACKAGE_NAME'], 'fabric'))
         displayName: "Testing: Fabric doctests"
 
-      - bash: |
-          pip install -q -r .actions/requirements.txt
-          python .actions/assistant.py copy_replace_imports --source_dir="./tests/tests_fabric" \
-            --source_import="lightning.fabric" \
-            --target_import="lightning_fabric"
-          python .actions/assistant.py copy_replace_imports --source_dir="./examples/fabric" \
-            --source_import="lightning.fabric" \
-            --target_import="lightning_fabric"
-        # without succeeded this could run even if the job has already failed
-        condition: and(succeeded(), eq(variables['PACKAGE_NAME'], 'fabric'))
-        displayName: "Adjust tests & examples"
-
       - bash: python -m coverage run --source ${COVERAGE_SOURCE} -m pytest tests_fabric/ -v --durations=50
         workingDirectory: tests/
         displayName: "Testing: fabric standard"

.azure/gpu-tests-pytorch.yml

@@ -53,20 +53,20 @@ jobs:
           image: "pytorchlightning/pytorch_lightning:base-cuda-py3.10-torch2.1-cuda12.1.1"
           PACKAGE_NAME: "pytorch"
         "PyTorch | latest":
-          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.7-cuda12.6.3"
+          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.8-cuda12.6.3"
           PACKAGE_NAME: "pytorch"
         #"PyTorch | future":
         #  image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.7-cuda12.6.3"
         #  PACKAGE_NAME: "pytorch"
         "Lightning | latest":
-          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.7-cuda12.6.3"
+          image: "pytorchlightning/pytorch_lightning:base-cuda-py3.12-torch2.8-cuda12.6.3"
           PACKAGE_NAME: "lightning"
     pool: lit-rtx-3090
     variables:
       DEVICES: $( python -c 'print("$(Agent.Name)".split("_")[-1])' )
       FREEZE_REQUIREMENTS: "1"
       PIP_CACHE_DIR: "/var/tmp/pip"
-      PL_RUN_CUDA_TESTS: "1"
+      RUN_ONLY_CUDA_TESTS: "1"
     container:
       image: $(image)
       # default shm size is 64m. Increase it to avoid:
@@ -82,8 +82,6 @@ jobs:
           echo "##vso[task.setvariable variable=TORCH_URL]https://download.pytorch.org/whl/cu${cuda_ver}/torch_stable.html"
           scope=$(python -c 'n = "$(PACKAGE_NAME)" ; print(dict(pytorch="pytorch_lightning").get(n, n))')
           echo "##vso[task.setvariable variable=COVERAGE_SOURCE]$scope"
-          python_ver=$(python -c "import sys; print(f'{sys.version_info.major}{sys.version_info.minor}')")
-          echo "##vso[task.setvariable variable=PYTHON_VERSION_MM]$python_ver"
         displayName: "set env. vars"
       - bash: |
           echo "##vso[task.setvariable variable=TORCH_URL]https://download.pytorch.org/whl/test/cu${CUDA_VERSION_MM}"
@@ -104,6 +102,12 @@ jobs:
           pip list
         displayName: "Image info & NVIDIA"
 
+      - bash: |
+          python .actions/assistant.py replace_oldest_ver
+          pip install "cython<3.0" wheel  # for compatibility
+        condition: contains(variables['Agent.JobName'], 'oldest')
+        displayName: "setting oldest dependencies"
+
       - bash: |
           PYTORCH_VERSION=$(python -c "import torch; print(torch.__version__.split('+')[0])")
           pip install -q wget packaging
@@ -113,10 +117,22 @@ jobs:
           done
         displayName: "Adjust dependencies"
 
+      - bash: |
+          pip install -U -q -r .actions/requirements.txt
+          python .actions/assistant.py copy_replace_imports --source_dir="./tests/tests_pytorch" \
+            --source_import="lightning.fabric,lightning.pytorch" \
+            --target_import="lightning_fabric,pytorch_lightning"
+          python .actions/assistant.py copy_replace_imports --source_dir="./examples/pytorch/basics" \
+            --source_import="lightning.fabric,lightning.pytorch" \
+            --target_import="lightning_fabric,pytorch_lightning"
+        # without succeeded this could run even if the job has already failed
+        condition: and(succeeded(), eq(variables['PACKAGE_NAME'], 'pytorch'))
+        displayName: "Adjust tests & examples"
+
       - bash: |
           set -e
           extra=$(python -c "print({'lightning': 'pytorch-'}.get('$(PACKAGE_NAME)', ''))")
-          pip install -e ".[${extra}dev]" pytest-timeout -U --extra-index-url="${TORCH_URL}"
+          pip install -e ".[${extra}dev]" -U --upgrade-strategy=eager --extra-index-url="${TORCH_URL}"
         displayName: "Install package & dependencies"
 
       - bash: pip uninstall -y lightning
@@ -143,17 +159,6 @@ jobs:
         condition: and(succeeded(), eq(variables['PACKAGE_NAME'], 'pytorch'))
         displayName: "Testing: PyTorch doctests"
 
-      - bash: |
-          python .actions/assistant.py copy_replace_imports --source_dir="./tests/tests_pytorch" \
-            --source_import="lightning.fabric,lightning.pytorch" \
-            --target_import="lightning_fabric,pytorch_lightning"
-          python .actions/assistant.py copy_replace_imports --source_dir="./examples/pytorch/basics" \
-            --source_import="lightning.fabric,lightning.pytorch" \
-            --target_import="lightning_fabric,pytorch_lightning"
-        # without succeeded this could run even if the job has already failed
-        condition: and(succeeded(), eq(variables['PACKAGE_NAME'], 'pytorch'))
-        displayName: "Adjust tests & examples"
-
       - bash: |
           bash .actions/pull_legacy_checkpoints.sh
           cd tests/legacy

.github/CONTRIBUTING.md

@@ -3,7 +3,7 @@
 Welcome to the PyTorch Lightning community! We're building the most advanced research platform on the planet to implement the latest, best practices
 and integrations that the amazing PyTorch team and other research organization rolls out!
 
-If you are new to open source, check out [this blog to get started with your first Open Source contribution](https://devblog.pytorchlightning.ai/quick-contribution-guide-86d977171b3a).
+If you are new to open source, check out [this blog to get started with your first Open Source contribution](https://medium.com/pytorch-lightning/quick-contribution-guide-86d977171b3a).
 
 ## Main Core Value: One less thing to remember
 
@@ -109,6 +109,50 @@ ______________________________________________________________________
 
 ## Guidelines
 
+### Development environment
+
+To set up a local development environment, we recommend using `uv`, which can be installed following their [instructions](https://docs.astral.sh/uv/getting-started/installation/).
+
+Once `uv` has been installed, begin by cloning the forked repository:
+
+```bash
+git clone https://github.com/{YOUR_GITHUB_USERNAME}/pytorch-lightning.git
+cd pytorch-lightning
+```
+
+> If you're using [Lightning Studio](https://lightning.ai) or already have your `uv venv` activated, you can quickly set up the project by running:
+
+```bash
+make setup
+```
+
+This will:
+
+- Install all required dependencies.
+- Perform an editable install of the `pytorch-lightning` project.
+- Install and configure `pre-commit`.
+
+#### Manual Setup (Optional)
+
+If you prefer more fine-grained control over the dependencies, you can set up the environment manually:
+
+```bash
+uv venv
+# uv venv --python 3.11 # use this instead if you need a specific python version
+
+source .venv/bin/activate # command may differ based on your shell
+uv pip install ".[dev, examples]"
+```
+
+Once the dependencies have been installed, install pre-commit and set up the git hook scripts:
+
+```bash
+uv pip install pre-commit
+pre-commit install
+```
+
+If you would like more information regarding the uv commands, please refer to uv's documentation for more information on their [pip interface](https://docs.astral.sh/uv/pip/).
+
 ### Developments scripts
 
 To build the documentation locally, simply execute the following commands from project root (only for Unix):

.github/checkgroup.yml

@@ -71,7 +71,7 @@ subprojects:
   #    paths:
   #      # tpu CI availability is very limited, so we only require tpu tests
   #      # to pass when their configurations are modified
-  #      - ".github/workflows/tpu-tests.yml"
+  #      - ".github/workflows/tpu-tests.yml.disabled"
   #      - "tests/tests_pytorch/run_tpu_tests.sh"
   #    checks:
   #      - "test-on-tpus (pytorch, pjrt, v4-8)"
@@ -135,7 +135,8 @@ subprojects:
       - "build-pl (3.11, 2.4, 12.1.1)"
       - "build-pl (3.12, 2.5, 12.1.1)"
       - "build-pl (3.12, 2.6, 12.4.1)"
-      - "build-pl (3.12, 2.7, 12.6.3, true)"
+      - "build-pl (3.12, 2.7, 12.6.3)"
+      - "build-pl (3.12, 2.8, 12.6.3, true)"
 
   # SECTION: lightning_fabric
 
@@ -181,7 +182,7 @@ subprojects:
   #    paths:
   #      # tpu CI availability is very limited, so we only require tpu tests
   #      # to pass when their configurations are modified
-  #      - ".github/workflows/tpu-tests.yml"
+  #      - ".github/workflows/tpu-tests.yml.disabled"
   #      - "tests/tests_fabric/run_tpu_tests.sh"
   #    checks:
   #      - "test-on-tpus (pytorch, pjrt, v4-8)"

.github/markdown-links-config.json

@@ -22,5 +22,9 @@
         "Accept-Encoding": "zstd, br, gzip, deflate"
       }
     }
-  ]
+  ],
+  "timeout": "20s",
+  "retryOn429": true,
+  "retryCount": 5,
+  "fallbackRetryDelay": "20s"
 }

.github/workflows/_build-packages.yml

@@ -51,7 +51,7 @@ jobs:
     needs: build-packages
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v5
         with: # download all build artifacts
           pattern: ${{ inputs.artifact-name }}-*
           merge-multiple: true

.github/workflows/_legacy-checkpoints.yml

@@ -149,13 +149,11 @@ jobs:
           title: Adding test for legacy checkpoint created with ${{ env.PL_VERSION }}
           committer: GitHub <noreply@github.com>
           author: ${{ github.actor }} <${{ github.actor }}@users.noreply.github.com>
-          commit-message: "update tutorials to `${{ env.PL_VERSION }}`"
-          body: "**This is automated addition of created checkpoints with the latest `lightning` release!**"
+          body: "**This is automated addition of created checkpoint with the latest `${{ env.PL_VERSION }}` `lightning` release!**"
           delete-branch: true
           token: ${{ secrets.PAT_GHOST }}
           labels: |
             checkpointing
             tests
             pl
           assignees: borda
-          reviewers: borda

.github/workflows/call-clear-cache.yml

@@ -23,18 +23,18 @@ on:
 jobs:
   cron-clear:
     if: github.event_name == 'schedule' || github.event_name == 'pull_request'
-    uses: Lightning-AI/utilities/.github/workflows/cleanup-caches.yml@v0.14.3
+    uses: Lightning-AI/utilities/.github/workflows/cleanup-caches.yml@v0.15.2
     with:
-      scripts-ref: v0.14.3
+      scripts-ref: v0.15.2
       dry-run: ${{ github.event_name == 'pull_request' }}
       pattern: "latest|docs"
       age-days: 7
 
   direct-clear:
     if: github.event_name == 'workflow_dispatch' || github.event_name == 'pull_request'
-    uses: Lightning-AI/utilities/.github/workflows/cleanup-caches.yml@v0.14.3
+    uses: Lightning-AI/utilities/.github/workflows/cleanup-caches.yml@v0.15.2
     with:
-      scripts-ref: v0.14.3
+      scripts-ref: v0.15.2
       dry-run: ${{ github.event_name == 'pull_request' }}
       pattern: ${{ inputs.pattern || 'pypi_wheels' }} # setting str in case of PR / debugging
       age-days: ${{ fromJSON(inputs.age-days) || 0 }} # setting 0 in case of PR / debugging

.github/workflows/ci-pkg-install.yml

@@ -50,7 +50,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v5
         with:
           name: dist-packages-${{ github.sha }}
           path: dist

.github/workflows/ci-schema.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   check:
-    uses: Lightning-AI/utilities/.github/workflows/check-schema.yml@v0.14.3
+    uses: Lightning-AI/utilities/.github/workflows/check-schema.yml@v0.15.2
     with:
       # skip azure due to the wrong schema file by MSFT
       # https://github.com/Lightning-AI/lightning-flash/pull/1455#issuecomment-1244793607