Remove support for Python 3.8 (#20071)

.github/checkgroup.yml

@@ -19,21 +19,21 @@ subprojects:
       - "!*.md"
       - "!**/*.md"
     checks:
-      - "pl-cpu (macOS-13, lightning, 3.8, 2.1, oldest)"
+      - "pl-cpu (macOS-13, lightning, 3.9, 2.1, oldest)"
       - "pl-cpu (macOS-14, lightning, 3.10, 2.1)"
       - "pl-cpu (macOS-14, lightning, 3.10, 2.2)"
       - "pl-cpu (macOS-14, lightning, 3.10, 2.3)"
-      - "pl-cpu (ubuntu-20.04, lightning, 3.8, 2.1, oldest)"
+      - "pl-cpu (ubuntu-20.04, lightning, 3.9, 2.1, oldest)"
       - "pl-cpu (ubuntu-20.04, lightning, 3.10, 2.1)"
       - "pl-cpu (ubuntu-20.04, lightning, 3.10, 2.2)"
       - "pl-cpu (ubuntu-20.04, lightning, 3.10, 2.3)"
-      - "pl-cpu (windows-2022, lightning, 3.8, 2.1, oldest)"
+      - "pl-cpu (windows-2022, lightning, 3.9, 2.1, oldest)"
       - "pl-cpu (windows-2022, lightning, 3.10, 2.1)"
       - "pl-cpu (windows-2022, lightning, 3.10, 2.2)"
       - "pl-cpu (windows-2022, lightning, 3.10, 2.3)"
-      - "pl-cpu (macOS-14, pytorch, 3.8, 2.1)"
-      - "pl-cpu (ubuntu-20.04, pytorch, 3.8, 2.1)"
-      - "pl-cpu (windows-2022, pytorch, 3.8, 2.1)"
+      - "pl-cpu (macOS-14, pytorch, 3.9, 2.1)"
+      - "pl-cpu (ubuntu-20.04, pytorch, 3.9, 2.1)"
+      - "pl-cpu (windows-2022, pytorch, 3.9, 2.1)"
       - "pl-cpu (macOS-12, pytorch, 3.11, 2.1)"
       - "pl-cpu (ubuntu-22.04, pytorch, 3.11, 2.1)"
       - "pl-cpu (windows-2022, pytorch, 3.11, 2.1)"
@@ -167,21 +167,21 @@ subprojects:
       - "!*.md"
       - "!**/*.md"
     checks:
-      - "fabric-cpu (macOS-13, lightning, 3.8, 2.1, oldest)"
+      - "fabric-cpu (macOS-13, lightning, 3.9, 2.1, oldest)"
       - "fabric-cpu (macOS-14, lightning, 3.11, 2.1)"
       - "fabric-cpu (macOS-14, lightning, 3.11, 2.2)"
       - "fabric-cpu (macOS-14, lightning, 3.10, 2.3)"
-      - "fabric-cpu (ubuntu-20.04, lightning, 3.8, 2.1, oldest)"
+      - "fabric-cpu (ubuntu-20.04, lightning, 3.9, 2.1, oldest)"
       - "fabric-cpu (ubuntu-20.04, lightning, 3.11, 2.1)"
       - "fabric-cpu (ubuntu-20.04, lightning, 3.11, 2.2)"
       - "fabric-cpu (ubuntu-20.04, lightning, 3.11, 2.3)"
-      - "fabric-cpu (windows-2022, lightning, 3.8, 2.1, oldest)"
+      - "fabric-cpu (windows-2022, lightning, 3.9, 2.1, oldest)"
       - "fabric-cpu (windows-2022, lightning, 3.11, 2.1)"
       - "fabric-cpu (windows-2022, lightning, 3.11, 2.2)"
       - "fabric-cpu (windows-2022, lightning, 3.11, 2.3)"
-      - "fabric-cpu (macOS-14, fabric, 3.8, 2.1)"
-      - "fabric-cpu (ubuntu-20.04, fabric, 3.8, 2.1)"
-      - "fabric-cpu (windows-2022, fabric, 3.8, 2.1)"
+      - "fabric-cpu (macOS-14, fabric, 3.9, 2.1)"
+      - "fabric-cpu (ubuntu-20.04, fabric, 3.9, 2.1)"
+      - "fabric-cpu (windows-2022, fabric, 3.9, 2.1)"
       - "fabric-cpu (macOS-12, fabric, 3.11, 2.1)"
       - "fabric-cpu (ubuntu-22.04, fabric, 3.11, 2.1)"
       - "fabric-cpu (windows-2022, fabric, 3.11, 2.1)"
@@ -248,27 +248,27 @@ subprojects:
       - "!*.md"
       - "!**/*.md"
     checks:
-      - "install-pkg (ubuntu-22.04, fabric, 3.8)"
+      - "install-pkg (ubuntu-22.04, fabric, 3.9)"
       - "install-pkg (ubuntu-22.04, fabric, 3.11)"
-      - "install-pkg (ubuntu-22.04, pytorch, 3.8)"
+      - "install-pkg (ubuntu-22.04, pytorch, 3.9)"
       - "install-pkg (ubuntu-22.04, pytorch, 3.11)"
-      - "install-pkg (ubuntu-22.04, lightning, 3.8)"
+      - "install-pkg (ubuntu-22.04, lightning, 3.9)"
       - "install-pkg (ubuntu-22.04, lightning, 3.11)"
-      - "install-pkg (ubuntu-22.04, notset, 3.8)"
+      - "install-pkg (ubuntu-22.04, notset, 3.9)"
       - "install-pkg (ubuntu-22.04, notset, 3.11)"
-      - "install-pkg (macOS-12, fabric, 3.8)"
+      - "install-pkg (macOS-12, fabric, 3.9)"
       - "install-pkg (macOS-12, fabric, 3.11)"
-      - "install-pkg (macOS-12, pytorch, 3.8)"
+      - "install-pkg (macOS-12, pytorch, 3.9)"
       - "install-pkg (macOS-12, pytorch, 3.11)"
-      - "install-pkg (macOS-12, lightning, 3.8)"
+      - "install-pkg (macOS-12, lightning, 3.9)"
       - "install-pkg (macOS-12, lightning, 3.11)"
-      - "install-pkg (macOS-12, notset, 3.8)"
+      - "install-pkg (macOS-12, notset, 3.9)"
       - "install-pkg (macOS-12, notset, 3.11)"
-      - "install-pkg (windows-2022, fabric, 3.8)"
+      - "install-pkg (windows-2022, fabric, 3.9)"
       - "install-pkg (windows-2022, fabric, 3.11)"
-      - "install-pkg (windows-2022, pytorch, 3.8)"
+      - "install-pkg (windows-2022, pytorch, 3.9)"
       - "install-pkg (windows-2022, pytorch, 3.11)"
-      - "install-pkg (windows-2022, lightning, 3.8)"
+      - "install-pkg (windows-2022, lightning, 3.9)"
       - "install-pkg (windows-2022, lightning, 3.11)"
-      - "install-pkg (windows-2022, notset, 3.8)"
+      - "install-pkg (windows-2022, notset, 3.9)"
       - "install-pkg (windows-2022, notset, 3.11)"

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

@@ -44,7 +44,7 @@ jobs:
       matrix:
         os: ["ubuntu-22.04", "macOS-12", "windows-2022"]
         pkg-name: ["fabric", "pytorch", "lightning", "notset"]
-        python-version: ["3.8", "3.11"]
+        python-version: ["3.9", "3.11"]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5

.github/workflows/ci-tests-fabric.yml

@@ -58,25 +58,25 @@ jobs:
           - { os: "ubuntu-22.04", pkg-name: "fabric", python-version: "3.11", pytorch-version: "2.1" }
           - { os: "windows-2022", pkg-name: "fabric", python-version: "3.11", pytorch-version: "2.1" }
           # "oldest" versions tests, only on minimum Python
-          - { os: "macOS-13", pkg-name: "lightning", python-version: "3.8", pytorch-version: "2.1", requires: "oldest" }
+          - { os: "macOS-13", pkg-name: "lightning", python-version: "3.9", pytorch-version: "2.1", requires: "oldest" }
           - {
               os: "ubuntu-20.04",
               pkg-name: "lightning",
-              python-version: "3.8",
+              python-version: "3.9",
               pytorch-version: "2.1",
               requires: "oldest",
             }
           - {
               os: "windows-2022",
               pkg-name: "lightning",
-              python-version: "3.8",
+              python-version: "3.9",
               pytorch-version: "2.1",
               requires: "oldest",
             }
           # "fabric" installs the standalone package
-          - { os: "macOS-14", pkg-name: "fabric", python-version: "3.8", pytorch-version: "2.1" }
-          - { os: "ubuntu-20.04", pkg-name: "fabric", python-version: "3.8", pytorch-version: "2.1" }
-          - { os: "windows-2022", pkg-name: "fabric", python-version: "3.8", pytorch-version: "2.1" }
+          - { os: "macOS-14", pkg-name: "fabric", python-version: "3.9", pytorch-version: "2.1" }
+          - { os: "ubuntu-20.04", pkg-name: "fabric", python-version: "3.9", pytorch-version: "2.1" }
+          - { os: "windows-2022", pkg-name: "fabric", python-version: "3.9", pytorch-version: "2.1" }
     timeout-minutes: 25 # because of building grpcio on Mac
     env:
       PACKAGE_NAME: ${{ matrix.pkg-name }}

.github/workflows/ci-tests-pytorch.yml

@@ -61,25 +61,25 @@ jobs:
           - { os: "ubuntu-22.04", pkg-name: "pytorch", python-version: "3.11", pytorch-version: "2.1" }
           - { os: "windows-2022", pkg-name: "pytorch", python-version: "3.11", pytorch-version: "2.1" }
           # "oldest" versions tests, only on minimum Python
-          - { os: "macOS-13", pkg-name: "lightning", python-version: "3.8", pytorch-version: "2.1", requires: "oldest" }
+          - { os: "macOS-13", pkg-name: "lightning", python-version: "3.9", pytorch-version: "2.1", requires: "oldest" }
           - {
               os: "ubuntu-20.04",
               pkg-name: "lightning",
-              python-version: "3.8",
+              python-version: "3.9",
               pytorch-version: "2.1",
               requires: "oldest",
             }
           - {
               os: "windows-2022",
               pkg-name: "lightning",
-              python-version: "3.8",
+              python-version: "3.9",
               pytorch-version: "2.1",
               requires: "oldest",
             }
           # "pytorch" installs the standalone package
-          - { os: "macOS-14", pkg-name: "pytorch", python-version: "3.8", pytorch-version: "2.1" }
-          - { os: "ubuntu-20.04", pkg-name: "pytorch", python-version: "3.8", pytorch-version: "2.1" }
-          - { os: "windows-2022", pkg-name: "pytorch", python-version: "3.8", pytorch-version: "2.1" }
+          - { os: "macOS-14", pkg-name: "pytorch", python-version: "3.9", pytorch-version: "2.1" }
+          - { os: "ubuntu-20.04", pkg-name: "pytorch", python-version: "3.9", pytorch-version: "2.1" }
+          - { os: "windows-2022", pkg-name: "pytorch", python-version: "3.9", pytorch-version: "2.1" }
     timeout-minutes: 50
     env:
       PACKAGE_NAME: ${{ matrix.pkg-name }}

.github/workflows/release-pkg.yml

@@ -24,7 +24,7 @@ defaults:
 env:
   FREEZE_REQUIREMENTS: 1
   TORCH_URL: "https://download.pytorch.org/whl/cpu/torch_stable.html"
-  PYTHON_VER: "3.8"
+  PYTHON_VER: "3.9"
 
 jobs:
   build-packages:

src/lightning/__setup__.py

@@ -93,8 +93,8 @@ def _setup_args() -> Dict[str, Any]:
         "long_description_content_type": "text/markdown",
         "include_package_data": True,
         "zip_safe": False,
-        "keywords": ["deep learning", "pytorch", "AI"],  # todo: aggregate tags from all packages
-        "python_requires": ">=3.8",  # todo: take the lowes based on all packages
+        "keywords": ["deep learning", "pytorch", "AI"],
+        "python_requires": ">=3.9",
         "entry_points": {
             "console_scripts": [
                 "fabric = lightning.fabric.cli:_main",

src/lightning/fabric/CHANGELOG.md

@@ -30,7 +30,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Removed support for PyTorch 2.1 ([#20009](https://github.com/Lightning-AI/lightning/pull/20009))
 
 
--
+- Removed support for Python 3.8 ([#20071](https://github.com/Lightning-AI/lightning/pull/20071))
 
 ### Fixed
 

src/lightning/fabric/utilities/imports.py

@@ -30,7 +30,6 @@
 _TORCH_GREATER_EQUAL_2_3 = compare_version("torch", operator.ge, "2.3.0")
 _TORCH_GREATER_EQUAL_2_4 = compare_version("torch", operator.ge, "2.4.0")
 
-_PYTHON_GREATER_EQUAL_3_8_0 = (sys.version_info.major, sys.version_info.minor) >= (3, 8)
 _PYTHON_GREATER_EQUAL_3_10_0 = (sys.version_info.major, sys.version_info.minor) >= (3, 10)
 
 _UTILITIES_GREATER_EQUAL_0_10 = compare_version("lightning_utilities", operator.ge, "0.10.0")

src/lightning/fabric/utilities/registry.py

@@ -12,13 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+from importlib.metadata import entry_points
 from inspect import getmembers, isclass
 from types import ModuleType
 from typing import Any, List, Type, Union
 
 from lightning_utilities import is_overridden
 
-from lightning.fabric.utilities.imports import _PYTHON_GREATER_EQUAL_3_8_0, _PYTHON_GREATER_EQUAL_3_10_0
+from lightning.fabric.utilities.imports import _PYTHON_GREATER_EQUAL_3_10_0
 
 _log = logging.getLogger(__name__)
 
@@ -35,16 +36,9 @@ def _load_external_callbacks(group: str) -> List[Any]:
         A list of all callbacks collected from external factories.
 
     """
-    if _PYTHON_GREATER_EQUAL_3_8_0:
-        from importlib.metadata import entry_points
-
-        factories = (
-            entry_points(group=group) if _PYTHON_GREATER_EQUAL_3_10_0 else entry_points().get(group, {})  # type: ignore[arg-type]
-        )
-    else:
-        from pkg_resources import iter_entry_points
-
-        factories = iter_entry_points(group)  # type: ignore[assignment]
+    factories = (
+        entry_points(group=group) if _PYTHON_GREATER_EQUAL_3_10_0 else entry_points().get(group, {})  # type: ignore[arg-type]
+    )
 
     external_callbacks: List[Any] = []
     for factory in factories:

src/lightning/pytorch/CHANGELOG.md

@@ -30,7 +30,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Removed support for PyTorch 2.1 ([#20009](https://github.com/Lightning-AI/lightning/pull/20009))
 
 
--
+- Removed support for Python 3.8 ([#20071](https://github.com/Lightning-AI/lightning/pull/20071))
+
 
 ### Fixed
 

src/lightning/pytorch/trainer/connectors/signal_connector.py

@@ -9,7 +9,7 @@
 
 import lightning.pytorch as pl
 from lightning.fabric.plugins.environments import SLURMEnvironment
-from lightning.fabric.utilities.imports import _IS_WINDOWS, _PYTHON_GREATER_EQUAL_3_8_0
+from lightning.fabric.utilities.imports import _IS_WINDOWS
 from lightning.pytorch.utilities.rank_zero import rank_prefixed_message, rank_zero_info
 
 # copied from signal.pyi
@@ -133,26 +133,8 @@ def _get_current_signal_handlers() -> Dict[_SIGNUM, _HANDLER]:
 
     @staticmethod
     def _valid_signals() -> Set[signal.Signals]:
-        """Returns all valid signals supported on the current platform.
-
-        Behaves identically to :func:`signals.valid_signals` in Python 3.8+ and implements the equivalent behavior for
-        older Python versions.
-
-        """
-        if _PYTHON_GREATER_EQUAL_3_8_0:
-            return signal.valid_signals()
-        if _IS_WINDOWS:
-            # supported signals on Windows: https://docs.python.org/3/library/signal.html#signal.signal
-            return {
-                signal.SIGABRT,
-                signal.SIGFPE,
-                signal.SIGILL,
-                signal.SIGINT,
-                signal.SIGSEGV,
-                signal.SIGTERM,
-                signal.SIGBREAK,
-            }
-        return set(signal.Signals)
+        """Returns all valid signals supported on the current platform."""
+        return signal.valid_signals()
 
     @staticmethod
     def _has_already_handler(signum: _SIGNUM) -> bool:

tests/tests_fabric/utilities/test_registry.py

@@ -1,8 +1,8 @@
 import contextlib
 from unittest import mock
-from unittest.mock import Mock
+from unittest.mock import MagicMock, Mock
 
-from lightning.fabric.utilities.imports import _PYTHON_GREATER_EQUAL_3_8_0, _PYTHON_GREATER_EQUAL_3_10_0
+from lightning.fabric.utilities.imports import _PYTHON_GREATER_EQUAL_3_10_0
 from lightning.fabric.utilities.registry import _load_external_callbacks
 
 
@@ -47,18 +47,14 @@ def factory_multiple_callbacks_list():
 
 @contextlib.contextmanager
 def _make_entry_point_query_mock(callback_factory):
-    query_mock = Mock()
+    query_mock = MagicMock()
     entry_point = Mock()
     entry_point.name = "mocked"
     entry_point.load.return_value = callback_factory
     if _PYTHON_GREATER_EQUAL_3_10_0:
         query_mock.return_value = [entry_point]
-        import_path = "importlib.metadata.entry_points"
-    elif _PYTHON_GREATER_EQUAL_3_8_0:
-        query_mock().get.return_value = [entry_point]
-        import_path = "importlib.metadata.entry_points"
     else:
-        query_mock.return_value = [entry_point]
-        import_path = "pkg_resources.iter_entry_points"
-    with mock.patch(import_path, query_mock):
+        query_mock().get.return_value = [entry_point]
+
+    with mock.patch("lightning.fabric.utilities.registry.entry_points", query_mock):
         yield

tests/tests_pytorch/trainer/connectors/test_callback_connector.py

@@ -14,11 +14,11 @@
 import contextlib
 import logging
 from unittest import mock
-from unittest.mock import Mock
+from unittest.mock import MagicMock, Mock
 
 import pytest
 import torch
-from lightning.fabric.utilities.imports import _PYTHON_GREATER_EQUAL_3_8_0, _PYTHON_GREATER_EQUAL_3_10_0
+from lightning.fabric.utilities.imports import _PYTHON_GREATER_EQUAL_3_10_0
 from lightning.pytorch import Callback, LightningModule, Trainer
 from lightning.pytorch.callbacks import (
     EarlyStopping,
@@ -293,20 +293,16 @@ def factory_multiple_callbacks_list():
 
 @contextlib.contextmanager
 def _make_entry_point_query_mock(callback_factory):
-    query_mock = Mock()
+    query_mock = MagicMock()
     entry_point = Mock()
     entry_point.name = "mocked"
     entry_point.load.return_value = callback_factory
     if _PYTHON_GREATER_EQUAL_3_10_0:
         query_mock.return_value = [entry_point]
-        import_path = "importlib.metadata.entry_points"
-    elif _PYTHON_GREATER_EQUAL_3_8_0:
-        query_mock().get.return_value = [entry_point]
-        import_path = "importlib.metadata.entry_points"
     else:
-        query_mock.return_value = [entry_point]
-        import_path = "pkg_resources.iter_entry_points"
-    with mock.patch(import_path, query_mock):
+        query_mock().get.return_value = [entry_point]
+
+    with mock.patch("lightning.fabric.utilities.registry.entry_points", query_mock):
         yield
 
 

tests/tests_pytorch/trainer/logging_/test_eval_loop_logging.py

@@ -24,7 +24,6 @@
 import numpy as np
 import pytest
 import torch
-from lightning.fabric.utilities.imports import _PYTHON_GREATER_EQUAL_3_8_0
 from lightning.pytorch import Trainer, callbacks
 from lightning.pytorch.callbacks.progress.rich_progress import _RICH_AVAILABLE
 from lightning.pytorch.demos.boring_classes import BoringModel, RandomDataset
@@ -557,8 +556,7 @@ def test_step(self, batch, batch_idx):
     ]
 
     def get_metrics_at_idx(idx):
-        mock_call = mock_log_metrics.mock_calls[idx]
-        return mock_call.kwargs["metrics"] if _PYTHON_GREATER_EQUAL_3_8_0 else mock_call[2]["metrics"]
+        return mock_log_metrics.mock_calls[idx].kwargs["metrics"]
 
     assert get_metrics_at_idx(2)["valid_loss_0_step"] == model.val_losses[2]
     assert get_metrics_at_idx(3)["valid_loss_0_step"] == model.val_losses[3]
@@ -736,8 +734,7 @@ def test_dataloader(self):
     cb_metrics = set(trainer.callback_metrics)
     assert cb_metrics == {"foo/dataloader_idx_0", "foo/dataloader_idx_1", "foobar"}
 
-    mock_call = mock_log_metrics.mock_calls[0]
-    logged_metrics = mock_call.kwargs["metrics"] if _PYTHON_GREATER_EQUAL_3_8_0 else mock_call[2]["metrics"]
+    logged_metrics = mock_log_metrics.mock_calls[0].kwargs["metrics"]
     cb_metrics.add("epoch")
     assert set(logged_metrics) == cb_metrics