chore: drop Python 3.9 support (#428)

Signed-off-by: SdgJlbl <sarah.diot-girard@owkin.com>

.github/workflows/python.yml

@@ -45,7 +45,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12"]
     name: Tests on Python ${{ matrix.python-version }}
     steps:
       - name: Set up python

changes/428.removed

@@ -0,0 +1 @@
+Drop Python 3.9 support.

pyproject.toml

@@ -13,7 +13,7 @@ name = "substra"
 description = "Low-level Python library for interacting with a Substra network"
 dynamic = ["version"]
 readme = "README.md"
-requires-python = ">= 3.9"
+requires-python = ">= 3.10"
 dependencies = [
     "requests!=2.32.*",
     "docker",
@@ -28,7 +28,6 @@ classifiers = [
     "Topic :: Utilities",
     "Natural Language :: English",
     "Operating System :: OS Independent",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",

substra/sdk/backends/local/compute/worker.py

@@ -135,12 +135,6 @@ def _get_cmd_template_inputs_outputs(
         ]
         return command_template
 
-    def _tmp_is_three_nine(self):
-        """Temporary helper function to remove as soon as support of Python 3.9 is dropped."""
-        import platform
-
-        return platform.python_version_tuple()[1] == "9"
-
     def _prepare_artifact_input(self, task_input, task_key, input_volume, multiple):
         outputs = self._db.list(
             schemas.Type.OutputAsset,
@@ -156,21 +150,15 @@ def _prepare_artifact_input(self, task_input, task_key, input_volume, multiple):
         assert output.kind == schemas.AssetKind.model, "The task_input value must be an artifact, not a performance"
         filename = _generate_filename()
         path_to_input = input_volume / filename
-        if self._tmp_is_three_nine():
-            Path(output.asset.address.storage_address).link_to(path_to_input)
-        else:
-            Path(path_to_input).hardlink_to(output.asset.address.storage_address)
+        Path(path_to_input).hardlink_to(output.asset.address.storage_address)
 
         return TaskResource(id=task_input.identifier, value=f"{TPL_VOLUME_INPUTS}/{filename}", multiple=multiple)
 
     def _prepare_dataset_input(
         self, dataset: models.Dataset, task_input: models.InputRef, input_volume: str, multiple: bool
     ):
         path_to_opener = input_volume / Filenames.OPENER.value
-        if self._tmp_is_three_nine():
-            Path(dataset.opener.storage_address).link_to(path_to_opener)
-        else:
-            Path(path_to_opener).hardlink_to(dataset.opener.storage_address)
+        Path(path_to_opener).hardlink_to(dataset.opener.storage_address)
         return TaskResource(
             id=task_input.identifier,
             value=f"{TPL_VOLUME_INPUTS}/{Filenames.OPENER.value}",