Fix Python version pin (#2085)

Author: mathbunnyru

images/docker-stacks-foundation/Dockerfile

@@ -117,7 +117,8 @@ RUN set -x && \
         'jupyter_core' && \
     rm -rf /tmp/bin/ && \
     # Pin major.minor version of python
-    mamba list python | grep '^python ' | tr -s ' ' | cut -d ' ' -f 1,2 >> "${CONDA_DIR}/conda-meta/pinned" && \
+    # https://conda.io/projects/conda/en/latest/user-guide/tasks/manage-pkgs.html#preventing-packages-from-updating-pinning
+    mamba list --full-name 'python' | tail -1 | tr -s ' ' | cut -d ' ' -f 1,2 | sed 's/\.[^.]*$/.*/' >> "${CONDA_DIR}/conda-meta/pinned" && \
     mamba clean --all -f -y && \
     fix-permissions "${CONDA_DIR}" && \
     fix-permissions "/home/${NB_USER}"

tests/docker-stacks-foundation/test_python_version.py

@@ -22,3 +22,13 @@ def test_python_version(container: TrackedContainer) -> None:
     major_minor_version = full_version[: full_version.rfind(".")]
 
     assert major_minor_version == EXPECTED_PYTHON_VERSION
+
+
+def test_python_pinned_version(container: TrackedContainer) -> None:
+    LOGGER.info(f"Checking that pinned python version is {EXPECTED_PYTHON_VERSION}.*")
+    logs = container.run_and_wait(
+        timeout=5,
+        tty=True,
+        command=["cat", "/opt/conda/conda-meta/pinned"],
+    )
+    assert logs.startswith(f"python {EXPECTED_PYTHON_VERSION}.*")