DM-48159 : Make Coverage import optional

doc/changes/DM-47159.bugfix.md

@@ -0,0 +1,3 @@
+Makes coverage package optional and lazy-loads it only when needed.
+Declares packaging extra for coverage, i.e., `pip install lsst-ctrl-mpexec[coverage]`.
+Updates minimum supported Python to 3.11 (dependency-driven change).

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "lsst-ctrl-mpexec"
-requires-python = ">=3.10.0"
+requires-python = ">=3.11.0"
 description = "Pipeline execution infrastructure for the Rubin Observatory LSST Science Pipelines."
 license = {text = "BSD 3-Clause License"}
 readme = "README.rst"
@@ -16,8 +16,9 @@ classifiers = [
     "License :: OSI Approved :: BSD License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
     "Topic :: Scientific/Engineering :: Astronomy",
 ]
 keywords = ["lsst"]
@@ -38,6 +39,7 @@ dynamic = ["version"]
 "Homepage" = "https://github.com/lsst/ctrl_mpexec"
 
 [project.optional-dependencies]
+coverage = ["coverage"]
 test = ["pytest >= 3.2"]
 
 [tool.setuptools.packages.find]

python/lsst/ctrl/mpexec/cli/cmd/commands.py

@@ -29,11 +29,11 @@
 from collections.abc import Iterator, Sequence
 from contextlib import contextmanager
 from functools import partial
+from importlib import import_module
 from tempfile import NamedTemporaryFile
 from typing import Any
 
 import click
-import coverage
 import lsst.pipe.base.cli.opt as pipeBaseOpts
 from lsst.ctrl.mpexec import Report
 from lsst.ctrl.mpexec.showInfo import ShowInfo
@@ -145,6 +145,11 @@ def coverage_context(kwargs: dict[str, Any]) -> Iterator[None]:
     if not kwargs.pop("coverage", False):
         yield
         return
+    # Lazily import coverage only when we might need it
+    try:
+        coverage = import_module("coverage")
+    except ModuleNotFoundError:
+        raise click.ClickException("coverage was requested but the coverage package is not installed.")
     with NamedTemporaryFile("w") as rcfile:
         rcfile.write(
             """

python/lsst/ctrl/mpexec/cli/opt/options.py

@@ -54,7 +54,9 @@
     "--debug", help="Enable debugging output using lsstDebug facility (imports debug.py).", is_flag=True
 )
 
-coverage_option = MWOptionDecorator("--coverage", help="Enable coverage output.", is_flag=True)
+coverage_option = MWOptionDecorator(
+    "--coverage", help="Enable coverage output (requires coverage package).", is_flag=True
+)
 
 coverage_report_option = MWOptionDecorator(
     "--cov-report/--no-cov-report",

tests/test_cliScript.py

@@ -28,10 +28,12 @@
 import os
 import tempfile
 import unittest
+import unittest.mock
 
 import click
 import lsst.utils.tests
 from lsst.ctrl.mpexec.cli import opt, script
+from lsst.ctrl.mpexec.cli.cmd.commands import coverage_context
 from lsst.ctrl.mpexec.cli.pipetask import cli as pipetaskCli
 from lsst.ctrl.mpexec.showInfo import ShowInfo
 from lsst.daf.butler.cli.utils import LogCliRunner, clickResultMsg
@@ -203,6 +205,25 @@
         self.assertNotEqual(result.exit_code, 0)
 
 
+class CoverageTestCase(unittest.TestCase):
+    """Test coverage context manager."""
+
+    @unittest.mock.patch.dict("sys.modules", coverage=unittest.mock.MagicMock())
+    def testWithCoverage(self):
+        """Test that the coverage context manager runs when invoked."""
+        with coverage_context({"coverage": True}):
+            self.assertTrue(True)
+
+    @unittest.mock.patch("lsst.ctrl.mpexec.cli.cmd.commands.import_module", side_effect=ModuleNotFoundError())
+    def testWithMissingCoverage(self, mock_import):
+        """Test that the coverage context manager complains when coverage is
+        not available.
+        """
+        with self.assertRaises(click.exceptions.ClickException):
+            with coverage_context({"coverage": True}):
+                pass
+
+
 if __name__ == "__main__":
     lsst.utils.tests.init()
     unittest.main()