Only force prog=cwltool for the cwl-runner alias (#1535)

Per review feedback: an unconditional prog="cwltool" would leak into
downstream tools that reuse cwltool.argparser.arg_parser() as their base
parser (e.g. Calrissian), changing their --help/usage program name.

Scope the override to the actual invocation name: set prog="cwltool"
only when invoked as the generic "cwl-runner" alias, otherwise leave it
None so argparse's basename default is preserved. Toil and Arvados are
unaffected either way (they build their own parsers). Added a test
asserting a downstream invocation name is preserved.

Author: arimu1

cwltool/argparser.py

@@ -89,7 +89,12 @@ def arg_parser() -> argparse.ArgumentParser:
     )
 
     parser = argparse.ArgumentParser(
-        prog="cwltool",
+        # Force the program name to "cwltool" only when invoked through the
+        # generic ``cwl-runner`` alias (see #1535). Leaving it as ``None`` for
+        # any other invocation preserves argparse's basename default, so
+        # downstream tools that reuse this parser (e.g. Calrissian) keep their
+        # own program name.
+        prog="cwltool" if os.path.basename(sys.argv[0]) == "cwl-runner" else None,
         formatter_class=RichHelpFormatter,
         description="Reference executor for Common Workflow Language standards. "
         "Not for production use.",

tests/test_toolargparse.py

@@ -280,14 +280,24 @@ def test_argparser_without_doc() -> None:
 
 
 def test_argparser_prog_is_cwltool(monkeypatch: pytest.MonkeyPatch) -> None:
-    """The program name is reported as ``cwltool`` even when invoked as ``cwl-runner``.
+    """The program name is reported as ``cwltool`` when invoked as ``cwl-runner``.
 
     Regression test for https://github.com/common-workflow-language/cwltool/issues/1535
     """
-    monkeypatch.setattr(sys, "argv", ["cwl-runner", "--help"])
+    monkeypatch.setattr(sys, "argv", ["/usr/local/bin/cwl-runner", "--help"])
     assert arg_parser().prog == "cwltool"
 
 
+def test_argparser_prog_preserves_downstream_name(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Reusers of ``arg_parser()`` keep their own program name (not forced to ``cwltool``).
+
+    Downstream tools such as Calrissian call :func:`arg_parser` directly and rely on
+    argparse's basename default; the ``cwl-runner`` override must not leak into them.
+    """
+    monkeypatch.setattr(sys, "argv", ["/usr/local/bin/calrissian", "--help"])
+    assert arg_parser().prog == "calrissian"
+
+
 @pytest.mark.parametrize(
     "job_order,expected_values",
     [