Now print a message if --show is used with pipetask run or qgraph

This makes it clear why the command finished without doing anything.

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

@@ -19,6 +19,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import sys
 from functools import partial
 from typing import Any
 
@@ -89,6 +90,15 @@ def _collectActions(ctx: click.Context, **kwargs: Any) -> dict[str, Any]:
     return kwargs
 
 
+def _unhandledShow(show: ShowInfo, cmd: str) -> None:
+    if show.unhandled:
+        print(
+            f"The following '--show' options were not known to the {cmd} command: "
+            f"{', '.join(show.unhandled)}",
+            file=sys.stderr,
+        )
+
+
 @click.command(cls=PipetaskCommand, epilog=epilog, short_help="Build pipeline definition.")
 @click.pass_context
 @ctrlMpExecOpts.show_option()
@@ -104,11 +114,7 @@ def build(ctx: click.Context, **kwargs: Any) -> None:
     kwargs = _collectActions(ctx, **kwargs)
     show = ShowInfo(kwargs.pop("show", []))
     script.build(**kwargs, show=show)
-    if show.unhandled:
-        print(
-            "The following '--show' options were not known to the build command: "
-            f"{', '.join(show.unhandled)}"
-        )
+    _unhandledShow(show, "build")
 
 
 @click.command(cls=PipetaskCommand, epilog=epilog)
@@ -126,10 +132,12 @@ def qgraph(ctx: click.Context, **kwargs: Any) -> None:
     show = ShowInfo(kwargs.pop("show", []))
     pipeline = script.build(**kwargs, show=show)
     if show.handled and not show.unhandled:
-        # The show option was given and all options were processed.
-        # No need to also build the quantum graph.
+        print("No quantum graph generated. "
+              "The --show option was given and all options were processed.",
+              file=sys.stderr)
         return
     script.qgraph(pipelineObj=pipeline, **kwargs, show=show)
+    _unhandledShow(show, "qgraph")
 
 
 @click.command(cls=PipetaskCommand, epilog=epilog)
@@ -141,13 +149,16 @@ def run(ctx: click.Context, **kwargs: Any) -> None:
     show = ShowInfo(kwargs.pop("show", []))
     pipeline = script.build(**kwargs, show=show)
     if show.handled and not show.unhandled:
-        # The show option was given and all options were processed.
-        # No need to also build the quantum graph.
+        print("No quantum graph generated or pipeline executed. "
+              "The --show option was given and all options were processed.",
+              file=sys.stderr)
         return
     qgraph = script.qgraph(pipelineObj=pipeline, **kwargs, show=show)
+    _unhandledShow(show, "run")
     if show.handled:
-        # The show option was given and all graph options were processed.
-        # No need to also run the pipeline.
+        print("No pipeline executed. "
+              "The --show option was given and all options were processed.",
+              file=sys.stderr)
         return
     script.run(qgraphObj=qgraph, **kwargs)