Experiment info fragility (#1247)

* tolerate users providing specs (e.g. with variants) to 'experiment info'

* proper distinction between 'bad variant' and 'bad value for valid variant'

* internal naming for clarity: we must have an experiment, not an experiment class

* try to improve error message

* auto style

* rm commented out code

---------

Co-authored-by: pearce8 <pearce8@llnl.gov>

Author: scheibelp

lib/benchpark/cmd/info.py

@@ -1,3 +1,4 @@
+import argparse
 import os
 import subprocess
 import textwrap
@@ -138,20 +139,26 @@ def _info_ramble_name(experiment_class):
             )
         )
 
-    experiment_spec = benchpark.spec.ExperimentSpec(args.name)
+    experiment_spec_str = " ".join(args.name)
+    experiment_spec = benchpark.spec.ExperimentSpec(experiment_spec_str)
     conc = experiment_spec.concretize()
-    experiment_class = conc.experiment
+    try:
+        experiment = conc.experiment
+    except Exception as e:
+        msg = (
+            f"'{experiment_spec_str}' must be a valid experiment spec;"
+            " some experiments require specifying additional variants"
+            " (e.g. experiments not inheriting MpiOnlyExperiment must"
+            " set +rocm or +cuda)."
+        )
+        raise ValueError(msg) from e
 
     if args.spack:
         subprocess.run(
             [
                 "spack",
                 "info",
-                (
-                    experiment_class.spack_name
-                    if experiment_class.spack_name
-                    else experiment_class.name
-                ),
+                (experiment.spack_name if experiment.spack_name else experiment.name),
             ]
         )
         return
@@ -160,20 +167,16 @@ def _info_ramble_name(experiment_class):
             [
                 "ramble",
                 "info",
-                (
-                    experiment_class.ramble_name
-                    if experiment_class.ramble_name
-                    else experiment_class.name
-                ),
+                (experiment.ramble_name if experiment.ramble_name else experiment.name),
             ]
         )
         return
     else:
         actions = {
-            "maintainers": (info_maintainers, [experiment_class]),
-            "ramble_name": (_info_ramble_name, [experiment_class]),
-            "spack_name": (_info_spack_name, [experiment_class]),
-            "variants": (info_variants, [experiment_class]),
+            "maintainers": (info_maintainers, [experiment]),
+            "ramble_name": (_info_ramble_name, [experiment]),
+            "spack_name": (_info_spack_name, [experiment]),
+            "variants": (info_variants, [experiment]),
         }
 
         # Call functions for enabled options, or all if no flag is set
@@ -218,7 +221,9 @@ def setup_parser(root_parser):
     experiment_parser.add_argument(
         "--maintainers", action="store_true", help="Maintainers"
     )
-    experiment_parser.add_argument("name", help="Experiment name")
+    experiment_parser.add_argument(
+        "name", nargs=argparse.REMAINDER, help="Experiment name"
+    )
 
 
 def command(args):

lib/benchpark/spec.py

@@ -323,14 +323,19 @@ def _concretize(self):
             name, values = variants_to_check.pop()
             checked.add((name, values))
 
-            conditions = [
-                w
-                for w, v_by_n in self.object_class.variants.items()
-                for n, v in v_by_n.items()
-                if n == name and v.validate_values_bool(values)
-            ]
-
-            if not conditions:
+            conditions = []
+            possible_variants = set()
+            for when, v_by_n in self.object_class.variants.items():
+                possible_variants.update(v_by_n.keys())
+                for n, v in v_by_n.items():
+                    if n == name:
+                        if not v.validate_values_bool(values):
+                            raise Exception(
+                                f"'{values}' is not valid for variant '{name}' on {self.name}"
+                            )
+                        conditions.append(when)
+
+            if name not in possible_variants:
                 raise Exception(f"{name} is not a valid variant of {self.name}")
 
             # This variant is already valid on self