Final grooming

Author: Vasileios Karakasis

reframe/core/systems.py

@@ -475,7 +475,7 @@ def create(cls, site_config):
                     )
                 )
 
-            env_patt = site_config.get('general/valid_env_names') or [r'.*']
+            env_patt = site_config.get('general/0/valid_env_names') or [r'.*']
             part_environs = [
                 ProgEnvironment(
                     name=e,

reframe/frontend/cli.py

@@ -260,6 +260,13 @@ def main():
         '-n', '--name', action='append', dest='names', default=[],
         metavar='PATTERN', help='Select checks whose name matches PATTERN'
     )
+
+    # FIXME: The following is the only selection option that has an associated
+    # (undocumented) configuration variable. This is to support pruning of the
+    # partition environments as the runtime is created, similarly to how the
+    # system partitions are treated. Currently, this facilitates the
+    # implementation of fixtures, but we should reconsider it: see discussion
+    # in https://github.com/eth-cscs/reframe/issues/2245
     select_options.add_argument(
         '-p', '--prgenv', action='append', default=[r'.*'],  metavar='PATTERN',
         configvar='general/valid_env_names',

reframe/frontend/loader.py

@@ -171,35 +171,40 @@ def load_from_module(self, module):
             return []
 
         self._set_defaults(registry)
-        candidates = registry.instantiate_all() if registry else []
-        legacy_candidates = legacy_registry() if legacy_registry else []
-        if self._external_vars and legacy_candidates:
+        test_pool = registry.instantiate_all() if registry else []
+        legacy_tests = legacy_registry() if legacy_registry else []
+        if self._external_vars and legacy_tests:
             getlogger().warning(
                 "variables of tests using the deprecated "
                 "'@parameterized_test' decorator cannot be set externally; "
                 "please use the 'parameter' builtin in your tests"
             )
 
         # Merge registries
-        candidates += legacy_candidates
+        test_pool += legacy_tests
 
-        # Serialize the fixture registries doing a level-order traversal
+        # Do a level-order traversal of the fixture registries of all tests in
+        # the test pool, instantiate all fixtures and generate the final set
+        # of candidate tests to load; the test pool is consumed at the end of
+        # the traversal and all instantiated tests (including fixtures) are
+        # stored in `candidate_tests`.
         candidate_tests = []
         fixture_registry = FixtureRegistry()
-        while candidates:
+        while test_pool:
             tmp_registry = FixtureRegistry()
-            while candidates:
-                c = candidates.pop()
+            while test_pool:
+                c = test_pool.pop()
                 reg = getattr(c, '_rfm_fixture_registry', None)
                 candidate_tests.append(c)
                 if reg:
                     tmp_registry.update(reg)
 
             # Instantiate the new fixtures and update the registry
             new_fixtures = tmp_registry.difference(fixture_registry)
-            candidates = new_fixtures.instantiate_all()
+            test_pool = new_fixtures.instantiate_all()
             fixture_registry.update(new_fixtures)
 
+        # Post-instantiation validation of the candidate tests
         tests = []
         for c in candidate_tests:
             if not isinstance(c, RegressionTest):