Reduce parallelism for Perl v5.42.0 tests

easystacks/software.eessi.io/2026.06/eessi-2026.06-eb-5.3.1-2026.1.yml

@@ -0,0 +1,2 @@
+easyconfigs:
+  - Perl-5.42.0-GCCcore-15.2.0.eb

eb_hooks.py

@@ -1684,6 +1684,18 @@ def pre_test_hook_lammps_ignore_failure_arm_generic(self, *args, **kwargs):
             self.cfg['test_cmd'] = test_cmd
 
 
+def pre_test_hook_perl_reduce_parallelism(self, *args, **kwargs):
+    """
+    Tests fail for Perl v5.42.0 when run with full parallelism. So, reduce parallelism.
+    See https://github.com/EESSI/software-layer/pull/1556#issuecomment-5183283054
+    """
+    if self.name == "Perl" and self.version == "5.42.0":
+        if hasattr(self, 'parallel'):
+            self.cfg.parallel = 1
+        else:
+            self.cfg['parallel'] = 1
+        print_msg("Limiting parallelism to 1 in the test step to avoid failures", log=self.log)
+
 def pre_test_hook_ignore_failing_tests_SciPybundle(self, *args, **kwargs):
     """
     Pre-test hook for SciPy-bundle: skip failing tests for selected SciPy-bundle versions
@@ -2319,6 +2331,7 @@ def post_easyblock_hook(self, *args, **kwargs):
     'Siesta': pre_test_hook_Siesta_ignore_failure_with_crosscompilation,
     'netCDF': pre_test_hook_ignore_failing_tests_netCDF,
     'OpenBabel': pre_test_hook_ignore_failing_tests_OpenBabel_a64fx,
+    'Perl': pre_test_hook_perl_reduce_parallelism,
     'PyTorch': pre_test_hook_increase_max_failed_tests_arm_PyTorch,
 }