Fix errors due to parallel property being unset

Move `set_parallel` to `post_init` which matches better than the `ready_step`.
That is described:
> creating build dir, resetting environment
> Verify if all is ok to start build.

None of that matches the behavior of a `set_parallel` call as opposed to
> Run post-initialization tasks.

When handling potentially additional limitations in extensions we need
to check if we have `parallel` set already before applying it.
This should only be the case for tests which take shortcuts in the logic
such as skipping `post_init`.

Author: Flamefire

easybuild/framework/easyblock.py

@@ -340,6 +340,7 @@ def post_init(self):
             # but needs to be correct if the build is performed in the installation directory
             self.log.info("Changing build dir to %s", self.installdir)
             self.builddir = self.installdir
+        self.set_parallel()
 
     # INIT/CLOSE LOG
     def _init_log(self):
@@ -2470,8 +2471,6 @@ def check_readiness_step(self):
         """
         Verify if all is ok to start build.
         """
-        self.set_parallel()
-
         # check whether modules are loaded
         loadedmods = self.modules_tool.loaded_modules()
         if len(loadedmods) > 0:

easybuild/framework/easyconfig/easyconfig.py

@@ -1258,6 +1258,11 @@ def all_dependencies(self):
 
         return self._all_dependencies
 
+    @property
+    def is_parallel_set(self):
+        """Return if the desired parallelism has been determined yet"""
+        return self._parallel is not None
+
     @property
     def parallel(self):
         """Number of parallel jobs to be used for building etc."""

easybuild/framework/extension.py

@@ -153,10 +153,11 @@ def __init__(self, mself, ext, extra_params=None):
                 self.log.debug("Skipping unknown custom easyconfig parameter '%s' for extension %s/%s: %s",
                                key, name, version, value)
 
-        # Take potentially new value into account
-        max_par = self.cfg['max_parallel']
-        if max_par is not None and max_par < self.cfg.parallel:
-            self.cfg.parallel = max_par
+        # If parallelism has been set already take potentially new limitation into account
+        if self.cfg.is_parallel_set:
+            max_par = self.cfg['max_parallel']
+            if max_par is not None and max_par < self.cfg.parallel:
+                self.cfg.parallel = max_par
 
         self.sanity_check_fail_msgs = []
         self.sanity_check_module_loaded = False