Fixes mode-based checks inside the `EventManager.apply` call (#777)

# Description

Noticed that we were checking for function arguments inside a for-loop,
which isn't necessary. Moved this check outside to make it simpler to
read the code.

Also noticed a small corner case in the event manager when reset is
called and `env_ids` is None. In that case, it would bypass the check
for min steps between reset and directly apply the term to the
environment. I am not sure if that was intentional. if so, I can revert
the behavior.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

source/extensions/omni.isaac.lab/config/extension.toml

 [package]
 
 # Note: Semantic Versioning is used: https://semver.org/
-version = "0.21.1"
+version = "0.21.2"
 
 # Description
 title = "Isaac Lab framework for Robot Learning"

source/extensions/omni.isaac.lab/docs/CHANGELOG.rst

 Changelog
 ---------
 
+0.21.2 (2024-08-13)
+~~~~~~~~~~~~~~~~~~~
+
+Fixed
+^^^^^
+
+* Moved event mode-based checks in the :meth:`omni.isaac.lab.managers.EventManager.apply` method outside
+  the loop that iterates over the event terms. This prevents unnecessary checks and improves readability.
+* Fixed the logic for global and per environment interval times when using the "interval" mode inside the
+  event manager. Earlier, the internal lists for these times were of unequal lengths which led to wrong indexing
+  inside the loop that iterates over the event terms.
+
+
 0.21.1 (2024-08-06)
 ~~~~~~~~~~~~~~~~~~~
 

source/extensions/omni.isaac.lab/omni/isaac/lab/envs/direct_rl_env.py

@@ -519,7 +519,7 @@ class DirectRLEnv(gym.Env):
         if self.cfg.events:
             if "reset" in self.event_manager.available_modes:
                 env_step_count = self._sim_step_counter // self.cfg.decimation
-                self.event_manager.apply(env_ids=env_ids, mode="reset", global_env_step_count=env_step_count)
+                self.event_manager.apply(mode="reset", env_ids=env_ids, global_env_step_count=env_step_count)
 
         # reset noise models
         if self.cfg.action_noise_model:

source/extensions/omni.isaac.lab/omni/isaac/lab/envs/manager_based_env.py

@@ -337,10 +337,10 @@ class ManagerBasedEnv:
         """
         # reset the internal buffers of the scene elements
         self.scene.reset(env_ids)
-        # apply events such as randomizations for environments that need a reset
+        # apply events such as randomization for environments that need a reset
         if "reset" in self.event_manager.available_modes:
             env_step_count = self._sim_step_counter // self.cfg.decimation
-            self.event_manager.apply(env_ids=env_ids, mode="reset", global_env_step_count=env_step_count)
+            self.event_manager.apply(mode="reset", env_ids=env_ids, global_env_step_count=env_step_count)
 
         # iterate over all managers and reset them
         # this returns a dictionary of information which is stored in the extras

source/extensions/omni.isaac.lab/omni/isaac/lab/envs/manager_based_rl_env.py

@@ -319,7 +319,7 @@ class ManagerBasedRLEnv(ManagerBasedEnv, gym.Env):
         # apply events such as randomizations for environments that need a reset
         if "reset" in self.event_manager.available_modes:
             env_step_count = self._sim_step_counter // self.cfg.decimation
-            self.event_manager.apply(env_ids=env_ids, mode="reset", global_env_step_count=env_step_count)
+            self.event_manager.apply(mode="reset", env_ids=env_ids, global_env_step_count=env_step_count)
 
         # iterate over all managers and reset them
         # this returns a dictionary of information which is stored in the extras

source/extensions/omni.isaac.lab/omni/isaac/lab/managers/manager_term_cfg.py

@@ -191,7 +191,7 @@ class EventTermCfg(ManagerTermBaseCfg):
     """
 
     interval_range_s: tuple[float, float] | None = None
-    """The range of time in seconds at which the term is applied.
+    """The range of time in seconds at which the term is applied. Defaults to None.
 
     Based on this, the interval is sampled uniformly between the specified
     range for each environment instance. The term is applied on the environment
@@ -202,21 +202,24 @@ class EventTermCfg(ManagerTermBaseCfg):
     """
 
     is_global_time: bool = False
-    """ Whether randomization should be tracked on a per-environment basis.
+    """Whether randomization should be tracked on a per-environment basis. Defaults to False.
 
-    If True, the same time for the interval is tracked for all the environments instead of
-    tracking the time per-environment.
+    If True, the same interval time is used for all the environment instances.
+    If False, the interval time is sampled independently for each environment instance
+    and the term is applied when the current time hits the interval time for that instance.
 
     Note:
         This is only used if the mode is ``"interval"``.
     """
 
     min_step_count_between_reset: int = 0
-    """The minimum number of environment steps between when term is applied.
+    """The number of environment steps after which the term is applied since its last application. Defaults to 0.
 
-    When mode is "reset", the term will not be applied on the next reset unless
-    the number of steps since the last application of the term has exceeded this.
-    This is useful to avoid calling this term too often and improve performance.
+    When the mode is "reset", the term is only applied if the number of environment steps since
+    its last application exceeds this quantity. This helps to avoid calling the term too often,
+    thereby improving performance.
+
+    If the value is zero, the term is applied on every call to the manager with the mode "reset".
 
     Note:
         This is only used if the mode is ``"reset"``.