feat: Add ENV_SAVED Action (#1302)

Adds an ENV_SAVED Action hook that allows hooking into the save mechanism and
running custom code after saving an environemnt.

Author: xitij2000

changelog.d/20251111_011520_kshitij_env_saved_action.md

@@ -0,0 +1,2 @@
+- [Feature] Add ENV_SAVED Action that allows hooks to run after a save
+  operation. (by @xitij2000)

tutor/env.py

@@ -342,6 +342,15 @@ def save(root: str, config: Config) -> None:
         save_all_from(src, os.path.join(root_env, dst), config)
 
     upgrade_obsolete(root)
+
+    config_copy = deepcopy(config)
+    hooks.Actions.ENV_SAVED.do(root_env, config_copy)
+    if config_copy != config:
+        fmt.echo_alert(
+            "A plugin just modified the config during the ENV_SAVED hook. "
+            "This could have unintended consequences."
+        )
+
     fmt.echo_info(f"Environment generated in {base_dir(root)}")
 
 

tutor/hooks/catalog.py

@@ -94,6 +94,16 @@ def run_this_on_start(root, config, name):
     #: :parameter kwargs: job named arguments.
     DO_JOB: Action[[str, Any]] = Action()
 
+    #: This action is called at the end of the tutor.env.save function after all
+    #: the changes to the environment have been applied, all obsolete config has
+    #: been upgraded.
+    #: Modifying the config object will not trigger changes in the configuration.
+    #: For all purposes, it should be considered read-only.
+    #:
+    #: :parameter str root: project root.
+    #: :parameter dict config: project configuration.
+    ENV_SAVED: Action[[str, Config]] = Action()
+
     #: Triggered when a single plugin needs to be loaded. Only plugins that have previously been
     #: discovered can be loaded (see :py:data:`CORE_READY`).
     #: