fix doc typo; add error handling

Author: themisvaltinos

docs/concepts/macros/macro_variables.md

@@ -141,4 +141,4 @@ The following variables are also available in [`before_all` and `after_all` stat
 
 * @this_env - A string value containing the name of the current [environment](../environments.md).
 * @schemas - A list of the schema names of the [virtual layer](../../concepts/glossary.md#virtual-layer) of the current environment.
-* @views - A list of the views names of the [virtual layer](../../concepts/glossary.md#virtual-layer) of the current environment.
+* @views - A list of the view names of the [virtual layer](../../concepts/glossary.md#virtual-layer) of the current environment.

docs/guides/configuration.md

@@ -1019,7 +1019,6 @@ For example, rather than using an `on_virtual_update` statement in each model to
 
 ```python linenums="1"
 from sqlmesh.core.macros import macro
-from sqlmesh.core.snapshot.definition import to_view_mapping
 
 @macro()
 def grant_select_privileges(evaluator):

sqlmesh/core/macros.py

@@ -497,19 +497,25 @@ def snapshots(self) -> t.Dict[str, Snapshot]:
         return self._snapshots
 
     @property
-    def this_env(self) -> t.Optional[str]:
+    def this_env(self) -> str:
         """Returns the name of the current environment in before after all."""
-        return self.locals.get("this_env")
+        if "this_env" not in self.locals:
+            raise SQLMeshError("Environment name is not available in this context")
+        return self.locals["this_env"]
 
     @property
-    def schemas(self) -> t.Optional[t.List[str]]:
+    def schemas(self) -> t.List[str]:
         """Returns the schemas of the current environment in before after all macros."""
-        return self.locals.get("schemas")
+        if "schemas" not in self.locals:
+            raise SQLMeshError("Schemas are not available in this context")
+        return self.locals["schemas"]
 
     @property
-    def views(self) -> t.Optional[t.List[str]]:
+    def views(self) -> t.List[str]:
         """Returns the views of the current environment in before after all macros."""
-        return self.locals.get("views")
+        if "views" not in self.locals:
+            raise SQLMeshError("Views are not available in this context")
+        return self.locals["views"]
 
     def var(self, var_name: str, default: t.Optional[t.Any] = None) -> t.Optional[t.Any]:
         """Returns the value of the specified variable, or the default value if it doesn't exist."""