Fix variable scopes in scripts (#138883)

Co-authored-by: Erik <erik@montnemery.com>

homeassistant/helpers/script.py

@@ -12,7 +12,6 @@ from datetime import datetime, timedelta
 from functools import partial
 import itertools
 import logging
-from types import MappingProxyType
 from typing import Any, Literal, TypedDict, cast, overload
 
 import async_interrupt
@@ -90,7 +89,7 @@ from . import condition, config_validation as cv, service, template
 from .condition import ConditionCheckerType, trace_condition_function
 from .dispatcher import async_dispatcher_connect, async_dispatcher_send_internal
 from .event import async_call_later, async_track_template
-from .script_variables import ScriptVariables
+from .script_variables import ScriptRunVariables, ScriptVariables
 from .template import Template
 from .trace import (
     TraceElement,
@@ -177,7 +176,7 @@ def _set_result_unless_done(future: asyncio.Future[None]) -> None:
         future.set_result(None)
 
 
-def action_trace_append(variables: dict[str, Any], path: str) -> TraceElement:
+def action_trace_append(variables: TemplateVarsType, path: str) -> TraceElement:
     """Append a TraceElement to trace[path]."""
     trace_element = TraceElement(variables, path)
     trace_append_element(trace_element, ACTION_TRACE_NODE_MAX_LEN)
@@ -189,7 +188,7 @@ async def trace_action(
     hass: HomeAssistant,
     script_run: _ScriptRun,
     stop: asyncio.Future[None],
-    variables: dict[str, Any],
+    variables: TemplateVarsType,
 ) -> AsyncGenerator[TraceElement]:
     """Trace action execution."""
     path = trace_path_get()
@@ -411,7 +410,7 @@ class _ScriptRun:
         self,
         hass: HomeAssistant,
         script: Script,
-        variables: dict[str, Any],
+        variables: ScriptRunVariables,
         context: Context | None,
         log_exceptions: bool,
     ) -> None:
@@ -485,14 +484,16 @@ class _ScriptRun:
             script_stack.pop()
             self._finish()
 
-        return ScriptRunResult(self._conversation_response, response, self._variables)
+        return ScriptRunResult(
+            self._conversation_response, response, self._variables.local_scope
+        )
 
     async def _async_step(self, log_exceptions: bool) -> None:
         continue_on_error = self._action.get(CONF_CONTINUE_ON_ERROR, False)
 
         with trace_path(str(self._step)):
             async with trace_action(
-                self._hass, self, self._stop, self._variables
+                self._hass, self, self._stop, self._variables.non_parallel_scope
             ) as trace_element:
                 if self._stop.done():
                     return
@@ -526,7 +527,7 @@ class _ScriptRun:
                         ex, continue_on_error, self._log_exceptions or log_exceptions
                     )
                 finally:
-                    trace_element.update_variables(self._variables)
+                    trace_element.update_variables(self._variables.non_parallel_scope)
 
     def _finish(self) -> None:
         self._script._runs.remove(self)  # noqa: SLF001
@@ -624,11 +625,16 @@ class _ScriptRun:
         except ScriptStoppedError as ex:
             raise asyncio.CancelledError from ex
 
-    async def _async_run_script(self, script: Script) -> None:
+    async def _async_run_script(
+        self, script: Script, *, parallel: bool = False
+    ) -> None:
         """Execute a script."""
         result = await self._async_run_long_action(
             self._hass.async_create_task_internal(
-                script.async_run(self._variables, self._context), eager_start=True
+                script.async_run(
+                    self._variables.enter_scope(parallel=parallel), self._context
+                ),
+                eager_start=True,
             )
         )
         if result and result.conversation_response is not UNDEFINED:
@@ -647,7 +653,7 @@ class _ScriptRun:
             """Run a script with a trace path."""
             trace_path_stack_cv.set(copy(trace_path_stack_cv.get()))
             with trace_path([str(idx), "sequence"]):
-                await self._async_run_script(script)
+                await self._async_run_script(script, parallel=True)
 
         results = await asyncio.gather(
             *(async_run_with_trace(idx, script) for idx, script in enumerate(scripts)),
@@ -760,14 +766,11 @@ class _ScriptRun:
             with trace_path("else"):
                 await self._async_run_script(if_data["if_else"])
 
-    @async_trace_path("repeat")
-    async def _async_step_repeat(self) -> None:  # noqa: C901
-        """Repeat a sequence."""
+    async def _async_do_step_repeat(self) -> None:  # noqa: C901
+        """Repeat a sequence helper."""
         description = self._action.get(CONF_ALIAS, "sequence")
         repeat = self._action[CONF_REPEAT]
 
-        saved_repeat_vars = self._variables.get("repeat")
-
         def set_repeat_var(
             iteration: int, count: int | None = None, item: Any = None
         ) -> None:
@@ -776,7 +779,7 @@ class _ScriptRun:
                 repeat_vars["last"] = iteration == count
             if item is not None:
                 repeat_vars["item"] = item
-            self._variables["repeat"] = repeat_vars
+            self._variables.define_local("repeat", repeat_vars)
 
         script = self._script._get_repeat_script(self._step)  # noqa: SLF001
         warned_too_many_loops = False
@@ -927,10 +930,14 @@ class _ScriptRun:
                 # while all the cpu time is consumed.
                 await asyncio.sleep(0)
 
-        if saved_repeat_vars:
-            self._variables["repeat"] = saved_repeat_vars
-        else:
-            self._variables.pop("repeat", None)  # Not set if count = 0
+    @async_trace_path("repeat")
+    async def _async_step_repeat(self) -> None:
+        """Repeat a sequence."""
+        self._variables = self._variables.enter_scope()
+        try:
+            await self._async_do_step_repeat()
+        finally:
+            self._variables = self._variables.exit_scope()
 
     ### Stop actions ###
 
@@ -959,11 +966,12 @@ class _ScriptRun:
     ## Variable actions ##
 
     async def _async_step_variables(self) -> None:
-        """Set a variable value."""
-        self._step_log("setting variables")
-        self._variables = self._action[CONF_VARIABLES].async_render(
-            self._hass, self._variables, render_as_defaults=False
-        )
+        """Define a local variable."""
+        self._step_log("defining local variables")
+        for key, value in (
+            self._action[CONF_VARIABLES].async_simple_render(self._variables).items()
+        ):
+            self._variables.define_local(key, value)
 
     ## External actions ##
 
@@ -1016,7 +1024,7 @@ class _ScriptRun:
         """Perform the device automation specified in the action."""
         self._step_log("device automation")
         await device_action.async_call_action_from_config(
-            self._hass, self._action, self._variables, self._context
+            self._hass, self._action, dict(self._variables), self._context
         )
 
     async def _async_step_event(self) -> None:
@@ -1189,12 +1197,15 @@ class _ScriptRun:
 
         self._step_log("wait for trigger", timeout)
 
-        variables = {**self._variables}
-        self._variables["wait"] = {
-            "remaining": timeout,
-            "completed": False,
-            "trigger": None,
-        }
+        variables = dict(self._variables)
+        self._variables.assign_parallel_protected(
+            "wait",
+            {
+                "remaining": timeout,
+                "completed": False,
+                "trigger": None,
+            },
+        )
         trace_set_result(wait=self._variables["wait"])
 
         if timeout == 0:
@@ -1240,7 +1251,9 @@ class _ScriptRun:
         timeout = self._get_timeout_seconds_from_action()
         self._step_log("wait template", timeout)
 
-        self._variables["wait"] = {"remaining": timeout, "completed": False}
+        self._variables.assign_parallel_protected(
+            "wait", {"remaining": timeout, "completed": False}
+        )
         trace_set_result(wait=self._variables["wait"])
 
         wait_template = self._action[CONF_WAIT_TEMPLATE]
@@ -1369,7 +1382,7 @@ async def _async_stop_scripts_at_shutdown(hass: HomeAssistant, event: Event) ->
         )
 
 
-type _VarsType = dict[str, Any] | Mapping[str, Any] | MappingProxyType[str, Any]
+type _VarsType = dict[str, Any] | Mapping[str, Any] | ScriptRunVariables
 
 
 def _referenced_extract_ids(data: Any, key: str, found: set[str]) -> None:
@@ -1407,7 +1420,7 @@ class ScriptRunResult:
 
     conversation_response: str | None | UndefinedType
     service_response: ServiceResponse
-    variables: dict[str, Any]
+    variables: Mapping[str, Any]
 
 
 class Script:
@@ -1422,7 +1435,6 @@ class Script:
         *,
         # Used in "Running <running_description>" log message
         change_listener: Callable[[], Any] | None = None,
-        copy_variables: bool = False,
         log_exceptions: bool = True,
         logger: logging.Logger | None = None,
         max_exceeded: str = DEFAULT_MAX_EXCEEDED,
@@ -1476,8 +1488,6 @@ class Script:
         self._parallel_scripts: dict[int, list[Script]] = {}
         self._sequence_scripts: dict[int, Script] = {}
         self.variables = variables
-        self._variables_dynamic = template.is_complex(variables)
-        self._copy_variables_on_run = copy_variables
 
     @property
     def change_listener(self) -> Callable[..., Any] | None:
@@ -1755,25 +1765,19 @@ class Script:
         if self.top_level:
             if self.variables:
                 try:
-                    variables = self.variables.async_render(
+                    run_variables = self.variables.async_render(
                         self._hass,
                         run_variables,
                     )
                 except exceptions.TemplateError as err:
                     self._log("Error rendering variables: %s", err, level=logging.ERROR)
                     raise
-            elif run_variables:
-                variables = dict(run_variables)
-            else:
-                variables = {}
 
+            variables = ScriptRunVariables.create_top_level(run_variables)
             variables["context"] = context
-        elif self._copy_variables_on_run:
-            # This is not the top level script, variables have been turned to a dict
-            variables = cast(dict[str, Any], copy(run_variables))
         else:
-            # This is not the top level script, variables have been turned to a dict
-            variables = cast(dict[str, Any], run_variables)
+            # This is not the top level script, run_variables is an instance of ScriptRunVariables
+            variables = cast(ScriptRunVariables, run_variables)
 
         # Prevent non-allowed recursive calls which will cause deadlocks when we try to
         # stop (restart) or wait for (queued) our own script run.
@@ -1999,7 +2003,6 @@ class Script:
                 max_runs=self.max_runs,
                 logger=self._logger,
                 top_level=False,
-                copy_variables=True,
             )
             parallel_script.change_listener = partial(
                 self._chain_change_listener, parallel_script

homeassistant/helpers/script_variables.py

@@ -2,8 +2,10 @@
 
 from __future__ import annotations
 
+from collections import ChainMap, UserDict
 from collections.abc import Mapping
-from typing import Any
+from dataclasses import dataclass, field
+from typing import Any, cast
 
 from homeassistant.core import HomeAssistant, callback
 
@@ -24,30 +26,23 @@ class ScriptVariables:
         hass: HomeAssistant,
         run_variables: Mapping[str, Any] | None,
         *,
-        render_as_defaults: bool = True,
         limited: bool = False,
     ) -> dict[str, Any]:
         """Render script variables.
 
-        The run variables are used to compute the static variables.
-
-        If `render_as_defaults` is True, the run variables will not be overridden.
-
+        The run variables are included in the result.
+        The run variables are used to compute the rendered variable values.
+        The run variables will not be overridden.
+        The rendering happens one at a time, with previous results influencing the next.
         """
         if self._has_template is None:
             self._has_template = template.is_complex(self.variables)
 
         if not self._has_template:
-            if render_as_defaults:
-                rendered_variables = dict(self.variables)
+            rendered_variables = dict(self.variables)
 
-                if run_variables is not None:
-                    rendered_variables.update(run_variables)
-            else:
-                rendered_variables = (
-                    {} if run_variables is None else dict(run_variables)
-                )
-                rendered_variables.update(self.variables)
+            if run_variables is not None:
+                rendered_variables.update(run_variables)
 
             return rendered_variables
 
@@ -56,7 +51,7 @@ class ScriptVariables:
         for key, value in self.variables.items():
             # We can skip if we're going to override this key with
             # run variables anyway
-            if render_as_defaults and key in rendered_variables:
+            if key in rendered_variables:
                 continue
 
             rendered_variables[key] = template.render_complex(
@@ -65,6 +60,197 @@ class ScriptVariables:
 
         return rendered_variables
 
+    @callback
+    def async_simple_render(self, run_variables: Mapping[str, Any]) -> dict[str, Any]:
+        """Render script variables.
+
+        Simply renders the variables, the run variables are not included in the result.
+        The run variables are used to compute the rendered variable values.
+        The rendering happens one at a time, with previous results influencing the next.
+        """
+        if self._has_template is None:
+            self._has_template = template.is_complex(self.variables)
+
+        if not self._has_template:
+            return self.variables
+
+        run_variables = dict(run_variables)
+        rendered_variables = {}
+
+        for key, value in self.variables.items():
+            rendered_variable = template.render_complex(value, run_variables)
+            rendered_variables[key] = rendered_variable
+            run_variables[key] = rendered_variable
+
+        return rendered_variables
+
     def as_dict(self) -> dict[str, Any]:
         """Return dict version of this class."""
         return self.variables
+
+
+@dataclass
+class _ParallelData:
+    """Data used in each parallel sequence."""
+
+    # `protected` is for variables that need special protection in parallel sequences.
+    # What this means is that such a variable defined in one parallel sequence will not be
+    # clobbered by the variable with the same name assigned in another parallel sequence.
+    # It also means that such a variable will not be visible in the outer scope.
+    # Currently the only such variable is `wait`.
+    protected: dict[str, Any] = field(default_factory=dict)
+    # `outer_scope_writes` is for variables that are written to the outer scope from
+    # a parallel sequence. This is used for generating correct traces of changed variables
+    # for each of the parallel sequences, isolating them from one another.
+    outer_scope_writes: dict[str, Any] = field(default_factory=dict)
+
+
+@dataclass(kw_only=True)
+class ScriptRunVariables(UserDict[str, Any]):
+    """Class to hold script run variables.
+
+    The purpose of this class is to provide proper variable scoping semantics for scripts.
+    Each instance institutes a new local scope, in which variables can be defined.
+    Each instance has a reference to the previous instance, except for the top-level instance.
+    The instances therefore form a chain, in which variable lookup and assignment is performed.
+    The variables defined lower in the chain naturally override those defined higher up.
+    """
+
+    # _previous is the previous ScriptRunVariables in the chain
+    _previous: ScriptRunVariables | None = None
+    # _parent is the previous non-empty ScriptRunVariables in the chain
+    _parent: ScriptRunVariables | None = None
+
+    # _local_data is the store for local variables
+    _local_data: dict[str, Any] | None = None
+    # _parallel_data is used for each parallel sequence
+    _parallel_data: _ParallelData | None = None
+
+    # _non_parallel_scope includes all scopes all the way to the most recent parallel split
+    _non_parallel_scope: ChainMap[str, Any]
+    # _full_scope includes all scopes (all the way to the top-level)
+    _full_scope: ChainMap[str, Any]
+
+    @classmethod
+    def create_top_level(
+        cls,
+        initial_data: Mapping[str, Any] | None = None,
+    ) -> ScriptRunVariables:
+        """Create a new top-level ScriptRunVariables."""
+        local_data: dict[str, Any] = {}
+        non_parallel_scope = full_scope = ChainMap(local_data)
+        self = cls(
+            _local_data=local_data,
+            _non_parallel_scope=non_parallel_scope,
+            _full_scope=full_scope,
+        )
+        if initial_data is not None:
+            self.update(initial_data)
+        return self
+
+    def enter_scope(self, *, parallel: bool = False) -> ScriptRunVariables:
+        """Return a new child scope.
+
+        :param parallel: Whether the new scope starts a parallel sequence.
+        """
+        if self._local_data is not None or self._parallel_data is not None:
+            parent = self
+        else:
+            parent = cast(  # top level always has local data, so we can cast safely
+                ScriptRunVariables, self._parent
+            )
+
+        parallel_data: _ParallelData | None
+        if not parallel:
+            parallel_data = None
+            non_parallel_scope = self._non_parallel_scope
+            full_scope = self._full_scope
+        else:
+            parallel_data = _ParallelData()
+            non_parallel_scope = ChainMap(
+                parallel_data.protected, parallel_data.outer_scope_writes
+            )
+            full_scope = self._full_scope.new_child(parallel_data.protected)
+
+        return ScriptRunVariables(
+            _previous=self,
+            _parent=parent,
+            _parallel_data=parallel_data,
+            _non_parallel_scope=non_parallel_scope,
+            _full_scope=full_scope,
+        )
+
+    def exit_scope(self) -> ScriptRunVariables:
+        """Exit the current scope.
+
+        Does no clean-up, but simply returns the previous scope.
+        """
+        if self._previous is None:
+            raise ValueError("Cannot exit top-level scope")
+        return self._previous
+
+    def __delitem__(self, key: str) -> None:
+        """Delete a variable (disallowed)."""
+        raise TypeError("Deleting items is not allowed in ScriptRunVariables.")
+
+    def __setitem__(self, key: str, value: Any) -> None:
+        """Assign value to a variable."""
+        self._assign(key, value, parallel_protected=False)
+
+    def assign_parallel_protected(self, key: str, value: Any) -> None:
+        """Assign value to a variable which is to be protected in parallel sequences."""
+        self._assign(key, value, parallel_protected=True)
+
+    def _assign(self, key: str, value: Any, *, parallel_protected: bool) -> None:
+        """Assign value to a variable.
+
+        Value is always assigned to the variable in the nearest scope, in which it is defined.
+        If the variable is not defined at all, it is created in the top-level scope.
+
+        :param parallel_protected: Whether variable is to be protected in parallel sequences.
+        """
+        if self._local_data is not None and key in self._local_data:
+            self._local_data[key] = value
+            return
+
+        if self._parent is None:
+            assert self._local_data is not None  # top level always has local data
+            self._local_data[key] = value
+            return
+
+        if self._parallel_data is not None:
+            if parallel_protected:
+                self._parallel_data.protected[key] = value
+                return
+            self._parallel_data.protected.pop(key, None)
+            self._parallel_data.outer_scope_writes[key] = value
+
+        self._parent._assign(key, value, parallel_protected=parallel_protected)  # noqa: SLF001
+
+    def define_local(self, key: str, value: Any) -> None:
+        """Define a local variable and assign value to it."""
+        if self._local_data is None:
+            self._local_data = {}
+            self._non_parallel_scope = self._non_parallel_scope.new_child(
+                self._local_data
+            )
+            self._full_scope = self._full_scope.new_child(self._local_data)
+        self._local_data[key] = value
+
+    @property
+    def data(self) -> Mapping[str, Any]:  # type: ignore[override]
+        """Return variables in full scope.
+
+        Defined here for UserDict compatibility.
+        """
+        return self._full_scope
+
+    @property
+    def non_parallel_scope(self) -> Mapping[str, Any]:
+        """Return variables in non-parallel scope."""
+        return self._non_parallel_scope
+
+    @property
+    def local_scope(self) -> Mapping[str, Any]:
+        """Return variables in local scope."""
+        return self._local_data if self._local_data is not None else {}

tests/helpers/test_script.py

@@ -452,6 +452,68 @@ async def test_service_response_data_errors(
         await script_obj.async_run(context=context)
 
 
+async def test_calling_service_response_data_in_scopes(hass: HomeAssistant) -> None:
+    """Test response variable is still set after scopes end."""
+    expected_var = {"data": "value-12345"}
+
+    def mock_service(call: ServiceCall) -> ServiceResponse:
+        """Mock service call."""
+        if call.return_response:
+            return expected_var
+        return None
+
+    hass.services.async_register(
+        "test", "script", mock_service, supports_response=SupportsResponse.OPTIONAL
+    )
+
+    sequence = cv.SCRIPT_SCHEMA(
+        {
+            "parallel": [
+                {
+                    "alias": "Sequential group",
+                    "sequence": [
+                        {
+                            "alias": "variables",
+                            "variables": {"state": "off"},
+                        },
+                        {
+                            "alias": "service step1",
+                            "action": "test.script",
+                            "response_variable": "my_response",
+                        },
+                    ],
+                }
+            ]
+        }
+    )
+
+    script_obj = script.Script(hass, sequence, "Test Name", "test_domain")
+
+    result = await script_obj.async_run(context=Context())
+
+    assert result.variables["my_response"] == expected_var
+
+    expected_trace = {
+        "0": [{"variables": {"my_response": expected_var}}],
+        "0/parallel/0/sequence/0": [{"variables": {"state": "off"}}],
+        "0/parallel/0/sequence/1": [
+            {
+                "result": {
+                    "params": {
+                        "domain": "test",
+                        "service": "script",
+                        "service_data": {},
+                        "target": {},
+                    },
+                    "running_script": False,
+                },
+                "variables": {"my_response": expected_var},
+            }
+        ],
+    }
+    assert_action_trace(expected_trace)
+
+
 async def test_data_template_with_templated_key(hass: HomeAssistant) -> None:
     """Test the calling of a service with a data_template with a templated key."""
     context = Context()
@@ -1706,6 +1768,90 @@ async def test_wait_variables_out(hass: HomeAssistant, mode, action_type) -> Non
             assert float(remaining) == 0.0
 
 
+async def test_wait_in_sequence(hass: HomeAssistant) -> None:
+    """Test wait variable is still set after sequence ends."""
+    sequence = cv.SCRIPT_SCHEMA(
+        [
+            {
+                "alias": "Sequential group",
+                "sequence": [
+                    {
+                        "alias": "variables",
+                        "variables": {"state": "off"},
+                    },
+                    {
+                        "alias": "wait template",
+                        "wait_template": "{{ state == 'off' }}",
+                    },
+                ],
+            },
+        ]
+    )
+
+    script_obj = script.Script(hass, sequence, "Test Name", "test_domain")
+
+    result = await script_obj.async_run(context=Context())
+
+    expected_var = {"completed": True, "remaining": None}
+
+    assert result.variables["wait"] == expected_var
+
+    expected_trace = {
+        "0": [{"variables": {"wait": expected_var}}],
+        "0/sequence/0": [{"variables": {"state": "off"}}],
+        "0/sequence/1": [
+            {
+                "result": {"wait": expected_var},
+                "variables": {"wait": expected_var},
+            }
+        ],
+    }
+    assert_action_trace(expected_trace)
+
+
+async def test_wait_in_parallel(hass: HomeAssistant) -> None:
+    """Test wait variable is not set after parallel ends."""
+    sequence = cv.SCRIPT_SCHEMA(
+        {
+            "parallel": [
+                {
+                    "alias": "Sequential group",
+                    "sequence": [
+                        {
+                            "alias": "variables",
+                            "variables": {"state": "off"},
+                        },
+                        {
+                            "alias": "wait template",
+                            "wait_template": "{{ state == 'off' }}",
+                        },
+                    ],
+                }
+            ]
+        }
+    )
+
+    script_obj = script.Script(hass, sequence, "Test Name", "test_domain")
+
+    result = await script_obj.async_run(context=Context())
+
+    expected_var = {"completed": True, "remaining": None}
+
+    assert "wait" not in result.variables
+
+    expected_trace = {
+        "0": [{}],
+        "0/parallel/0/sequence/0": [{"variables": {"state": "off"}}],
+        "0/parallel/0/sequence/1": [
+            {
+                "result": {"wait": expected_var},
+                "variables": {"wait": expected_var},
+            }
+        ],
+    }
+    assert_action_trace(expected_trace)
+
+
 async def test_wait_for_trigger_bad(
     hass: HomeAssistant, caplog: pytest.LogCaptureFixture
 ) -> None:

tests/helpers/test_script_variables.py

@@ -5,12 +5,13 @@ import pytest
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import TemplateError
 from homeassistant.helpers import config_validation as cv
+from homeassistant.helpers.script_variables import ScriptRunVariables, ScriptVariables
 
 
 async def test_static_vars() -> None:
     """Test static vars."""
     orig = {"hello": "world"}
-    var = cv.SCRIPT_VARIABLES_SCHEMA(orig)
+    var = ScriptVariables(orig)
     rendered = var.async_render(None, None)
     assert rendered is not orig
     assert rendered == orig
@@ -20,31 +21,28 @@ async def test_static_vars_run_args() -> None:
     """Test static vars."""
     orig = {"hello": "world"}
     orig_copy = dict(orig)
-    var = cv.SCRIPT_VARIABLES_SCHEMA(orig)
+    var = ScriptVariables(orig)
     rendered = var.async_render(None, {"hello": "override", "run": "var"})
     assert rendered == {"hello": "override", "run": "var"}
     # Make sure we don't change original vars
     assert orig == orig_copy
 
 
-async def test_static_vars_no_default() -> None:
+async def test_static_vars_simple() -> None:
     """Test static vars."""
     orig = {"hello": "world"}
-    var = cv.SCRIPT_VARIABLES_SCHEMA(orig)
-    rendered = var.async_render(None, None, render_as_defaults=False)
-    assert rendered is not orig
-    assert rendered == orig
+    var = ScriptVariables(orig)
+    rendered = var.async_simple_render({})
+    assert rendered is orig
 
 
-async def test_static_vars_run_args_no_default() -> None:
+async def test_static_vars_run_args_simple() -> None:
     """Test static vars."""
     orig = {"hello": "world"}
     orig_copy = dict(orig)
-    var = cv.SCRIPT_VARIABLES_SCHEMA(orig)
-    rendered = var.async_render(
-        None, {"hello": "override", "run": "var"}, render_as_defaults=False
-    )
-    assert rendered == {"hello": "world", "run": "var"}
+    var = ScriptVariables(orig)
+    rendered = var.async_simple_render({"hello": "override", "run": "var"})
+    assert rendered is orig
     # Make sure we don't change original vars
     assert orig == orig_copy
 
@@ -78,14 +76,14 @@ async def test_template_vars_run_args(hass: HomeAssistant) -> None:
     }
 
 
-async def test_template_vars_no_default(hass: HomeAssistant) -> None:
+async def test_template_vars_simple(hass: HomeAssistant) -> None:
     """Test template vars."""
     var = cv.SCRIPT_VARIABLES_SCHEMA({"hello": "{{ 1 + 1 }}"})
-    rendered = var.async_render(hass, None, render_as_defaults=False)
+    rendered = var.async_simple_render({})
     assert rendered == {"hello": 2}
 
 
-async def test_template_vars_run_args_no_default(hass: HomeAssistant) -> None:
+async def test_template_vars_run_args_simple(hass: HomeAssistant) -> None:
     """Test template vars."""
     var = cv.SCRIPT_VARIABLES_SCHEMA(
         {
@@ -93,16 +91,13 @@ async def test_template_vars_run_args_no_default(hass: HomeAssistant) -> None:
             "something_2": "{{ run_var_ex + 1 }}",
         }
     )
-    rendered = var.async_render(
-        hass,
+    rendered = var.async_simple_render(
         {
             "run_var_ex": 5,
             "something_2": 1,
-        },
-        render_as_defaults=False,
+        }
     )
     assert rendered == {
-        "run_var_ex": 5,
         "something": 6,
         "something_2": 6,
     }
@@ -113,3 +108,90 @@ async def test_template_vars_error(hass: HomeAssistant) -> None:
     var = cv.SCRIPT_VARIABLES_SCHEMA({"hello": "{{ canont.work }}"})
     with pytest.raises(TemplateError):
         var.async_render(hass, None)
+
+
+async def test_script_vars_exit_top_level() -> None:
+    """Test exiting top level script run variables."""
+    script_vars = ScriptRunVariables.create_top_level()
+    with pytest.raises(ValueError):
+        script_vars.exit_scope()
+
+
+async def test_script_vars_delete_var() -> None:
+    """Test deleting from script run variables."""
+    script_vars = ScriptRunVariables.create_top_level({"x": 1, "y": 2})
+    with pytest.raises(TypeError):
+        del script_vars["x"]
+    with pytest.raises(TypeError):
+        script_vars.pop("y")
+    assert script_vars._full_scope == {"x": 1, "y": 2}
+
+
+async def test_script_vars_scopes() -> None:
+    """Test script run variables scopes."""
+    script_vars = ScriptRunVariables.create_top_level()
+    script_vars["x"] = 1
+    script_vars["y"] = 1
+    assert script_vars["x"] == 1
+    assert script_vars["y"] == 1
+
+    script_vars_2 = script_vars.enter_scope()
+    script_vars_2.define_local("x", 2)
+    assert script_vars_2["x"] == 2
+    assert script_vars_2["y"] == 1
+
+    script_vars_3 = script_vars_2.enter_scope()
+    script_vars_3["x"] = 3
+    script_vars_3["y"] = 3
+    assert script_vars_3["x"] == 3
+    assert script_vars_3["y"] == 3
+
+    script_vars_4 = script_vars_3.enter_scope()
+    assert script_vars_4["x"] == 3
+    assert script_vars_4["y"] == 3
+
+    assert script_vars_4.exit_scope() is script_vars_3
+
+    assert script_vars_3._full_scope == {"x": 3, "y": 3}
+    assert script_vars_3.local_scope == {}
+
+    assert script_vars_3.exit_scope() is script_vars_2
+
+    assert script_vars_2._full_scope == {"x": 3, "y": 3}
+    assert script_vars_2.local_scope == {"x": 3}
+
+    assert script_vars_2.exit_scope() is script_vars
+
+    assert script_vars._full_scope == {"x": 1, "y": 3}
+    assert script_vars.local_scope == {"x": 1, "y": 3}
+
+
+async def test_script_vars_parallel() -> None:
+    """Test script run variables parallel support."""
+    script_vars = ScriptRunVariables.create_top_level({"x": 1, "y": 1, "z": 1})
+
+    script_vars_2a = script_vars.enter_scope(parallel=True)
+    script_vars_3a = script_vars_2a.enter_scope()
+
+    script_vars_2b = script_vars.enter_scope(parallel=True)
+    script_vars_3b = script_vars_2b.enter_scope()
+
+    script_vars_3a["x"] = "a"
+    script_vars_3a.assign_parallel_protected("y", "a")
+
+    script_vars_3b["x"] = "b"
+    script_vars_3b.assign_parallel_protected("y", "b")
+
+    assert script_vars_3a._full_scope == {"x": "b", "y": "a", "z": 1}
+    assert script_vars_3a.non_parallel_scope == {"x": "a", "y": "a"}
+
+    assert script_vars_3b._full_scope == {"x": "b", "y": "b", "z": 1}
+    assert script_vars_3b.non_parallel_scope == {"x": "b", "y": "b"}
+
+    assert script_vars_3a.exit_scope() is script_vars_2a
+    assert script_vars_2a.exit_scope() is script_vars
+    assert script_vars_3b.exit_scope() is script_vars_2b
+    assert script_vars_2b.exit_scope() is script_vars
+
+    assert script_vars._full_scope == {"x": "b", "y": 1, "z": 1}
+    assert script_vars.local_scope == {"x": "b", "y": 1, "z": 1}