fix: Port eval identifier validation and persona template rendering to v1

src/google/adk/evaluation/_path_validation.py

@@ -0,0 +1,40 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+
+def validate_path_segment(value: str, field_name: str) -> None:
+  """Rejects values that could alter a filesystem path.
+
+  Args:
+    value: The caller-supplied identifier.
+    field_name: Human-readable field name used in error messages.
+
+  Raises:
+    ValueError: If the value contains path separators, traversal segments, or
+      null bytes.
+  """
+  if not value:
+    raise ValueError(f"{field_name} must not be empty.")
+  if "\x00" in value:
+    raise ValueError(f"{field_name} must not contain null bytes.")
+  if "/" in value or "\\" in value:
+    raise ValueError(
+        f"{field_name} {value!r} must not contain path separators."
+    )
+  if value in (".", ".."):
+    raise ValueError(
+        f"{field_name} {value!r} must not contain traversal segments."
+    )

src/google/adk/evaluation/gcs_eval_set_results_manager.py

@@ -23,6 +23,7 @@
 from ..errors.not_found_error import NotFoundError
 from ._eval_set_results_manager_utils import create_eval_set_result
 from ._eval_set_results_manager_utils import parse_eval_set_result_json
+from ._path_validation import validate_path_segment
 from .eval_result import EvalCaseResult
 from .eval_result import EvalSetResult
 from .eval_set_results_manager import EvalSetResultsManager
@@ -54,11 +55,13 @@ def __init__(self, bucket_name: str, **kwargs):
       )
 
   def _get_eval_history_dir(self, app_name: str) -> str:
+    validate_path_segment(app_name, "app_name")
     return f"{app_name}/{_EVAL_HISTORY_DIR}"
 
   def _get_eval_set_result_blob_name(
       self, app_name: str, eval_set_result_id: str
   ) -> str:
+    validate_path_segment(eval_set_result_id, "eval_set_result_id")
     eval_history_dir = self._get_eval_history_dir(app_name)
     return f"{eval_history_dir}/{eval_set_result_id}{_EVAL_SET_RESULT_FILE_EXTENSION}"
 
@@ -80,6 +83,8 @@ def save_eval_set_result(
       eval_case_results: list[EvalCaseResult],
   ) -> None:
     """Creates and saves a new EvalSetResult given eval_case_results."""
+    validate_path_segment(app_name, "app_name")
+    validate_path_segment(eval_set_id, "eval_set_id")
     eval_set_result = create_eval_set_result(
         app_name, eval_set_id, eval_case_results
     )

src/google/adk/evaluation/gcs_eval_sets_manager.py

@@ -29,6 +29,7 @@
 from ._eval_sets_manager_utils import get_eval_case_from_eval_set
 from ._eval_sets_manager_utils import get_eval_set_from_app_and_id
 from ._eval_sets_manager_utils import update_eval_case_in_eval_set
+from ._path_validation import validate_path_segment
 from .eval_case import EvalCase
 from .eval_set import EvalSet
 from .eval_sets_manager import EvalSetsManager
@@ -60,9 +61,11 @@ def __init__(self, bucket_name: str, **kwargs):
       )
 
   def _get_eval_sets_dir(self, app_name: str) -> str:
+    validate_path_segment(app_name, "app_name")
     return f"{app_name}/{_EVAL_SETS_DIR}"
 
   def _get_eval_set_blob_name(self, app_name: str, eval_set_id: str) -> str:
+    validate_path_segment(eval_set_id, "eval_set_id")
     eval_sets_dir = self._get_eval_sets_dir(app_name)
     return f"{eval_sets_dir}/{eval_set_id}{_EVAL_SET_FILE_EXTENSION}"
 

src/google/adk/evaluation/local_eval_set_results_manager.py

@@ -22,6 +22,7 @@
 from ..errors.not_found_error import NotFoundError
 from ._eval_set_results_manager_utils import create_eval_set_result
 from ._eval_set_results_manager_utils import parse_eval_set_result_json
+from ._path_validation import validate_path_segment
 from .eval_result import EvalCaseResult
 from .eval_result import EvalSetResult
 from .eval_set_results_manager import EvalSetResultsManager
@@ -46,6 +47,8 @@ def save_eval_set_result(
       eval_case_results: list[EvalCaseResult],
   ) -> None:
     """Creates and saves a new EvalSetResult given eval_case_results."""
+    validate_path_segment(app_name, "app_name")
+    validate_path_segment(eval_set_id, "eval_set_id")
     eval_set_result = create_eval_set_result(
         app_name, eval_set_id, eval_case_results
     )
@@ -67,6 +70,7 @@ def get_eval_set_result(
       self, app_name: str, eval_set_result_id: str
   ) -> EvalSetResult:
     """Returns an EvalSetResult identified by app_name and eval_set_result_id."""
+    validate_path_segment(eval_set_result_id, "eval_set_result_id")
     # Load the eval set result file data.
     maybe_eval_result_file_path = (
         os.path.join(
@@ -97,4 +101,5 @@ def list_eval_set_results(self, app_name: str) -> list[str]:
     return eval_result_files
 
   def _get_eval_history_dir(self, app_name: str) -> str:
+    validate_path_segment(app_name, "app_name")
     return os.path.join(self._agents_dir, app_name, _ADK_EVAL_HISTORY_DIR)

src/google/adk/evaluation/local_eval_sets_manager.py

@@ -33,6 +33,7 @@
 from ._eval_sets_manager_utils import get_eval_case_from_eval_set
 from ._eval_sets_manager_utils import get_eval_set_from_app_and_id
 from ._eval_sets_manager_utils import update_eval_case_in_eval_set
+from ._path_validation import validate_path_segment
 from .eval_case import EvalCase
 from .eval_case import IntermediateData
 from .eval_case import Invocation
@@ -247,6 +248,7 @@ def list_eval_sets(self, app_name: str) -> list[str]:
     Raises:
       NotFoundError: If the eval directory for the app is not found.
     """
+    validate_path_segment(app_name, "app_name")
     eval_set_file_path = os.path.join(self._agents_dir, app_name)
     eval_sets = []
     try:
@@ -310,6 +312,8 @@ def delete_eval_case(
     self._save_eval_set(app_name, eval_set_id, updated_eval_set)
 
   def _get_eval_set_file_path(self, app_name: str, eval_set_id: str) -> str:
+    validate_path_segment(app_name, "app_name")
+    validate_path_segment(eval_set_id, "eval_set_id")
     return os.path.join(
         self._agents_dir,
         app_name,

src/google/adk/evaluation/simulation/llm_backed_user_simulator_prompts.py

@@ -185,7 +185,6 @@ def get_llm_backed_user_simulator_prompt(
   """Formats the prompt for the llm-backed user simulator"""
   from jinja2 import DictLoader
   from jinja2 import pass_context
-  from jinja2 import Template
   from jinja2.sandbox import SandboxedEnvironment
 
   templates = {
@@ -200,7 +199,7 @@ def get_llm_backed_user_simulator_prompt(
   def _render_string_filter(context, template_string):
     if not template_string:
       return ""
-    return Template(template_string).render(context)
+    return template_env.from_string(template_string).render(context.get_all())
 
   template_env.filters["render_string_filter"] = _render_string_filter
 

src/google/adk/evaluation/simulation/per_turn_user_simulator_quality_prompts.py

@@ -221,9 +221,8 @@ def get_per_turn_user_simulator_quality_prompt(
 ):
   """Formats the prompt for the per turn user simulator evaluator"""
   from jinja2 import DictLoader
-  from jinja2 import Environment
   from jinja2 import pass_context
-  from jinja2 import Template
+  from jinja2.sandbox import SandboxedEnvironment
 
   templates = {
       "verifier_instructions": (
@@ -232,13 +231,13 @@ def get_per_turn_user_simulator_quality_prompt(
           )
       ),
   }
-  template_env = Environment(loader=DictLoader(templates))
+  template_env = SandboxedEnvironment(loader=DictLoader(templates))
 
   @pass_context
   def _render_string_filter(context, template_string):
     if not template_string:
       return ""
-    return Template(template_string).render(context)
+    return template_env.from_string(template_string).render(context.get_all())
 
   template_env.filters["render_string_filter"] = _render_string_filter
 

tests/unittests/evaluation/simulation/test_llm_backed_user_simulator_prompts.py

@@ -21,6 +21,7 @@
 from google.adk.evaluation.simulation.llm_backed_user_simulator_prompts import is_valid_user_simulator_template
 from google.adk.evaluation.simulation.user_simulator_personas import UserBehavior
 from google.adk.evaluation.simulation.user_simulator_personas import UserPersona
+from jinja2.exceptions import SecurityError
 import pytest
 
 _MOCK_DEFAULT_TEMPLATE = textwrap.dedent("""\
@@ -208,6 +209,57 @@ def test_get_llm_backed_user_simulator_prompt_with_persona(self, mocker):
       test stop""").strip()
     assert prompt == expected_prompt
 
+  def test_get_llm_backed_user_simulator_prompt_renders_persona_templates_in_sandbox(
+      self,
+  ):
+    user_persona = UserPersona(
+        id="test_persona",
+        description="Test persona description",
+        behaviors=[
+            UserBehavior(
+                name="Behavior {{ stop_signal }}",
+                description="Description {{ stop_signal }}",
+                behavior_instructions=["instruction {{ stop_signal }}"],
+                violation_rubrics=["rubric 1"],
+            )
+        ],
+    )
+
+    prompt = get_llm_backed_user_simulator_prompt(
+        conversation_plan="test plan",
+        conversation_history="test history",
+        stop_signal="test stop",
+        user_persona=user_persona,
+    )
+
+    assert "## Behavior test stop" in prompt
+    assert "Description test stop" in prompt
+    assert "  * instruction test stop" in prompt
+
+  def test_get_llm_backed_user_simulator_prompt_blocks_unsafe_persona_templates(
+      self,
+  ):
+    user_persona = UserPersona(
+        id="test_persona",
+        description="Test persona description",
+        behaviors=[
+            UserBehavior(
+                name="{{ ''.__class__.__mro__ }}",
+                description="Test behavior description",
+                behavior_instructions=["instruction 1"],
+                violation_rubrics=["rubric 1"],
+            )
+        ],
+    )
+
+    with pytest.raises(SecurityError):
+      get_llm_backed_user_simulator_prompt(
+          conversation_plan="test plan",
+          conversation_history="test history",
+          stop_signal="test stop",
+          user_persona=user_persona,
+      )
+
 
 class TestIsValidUserSimulatorTemplate:
   """Test cases for is_valid_user_simulator_template."""

tests/unittests/evaluation/simulation/test_per_turn_user_simulation_quality_prompts.py

@@ -20,6 +20,8 @@
 from google.adk.evaluation.simulation.per_turn_user_simulator_quality_prompts import get_per_turn_user_simulator_quality_prompt
 from google.adk.evaluation.simulation.user_simulator_personas import UserBehavior
 from google.adk.evaluation.simulation.user_simulator_personas import UserPersona
+from jinja2.exceptions import SecurityError
+import pytest
 
 _MOCK_DEFAULT_TEMPLATE = textwrap.dedent("""\
   Default template
@@ -182,3 +184,56 @@ def test_get_per_turn_user_simulator_quality_prompt_with_persona(
       # Stop signal
       stop""").strip()
     assert prompt == expected_prompt
+
+  def test_get_per_turn_user_simulator_quality_prompt_renders_persona_templates_in_sandbox(
+      self,
+  ):
+    persona = UserPersona(
+        id="test_persona",
+        description="Test persona description.",
+        behaviors=[
+            UserBehavior(
+                name="criteria {{ stop_signal }}",
+                description="Test behavior {{ stop_signal }}.",
+                behavior_instructions=["instruction1"],
+                violation_rubrics=["violation {{ stop_signal }}"],
+            )
+        ],
+    )
+
+    prompt = get_per_turn_user_simulator_quality_prompt(
+        conversation_plan="plan",
+        conversation_history="history",
+        generated_user_response="response",
+        stop_signal="stop",
+        user_persona=persona,
+    )
+
+    assert "## Criteria: criteria stop" in prompt
+    assert "Test behavior stop." in prompt
+    assert "  * violation stop" in prompt
+
+  def test_get_per_turn_user_simulator_quality_prompt_blocks_unsafe_persona_templates(
+      self,
+  ):
+    persona = UserPersona(
+        id="test_persona",
+        description="Test persona description.",
+        behaviors=[
+            UserBehavior(
+                name="{{ ''.__class__.__mro__ }}",
+                description="Test behavior description.",
+                behavior_instructions=["instruction1"],
+                violation_rubrics=["violation1"],
+            )
+        ],
+    )
+
+    with pytest.raises(SecurityError):
+      get_per_turn_user_simulator_quality_prompt(
+          conversation_plan="plan",
+          conversation_history="history",
+          generated_user_response="response",
+          stop_signal="stop",
+          user_persona=persona,
+      )

tests/unittests/evaluation/test__path_validation.py

@@ -0,0 +1,52 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+from google.adk.evaluation._path_validation import validate_path_segment
+import pytest
+
+
+@pytest.mark.parametrize(
+    "value", ["eval_set_1", "my-app", "App Name 1", "résumé", "a.b.c"]
+)
+def test_validate_path_segment_accepts_valid_value(value):
+  validate_path_segment(value, "field")
+
+
+def test_validate_path_segment_rejects_empty():
+  with pytest.raises(ValueError, match="must not be empty"):
+    validate_path_segment("", "field")
+
+
+def test_validate_path_segment_rejects_null_byte():
+  with pytest.raises(ValueError, match="must not contain null bytes"):
+    validate_path_segment("foo\x00bar", "field")
+
+
+@pytest.mark.parametrize("value", ["foo/bar", "foo\\bar", "/", "\\"])
+def test_validate_path_segment_rejects_path_separators(value):
+  with pytest.raises(ValueError, match="must not contain path separators"):
+    validate_path_segment(value, "field")
+
+
+@pytest.mark.parametrize("value", [".", ".."])
+def test_validate_path_segment_rejects_traversal_segments(value):
+  with pytest.raises(ValueError, match="must not contain traversal segments"):
+    validate_path_segment(value, "field")
+
+
+def test_validate_path_segment_includes_field_name_in_error():
+  with pytest.raises(ValueError, match="eval_set_id"):
+    validate_path_segment("", "eval_set_id")