[Bugfix] properly handle nested json with llama3 tool parser (#27701)

Signed-off-by: Aydin Abiar <aydin@anyscale.com>
Signed-off-by: Aydin Abiar <62435714+Aydin-ab@users.noreply.github.com>
Co-authored-by: Aydin Abiar <aydin@anyscale.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Chauncey <chaunceyjiang@gmail.com>

tests/entrypoints/openai/tool_parsers/test_llama3_json_tool_parser.py

@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
+from unittest.mock import MagicMock, patch
+
 import pytest
 
 from vllm.entrypoints.openai.protocol import ExtractedToolCallInformation
@@ -132,3 +134,129 @@ def test_extract_tool_calls_multiple_json_with_surrounding_text(parser):
     assert result.tool_calls[0].function.name == "searchTool"
     assert result.tool_calls[1].function.name == "getOpenIncidentsTool"
     assert result.tool_calls[2].function.name == "searchTool"
+
+
+def test_extract_tool_calls_deeply_nested_json(parser):
+    # Test with deeply nested JSON parameters (5 levels)
+    model_output = (
+        '{"name": "complexTool", '
+        '"parameters": {'
+        '"level1": {'
+        '"level2": {'
+        '"level3": {'
+        '"level4": {'
+        '"value": "deep"'
+        "}}}}}}"
+    )
+    result = parser.extract_tool_calls(model_output, None)
+
+    assert result.tools_called is True
+    assert len(result.tool_calls) == 1
+    assert result.tool_calls[0].function.name == "complexTool"
+    # Verify the nested structure is preserved in the arguments
+    import json
+
+    args = json.loads(result.tool_calls[0].function.arguments)
+    assert args["level1"]["level2"]["level3"]["level4"]["value"] == "deep"
+
+
+def test_extract_tool_calls_multiple_with_deep_nesting(parser):
+    # Test with multiple tool calls where some have deeply nested parameters
+    model_output = (
+        '{"name": "simpleTool", "parameters": {"value": "test"}}; '
+        '{"name": "complexTool", "parameters": '
+        '{"config": {"database": {"connection": {"pool": {"size": 10}}}}}}'
+    )
+    result = parser.extract_tool_calls(model_output, None)
+
+    assert result.tools_called is True
+    assert len(result.tool_calls) == 2
+
+    # Check first tool call
+    assert result.tool_calls[0].function.name == "simpleTool"
+    import json
+
+    args0 = json.loads(result.tool_calls[0].function.arguments)
+    assert args0["value"] == "test"
+
+    # Check second tool call with deep nesting
+    assert result.tool_calls[1].function.name == "complexTool"
+    args1 = json.loads(result.tool_calls[1].function.arguments)
+    assert args1["config"]["database"]["connection"]["pool"]["size"] == 10
+
+
+def test_extract_tool_calls_with_quotes_and_brackets_in_string(parser):
+    # Test with quotes and brackets inside quoted string values
+    model_output = (
+        '{"name": "searchTool", '
+        '"parameters": {'
+        '"query": "test {value} [complex]",'
+        '"nested": {"inner": "more {brackets}"}'
+        "}}"
+    )
+    result = parser.extract_tool_calls(model_output, None)
+
+    assert result.tools_called is True
+    assert len(result.tool_calls) == 1
+    assert result.tool_calls[0].function.name == "searchTool"
+    # Verify the string values are preserved including brackets and quotes
+    import json
+
+    args = json.loads(result.tool_calls[0].function.arguments)
+    assert args["query"] == "test {value} [complex]"
+    assert args["nested"]["inner"] == "more {brackets}"
+
+
+def test_extract_tool_calls_with_escaped_quotes_in_nested_json(parser):
+    # Test with escaped quotes in deeply nested JSON
+    model_output = (
+        '{"name": "parserTool", "parameters": {"text": "He said \\"Hello {world}\\""}}'
+    )
+    result = parser.extract_tool_calls(model_output, None)
+
+    assert result.tools_called is True
+    assert len(result.tool_calls) == 1
+    assert result.tool_calls[0].function.name == "parserTool"
+    # Verify escaped quotes are preserved
+    import json
+
+    args = json.loads(result.tool_calls[0].function.arguments)
+    assert args["text"] == 'He said "Hello {world}"'
+
+
+def test_extract_tool_calls_missing_name_key(parser):
+    # Test that missing "name" key returns content
+    model_output = '{"parameters": {}}'
+    result = parser.extract_tool_calls(model_output, None)
+
+    assert result.tools_called is False
+    assert len(result.tool_calls) == 0
+    assert result.content == model_output
+
+
+def test_extract_tool_calls_missing_parameters_and_arguments_key(parser):
+    # Test that missing both "parameters" and "arguments" keys returns content
+    model_output = '{"name": "toolWithoutParams"}'
+    result = parser.extract_tool_calls(model_output, None)
+
+    assert result.tools_called is False
+    assert len(result.tool_calls) == 0
+    assert result.content == model_output
+
+
+def test_regex_timeout_handling(parser):
+    """Test regex timeout is handled gracefully"""
+    fake_problematic_input = "{hello world[A(A=" + "\t)A(A=,\t" * 2
+
+    # create a mock regex that raises TimeoutError
+    mock_regex = MagicMock()
+    mock_regex.finditer.side_effect = TimeoutError("Regex timeout")
+
+    with patch.object(parser, "tool_call_start_regex", mock_regex):
+        result = parser.extract_tool_calls(fake_problematic_input, None)
+
+        # should treat as regular text when regex times out
+        assert result.content == fake_problematic_input
+        assert result.tools_called is False
+        assert len(result.tool_calls) == 0
+        mock_regex.finditer.assert_called_once()