Fix handling of special yaml values in config.

Author: nubtron

datadog_checks_base/datadog_checks/base/checks/base.py

@@ -1490,7 +1490,8 @@ def load_config(yaml_str: str) -> Any:
 
         decoded = stdout.strip().decode()
         try:
-            return eval(decoded)
+            special_values = {"nan": float("nan"), "inf": float("inf"), "-inf": float("-inf")}
+            return eval(decoded, special_values)
         # a single, literal unquoted string
         except Exception:
             return decoded

datadog_checks_base/tests/base/checks/test_agent_check.py

@@ -5,6 +5,7 @@
 # Licensed under a 3-clause BSD style license (see LICENSE)
 import json
 import logging
+import math
 import os
 import re
 from typing import Any  # noqa: F401
@@ -50,6 +51,39 @@ def test_load_config():
         AgentCheck.load_config(':')
 
 
+def test_parse_special_values_in_load_config():
+    assert AgentCheck.load_config("boolean: true") == {"boolean": True}
+    assert AgentCheck.load_config("boolean: false") == {"boolean": False}
+
+    assert AgentCheck.load_config("number: .inf") == {"number": float("inf")}
+    assert AgentCheck.load_config("number: .INF") == {"number": float("inf")}
+
+    assert AgentCheck.load_config("number: -.inf") == {"number": float("-inf")}
+    assert AgentCheck.load_config("number: -.INF") == {"number": float("-inf")}
+
+    assert AgentCheck.load_config("number: 0xF") == {"number": 15.0}  # Hexadecimal
+    assert AgentCheck.load_config("number: 0b1111") == {"number": 15.0}  # Binary
+
+    assert AgentCheck.load_config("number: !!int 1 ") == {"number": 1}
+    assert isinstance(AgentCheck.load_config("number: !!int 1 ")["number"], int)
+
+    assert AgentCheck.load_config("number: !!float 1 ") == {"number": 1}
+    assert isinstance(AgentCheck.load_config("number: !!float 1 ")["number"], float)
+
+    # Check that "inf" is still a string
+    assert AgentCheck.load_config("string: inf") == {"string": "inf"}
+    assert isinstance(AgentCheck.load_config("string: inf")["string"], str)
+
+    # Check that quoted ".inf" is still a string
+    assert AgentCheck.load_config("string: \".inf\"") == {"string": ".inf"}
+    assert isinstance(AgentCheck.load_config("string: \".inf\"")["string"], str)
+
+    # nan values are not equal to themselves
+    config = AgentCheck.load_config("number: .nan")
+    assert "number" in config
+    assert math.isnan(config["number"])
+
+
 def test_persistent_cache(datadog_agent):
     check = AgentCheck()
     check.check_id = 'test'