From 43b8238503e6fe6389fa09f3f335dc031351eb1a Mon Sep 17 00:00:00 2001
From: Filip Uhlik <filip.uhlik@rossum.ai>
Date: Thu, 1 Jun 2023 21:48:52 +0200
Subject: [PATCH] [#186] options: add default not found value option

---
 jmespath/visitor.py  | 7 ++++---
 tests/test_search.py | 7 +++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/jmespath/visitor.py b/jmespath/visitor.py
index 15fb1774..f3a41009 100644
--- a/jmespath/visitor.py
+++ b/jmespath/visitor.py
@@ -58,7 +58,7 @@ def _is_actual_number(x):
 
 class Options(object):
     """Options to control how a JMESPath function is evaluated."""
-    def __init__(self, dict_cls=None, custom_functions=None):
+    def __init__(self, dict_cls=None, custom_functions=None, not_found_value=None):
         #: The class to use when creating a dict.  The interpreter
         #  may create dictionaries during the evaluation of a JMESPath
         #  expression.  For example, a multi-select hash will
@@ -69,6 +69,7 @@ def __init__(self, dict_cls=None, custom_functions=None):
         #  have predictable key ordering.
         self.dict_cls = dict_cls
         self.custom_functions = custom_functions
+        self.not_found_value = not_found_value
 
 
 class _Expression(object):
@@ -133,9 +134,9 @@ def visit_subexpression(self, node, value):
 
     def visit_field(self, node, value):
         try:
-            return value.get(node['value'])
+            return value.get(node['value'], self._options.not_found_value)
         except AttributeError:
-            return None
+            return self._options.not_found_value
 
     def visit_comparator(self, node, value):
         # Common case: comparator is == or !=
diff --git a/tests/test_search.py b/tests/test_search.py
index 4832079b..c8507078 100644
--- a/tests/test_search.py
+++ b/tests/test_search.py
@@ -62,3 +62,10 @@ def test_can_handle_decimals_as_numeric_type(self):
         result = decimal.Decimal('3')
         self.assertEqual(jmespath.search('[?a >= `1`].a', [{'a': result}]),
                          [result])
+
+
+class TestNotFoundValueOption(unittest.TestCase):
+    def test_can_supply_custom_not_found_value(self):
+        opt = jmespath.Options(not_found_value='foo')
+        value = jmespath.search('b', {'a': 1}, opt)
+        self.assertEqual(value, 'foo')