Fix for brace-trimming regression (#108)

* adds tests for tokenized paths
* only strip a trailing } when it’s truly unmatched

Author: rsgalloway

lib/envstack/util.py

@@ -355,13 +355,15 @@ def evaluate_modifiers(
         resolving = set()
 
     def sanitize_value(value):
-        # sanitize the value to ensure it is a string or a path
         if (
             isinstance(value, str)
             and value.endswith("}")
             and not value.startswith("${")
         ):
-            return value.rstrip("}")
+            # trim a dangling '}' when there's no matching '{'
+            if value.count("{") == 0 and value.count("}") == 1:
+                return value.rstrip("}")
+            return value
         elif isinstance(value, str) and detect_path(value):
             return dedupe_paths(value)
         return value

tests/test_util.py

@@ -124,6 +124,61 @@ def test_pathlike_value_colon_separated(self):
         result = evaluate_modifiers(expression, environ)
         self.assertEqual(result, f"/usr/local/lib/env{os.pathsep}/mnt/env")
 
+    def test_tokenized_value_single(self):
+        """Test tokenized value with a single token."""
+        expression = "${ROOT}/{foo}"
+        environ = {
+            "ROOT": "/var/tmp",
+        }
+        result = evaluate_modifiers(expression, environ)
+        self.assertEqual(
+            result, r"/var/tmp/{foo}"
+        )
+
+    def test_tokenized_value_trailing_slash(self):
+        """Test tokenized value with a single token and trailing slash."""
+        expression = "${ROOT}/{foo}/"
+        environ = {
+            "ROOT": "/var/tmp",
+        }
+        result = evaluate_modifiers(expression, environ)
+        self.assertEqual(
+            result, r"/var/tmp/{foo}/"
+        )
+
+    def test_tokenized_value_two_tokens(self):
+        """Test tokenized value with two tokens."""
+        expression = "${ROOT}/{foo}/{bar}"
+        environ = {
+            "ROOT": "/var/tmp",
+        }
+        result = evaluate_modifiers(expression, environ)
+        self.assertEqual(
+            result, r"/var/tmp/{foo}/{bar}"
+        )
+
+    def test_tokenized_value_three_tokens(self):
+        """Test tokenized value with three tokens."""
+        expression = "${ROOT}/{foo}/{bar}/{baz}"
+        environ = {
+            "ROOT": "/var/tmp",
+        }
+        result = evaluate_modifiers(expression, environ)
+        self.assertEqual(
+            result, r"/var/tmp/{foo}/{bar}/{baz}"
+        )
+
+    def test_tokenized_value_three_tokens_slash(self):
+        """Test tokenized value with three tokens and a trailing slash."""
+        expression = "${ROOT}/{foo}/{bar}/{baz}/"
+        environ = {
+            "ROOT": "/var/tmp",
+        }
+        result = evaluate_modifiers(expression, environ)
+        self.assertEqual(
+            result, r"/var/tmp/{foo}/{bar}/{baz}/"
+        )
+
     def test_default_value_with_default_args(self):
         """Test default value with default args."""
         expression = "${HELLO:=world}"