🐛 fix incorrect parsing of nested params with closing square bracket ] in the property name

pyproject.toml

@@ -37,6 +37,10 @@ classifiers = [
     "Topic :: Internet :: WWW/HTTP",
     "Topic :: Software Development :: Libraries",
 ]
+dependencies = [
+    "regex>=2024.4.16",
+    "types-regex>=2024.4.16.20240423",
+]
 dynamic = ["version"]
 
 [project.urls]

requirements_dev.txt

@@ -1,4 +1,6 @@
-pytest>=8.1.1
+regex>=2024.4.16
+types-regex>=2024.4.16.20240423
+pytest>=8.1.2
 pytest-cov>=5.0.0
 mypy>=1.10.0
 toml>=0.10.2

src/qs_codec/decode.py

@@ -4,6 +4,8 @@
 import typing as t
 from math import isinf
 
+from regex import regex
+
 from .enums.charset import Charset
 from .enums.duplicates import Duplicates
 from .enums.sentinel import Sentinel
@@ -159,10 +161,10 @@ def _parse_keys(given_key: t.Optional[str], val: t.Any, options: DecodeOptions,
     key: str = re.sub(r"\.([^.[]+)", r"[\1]", given_key) if options.allow_dots else given_key
 
     # The regex chunks
-    brackets: re.Pattern[str] = re.compile(r"(\[[^[\]]*])")
+    brackets: regex.Pattern[str] = regex.compile(r"\[(?:[^\[\]]|(?R))*\]")
 
     # Get the parent
-    segment: t.Optional[t.Match] = brackets.search(key) if options.depth > 0 else None
+    segment: t.Optional[regex.Match] = brackets.search(key) if options.depth > 0 else None
     parent: str = key[0 : segment.start()] if segment is not None else key
 
     # Stash the parent if it exists
@@ -173,7 +175,7 @@ def _parse_keys(given_key: t.Optional[str], val: t.Any, options: DecodeOptions,
     while options.depth > 0 and (segment := brackets.search(key)) is not None and i < options.depth:
         i += 1
         if segment is not None:
-            keys.append(segment.group(1))
+            keys.append(segment.group())
             # Update the key to start searching from the next position
             key = key[segment.end() :]
 

tests/unit/fixed_qs_issues_test.py

@@ -0,0 +1,14 @@
+import typing as t
+
+from qs_codec import EncodeOptions, decode, encode
+
+
+class TestFixedQsIssues:
+    """Test cases for fixed issues."""
+
+    def test_qs_issue_493(self) -> None:
+        """Test case for https://github.com/ljharb/qs/issues/493"""
+        original: t.Dict[str, t.Any] = {"search": {"withbracket[]": "foobar"}}
+        encoded: str = "search[withbracket[]]=foobar"
+        assert encode(original, options=EncodeOptions(encode=False)) == encoded
+        assert decode(encoded) == original