From 0fb58e0978918e54013f83873156d222038201cc Mon Sep 17 00:00:00 2001
From: Himanshu <hemanshudhaduk406@gmail.com>
Date: Mon, 19 Oct 2026 14:36:47 +0530
Subject: [PATCH 1/2] Handle brackets in collection file paths

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 AUTHORS              |  1 +
 src/_pytest/main.py  | 16 ++++++++++++----
 testing/test_main.py | 17 +++++++++++++++++
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index bd1e27cb37d..42942c8c84b 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -211,6 +211,7 @@ Harald Armin Massa
 Harshna
 Henk-Jaap Wagenaar
 Henry Schreiner
+Himanshu
 Holger Kohr
 Hugo van Kemenade
 Hui Wang (coldnight)
diff --git a/src/_pytest/main.py b/src/_pytest/main.py
index d43a68b4679..554db2dfbeb 100644
--- a/src/_pytest/main.py
+++ b/src/_pytest/main.py
@@ -1152,11 +1152,19 @@ def resolve_collection_argument(
     If the path doesn't exist, raise UsageError.
     If the path is a directory and selection parts are present, raise UsageError.
     """
-    base, squacket, rest = arg.partition("[")
-    strpath, *parts = base.split("::")
-    if squacket and not parts:
+    selection_start = arg.find("::")
+    strpath = arg if selection_start == -1 else arg[:selection_start]
+    if "[" in strpath and not safe_exists(absolutepath(invocation_path / strpath)):
         raise UsageError(f"path cannot contain [] parametrization: {arg}")
-    parametrization = f"{squacket}{rest}" if squacket else None
+
+    path_and_parts = arg
+    parametrization = None
+    if selection_start != -1:
+        parametrization_start = arg.find("[", selection_start + 2)
+        if parametrization_start != -1:
+            path_and_parts = arg[:parametrization_start]
+            parametrization = arg[parametrization_start:]
+    strpath, *parts = path_and_parts.split("::")
     module_name = None
     if as_pypath:
         pyarg_strpath = search_pypath(
diff --git a/testing/test_main.py b/testing/test_main.py
index 41d7055df26..46fcb3b648b 100644
--- a/testing/test_main.py
+++ b/testing/test_main.py
@@ -166,6 +166,23 @@ def test_file(self, invocation_path: Path) -> None:
             original_index=40,
         )
 
+    def test_file_with_brackets_in_name(
+        self, invocation_path: Path, pytester: Pytester
+    ) -> None:
+        path = invocation_path / "src/pkg/test_[helper].py"
+        path.write_text("def test_example(): pass\n", encoding="utf-8")
+
+        assert resolve_collection_argument(invocation_path, str(path), 0) == (
+            CollectionArgument(
+                path=path,
+                parts=[],
+                parametrization=None,
+                module_name=None,
+                original_index=0,
+            )
+        )
+        pytester.runpytest(str(path)).assert_outcomes(passed=1)
+
     def test_dir(self, invocation_path: Path) -> None:
         """Directory and parts."""
         assert resolve_collection_argument(

From d9ba697f395b5d5b2609c6f8ddf05615e6bfd23e Mon Sep 17 00:00:00 2001
From: Himanshu <hemanshudhaduk406@gmail.com>
Date: Mon, 19 Oct 2026 15:10:46 +0530
Subject: [PATCH 2/2] Add changelog for PR 15217

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 changelog/15217.bugfix.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog/15217.bugfix.rst

diff --git a/changelog/15217.bugfix.rst b/changelog/15217.bugfix.rst
new file mode 100644
index 00000000000..f81a7b2f07d
--- /dev/null
+++ b/changelog/15217.bugfix.rst
@@ -0,0 +1 @@
+Fixed test collection for Python files whose names contain square brackets.