From 111202286995334e0a9aa8104d6879f3b0ddd106 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bern=C3=A1t=20G=C3=A1bor?= <gaborjbernat@gmail.com>
Date: Mon, 2 Nov 2026 16:59:15 -0800
Subject: [PATCH 1/2] =?UTF-8?q?=F0=9F=90=9B=20fix(py-info):=20stop=20repea?=
 =?UTF-8?q?ted=20base=20probes?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

A candidate can report the same base directory with changing path
spellings and evade the prefix cycle check. Compare canonical paths
while keeping the reported path for interpreter discovery.
---
 docs/changelog/190.bugfix.rst    |  1 +
 src/python_discovery/_py_info.py |  6 ++++--
 tests/test_py_info_extra.py      | 15 +++++++++++++++
 3 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 docs/changelog/190.bugfix.rst

diff --git a/docs/changelog/190.bugfix.rst b/docs/changelog/190.bugfix.rst
new file mode 100644
index 0000000..1297457
--- /dev/null
+++ b/docs/changelog/190.bugfix.rst
@@ -0,0 +1 @@
+Stop repeated interpreter queries when a virtual environment reports the same base prefix with different path spellings.
diff --git a/src/python_discovery/_py_info.py b/src/python_discovery/_py_info.py
index 09733de..f4d26b1 100644
--- a/src/python_discovery/_py_info.py
+++ b/src/python_discovery/_py_info.py
@@ -10,6 +10,7 @@
 import sys
 from collections import OrderedDict
 from itertools import product
+from os.path import normcase, realpath
 from string import digits
 from typing import TYPE_CHECKING, ClassVar, Final, NamedTuple, TypedDict
 
@@ -462,7 +463,8 @@ def resolve_to_system(cls, cache: PyInfoCache | None, target: PythonInfo) -> Pyt
         prefixes = OrderedDict()
         while target.system_executable is None:
             prefix = target.real_prefix or target.base_prefix or target.prefix
-            if prefix in prefixes:
+            prefix_key = normcase(realpath(prefix))
+            if prefix_key in prefixes:
                 if len(prefixes) == 1:
                     _LOGGER.info("%r links back to itself via prefixes", target)
                     target.system_executable = target.executable
@@ -472,7 +474,7 @@ def resolve_to_system(cls, cache: PyInfoCache | None, target: PythonInfo) -> Pyt
                 _LOGGER.error("%d: prefix=%s, info=%r", len(prefixes) + 1, prefix, target)
                 msg = "prefixes are causing a circle {}".format("|".join(prefixes.keys()))
                 raise RuntimeError(msg)
-            prefixes[prefix] = target
+            prefixes[prefix_key] = target
             target = target.discover_exe(cache, prefix=prefix, exact=False)
         if target.executable != target.system_executable:
             resolved = cls.from_exe(target.system_executable, cache)
diff --git a/tests/test_py_info_extra.py b/tests/test_py_info_extra.py
index 016636a..deedb5a 100644
--- a/tests/test_py_info_extra.py
+++ b/tests/test_py_info_extra.py
@@ -168,6 +168,21 @@ def test_resolve_to_system_single_prefix_self_link(mocker: MockerFixture, caplog
     assert any("links back to itself" in r.message for r in caplog.records)
 
 
+def test_resolve_to_system_repeated_prefix_with_parent_segments(tmp_path: Path, mocker: MockerFixture) -> None:
+    (tmp_path / "child").mkdir()
+    target = PythonInfo()
+    target.system_executable = target.real_prefix = None
+    target.base_prefix = str(tmp_path)
+    repeated = PythonInfo()
+    repeated.system_executable = repeated.real_prefix = None
+    repeated.base_prefix = str(tmp_path / "child" / "..")
+    mocker.patch.object(PythonInfo, "discover_exe", return_value=repeated)
+
+    result = PythonInfo.resolve_to_system(None, target)
+
+    assert result.system_executable == repeated.executable
+
+
 def test_discover_exe_cache_hit() -> None:
     info = copy.deepcopy(CURRENT)
     cached = copy.deepcopy(CURRENT)

From 68e57e08565e25d3ee470a6579687c961a93d685 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bern=C3=A1t=20G=C3=A1bor?= <gaborjbernat@gmail.com>
Date: Mon, 2 Nov 2026 17:02:12 -0800
Subject: [PATCH 2/2] =?UTF-8?q?=F0=9F=93=9D=20docs(news):=20link=20prefix?=
 =?UTF-8?q?=20fix=20to=20PR=20219?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/changelog/{190.bugfix.rst => 219.bugfix.rst} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename docs/changelog/{190.bugfix.rst => 219.bugfix.rst} (100%)

diff --git a/docs/changelog/190.bugfix.rst b/docs/changelog/219.bugfix.rst
similarity index 100%
rename from docs/changelog/190.bugfix.rst
rename to docs/changelog/219.bugfix.rst