From 0a3816ebf3d241248a330d9390999b5520f840e9 Mon Sep 17 00:00:00 2001
From: HandSonic <8078023+HandSonic@users.noreply.github.com>
Date: Sun, 12 May 2024 01:44:50 +0800
Subject: [PATCH] Fix #1949: zipapp virtual environment creation fails if
 zipapp path is symlinked (#2722)

Co-authored-by: HandSonic <3>
---
 docs/changelog/1949.bugfix.rst   |  1 +
 src/virtualenv/util/zipapp.py    |  8 ++++++--
 tests/integration/test_zipapp.py | 19 +++++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 docs/changelog/1949.bugfix.rst

diff --git a/docs/changelog/1949.bugfix.rst b/docs/changelog/1949.bugfix.rst
new file mode 100644
index 000000000..fa77dc9b9
--- /dev/null
+++ b/docs/changelog/1949.bugfix.rst
@@ -0,0 +1 @@
+``virtualenv.pyz`` no longer fails when zipapp path contains a symlink - by :user:`HandSonic` and :user:`petamas`.
diff --git a/src/virtualenv/util/zipapp.py b/src/virtualenv/util/zipapp.py
index f736e3763..958db1543 100644
--- a/src/virtualenv/util/zipapp.py
+++ b/src/virtualenv/util/zipapp.py
@@ -23,8 +23,12 @@ def extract(full_path, dest):
 
 
 def _get_path_within_zip(full_path):
-    full_path = os.path.abspath(str(full_path))
-    sub_file = full_path[len(ROOT) + 1 :]
+    full_path = os.path.realpath(os.path.abspath(str(full_path)))
+    prefix = f"{ROOT}{os.sep}"
+    if not full_path.startswith(prefix):
+        msg = f"full_path={full_path} should start with prefix={prefix}."
+        raise RuntimeError(msg)
+    sub_file = full_path[len(prefix) :]
     if IS_WIN:
         # paths are always UNIX separators, even on Windows, though __file__ still follows platform default
         sub_file = sub_file.replace(os.sep, "/")
diff --git a/tests/integration/test_zipapp.py b/tests/integration/test_zipapp.py
index 7157a9e75..dfc6d9759 100644
--- a/tests/integration/test_zipapp.py
+++ b/tests/integration/test_zipapp.py
@@ -9,6 +9,7 @@
 from flaky import flaky
 
 from virtualenv.discovery.py_info import PythonInfo
+from virtualenv.info import fs_supports_symlink
 from virtualenv.run import cli_run
 
 HERE = Path(__file__).parent
@@ -83,6 +84,24 @@ def _run(*args):
     return _run
 
 
+@pytest.fixture()
+def call_zipapp_symlink(zipapp, tmp_path, zipapp_test_env, temp_app_data):  # noqa: ARG001
+    def _run(*args):
+        symlinked = zipapp.parent / "symlinked_virtualenv.pyz"
+        symlinked.symlink_to(str(zipapp))
+        cmd = [str(zipapp_test_env), str(symlinked), "-vv", str(tmp_path / "env"), *list(args)]
+        subprocess.check_call(cmd)
+
+    return _run
+
+
+@pytest.mark.skipif(not fs_supports_symlink(), reason="symlink not supported")
+def test_zipapp_in_symlink(capsys, call_zipapp_symlink):
+    call_zipapp_symlink("--reset-app-data")
+    _out, err = capsys.readouterr()
+    assert not err
+
+
 @flaky(max_runs=2, min_passes=1)
 def test_zipapp_help(call_zipapp, capsys):
     call_zipapp("-h")