Preserve original letter-casing for displaying

Simplify input path as a relative path to current working directory,
while preserving the original letter-casing at best effort.

Author: wdhongtw

news/6823.bugfix.rst

@@ -0,0 +1 @@
+Better preserve original casing when a path is displayed.

src/pip/_internal/utils/misc.py

@@ -182,10 +182,12 @@ def rmtree_errorhandler(
 def display_path(path: str) -> str:
     """Gives the display value for a given path, making it relative to cwd
     if possible."""
-    path = os.path.normcase(os.path.abspath(path))
-    if path.startswith(os.getcwd() + os.path.sep):
-        path = "." + path[len(os.getcwd()) :]
-    return path
+    try:
+        relative = Path(path).relative_to(Path.cwd(), walk_up=False)
+    except ValueError:
+        # If the path isn't relative to the CWD, leave it alone
+        return path
+    return os.path.join(".", relative)
 
 
 def backup_dir(dir: str, ext: str = ".bak") -> str:

tests/unit/test_utils.py

@@ -14,7 +14,7 @@
 from io import BytesIO
 from pathlib import Path
 from typing import Any, Callable, NoReturn
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 
 import pytest
 
@@ -50,6 +50,7 @@
     split_auth_from_netloc,
     split_auth_netloc_from_url,
     tabulate,
+    display_path,
 )
 
 
@@ -320,6 +321,39 @@ def test_rmtree_retries_for_3sec(monkeypatch: pytest.MonkeyPatch) -> None:
     )
 
 
+class Test_display_path:
+    on_unix = pytest.mark.skipif("sys.platform == 'win32'")
+    on_win32 = pytest.mark.skipif("sys.platform != 'win32'")
+
+    @pytest.mark.parametrize(
+        "path, fake_cwd, expected",
+        [
+            pytest.param(
+                *("/home/name/project", Path("/home/name"), "./project"),
+                marks=on_unix,
+            ),
+            pytest.param(
+                *("/home", Path("/home/name"), "/home"),
+                marks=on_unix,
+                id="not-go-up",
+            ),
+            pytest.param(
+                *("C:\\Name\\Project", Path("C:\\Name"), ".\\Project"),
+                marks=on_win32,
+            ),
+            pytest.param(
+                *("D:\\Data", Path("C:\\Name"), "D:\\Data"),
+                marks=on_win32,
+            ),
+        ],
+    )
+    def test_display(self, path: str, fake_cwd: Path, expected: str) -> None:
+        with patch("pathlib.Path.cwd") as cwd_func:
+            cwd_func.return_value = fake_cwd
+            got = display_path(path)
+            assert got == expected
+
+
 class Test_normalize_path:
     # Technically, symlinks are possible on Windows, but you need a special
     # permission bit to create them, and Python 2 doesn't support it anyway, so