Merge pull request #19547 from DWesl/cyg2win32-use-cygpath

BLD: Use cygpath utility for path conversion in cyg2win32

numpy/distutils/misc_util.py

@@ -376,10 +376,42 @@ def blue_text(s):
 
 #########################
 
-def cyg2win32(path):
-    if sys.platform=='cygwin' and path.startswith('/cygdrive'):
-        path = path[10] + ':' + os.path.normcase(path[11:])
-    return path
+def cyg2win32(path: str) -> str:
+    """Convert a path from Cygwin-native to Windows-native.
+
+    Uses the cygpath utility (part of the Base install) to do the
+    actual conversion.  Falls back to returning the original path if
+    this fails.
+
+    Handles the default ``/cygdrive`` mount prefix as well as the
+    ``/proc/cygdrive`` portable prefix, custom cygdrive prefixes such
+    as ``/`` or ``/mnt``, and absolute paths such as ``/usr/src/`` or
+    ``/home/username``
+
+    Parameters
+    ----------
+    path : str
+       The path to convert
+
+    Returns
+    -------
+    converted_path : str
+        The converted path
+
+    Notes
+    -----
+    Documentation for cygpath utility:
+    https://cygwin.com/cygwin-ug-net/cygpath.html
+    Documentation for the C function it wraps:
+    https://cygwin.com/cygwin-api/func-cygwin-conv-path.html
+
+    """
+    if sys.platform != "cygwin":
+        return path
+    return subprocess.check_output(
+        ["/usr/bin/cygpath", "--windows", path], universal_newlines=True
+    )
+
 
 def mingw32():
     """Return true when using mingw32 environment.