diff --git a/Doc/library/pathlib.rst b/Doc/library/pathlib.rst index 83f7c836f0e..bf6fee44df2 100644 --- a/Doc/library/pathlib.rst +++ b/Doc/library/pathlib.rst @@ -551,7 +551,9 @@ Pure paths provide the following methods and properties: File "", line 1, in File "pathlib.py", line 694, in relative_to .format(str(self), str(formatted))) - ValueError: '/etc/passwd' does not start with '/usr' + ValueError: '/etc/passwd' is not in the subpath of '/usr' OR one path is relative and the other absolute. + + NOTE: This function is part of :class:`PurePath` and works with strings. It does not check or access the underlying file structure. .. method:: PurePath.with_name(name) diff --git a/Lib/pathlib.py b/Lib/pathlib.py index f98d69eb04a..9f5e27b9117 100644 --- a/Lib/pathlib.py +++ b/Lib/pathlib.py @@ -922,7 +922,8 @@ def relative_to(self, *other): cf = self._flavour.casefold_parts if (root or drv) if n == 0 else cf(abs_parts[:n]) != cf(to_abs_parts): formatted = self._format_parsed_parts(to_drv, to_root, to_parts) - raise ValueError("{!r} does not start with {!r}" + raise ValueError("{!r} is not in the subpath of {!r}" + " OR one path is relative and the other is absolute." .format(str(self), str(formatted))) return self._from_parsed_parts('', root if n == 1 else '', abs_parts[n:]) diff --git a/Misc/NEWS.d/next/Library/2020-04-20-22-08-36.bpo-23082.iX90Id.rst b/Misc/NEWS.d/next/Library/2020-04-20-22-08-36.bpo-23082.iX90Id.rst new file mode 100644 index 00000000000..13ed0defe52 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-04-20-22-08-36.bpo-23082.iX90Id.rst @@ -0,0 +1 @@ +Updated the error message and docs of PurePath.relative_to() to better reflect the function behaviour. \ No newline at end of file