From b54354860f865f4acb175bda9bbb94fc26def6e3 Mon Sep 17 00:00:00 2001
From: Aviv Palivoda <palaviv@gmail.com>
Date: Sat, 11 May 2019 18:06:06 +0300
Subject: [PATCH 1/2] Move fspath to _os

---
 Lib/os.py           | 31 -------------------------------
 vm/src/stdlib/os.rs | 17 ++++++++++++++++-
 2 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/Lib/os.py b/Lib/os.py
index c768946c52..cb49481dff 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -133,34 +133,3 @@ def getenv(key, default=None):
     The optional second argument can specify an alternate default.
     key, default and the result are str."""
     return environ.get(key, default)
-
-
-def fspath(path):
-    """Return the path representation of a path-like object.
-
-    If str or bytes is passed in, it is returned unchanged. Otherwise the
-    os.PathLike interface is used to get the path representation. If the
-    path representation is not str or bytes, TypeError is raised. If the
-    provided path is not str, bytes, or os.PathLike, TypeError is raised.
-    """
-    if isinstance(path, (str, bytes)):
-        return path
-
-    # Work from the object's type to match method resolution of other magic
-    # methods.
-    path_type = type(path)
-    try:
-        path_repr = path_type.__fspath__(path)
-    except AttributeError:
-        if hasattr(path_type, '__fspath__'):
-            raise
-        else:
-            raise TypeError("expected str, bytes or os.PathLike object, "
-                            "not " + path_type.__name__)
-    if isinstance(path_repr, (str, bytes)):
-        return path_repr
-    else:
-        raise TypeError("expected {}.__fspath__() to return str or bytes, "
-                        "not {}".format(path_type.__name__,
-                                        type(path_repr).__name__))
-
diff --git a/vm/src/stdlib/os.rs b/vm/src/stdlib/os.rs
index c01b5aaac2..a69a97cc24 100644
--- a/vm/src/stdlib/os.rs
+++ b/vm/src/stdlib/os.rs
@@ -14,9 +14,10 @@ use crate::obj::objint::PyIntRef;
 use crate::obj::objiter;
 use crate::obj::objstr;
 use crate::obj::objstr::PyStringRef;
+use crate::obj::objtype;
 use crate::obj::objtype::PyClassRef;
 use crate::pyobject::{
-    ItemProtocol, PyClassImpl, PyObjectRef, PyRef, PyResult, PyValue, TryIntoRef,
+    ItemProtocol, PyClassImpl, PyObjectRef, PyRef, PyResult, PyValue, TryIntoRef, TypeProtocol,
 };
 use crate::vm::VirtualMachine;
 
@@ -492,6 +493,19 @@ fn os_chdir(path: PyStringRef, vm: &VirtualMachine) -> PyResult<()> {
     env::set_current_dir(&path.value).map_err(|s| vm.new_os_error(s.to_string()))
 }
 
+fn os_fspath(path: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+    if objtype::issubclass(&path.class(), &vm.ctx.str_type())
+        || objtype::issubclass(&path.class(), &vm.ctx.bytes_type())
+    {
+        Ok(path)
+    } else {
+        Err(vm.new_type_error(format!(
+            "expected str or bytes object, not {}",
+            path.class()
+        )))
+    }
+}
+
 pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
     let ctx = &vm.ctx;
 
@@ -549,6 +563,7 @@ pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
         "symlink" => ctx.new_rustfunc(os_symlink),
         "getcwd" => ctx.new_rustfunc(os_getcwd),
         "chdir" => ctx.new_rustfunc(os_chdir),
+        "fspath" => ctx.new_rustfunc(os_fspath),
         "O_RDONLY" => ctx.new_int(0),
         "O_WRONLY" => ctx.new_int(1),
         "O_RDWR" => ctx.new_int(2),

From d96d04f0fde2bb4b567bac75d70ebf0c53cf8069 Mon Sep 17 00:00:00 2001
From: Aviv Palivoda <palaviv@gmail.com>
Date: Sat, 11 May 2019 18:08:47 +0300
Subject: [PATCH 2/2] Add os.fspath tests

---
 tests/snippets/stdlib_os.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tests/snippets/stdlib_os.py b/tests/snippets/stdlib_os.py
index 39d5e7bdcb..32cb7d4a9b 100644
--- a/tests/snippets/stdlib_os.py
+++ b/tests/snippets/stdlib_os.py
@@ -49,6 +49,10 @@
 	assert os.altsep == None
 	assert os.pathsep == ":"
 
+assert os.fspath("Testing") == "Testing"
+assert os.fspath(b"Testing") == b"Testing"
+assert_raises(TypeError, lambda: os.fspath([1,2,3]))
+
 class TestWithTempDir():
 	def __enter__(self):
 		if os.name == "nt":