From 944aca0198f6c3bba0c6029be9efb9e2d0cfe47b Mon Sep 17 00:00:00 2001
From: Wessel Bruinsma <wessel.p.bruinsma@gmail.com>
Date: Sun, 5 Jun 2022 16:44:56 +0200
Subject: [PATCH] Fix bug in `unquote`

---
 plum/util.py                                |  8 ++++++--
 tests/dispatcher/test_future_annotations.py | 12 ++++++++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/plum/util.py b/plum/util.py
index 6c53f43a..9e8f51f8 100644
--- a/plum/util.py
+++ b/plum/util.py
@@ -136,12 +136,16 @@ def check_future_annotations(frame=None):
 def unquote(x):
     """Remove quotes from a string at the outermost level.
 
+    If `x` is not a string, `x` is returned immediately.
+
     Args:
-        x (str): String to remove quotes from.
+        x (str or object): String to remove quotes from.
 
     Return:
-        str: `x` but without quotes.
+        str or object: `x` but without quotes.
     """
+    if not isinstance(x, str):
+        return x
     while len(x) >= 2 and x[0] == x[-1] and x[0] in {'"', "'"}:
         x = x[1:-1]
     return x
diff --git a/tests/dispatcher/test_future_annotations.py b/tests/dispatcher/test_future_annotations.py
index c753445b..f40aeed4 100644
--- a/tests/dispatcher/test_future_annotations.py
+++ b/tests/dispatcher/test_future_annotations.py
@@ -49,10 +49,18 @@ def f(x: int):
     with pytest.raises(NotFoundLookupError):
         f("1")
 
-    @f.dispatch
-    def f(x: str):
+    def g(x: str):
         return "str"
 
+    f.dispatch(g)
+
+    assert f(1) == "int"
+    assert f("1") == "str"
+
+    # Extending `f` again will cause `g`s type hints to be processed again, which should
+    # now be types rather than strings. We check that this also works.
+    f.dispatch(g)
+
     assert f(1) == "int"
     assert f("1") == "str"