From 811c9a6b1fcd03a09a2256469fc48afe5598dac9 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Tue, 5 Oct 2021 10:19:36 +0200
Subject: [PATCH] Make `Path.__deepcopy__` interact better with subclasses,
 e.g. TextPath.

---
 lib/matplotlib/path.py                | 11 ++++-------
 lib/matplotlib/tests/test_textpath.py | 10 ++++++++++
 2 files changed, 14 insertions(+), 7 deletions(-)
 create mode 100644 lib/matplotlib/tests/test_textpath.py

diff --git a/lib/matplotlib/path.py b/lib/matplotlib/path.py
index 4280d55eeacd..43d3f2fd95da 100644
--- a/lib/matplotlib/path.py
+++ b/lib/matplotlib/path.py
@@ -272,13 +272,10 @@ def __deepcopy__(self, memo=None):
         Return a deepcopy of the `Path`.  The `Path` will not be
         readonly, even if the source `Path` is.
         """
-        try:
-            codes = self.codes.copy()
-        except AttributeError:
-            codes = None
-        return self.__class__(
-            self.vertices.copy(), codes,
-            _interpolation_steps=self._interpolation_steps)
+        # Deepcopying arrays (vertices, codes) strips the writeable=False flag.
+        p = copy.deepcopy(super(), memo)
+        p._readonly = False
+        return p
 
     deepcopy = __deepcopy__
 
diff --git a/lib/matplotlib/tests/test_textpath.py b/lib/matplotlib/tests/test_textpath.py
new file mode 100644
index 000000000000..e421d2623cad
--- /dev/null
+++ b/lib/matplotlib/tests/test_textpath.py
@@ -0,0 +1,10 @@
+import copy
+
+from matplotlib.textpath import TextPath
+
+
+def test_copy():
+    tp = TextPath((0, 0), ".")
+    assert copy.deepcopy(tp).vertices is not tp.vertices
+    assert (copy.deepcopy(tp).vertices == tp.vertices).all()
+    assert copy.copy(tp).vertices is tp.vertices