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bpo-32424: Deprecate xml.etree.ElementTree.Element.copy() in favor of copy.copy() #12995

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scoder merged 1 commit into from
Sep 10, 2019
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bpo-32424: Deprecate xml.etree.ElementTree.Element.copy() in favor of copy.copy() #12995

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29 changes: 29 additions & 0 deletions Lib/test/test_xml_etree.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1958,6 +1958,35 @@ def test___init__(self):
self.assertIsNot(element_foo.attrib, attrib)
self.assertNotEqual(element_foo.attrib, attrib)

def test_copy(self):
# Only run this test if Element.copy() is defined.
if "copy" not in dir(ET.Element):
raise unittest.SkipTest("Element.copy() not present")

element_foo = ET.Element("foo", { "zix": "wyp" })
element_foo.append(ET.Element("bar", { "baz": "qix" }))

with self.assertWarns(DeprecationWarning):
element_foo2 = element_foo.copy()

# elements are not the same
self.assertIsNot(element_foo2, element_foo)

# string attributes are equal
self.assertEqual(element_foo2.tag, element_foo.tag)
self.assertEqual(element_foo2.text, element_foo.text)
self.assertEqual(element_foo2.tail, element_foo.tail)

# number of children is the same
self.assertEqual(len(element_foo2), len(element_foo))

# children are the same
for (child1, child2) in itertools.zip_longest(element_foo, element_foo2):
self.assertIs(child1, child2)

# attrib is a copy
self.assertEqual(element_foo2.attrib, element_foo.attrib)

def test___copy__(self):
element_foo = ET.Element("foo", { "zix": "wyp" })
element_foo.append(ET.Element("bar", { "baz": "qix" }))
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7 changes: 7 additions & 0 deletions Lib/xml/etree/ElementTree.py
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Original file line number Diff line number Diff line change
Expand Up @@ -194,6 +194,13 @@ def copy(self):
original tree.

"""
warnings.warn(
"elem.copy() is deprecated. Use copy.copy(elem) instead.",
DeprecationWarning
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@scoder scoder Apr 28, 2019

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Not sure if we should issue a DeprecationWarning straight away (or a PendingDeprecationWarning first), although I personally wouldn't mind, given that the C implementation has shadowed this method for years (in CPython, that is).
@serhiy-storchaka, what do you think?

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@GPHemsley GPHemsley May 11, 2019

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FWIW, copy() does not appear in the documentation, either.

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@GPHemsley GPHemsley May 11, 2019 •
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Also, I can't find any record of copy ever having been available in the C implementation; it looks like it was __copy__ from the beginning.

The first appearance of copy in the Python implementation was in f15351d (first released in Python 3.1 and 2.7.4), which deemed it "experimental". 84fae78 (first released in Python 3.4) removed that designation when switching from comments to docstrings.

)
return self.__copy__()

def __copy__(self):
elem = self.makeelement(self.tag, self.attrib)
elem.text = self.text
elem.tail = self.tail
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3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2019-04-28-10-34-19.bpo-32424.eqNPhM.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Deprecate xml.etree.ElementTree.Element.copy() in favor of copy.copy().

Patch by Gordon P. Hemsley