Skip to content

gh-132762: Fix underallocation bug in dict.fromkeys() and expand test coverage #133627

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 5 commits into from
May 8, 2025
Merged

gh-132762: Fix underallocation bug in dict.fromkeys() and expand test coverage #133627

Changes from 1 commit
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
7aa4034
dict_set_fromkeys now properly calculates new_size
angela-tarantula May 7, 2025
5717052
modified a fromkeys() test to cover edge case where input is large set
angela-tarantula May 7, 2025
f32cc28
4 new tests for fromkeys() to ensure full coverage
angela-tarantula May 7, 2025
b13afeb
📜🤖 Added by blurb_it.
blurb-it[bot] May 8, 2025
049f6f9
Merge branch 'main' into fix-issue-132762
angela-tarantula May 8, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Next Next commit
4 new tests for fromkeys() to ensure full coverage 
previously covered:
 - fast path for dictionary inputs
 - fast path when object's constructor returns non-empty dict (too small
   for good coverage)

now additionally covered:
 - fast path for set inputs
 - slow path for non-set, non-dictionary inputs
 - fast path when object's constructor returns *large* non-empty dict
 - slow path when object is a proper subclass of dict
  • Loading branch information
@angela-tarantula
angela-tarantula committed May 8, 2025
commit f32cc2833d9e5dec995637f97c3886ab23d42bae
21 changes: 19 additions & 2 deletions Lib/test/test_dict.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -338,9 +338,17 @@ def __setitem__(self, key, value):
self.assertRaises(Exc, baddict2.fromkeys, [1])

# test fast path for dictionary inputs
res = dict(zip(range(6), [0]*6))
d = dict(zip(range(6), range(6)))
self.assertEqual(dict.fromkeys(d, 0), dict(zip(range(6), [0]*6)))

self.assertEqual(dict.fromkeys(d, 0), res)
# test fast path for set inputs
d = set(range(6))
self.assertEqual(dict.fromkeys(d, 0), res)
# test slow path for other iterable inputs
d = list(range(6))
self.assertEqual(dict.fromkeys(d, 0), res)

# test fast path when object's constructor returns large non-empty dict
class baddict3(dict):
def __new__(cls):
return d
Expand All @@ -349,6 +357,15 @@ def __new__(cls):
res.update(a=None, b=None, c=None)
self.assertEqual(baddict3.fromkeys({"a", "b", "c"}), res)

# test slow path when object is a proper subclass of dict
class baddict4(dict):
def __init__(self):
dict.__init__(self, d)
d = {i : i for i in range(1000)}
res = d.copy()
res.update(a=None, b=None, c=None)
self.assertEqual(baddict4.fromkeys({"a", "b", "c"}), res)

def test_copy(self):
d = {1: 1, 2: 2, 3: 3}
self.assertIsNot(d.copy(), d)
Expand Down
Loading