[issue35304] The return of truncate(size=None) (file io) is unexpected

[liugang]

liugang <liugang93 at 163.com> added the comment:

# Run in Windows 10

# Code snippet 1
f = open('test', "w+")
f.write('xxx\nyyy\nzzz')

f.seek(0)

f.readline()
print(f.tell())  # 5

x = f.truncate()
print(x)  # 13 - why it is 13, not 5?


# Code snippet 2
f = open('test', "w+")
f.write('xxx\nyyy\nzzz')

f.seek(0)

f.readline()
print(f.tell())  # 5

f.seek(f.tell())

x = f.truncate()
print(x)  # 5

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue35304>
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