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id() for str stays the same after * 1 #2864

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youknowone merged 2 commits into from
Aug 12, 2021
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Merged

id() for str stays the same after * 1 #2864

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06d33f8
`id()` for `str` stays the same after `* 1`, refs #2840
sobolevn Aug 12, 2021
201664e
avoid vm.new_stringref in pystr.rs
youknowone Aug 12, 2021
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3 changes: 2 additions & 1 deletion extra_tests/snippets/bytes.py
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Original file line number Diff line number Diff line change
Expand Up @@ -633,7 +633,8 @@ def __bytes__(self):
assert id(a) == id(a)
assert id(a) != id(a * -1)
assert id(a) != id(a * 0)
assert id(a) == id(a * 1) # only case when `id` stays the same
assert id(a) == id(a * 1) # only cases
assert id(a) == id(1 * a) # when `id` stays the same
assert id(a) != id(a * 2)


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29 changes: 27 additions & 2 deletions extra_tests/snippets/strings.py
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Expand Up @@ -632,7 +632,7 @@ def test_removeprefix():
assert s_uc.removeprefix('😱') == s_ref_uc[1:]
assert s_uc.removeprefix('😱fo') == s_ref_uc[3:]
assert s_uc.removeprefix('😱foo') == s_ref_uc[4:]

assert s_uc.removeprefix('🖖') == s_ref_uc
assert s_uc.removeprefix('foo') == s_ref_uc
assert s_uc.removeprefix(' ') == s_ref_uc
Expand Down Expand Up @@ -676,7 +676,7 @@ def test_removesuffix():
assert s_uc.removesuffix('🖖') == s_ref_uc[:-1]
assert s_uc.removesuffix('oo🖖') == s_ref_uc[:-3]
assert s_uc.removesuffix('foo🖖') == s_ref_uc[:-4]

assert s_uc.removesuffix('😱') == s_ref_uc
assert s_uc.removesuffix('foo') == s_ref_uc
assert s_uc.removesuffix(' ') == s_ref_uc
Expand All @@ -702,3 +702,28 @@ def test_removesuffix_types():
skip_if_unsupported(3,9,test_removeprefix_types)
skip_if_unsupported(3,9,test_removesuffix)
skip_if_unsupported(3,9,test_removesuffix_types)


# Regression to
# https://github.com/RustPython/RustPython/issues/2840

a = 'abc123()'

assert id(a) == id(a)
assert id(a) != id(a * -1)
assert id(a) != id(a * 0)
assert id(a) == id(a * 1) # only cases
assert id(a) == id(1 * a) # when `id` stays the same
assert id(a) != id(a * 2)


class MyString(str):
pass

b = MyString('0123abc*&')
assert id(b) == id(b)
assert id(b) != id(b * -1)
assert id(b) != id(b * 0)
assert id(b) != id(b * 1)
assert id(b) != id(1 * b)
assert id(b) != id(b * 2)
11 changes: 9 additions & 2 deletions vm/src/builtins/pystr.rs
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Expand Up @@ -329,8 +329,15 @@ impl PyStr {

#[pymethod(name = "__rmul__")]
#[pymethod(magic)]
fn mul(&self, value: isize) -> String {
self.value.repeat(value.to_usize().unwrap_or(0))
fn mul(zelf: PyRef<Self>, value: isize, vm: &VirtualMachine) -> PyRef<Self> {
if value == 1 && zelf.class().is(&vm.ctx.types.str_type) {
// Special case: when some `str` is multiplied by `1`,
// nothing really happens, we need to return an object itself
// with the same `id()` to be compatible with CPython.
// This only works for `str` itself, not its subclasses.
return zelf;
}
Self::from(zelf.value.repeat(value.to_usize().unwrap_or(0))).into_ref(vm)
}

#[pymethod(magic)]
Expand Down