Convert PyString append functions to void #6
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gatesn
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delta003
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Sep 1, 2023
| pub fn asSlice(self: PyString) ![:0]const u8 { | ||
| var size: i64 = 0; | ||
| const buffer: [*]const u8 = ffi.PyUnicode_AsUTF8AndSize(self.obj.py, &size) orelse return PyError.Propagate; | ||
| return @ptrCast(buffer[0..@intCast(size + 1)]); | ||
| const buffer: [*:0]const u8 = ffi.PyUnicode_AsUTF8AndSize(self.obj.py, &size) orelse return PyError.Propagate; |
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You can't deallocate this slice so what's the reason this API returns sentinel terminated slice? Or should we prefer that in other APIs as well
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Where the slice is indeed null terminated, I think it's more accurate to report it as a null terminated slice. That captures that there are indeed (slice.len + 1) bytes associated with that pointer. If a user needs to pass that slice into some other function that requires null termination, then they know that it already is.
delta003
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Sep 1, 2023
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gatesn
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Sep 4, 2023
I was mistaken in #6 - strings are in fact immutable but the (undocumented) PyUnicode_Append function steals a reference to the LHS.
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Instead of returning a new object, the CPython API effectively decref's the LHS and places a new string in its place.
This PR therefore changes our append functions to also mutate the py.PyString's internal pointer. It makes it more obvious that there's nothing to decref.