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Fix string construction #1862

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Merged
merged 1 commit into from
Jul 11, 2022
Merged

Fix string construction #1862

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51 changes: 45 additions & 6 deletions src/runtime/Types/ClassObject.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -106,24 +106,63 @@ static NewReference tp_new_impl(BorrowedReference tp, BorrowedReference args, Bo

/// <summary>
/// Construct a new .NET String object from Python args
///
/// This manual implementation of all individual relevant constructors
/// is required because System.String can't be allocated uninitialized.
///
/// Additionally, it implements `String(pythonStr)`
/// </summary>
private static NewReference NewString(BorrowedReference args, BorrowedReference tp)
{
if (Runtime.PyTuple_Size(args) == 1)
var argCount = Runtime.PyTuple_Size(args);

string? result = null;
if (argCount == 1)
{
BorrowedReference ob = Runtime.PyTuple_GetItem(args, 0);
if (Runtime.PyString_Check(ob))
{
if (Runtime.GetManagedString(ob) is string val)
return CLRObject.GetReference(val, tp);
result = val;
}
else if (Converter.ToManagedValue(ob, typeof(char[]), out object? arr, false))
{
result = new String((char[])arr!);
}
}
else if (argCount == 2)
{
BorrowedReference p1 = Runtime.PyTuple_GetItem(args, 0);
BorrowedReference p2 = Runtime.PyTuple_GetItem(args, 1);

// TODO: Initialise using constructors instead

Exceptions.SetError(Exceptions.TypeError, "no constructors match given arguments");
return default;
if (
Converter.ToManagedValue(p1, typeof(char), out object? chr, false) &&
Converter.ToManagedValue(p2, typeof(int), out object? count, false)
)
{
result = new String((char)chr!, (int)count!);
}
}
else if (argCount == 3)
{
BorrowedReference p1 = Runtime.PyTuple_GetItem(args, 0);
BorrowedReference p2 = Runtime.PyTuple_GetItem(args, 1);
BorrowedReference p3 = Runtime.PyTuple_GetItem(args, 2);

if (
Converter.ToManagedValue(p1, typeof(char[]), out object? arr, false) &&
Converter.ToManagedValue(p2, typeof(int), out object? offset, false) &&
Converter.ToManagedValue(p3, typeof(int), out object? length, false)
)
{
result = new String((char[])arr!, (int)offset!, (int)length!);
}
}

if (result != null)
return CLRObject.GetReference(result!, tp);

Exceptions.SetError(Exceptions.TypeError, "no constructors match given arguments");
return default;
}

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17 changes: 17 additions & 0 deletions tests/test_constructors.py
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Original file line number Diff line number Diff line change
Expand Up @@ -69,3 +69,20 @@ def test_default_constructor_fallback():

with pytest.raises(TypeError):
ob = DefaultConstructorMatching("2")


def test_string_constructor():
from System import String, Char, Array

ob = String('A', 10)
assert ob == 'A' * 10

arr = Array[Char](10)
for i in range(10):
arr[i] = Char(str(i))

ob = String(arr)
assert ob == "0123456789"

ob = String(arr, 5, 4)
assert ob == "5678"