[Issue 24773] New: Stable sort() invokes the destructor on uninitialized elements

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24773

          Issue ID: 24773
           Summary: Stable sort() invokes the destructor on uninitialized
                    elements
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: sludwig at outerproduct.org

The TimSort implementation creates a temporary uninitialized array for copying
ranges of elements to. While this works fine for POD values, element types with
an elaborate destructor/postblit/copy constructor will be invoked with
uninitialized data, possibly leading to crashes or data corruption.

Test case:
---
import std.algorithm;
struct S {
    int i = 42;
    ~this() { assert(i == 42); }
}
void main()
{
    auto array = new S[](400);
    array.sort!((a, b) => false, SwapStrategy.stable);
}
---

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