[tialaramex]

> Ok, I'll keep it short: I'm far from alone being surprised that a sort allocates temporary memory...

In a sense I'm sure this is true. C++ programmers routinely report being astonished about all sorts of properties of the language they have previously insisted they know well and who could blame them (for the former, at least).

Again, this is not symmetrical. LE and BE are symmetrical, if you have to pick one there isn't a "safe default" that isn't surprising to people who expected the other one†. In contrast sort stability isn't like that, all stable sorts also meet the criteria for an unstable sort. Likewise all the in-place sorts meet the criteria for an allocating sort.

C++ chooses to offer an unstable sort just named "sort". It doesn't offer a stable in place sort at all, but it does offer a stable allocating sort and names that stable_sort

† But what you can do is where it matters you explicitly offer the LE and BE options and silently whichever is native on your target is fast. Users can write whichever they meant and their program works rather than "Oops, by default on this platform it's the opposite byte order, there's a special conversion function to run". Needless to say C++ doesn't do this either.