[Interop] Array#swap invocable, but not readable

[fniephaus]

I'm getting errors when trying to display the API of an Array, because of Array#swap. It's listed as part of getMembers and can be invoked. But it does not seem to be a readable member. I'm not too familiar with the API of Array, but I couldn't find #swap in the class documentation, so it may be TruffleRuby-specific.

Repro session

$ polyglot --shell --jvm
GraalVM MultiLanguage Shell 19.3.0
Copyright (c) 2013-2019, Oracle and/or its affiliates
  Python version 3.7.4
  Ruby version 2.6.2
python> import polyglot
python> x = polyglot.eval(language='ruby', string='[1, 2]')
python> [key for key in dir(x) if not hasattr(x, key)]
['swap'] # EMPTY LIST EXPECTED
python> x.swap(0,1)
1
python> x
[2, 1] # WORKED AS EXPECTED

[eregon]

Thank you for the bug report, I can reproduce.
Array#swap is indeed an internal method, marked as protected.
protected is between public and private and that's probably why it appears in one case but not the other.

@pitr-ch Could you take a look at this?

I think there are two things to fix:

• Should protected methods be listed in getMembers() and isMemberReadable()? We need to be consistent.
• We should probably hide Array#swap, private + Truffle.privately {} or better Truffle::ArrayOperations.swap.

[pitr-ch]

fixed in 25b684e