Yesterday we had the following discussion on #perl6-dev about this ticket:
start of discussion on IRC -- cmp.
http://irclog.perlgeek.de/perl6-dev/2016-09-19#i_13238477
bartolin lizmat: I saw your commit 9b6f2eb543 in the backlog. does that
shed a different light on RT #128320 and the related rakudo PR 780? (that PR
has conflicts now)
synopsebot6 Link: https://rt.perl.org/rt3//Public/Bug/Display.html?id=128320
lizmat bartolin: looking
lizmat bartolin: I don't think so, because #128320 is about Arrays not
Lists
lizmat ah, reading the pull request: perhaps the jvm has problems pushing
nqp::null to an array ?
timotimo we don't have something like VMNull on JVM? that surprises me
arnsholt IIRC nqp::null on JVM is just plain null
lizmat well, that's basically what
https://github.com/rakudo/rakudo/pull/780/files does: make sure we don't push
nqp::null
arnsholt There are two potential solutions here, IMO
arnsholt Either guard against the null from Rakudo (like in the PR), or
find the spot in the Java runtime code that doesn't check for null and add a
null check there instead
bartolin lizmat: IIRC the problem occured because we used map in the
failing code -- and inside map the List iterator is used
arnsholt I'd be inclined to go for finding the problem in the Java code, I
think
bartolin sounds fair. I'll add this discussion to the ticket (and close the
PR)
bartolin arnsholt++ lizmat++ # thanks for looking
lizmat bartolin: if this is still a problem, then I could make it JVM only
bartolin lizmat: no, it's not a big problem (not worth a special case IMHO)
lizmat ok
bartolin (I fudged the failing test as todo some time ago)
lizmat well, if it's todoed, is no longer NPEing ?
lizmat *it's
bartolin it's a 'lives-ok' test :-)
lizmat but still, an NPE would exit the test script, wouldn't be
catchable ?
timotimo not sure if we turn an NPE into a perl6-level catchable exception
bartolin well, the test file (S32-array/delete.t) has no passed todos and
it does not die, either
* lizmat is building an up-to-date JVM backend
lizmat bartolin: seems the problem on JVM is now also gone:
lizmat $ ./perl6-j -e 'my @a; @a[1] = 42; say @a.map: { 1 }'
lizmat (1 1)
lizmat oops, it isn't:
lizmat $ ./perl6-j -e 'my @a; @a[1] = 42; say map { $_ }, @a'
lizmat java.lang.NullPointerException
lizmat in block at -e line 1
bartolin yepp, it's only the sub form of map
lizmat m: sub a(+v) { dd v }; a( my @ = ^10 )
camelia rakudo-moar 77a7a4: OUTPUT«(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)»
lizmat m: sub a(+@v) { dd @v }; a( my @ = ^10 )
camelia rakudo-moar 77a7a4: OUTPUT«[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]»
lizmat seems like adding a sigil makes it an Array, and thus circumvent
the issue
bartolin lizmat: you mean in multi sub map?
lizmat yeah...
lizmat testing that now
bartolin hmm, Larry introduced the +value there exactly one year ago
(d9c21e99f5)
lizmat ./perl6-j -e 'my @a; @a[1] = 42; say map { $_ }, @a'
lizmat ((Mu) 42)
lizmat bartolin: alas, no go
lizmat m: my @a = ^10; map { $_ = 42 }, @a; dd @a # this breaks
camelia rakudo-moar 77a7a4: OUTPUT«Array @a = [42, 42, 42, 42, 42, 42, 42,
42, 42, 42]»
lizmat apparently the array is a copy
bartolin ah.
bartolin anyway, it's not the biggest problem with the jvm backend ... but
thanks for looking!
lizmat bartolin: yw
end of discussion on IRC -- powered by
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