Bug #126036 for Future-AsyncAwait: TODO: handle cx->blk_eval.old_eval

Fri Aug 10 07:29:01 2018 leonerd-cpan [...] leonerd.org.uk - Ticket created

Subject:

TODO: handle cx->blk_eval.old_eval_root

Seems hard to trigger in unit tests, but in a realworld example it appears to be associated with an END{} block. -- Paul Evans

Thu Jan 03 10:25:43 2019 leonerd-cpan [...] leonerd.org.uk - Correspondence added

Might all be a consequence of https://rt.cpan.org/Ticket/Display.html?id=126037 so I'll park this one until that is fixed first. -- Paul Evans

Sat Jan 05 08:45:31 2019 leonerd-cpan [...] leonerd.org.uk - Correspondence added

On Thu Jan 03 10:25:43 2019, PEVANS wrote: Show quoted text

> Might all be a consequence of > > https://rt.cpan.org/Ticket/Display.html?id=126037 > > so I'll park this one until that is fixed first.

Still happening. Test case currently is via Device::Chip::SSD1306 Program runs successfully until exit time, but then aborts $ perl -Mblib examples/ssd1306.pl -A BusPirate:serial=/dev/ttyACM1 -I I2C Future::AsyncAwait panic: TODO: handle cx->blk_eval.old_eval_root Aborted -- Paul Evans

Sat Jan 05 09:00:27 2019 leonerd-cpan [...] leonerd.org.uk - Correspondence added

Related to the END block: END { print STDERR "ENDing\n"; $chip and $chip->display( 0 )->get; $chip and $chip->power(0)->get; } Causes ENDing Future::AsyncAwait panic: TODO: handle cx->blk_eval.old_eval_root Aborted But by adding at normal program shutdown # Normal controlled shutdown to avoid END $chip->display( 0 )->get; $chip->power(0)->get; undef $chip; Then the problem goes away. -- Paul Evans

Sat Jan 05 09:00:43 2019 leonerd-cpan [...] leonerd.org.uk - Subject changed from 'TODO: handle cx->blk_eval.old_eval_root' to 'TODO: handle cx->blk_eval.old_eval_root at END time'

Sat Jan 05 13:26:15 2019 leonerd-cpan [...] leonerd.org.uk - Correspondence added

Minimal test case turns out to be simple enough -- Paul Evans

Subject:

rt126036.pl

#!/usr/bin/perl use strict; use warnings; use Future; use Future::AsyncAwait; my $f1 = Future->new; async sub func { await $f1 } END { my $f2 = func(); $f1->done( "OK\n" ); print $f2->get; }

Sat Jan 05 14:31:45 2019 leonerd-cpan [...] leonerd.org.uk - Correspondence added

A reading of source suggests that we don't need to care about old_eval_root; it's used just to restore lower-down state by the PUSHEVAL and POPEVAL macros. We can just ignore these two fields. Relatedly for similar reasons, we can ignore the blk_eval.cur_text field, and if we do that we gain support for being called from both END {} and string-eval cases. -- Paul Evans

Subject:

rt126036.patch

=== modified file 'lib/Future/AsyncAwait.xs' --- lib/Future/AsyncAwait.xs 2019-01-04 18:13:42 +0000 +++ lib/Future/AsyncAwait.xs 2019-01-05 19:28:59 +0000 @@ -734,15 +734,18 @@ panic("TODO: handle CXt_EVAL without CXp_TRYBLOCK\n"); if(cx->blk_eval.old_namesv) panic("TODO: handle cx->blk_eval.old_namesv\n"); - if(cx->blk_eval.old_eval_root) - panic("TODO: handle cx->blk_eval.old_eval_root\n"); - if(cx->blk_eval.cur_text) - panic("TODO: handle cx->blk_eval.cur_text\n"); if(cx->blk_eval.cv) panic("TODO: handle cx->blk_eval.cv\n"); if(cx->blk_eval.cur_top_env != PL_top_env) panic("TODO: handle cx->blk_eval.cur_top_env\n"); + /* + * It seems we don't need to care about blk_eval.old_eval_root or + * blk_eval.cur_text, and if we ignore these then it works fine via + * string eval(). + * https://rt.cpan.org/Ticket/Display.html?id=126036 + */ + frame->type = CXt_EVAL; frame->gimme = cx->blk_gimme;

Sat Jan 05 14:31:45 2019 leonerd-cpan [...] leonerd.org.uk - Status changed from 'new' to 'patched'

Sat Jan 05 20:37:55 2019 leonerd-cpan [...] leonerd.org.uk - Correspondence added

Released in 0.18 -- Paul Evans

Sat Jan 05 20:37:56 2019 leonerd-cpan [...] leonerd.org.uk - Status changed from 'patched' to 'resolved'

Sat Jan 05 20:37:56 2019 leonerd-cpan [...] leonerd.org.uk - Fixed in 0.18 added

Bug #126036 for Future-AsyncAwait: TODO: handle cx->blk_eval.old_eval_root at END time