DAVEM TPF Grant#2 June 2016 report

I didn't really do much that stands this month; I just reduced the backlog
in my p5p mailbox a bit, and worked on several miscellaneous tickets.

The most noteworthy bugfix related to $@ getting overwritten while exiting
an eval scope. Earlier work by Zefram had ensured that $@ is assigned to
in a late stage of scope unwinding, but it turns out that in void context
or after a die, the temps stack was still being freed *after* $@ had been
assigned to, which could result in destructors being called that could
overwrite $@. (My work last year on the context stack meant that this had
already been fixed for scalar and list context evals). For example:

    sub DESTROY { $@ = "spurious\n" }
    eval  { die ((bless []) ?  "foo" : "bar") };
    print $@; # prints "spurious" rather than "foo"

I did some refactoring of the eval code and then provided a fix,
but this broke a Variable::Magic test and has been temporarily reverted

SUMMARY:
     11:59 "Confused by eval behavior" thread
      0:28 [perl #124216] Perl_sv_clear: Assertion
      1:57 [perl #127759] die inside sort comparitor causes SV error
      1:23 [perl #127774] segfault in caller()
      2:54 [perl #127834] @INC issues
      0:50 [perl #127875] Blead breaks Scope::Upper
      0:29 [perl #128189] Assert fail in sv.c
      0:22 [perl #128238] Assert fail in gv.c
      0:41 [perl #128252] Assert fail in op.c sub{\@0[0]=0}
      3:26 [perl #128254] Taint-mode assert fail in Perl_magic_clearisa
      0:45 [perl #128307] Bleadperl v5.25.0-40-ga52f2cc breaks GAAS/perl-lisp-0.06.tar.gz
      2:21 fix Coro to run under 5.24.0
      1:00 fix Time::HiRes utime.t test hanging
      1:39 fix build warnings and smoke failures
     12:44 process p5p mailbox
      0:58 reformat perl -V output
      3:37 sort out (mini)perlmain.c generation
    ------
     47:33 TOTAL (HH::MM)


As of 2016/06/30: since the beginning of the grant:

 141.6 weeks
1968.0 total hours
  13.9 average hours per week

There are 32 hours left on the grant.

-- 
"Strange women lying in ponds distributing swords is no basis for a system
of government. Supreme executive power derives from a mandate from the
masses, not from some farcical aquatic ceremony."
    -- Dennis, "Monty Python and the Holy Grail"

• DAVEM TPF Grant#2 June 2016 report by Dave Mitchell
• Re: DAVEM TPF Grant#2 June 2016 report by Marcus Holland-Moritz