RE: [Problem] test_must_fail makes possibly questionable assumptions about exit_code.

On February 28, 2018 2:49 AM, Peff wrote:

On Wed, Feb 28, 2018 at 07:42:51AM +0000, Eric Wong wrote:

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 a) We could override the meaning of die() in Git.pm.  This feels
    ugly but if it works, it would be a very small patch.

Unlikely to work since I think we use eval {} to trap exceptions
from die.

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 b) We could forbid use of die() and use some git_die() instead (but
    with a better name) for our own error handling.

Call sites may be dual-use: "die" can either be caught by an eval
or used to show an error message to the user.

<snip>

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 d) We could wrap each command in an eval {...} block to convert the
    result from die() to exit 128.

I prefer option d)

FWIW, I agree with all of that. You can do (d) without an enclosing
eval block by just hooking the __DIE__ handler, like:

$SIG{__DIE__} = sub {
  print STDERR "fatal: @_\n";
  exit 128;
};

Looks like it has the same problems I pointed out with a) and b).

You're right. I cut down my example too much and dropped the necessary
eval magic. Try this:

-- >8 --
SIG{__DIE__} = sub {
  CORE::die @_ if $^S || !defined($^S);
  print STDERR "fatal: @_";
  exit 128;
};

eval {
  die "inside eval";
};
print "eval status: $@" if $@;

die "outside eval";
-- 8< --

Running that should produce:

$ perl foo.pl; echo $?
eval status: inside eval at foo.pl line 8.
fatal: outside eval at foo.pl line 12.
128

It may be getting a little too black-magic, though. Embedding in an eval is at
least straightforward, if a bit more invasive.

I like this solution. The $64K question for me is how (a.k.a. where) to instrument this broadly instead of in each perl fragment in the test suite.  The code:

$SIG{__DIE__} = sub {
  CORE::die @_ if $^S || !defined($^S);
  print STDERR "fatal: @_";
  exit 128;
};

eval {
  die "inside eval";
};

print "eval status: $@" if $@;

die "outside eval";

as tested above, in NonStop results in an exit code of 128 whether run from a script or from stdin (a good thing). I'm happy to do the heavy lifting on this, but  a bit more direction as to the implementation would help.

Cheers,
Randall