From @masak

r30374​:
$ echo -n > empty
$ < empty ./perl6 -e 'say $*IN.slurp' # works, empty line

$ < empty ./perl6 -e 'say $*IN.slurp.WHAT' # yes
Str
$ < empty ./perl6 -e 'say $*IN.slurp.perl' # yes
""
$ $ < empty ./perl6 -e 'say split("\n", "a\nb\nc").perl' # this works too
["a", "b", "c"]
$ < empty ./perl6 -e 'say split("\n", $*IN.slurp)' # but this fails
Null PMC access in get_integer()
[...]
Segmentation fault

From @ronaldxs

$ < empty ./perl6 -e 'say split("\n", $*IN.slurp)' # but this fails
Null PMC access in get_integer()
[...]
Segmentation fault

The following variation of your script may provide some insight into
the problem​:

< empty ./perl6 -e 'my $x = ""; my $y = $*IN.slurp; if $x eq $y {
say "both empty"; } ; say split("\n", $x); say "split simple empty
str"; say split("\n", $y);'

The script outputs when run​:
both empty

split simple empty str
Null PMC access in get_integer()
[ ... ]
Segmentation Fault

The RT System itself - Status changed from 'new' to 'open'

From @ronaldxs

$ < empty ./perl6 -e 'say split("\n", $*IN.slurp)' # but this fails

Two proposed patches attached. The patch to src/pmc/parrotiio.pmc seems
to fix the problem as originally stated. Then the patch to
languages/perl6/src/classes/Str.pir seems to fix 'say
$*IN.slurp.split("\n")'. If you have any questions please ask.

Ron

From @ronaldxs

Index: src/pmc/parrotio.pmc
===================================================================
--- src/pmc/parrotio.pmc	(revision 30637)
+++ src/pmc/parrotio.pmc	(working copy)
@@ -307,7 +307,7 @@
                 Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_PIO_ERROR,
                     "Cannot slurp from empty filehandle");
 
-            result = NULL;
+            result = string_make_empty(INTERP, enum_stringrep_one, 0);
 
             do {
                 STRING * const part = PIO_reads(INTERP, SELF, 4096);
Index: languages/perl6/src/classes/Str.pir
===================================================================
--- languages/perl6/src/classes/Str.pir	(revision 30637)
+++ languages/perl6/src/classes/Str.pir	(working copy)
@@ -46,7 +46,7 @@
     .return(retv)
 .end
 
-.sub 'split' :method :multi('Perl6Str')
+.sub 'split' :method
     .param string delim
     .local string objst
     .local pmc pieces

From @masak

---------- Forwarded message ----------
From​: Ron Schmidt via RT <perl6-bugs-followup@​perl.org>
Date​: Fri, Aug 29, 2008 at 10​:14 PM
Subject​: [perl #​58150] Doing split on the result of a slurped empty
file results in a Null PMC Access in rakudo
To​: cmasak@​gmail.com

$ < empty ./perl6 -e 'say split("\n", $*IN.slurp)' # but this fails

Two proposed patches attached. The patch to src/pmc/parrotiio.pmc seems
to fix the problem as originally stated. Then the patch to
languages/perl6/src/classes/Str.pir seems to fix 'say
$*IN.slurp.split("\n")'. If you have any questions please ask.

Ron

From @masak

Index: src/pmc/parrotio.pmc
===================================================================
--- src/pmc/parrotio.pmc	(revision 30637)
+++ src/pmc/parrotio.pmc	(working copy)
@@ -307,7 +307,7 @@
                 Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_PIO_ERROR,
                     "Cannot slurp from empty filehandle");
 
-            result = NULL;
+            result = string_make_empty(INTERP, enum_stringrep_one, 0);
 
             do {
                 STRING * const part = PIO_reads(INTERP, SELF, 4096);
Index: languages/perl6/src/classes/Str.pir
===================================================================
--- languages/perl6/src/classes/Str.pir	(revision 30637)
+++ languages/perl6/src/classes/Str.pir	(working copy)
@@ -46,7 +46,7 @@
     .return(retv)
 .end
 
-.sub 'split' :method :multi('Perl6Str')
+.sub 'split' :method
     .param string delim
     .local string objst
     .local pmc pieces

From @jnthn

On Fri Aug 29 13​:14​:19 2008, ronaldxs wrote​:

$ < empty ./perl6 -e 'say split("\n", $*IN.slurp)' # but this fails

Two proposed patches attached. The patch to src/pmc/parrotiio.pmc seems
to fix the problem as originally stated. Then the patch to
languages/perl6/src/classes/Str.pir seems to fix 'say
$*IN.slurp.split("\n")'. If you have any questions please ask.

Thanks for the patches! The first one to ParrotIO, I fully agree with so
I have applied it in r30981 (if you slurp an empty file, the empty
string would seem a much more sensible and predictable result than a
NULL string, which suggests something went wrong with the read). And
this fixes the test that was originally submitted for this ticket. :-)

The second patch was not quite correct - we need to have it :multi for
when we implement the regex variant. I changed it to​:

.sub 'split' :method :multi('String')

So it's a bit more liberal about what sorts of strings it gets for now.

Thanks!

Jonathan

@jnthn - Status changed from 'open' to 'resolved'

From @pmichaud

On Thu, Sep 11, 2008 at 05​:34​:14AM -0700, jnthn@​jnthn.net via RT wrote​:

The second patch was not quite correct - we need to have it :multi for
when we implement the regex variant. I changed it to​:

.sub 'split' :method :multi('String')

So it's a bit more liberal about what sorts of strings it gets for now.

Not only that, but split needs to go into Any so that we can
split on things that aren't strings yet (i.e., by stringifying
the invocant).

Pm