Re: [go-nuts] Panic getting swallowed by defer in Go 1.11
NB I’m unable to reproduce this bug without the pointer indirection.
On Tuesday, September 4, 2018 at 3:38:35 AM UTC+10, Sam Whited wrote:
>
> On Mon, Sep 3, 2018, at 04:10, ama...@naucera.net wrote:
> > type S []int
> >
> > func (s *S) Last() int {
> > return (*s)[len(*s) - 1]
> > }
>
> On an unrelated matter, the extra indirection is (probably) not what you
> want here, slices are already a pointer type. For more information see
> https://blog.golang.org/go-slices-usage-and-internals.
>
> That is to say, the following works in more or less the same way (and is
> much easier to read):
>
> func (s S) Last() int {
> return s[len(s)-1]
> }
>
> Apologies if this is something you're already aware of; for future
> generations finding this thread I wanted to mention it.
>
> —Sam
>
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Re: [go-nuts] Panic getting swallowed by defer in Go 1.11
NB I']m
On Tuesday, September 4, 2018 at 3:38:35 AM UTC+10, Sam Whited wrote:
>
> On Mon, Sep 3, 2018, at 04:10, ama...@naucera.net wrote:
> > type S []int
> >
> > func (s *S) Last() int {
> > return (*s)[len(*s) - 1]
> > }
>
> On an unrelated matter, the extra indirection is (probably) not what you
> want here, slices are already a pointer type. For more information see
> https://blog.golang.org/go-slices-usage-and-internals.
>
> That is to say, the following works in more or less the same way (and is
> much easier to read):
>
> func (s S) Last() int {
> return s[len(s)-1]
> }
>
> Apologies if this is something you're already aware of; for future
> generations finding this thread I wanted to mention it.
>
> —Sam
>
--
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Re: [go-nuts] Panic getting swallowed by defer in Go 1.11
Thanks, that looks like what I’m seeing (I’m able to coax it to produce a
pointer which segfaults the runtime).
On Tuesday, September 4, 2018 at 3:34:43 AM UTC+10, Paul Jolly wrote:
>
> I suspect that you've just run into some variation on
> https://github.com/golang/go/issues/27378
>
> Giovanni/Daniel/others better placed might be able to confirm more
> precisely however.
>
>
> On Mon, 3 Sep 2018 at 17:49, > wrote:
> >
> > Hi all,
> >
> > Since Go 1.11, the following test seems to pass when I would expect it
> to panic with index out of range:
> >
> > package weirdness
> >
> > import "testing"
> >
> >
> > type S []int
> >
> > func (s *S) Last() int {
> > return (*s)[len(*s) - 1]
> > }
> >
> >
> > func TestWeirdness(t *testing.T) {
> > var s S
> >
> > defer func() {}()
> >
> > s.Last()
> > }
> >
> > Strangely, if the declaration of the s variable is moved below the
> defer, it panics as expected. Any idea what’s going on?
> >
> > --
> > You received this message because you are subscribed to the Google
> Groups "golang-nuts" group.
> > To unsubscribe from this group and stop receiving emails from it, send
> an email to golang-nuts...@googlegroups.com .
> > For more options, visit https://groups.google.com/d/optout.
>
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Re: [go-nuts] Panic getting swallowed by defer in Go 1.11
On Mon, Sep 3, 2018, at 04:10, ama...@naucera.net wrote:
> type S []int
>
> func (s *S) Last() int {
> return (*s)[len(*s) - 1]
> }
On an unrelated matter, the extra indirection is (probably) not what you want
here, slices are already a pointer type. For more information see
https://blog.golang.org/go-slices-usage-and-internals.
That is to say, the following works in more or less the same way (and is much
easier to read):
func (s S) Last() int {
return s[len(s)-1]
}
Apologies if this is something you're already aware of; for future generations
finding this thread I wanted to mention it.
—Sam
--
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"golang-nuts" group.
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Re: [go-nuts] Panic getting swallowed by defer in Go 1.11
I suspect that you've just run into some variation on
https://github.com/golang/go/issues/27378
Giovanni/Daniel/others better placed might be able to confirm more
precisely however.
On Mon, 3 Sep 2018 at 17:49, wrote:
>
> Hi all,
>
> Since Go 1.11, the following test seems to pass when I would expect it to
> panic with index out of range:
>
> package weirdness
>
> import "testing"
>
>
> type S []int
>
> func (s *S) Last() int {
> return (*s)[len(*s) - 1]
> }
>
>
> func TestWeirdness(t *testing.T) {
> var s S
>
> defer func() {}()
>
> s.Last()
> }
>
> Strangely, if the declaration of the s variable is moved below the defer, it
> panics as expected. Any idea what’s going on?
>
> --
> You received this message because you are subscribed to the Google Groups
> "golang-nuts" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to golang-nuts+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
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