fix substr outside of string in Mojo::Asset::Memory

[leejo]

We updated to v6.62 (from v6.42) this morning and are seeing some odd behaviour, after a restart we sometimes get pages rendered as the raw HTML as if the headers are being sent through twice. We're still investigating this.

The one thing i do notice is substr outside of string at lib/perl5/site_perl/5.16.3/Mojo/Asset/Memory.pm line 41 warnings since the update. I've included a PR here to fix this issue. The important point is that a substr outside of a string will return undef and if that is being fed into length then unexpected things might be happening, observe:

> perl -E 'say length(substr("foo",4))'

> perl -E 'say length(substr("foo",3))'
0

[kraih]

Thanks for your effort, but i'm afraid this pull request did not pass the vote.

[mattp-]

seeing this as well, unsure what the cause is. if there is a reason this was rejected, can you help explain how to stop this warning from occurring?

[kraih]

@mattp- This was submitted as a new feature, instead of a bug fix. Which means it needs a certain number of votes to be accepted, and that it did not reach.

[mattp-]

ah ok. I actually just realized what was causing this for any future people who stumble upon this kind of issue:
I was rendering twice by calling $c->reply->not_found, but not actually returning in the controller method itself, so a second render was occurring with null/undef being returned. thanks for the quick response.