Fix bad reference to Sprockets::Asset.pathname

[subdigital]

I came across this error after upgrading a project to Sprockets 4.0 that uses inline_svg:

undefined method `pathname' for #Sprockets::Asset:0x00007f838e266b50

I'm not sure when this changed, but this PR adds in support for it. Let me know if there's anything more defensive we should do here... (like respond_to? checks for the old way?)

Also fixed up the credit URL in the comment, as that original repo has since been deleted.

[jamesmartin]

Thanks for the PR @subdigital. ✨

I'm a little surprised that I haven't run into this before with my test app, which I use to test this gem on versions 3, 4, 5 and 6 of Rails. I guess Sprockets 4.0 was only released a month ago (even though it's been in beta for a couple of years), so I probably need to go update my test app! 😆

In any case, this looks good, but I'll give it some thorough testing on the older versions of Rails before merging. 👍

[olleolleolle]

The Sprockets change this is about happened between v3 and v4.

These two commits explain why the above change is good as it stands:

• This commit deprecated Sprockets::Asset#pathname and said to use the #filename instead:
  rails/sprockets@d34a2d0#diff-e4d6c4197c87667f5f828ec89f40c8df
• This commit "Pull require pathname into sprockets/legacy.rb" moved the require:
  rails/sprockets@ff847ea#diff-e4d6c4197c87667f5f828ec89f40c8df

[kylefox]

Just curious, is this backwards-compatible with Sprockets 3?

[jamesmartin]

Just curious, is this backwards-compatible with Sprockets 3?

I just tested this locally with a Rails 5 App using Sprockets 3 and it seems to work just fine. Was there anything in particular that you're concerned about, @kylefox? 🤔

Also, I merged @subdigital's changes into a temporary branch in this repo and let the integration tests run, which all passed.

[kylefox]

Was there anything in particular that you're concerned about

@jamesmartin Nothing in particular, no — I just know our team has run into a handful of cryptic errors (originating in other libraries, not inline_svg) related to Sprockets 3, which unfortunately our app is stuck to for the time being 😕

Thanks for checking, I'll give this a whirl at some point myself. But don't hold up a merge/release because of me 👍

[jamesmartin]

Released in patch version v1.7.1.