Fix #302

[nholland94]

Fixes#302 by adding an extra check for null sources.

[tromey]

I suspect that in the case where aRelativePath is non-null and mapping.source is null, that this should evaluate to aRelativePath.

So maybe this ought to be fixed in util.join instead; that function already tries to handle the empty string, changing it to handle null and/or undefined as well seems reasonable.

What do you think?

[nholland94]

That makes sense. I will change that and push up the new change soon.

[codehag]

This pr has been open for a long time, what is the current status? is it still relevant?

[tromey]

I think the bug still exists, but this patch still needs an update and a test case.

[nholland94]

I apologize for the lack of update on this in so long. I had forgotten about this, but the new comments notified my and reminded me of this.

I moved the check for undefined mapping source into the util.join function as originally discussed.

[jasonLaster]

Ping @nholland94 do you think you could help add a test?

[loganfsmyth]

Do we know where the null source value is coming from? It's not really clear that anything other than a string should be allowed, so I'm wondering if fixing it at the source would be a better solution.

[loganfsmyth]

I've landed #371 which removes all this logic, so I'm going to close this. If this is still an issue, let's continue the discussion in #302

[nikolay-borzov]

null source value might come from webpack generated code. You can use create-react-app to get source map with null source