Broken top navigation links at 404 page

[jounderwood]

1. Go to non existing page, for example - https://reactjs.org/component-api.md (I get it from react native docs "React.Component API" https://facebook.github.io/react-native/docs/state.html)
2. Click on any top navigation link "Docs", "Tutorial", etc.

Errors in console

Tried in latest chrome and safari.

[gaearon]

Looks related to #365.
cc @KyleAMathews

[bvaughn]

Yeah, sounds like the same thing I'm describing in this comment. ☹️

Thanks for reporting. We'll try to dig into this soon.

[bvaughn]

Unfortunately this can't be repro'd in dev mode because Gatsby handles 404s very different in dev vs prod. Shortest path to repro locally is yarn build && serve ./public.

The error is from trying to push to window.___history which doesn't exist.

My current guess is that Gatsby isn't properly executing this code which sets window.___history = history in the event of a 404. (I think the short-circuit here prevents the attachment code from running.)

[bvaughn]

Just as a proof-of-concept, I added a line to this short-circuit that sets a dummy window.___history:

if (!page) {
  console.log(`A page wasn't found for "${path}"`)
  window.___history = []; // TEST
  return
}

This prevents the undefined runtime error (but doesn't "fix" things since this isn't the react-router history object).

[bvaughn]

It's interesting to note that this defect doesn't seem to impact the Gatsby site.

Just to rule it out, I did a quick yarn upgrade-interactive bump of Gatsby and all of its plug-ins locally and...it seems to fix this issue 😅 I'll test further and submit a PR shortly.

[KyleAMathews]

Sorry for not being able to jump on this :-( in a gazillion meetings today but I'll get on this tonight and look into why it could be undefined.

[bvaughn]

No problem Kyle. I started digging into it before I realized that it wasn't happening on the Gatsby site, at which point I updated all of the Gatsby plugins and now it doesn't happen on the React site either. 😄

We could bisect to find out when it was fixed, if it's important to know.

[KyleAMathews]

@ataylorme reported this on a site he's building where it's happening on every initial page load — with that I was able to dive into the issue and make this PR gatsbyjs/gatsby#3313

It's out in the latest gatsby release.

[bvaughn]

🎉 Nice!