CI: site generation failure should block PR merges

[StefanKarpinski]

https://www.julialang.org/blog/ is currently a 404

[logankilpatrick]

Yep, just pushed a commit but not clear as to why

[StefanKarpinski]

Locally, Franklin can't generate the site at all for me due to a syntax error in the JuliaCon highlights post.

[logankilpatrick]

Good catch. It really is the little things (:head-bang)

[rikhuijzer]

tlienart/Franklin.jl#785

[tlienart]

While I agree that Franklin should fail more explicitly and block the deployment, the current workflow to avoid this should be:

1. Get stuff locally and test them locally, if it fails there it will definitely not deploy properly
2. Check the preview, if you add new commits you'll have to do another PR as the preview doesn't get updated afaik
3. Merge

[giordano]

Preview doesn't work for pull requests from forks, which is the case for #1356. So at the moment we can't rely on always having the preview deployed

[StefanKarpinski]

I've changed the title to reflect that the blog is back but the root problem is that CI should prevent breaking the site by merging an apparently passing pull request.

[rikhuijzer]

I'm grepping the logs for "Franklin Warning" and this works well for a year already (https://github.com/rikhuijzer/huijzer.xyz/blob/main/.github/workflows/CI.yml). That's the easy solution.

If you want to make things really reliable, fix tlienart/Franklin.jl#785 or write your own logic and tests to verify that Julia exits with exit code 1 when there is a problem in the Markdown/embedded Julia code.

[tlienart]

@rikhuijzer would you mind maybe opening a PR here with your warning grepper? I'll eventually get to fixing 785 but not sure when and this seems pretty important :) thanks!