Worklog

The irony: Netlify uses Deno but its Deno builder is so old it can't upgrade itself — 2025-06-18

So, this is strange. Netlify includes Deno as a possible build tool for website deploys. But the version is pretty out of date. I was getting irrecoverable lockfile version errors. I had found a solution offered by Very Bad Frags see here, which was to make the build command deno upgrade && deno task build. That worked; but now I was getting these lockfile version errors again.

It took me a while to find the cause. Only after I replaced the && with ; and saw the lockfile version error appearing twice did I discover that Deno was trying to parse the lockfile in the current directory when running the upgrade command. This has been fixed, but apparently Netlify's version of Deno predates this fix!

And so I seem to be stuck. I can't work around the older version of Deno that Netlify supplies. Do I have to install Deno manually with every build? Or can I cd somewhere else for the upgrade command? Sounds really fragile if it even works.

Well! It turns out that works. My build command in netlify.toml is now: cd ~; deno upgrade; cd - && deno task build. Wow, what a hacky workaround!

And the irony? Netlify uses Deno for its Edge functions.