It looks like it's successful at restoring the cache, but it's not faster to build. It still counts from 1 to 165. Is it using the cache?

In retrospect, sorry for suggesting caching the build folder! I was just interested in the idea of caching the build, but knew I didn't know how to do it.

Timestamps may be a problem. Not sure meson cache is meant to be restored like this.

Could ccache be another option (in case you haven't thought of it already)?

Yes, that's what I realized we'd have to do! You can't cache meson this way because of timestamps.

We should not be building N times for a given Python version on a given platform. Build once, test several configurations?

What configurations do you have other than different platforms/Python versions? Different versions of other dependencies?

(That said, this will already be a huge improvement, so besides getting the cache working, optimizations could be a follow-up.)

For any given platform, we build with a known set of dependencies. But, you're right, that can be a secondary optimization.

It doesn't look like ccache helped here 🤔

OK, the caching is roughly working. Takes a build down from ~4.5mins to ~1min. Will need to adjust the CI a bit, because looks like the caching is too granular. E.g., the pre-build still rebuilds from source, despite having access to a cache (hits: <2%).

Hello scikit-image core devs! There hasn't been any activity on this PR for more than 180 days. I have marked it as "dormant" to make it easy to find.

To our contributors, thank you for your contribution and apologies if this contribution fell through the cracks! Hopefully this ping will help bring some fresh attention to the review. If you need help, you can always reach out on our forum

If you think that this PR is no longer relevant, you may close it, or we may do it at some point (either way, it will be done manually). If you think the PR is valuable but you no longer have the bandwidth to update it, please let us know, so that someone can take it over. 🙏