As I was playing with --bundle-uri again, I found a new oddity: git doesn't seem to follow redirects when resolving the URI, and the error feedback is less than ideal.
One of the few projects which seem to publicly use and advertise bundles (or at least one of the few that's easy to find) is the kernel, they have a pages recommending either using a custom script[0] or fetching the bundle locally then cloning it[1] -- the latter in order to resume the bundle download on poor connections. I figured I could just
git clone --bundle-uri=https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/clone.bundle https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
however that immediately prints
warning: failed to download bundle from URI
'https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/clone.bundle'
warning: failed to fetch objects from bundle URI
'https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/clone.bundle'From what I understand, this is because the bundle-uri above is a permanent redirect to https://mirrors.edge.kernel.org/pub/scm/.bundles/pub/scm/linux/kernel/git/torvalds/linux/clone.bundle, and while wget will follow redirects by default that is not the case of curl. Thus git finds itself with essentially no content, and definitely not bundle content.
[0]: https://www.kernel.org/best-way-to-do-linux-clones-for-your-ci.html [1]: https://www.kernel.org/cloning-linux-from-a-bundle.html