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by lobster_johnson 2949 days ago
The vgo proposal explicitly rejects the "Cargo way" [1]. There's no lock file, and the MVS algorithm requires, as far as I recall, that the go.mod file is modified whenever the developer wants to update to a new version.

[1] https://research.swtch.com/vgo-repro
1 comments
jchw 2948 days ago
Indeed, but it does seem like a central repository is possibly the direction it's headed, or at least away from source repositories. Personally, I won't be too upset by MVS if it's one of the only deviations, though I do agree with Sam Boyer on the matter, who I actually had the pleasure of speaking with a bit ago.
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steveklabnik 2948 days ago
Cargo doesn’t require a central repository at all, to be clear.
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dikaiosune 2948 days ago
I'd actually be interested to find out how Cargo's performance compares in a situation as TheDong describes where all of the dependencies are being fetched directly from git.

Part of me wants to say "well of course Rust's tool is faster" but it would be interesting to see just how much crates.io acts as a performance optimization for running builds, installing deps, etc.

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greysteil 2948 days ago
Cargo performs dependency resolution, so fetching from git would (and does) significantly slow it down - it wound need to perform git operations to get the tags for each dependency (quick) and then checkout each tag to look for the subdependencies of that package at that version (slow).

Having a central registry is a must for package managers that perform version resolution and want to do so quickly, as it can serve them all the metadata they need to do that resolution.

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steveklabnik 2948 days ago
My perception is that the initial clone is slow, but that’s it. A detailed comparison with actual numbers would be interesting!

When you depend on a git dep, you can say if you want a particular branch, tag, rev, whatever. So it’s only a clone + checkout. From there you read the Cargo.toml, same as anything else. That’s my understanding anyway, it’s been a while since I poked at the guts.

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greysteil 2948 days ago
You’re totally right - I was thinking of Composer, which does flat resolution for git sources so has to go through the above. Cargo sidesteps that issue completely by taking the head commit or whatever’s asked for :-)
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