Comment by LegionMammal978
15 hours ago
> The implicit update surface is somewhat limited by the fact that versions in Cargo.toml implicitly assume the `^` operator on versions that don't specify a different operator, so "1.2.3" means "1.2.x, where x >= 3". For reasons that have never been clear to me, people also seem to really like not putting the patch version in though and just putting stuff like "1.2", meaning that anything other than a major version bump will get pulled in.
Not quite: "1.2.3" = "^1.2.3" = ">=1.2.3, <2.0.0" in Cargo [0], and "1.2" = "^1.2.0" = ">=1.2.0, <2.0.0", so you get the "1.x.x" behavior either way. If you actually want the "1.2.x" behavior (e.g., I've sometimes used that behavior for gmp-mpfr-sys), you should write "~1.2.3" = ">=1.2.3, <1.3.0".
[0] https://doc.rust-lang.org/cargo/reference/specifying-depende...
I don't know how I got this wrong because I literally went and looked at that page to try to remind myself, but I somehow misread it, because you're definitely right. This probably isn't the first time I've gotten this wrong either.
From thinking it through more closely, it does actually seem like it might be a little safer to avoid specifying the patch version; it seems like putting 1.2.3 would fail to resolve any valid version in the case that 1.2.2 is the last non-yanked version and 1.2.3 is yanked. I feel like "1.2.3" meaning "~1.2.3" would have been a better default, since it at least provides some useful tradeoff compared to "1.2", but with the way it actually works, it seems like putting a full version with no operator is basically worse than either of the other options, which is disappointing.