Chrono 0.3.1 breaks backwards compatibility with Chrono 0.3.0

[Razican]

I am using Rocket 0.2.8, and for that, I need to use Serde 0.9 (for now). It worked great with chrono 0.3.0, but chrono 0.3.1 updates to Serde 1.0, which breaks backwards compatibility.

[SergioBenitez]

Indeed. @lifthrasiir, dcf1933 should have bumped the chrono version to 0.4. As it stands, semantic versioning has been broken, and any applications using chrono 0.3 are liable to break as a result. I'd recommend yanking chrono 0.3.1 and publishing 0.4 with the serde 1.0 upgrade.

Edit: I've read your commit message, which states:

Technically this is a breaking change, but the minor version was not
effective in avoiding dependency breakages anyway (because Cargo
will silently compile two versions of crates).

This is misguided. There's no issue with Cargo compiling two versions of a crate unless types are mixed between them. In that case, the user will get strange errors, yes, but if semantic versioning has been upheld, then the user can roll a dependency back or forward accordingly to resolve the issue. With your change, on the other hand, the user can't do this.

Please reconsider. This is bad precedent.

[quodlibetor]

related to #146 , where @lifthrasiir has commented.

FWIW I agree that having a semver-incompatible change in a patch release is an issue, especially since serde 1.0 already splits the ecosystem, it's easier to manage dependencies if chrono 0.4 is serde-1.0 compatible and chrono 0.3 is serde 0.9 compatible.

[durka]

This broke my code as well (the commit where I had to pin chrono along with the rest of my routine updates). I've submitted a PR to fix the issue.

[SergioBenitez]

@lifthrasiir Can you comment and/or remedy the situation?

[durka]

@SergioBenitez see #146 (comment)