uuid 0.7 not being used because of features in manifest

[jkcclemens]

Setup

Versions

• Rust: rust version 1.30.0 (da5f414c2 2018-10-24)
• Diesel: 1.3.3
• Database: Any
• Operating System: Any

Feature Flags

• diesel: uuid

Problem Description

As far as I can tell, uuid 0.7 will never be used because it doesn't match the requirements. While 0.7 is indeed >= 0.2 and < 0.8.0, it does not have a use_std feature, which locks uuid to 0.6. The feature was renamed to std in 0.7 and is a default feature.

I forked diesel and changed Cargo.toml to use std, then used a patch section in one of my projects. Updating to my fork removed uuid 0.6 and added uuid 0.7. Reverting back to the official git adds uuid 0.6 back.

Checklist

• I have already looked over the issue tracker for similar issues.
• This issue can be reproduced on Rust's stable channel. (Your issue will be
  closed if this is not the case)

[weiznich]

Uuid 0.7 get's never used because the last release of diesel has no support for uuid 0.7, only master supports the new version.

[jkcclemens]

No, master does not. That's why I made this issue.

master explicitly will not use uuid 0.7, since uuid 0.7 misses the feature that master requests.

[weiznich]

If uuid changed the name of that feature there is no way for diesel to support both versions. That means we cannot update uuid to a newer version without releasing diesel 2.0 because this would remove support for old versions of uuid.

[jkcclemens]

Perhaps you should revert #1861 to explicitly show that you won't support uuid 0.7, then.

For what it's worth, use_std was deprecated in uuid 0.6.

[weiznich]

For what it's worth, use_std was deprecated in uuid 0.6.

This doesn't help us because we also support older versions of uuid.