crates.io feature validation inconsistent with cargo/rustc

[iliekturtles]

crates.io's feature validation is inconsistent and rejects features with "." even though these features are accepted by cargo/rustc. This validation isn't applied when using cargo publish --dry-run.

$ cargo publish
...
   Uploading uom v0.18.0 (file:///S:/uom)
error: api errors: invalid upload request: invalid value: string "1.20.0", expected a valid feature name
 containing only letters, numbers, hyphens, or underscores at line 1 column 931

This appears to be the check:

crates.io/src/views/krate_publish.rs

Line 110 in 0ccbf09

if !Crate::valid_feature_name(&s) {

As a workaround I was able to change the 1.20.0 feature to 1_20_0.

[sgrif]

@alexcrichton Is cargo intended to accept this feature name?

[alexcrichton]

Currently yeah it's intended to reject that, we wanted to stick to "mostly rust identifiers" for now

[sgrif]

Thanks! @iliekturtles the bug is in Cargo not crates.io. It should be getting rejected there.

[iliekturtles]

Great, will submit a new issue this week!