Build Failure: env_logger doesn’t recognize feature anstream

[rootsza]

I’m experiencing a build failure when installing the eppo-server-sdk gem (version 3.3.0) because the underlying Rust crate (eppo_client) specifies a feature called anstream for env_logger, but env_logger doesn’t have a feature by that name.

error: failed to select a version for env_logger.
    ... required by package eppo_client v3.3.0 (...)
versions that meet the requirements ^0.11.3 (locked to 0.11.5) are: 0.11.5

the package `eppo_client` depends on `env_logger`, with features: `anstream` but `env_logger` does not have these features.
 It has an optional dependency with that name, but that dependency uses the "dep:" syntax in the features table, so it does not have an implicit feature with that name.

failed to select a version for `env_logger` which could resolve this conflict
make: *** [target/release/libeppo_client.dylib] Error 101

make failed, exit code 2

Steps to Reproduce

In a Ruby project, add gem 'eppo-server-sdk', '3.3.0' to your Gemfile.
Run bundle install (or gem install eppo-server-sdk -v 3.3.0).
Observe that the build fails with env_logger feature mismatch.

OS: macOS
Ruby version: 3.4.1
Bundler version: 2.5.9
eppo-server-sdk version: 3.3.0

[rasendubi]

hm, that's interesting because we don't specify anstream as a required feature...

Could you share full logs? What is you version of cargo?