Unstable Feature Usage Metrics

Unstable Feature Usage Metrics

Track unstable feature usage trends by Rust users.

Motivation

• Support feature stabilization prioritization.
• Helping teams know which unstable features to invest their energy into.
• Evaluating how representative crates.io is as a sample of the rust ecosystem (will we see different patterns in crates.io feature usage vs private feature usage?)

Context

• research paper on unstable feature usage in the rust ecosystem

Steps / History (PROVISIONAL)

• define the format the metrics will be stored in
• add flag to dump unstable feature status metrics (what features exist, if they're stable or not, both for library and lang/compiler, tidy may already support this for lib features)
• add flag to enable unstable feature usage metrics in the compiler
• front end to display reports based on gathered usage and status metrics
• back end to save metrics data from published crates.io crates (private data should be anonymous and stored separately once we have established the ability to gather that in a statistically relevant volume)
• integrate with docs.rs to have it gather metrics and upload them to the backend while building newly uploaded crate versions

Start by reviewing the existing compiler and tidy support for dumping unstable feature status and usage metrics, then examine the unchecked work involving metric storage, reporting, crates.io, and docs.rs. The issue is complete only when the remaining collection, storage, and reporting pieces have defined formats and working integrations.