Trait EnvSource 

pub trait EnvSource: Send + Sync {
    // Required method
    fn var(&self, name: &str) -> Option<String>;

    // Provided method
    fn vars(&self) -> Vec<(String, String)> { ... }
}

Read-only lookup for an environment variable name.

Production code wires up ProcessEnvSource (which calls std::env::var). Tests wire up MapEnvSource to drive deterministic branches without mutating the process env.

Required Methods

fn var(&self, name: &str) -> Option<String>

Look up name and return its value, or None if unset.

Provided Methods

fn vars(&self) -> Vec<(String, String)>

Snapshot every (name, value) pair this source can enumerate.

Callers that need to scan the whole env (e.g. the determinism harness’s Windows inherit-everything pass, which drops a credential deny-list out of the host env) use this instead of std::env::vars() so a test can inject a closed map of fixture entries. The default implementation returns an empty Vec so any source that only supports point lookups (a stub, a small fixture) stays usable for var(...)-only call sites without extra boilerplate.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl EnvSource for MapEnvSource

impl EnvSource for ProcessEnvSource