fix: 🚨 Fix pedantic clippy warnings

Author: twihno

envconfig/src/error.rs

@@ -13,10 +13,10 @@ impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             Error::EnvVarMissing { name } => {
-                write!(f, "Environment variable {} is missing", name)
+                write!(f, "Environment variable {name} is missing")
             }
             Error::ParseError { name } => {
-                write!(f, "Failed to parse environment variable {}", name)
+                write!(f, "Failed to parse environment variable {name}")
             }
         }
     }

envconfig/src/traits.rs

@@ -4,7 +4,11 @@ use std::collections::HashMap;
 /// Indicates that structure can be initialize from environment variables.
 pub trait Envconfig {
     /// Initialize structure from environment variables.
-    /// Deprecated in favor of init_from_env().
+    /// Deprecated in favor of [`::init_from_env()`].
+    ///
+    /// # Errors
+    /// - Environment variable is missing.
+    /// - Failed to parse environment variable.
     #[deprecated(
         since = "0.9.0",
         note = "Function init() is deprecated. Please use init_from_env() instead."
@@ -14,11 +18,19 @@ pub trait Envconfig {
         Self: Sized;
 
     /// Initialize structure from environment variables.
+    ///
+    /// # Errors
+    /// - Environment variable is missing.
+    /// - Failed to parse environment variable.
     fn init_from_env() -> Result<Self, Error>
     where
         Self: Sized;
 
     /// Initialize structure from a hashmap.
+    ///
+    /// # Errors
+    /// - Environment variable is missing.
+    /// - Failed to parse environment variable.
     fn init_from_hashmap(hashmap: &HashMap<String, String>) -> Result<Self, Error>
     where
         Self: Sized;

envconfig/src/utils.rs

@@ -5,18 +5,19 @@ use crate::error::Error;
 use std::collections::HashMap;
 
 /// Load an environment variable by name and parse it into type `T`.
-/// The function is used by `envconfig_derive` to implement `init()`.
 ///
-/// It returns `Error` in the following cases:
+/// This function can also use a hashmap as a fallback or for testing purposes.
+///
+/// # Errors
 /// - Environment variable is not present
 /// - Parsing failed
-pub fn load_var<T: FromStr>(
+pub fn load_var<T: FromStr, S: ::std::hash::BuildHasher>(
     var_name: &'static str,
-    hashmap: Option<&HashMap<String, String>>,
+    hashmap: Option<&HashMap<String, String, S>>,
 ) -> Result<T, Error> {
     match hashmap {
         None => env::var(var_name).ok(),
-        Some(hashmap) => hashmap.get(var_name).map(|val| val.to_string()),
+        Some(hashmap) => hashmap.get(var_name).map(std::string::ToString::to_string),
     }
     .ok_or(Error::EnvVarMissing { name: var_name })
     .and_then(|string_value| {
@@ -26,14 +27,21 @@ pub fn load_var<T: FromStr>(
     })
 }
 
-pub fn load_var_with_default<T: FromStr>(
+/// Tries to load an environment variable by name and parse it into type `T`.
+/// If the environment variable is not present, it returns a default value.
+///
+/// This function can also use a hashmap as a fallback or for testing purposes.
+///
+/// # Errors
+/// - Parsing failed
+pub fn load_var_with_default<T: FromStr, S: ::std::hash::BuildHasher>(
     var_name: &'static str,
-    hashmap: Option<&HashMap<String, String>>,
+    hashmap: Option<&HashMap<String, String, S>>,
     default: &'static str,
 ) -> Result<T, Error> {
     let opt_var = match hashmap {
         None => env::var(var_name).ok(),
-        Some(hashmap) => hashmap.get(var_name).map(|val| val.to_string()),
+        Some(hashmap) => hashmap.get(var_name).map(std::string::ToString::to_string),
     };
 
     let string_value = match opt_var {
@@ -46,13 +54,20 @@ pub fn load_var_with_default<T: FromStr>(
         .map_err(|_| Error::ParseError { name: var_name })
 }
 
-pub fn load_optional_var<T: FromStr>(
+/// Tries to load an environment variable by name and parse it into type `T`.
+/// If the environment variable is not present, it returns `None`.
+///
+/// This function can also use a hashmap as a fallback or for testing purposes.
+///
+/// # Errors
+/// - Parsing failed
+pub fn load_optional_var<T: FromStr, S: ::std::hash::BuildHasher>(
     var_name: &'static str,
-    hashmap: Option<&HashMap<String, String>>,
+    hashmap: Option<&HashMap<String, String, S>>,
 ) -> Result<Option<T>, Error> {
     let opt_var = match hashmap {
         None => env::var(var_name).ok(),
-        Some(hashmap) => hashmap.get(var_name).map(|val| val.to_string()),
+        Some(hashmap) => hashmap.get(var_name).map(std::string::ToString::to_string),
     };
 
     match opt_var {

envconfig_derive/Cargo.toml

@@ -17,6 +17,6 @@ workspace = true
 proc-macro = true
 
 [dependencies]
-syn = { version = "2.0.76", features = ["parsing", "derive"] }
+syn = { version = "2.0.77", features = ["parsing", "derive"] }
 quote = { version = "1.0.37", features = [] }
 proc-macro2 = { version = "1.0.86", features = [] }