refac: made error simple

... and remove failure package

itconfig-tests/tests/get_env.rs

@@ -20,7 +20,7 @@ fn get_env_with_invalid_value() {
 fn get_result_of_missing_env() {
     let env_name = String::from("TEST_CASE_3");
     let env_val = get_env::<String>(&env_name);
-    assert_eq!(env_val, Err(MissingVariable { env_name }))
+    assert_eq!(env_val, Err(MissingVariable(env_name)))
 }
 
 #[test]
@@ -28,7 +28,7 @@ fn get_result_of_env_with_invalid_value() {
     let env_name = String::from("TEST_CASE_4");
     env::set_var(&env_name, "30r");
     let env_val = get_env::<u32>(&env_name);
-    assert_eq!(env_val, Err(FailedToParse { env_name }))
+    assert_eq!(env_val, Err(FailedToParse(env_name)))
 }
 
 #[test]

itconfig/Cargo.toml

@@ -15,8 +15,7 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-failure = { version = "0.1.7", features = ["derive"]}
+serde_json = { version = "1", optional = true }
-serde_json = { version = "1.0.44", optional = true }
 itconfig-macro = { version = "1.0", path = "../itconfig-macro", optional = true }
 
 [dev-dependencies]

itconfig/src/enverr.rs

@@ -1,9 +0,0 @@
-use failure::Fail;
-
-#[derive(Debug, Fail, PartialEq)]
-pub enum EnvError {
-    #[fail(display = r#"Environment variable "{}" is missing"#, env_name)]
-    MissingVariable { env_name: String },
-    #[fail(display = r#"Failed to parse environment variable "{}""#, env_name)]
-    FailedToParse { env_name: String },
-}

itconfig/src/error.rs

@@ -0,0 +1,23 @@
+use std::error;
+use std::fmt;
+
+#[derive(Debug, PartialEq)]
+pub enum EnvError {
+    MissingVariable(String),
+    FailedToParse(String),
+}
+
+impl fmt::Display for EnvError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match &self {
+            EnvError::MissingVariable(env_name) => {
+                write!(f, r#"Environment variable "{}" is missing"#, env_name)
+            }
+            EnvError::FailedToParse(env_name) => {
+                write!(f, r#"Failed to parse environment variable "{}""#, env_name)
+            }
+        }
+    }
+}
+
+impl error::Error for EnvError {}

itconfig/src/getenv.rs

@@ -40,9 +40,7 @@ where
     T: FromEnvString,
 {
     get_env_or(env_name, |_| {
-        Err(EnvError::MissingVariable {
+        Err(EnvError::MissingVariable(env_name.to_string()))
-            env_name: env_name.to_string(),
-        })
     })
 }
 
@@ -130,9 +128,9 @@ fn parse_env_variable<T>(env_name: &str, env_str: EnvString) -> Result<T, EnvErr
 where
     T: FromEnvString,
 {
-    env_str.parse::<T>().map_err(|_| EnvError::FailedToParse {
+    env_str
-        env_name: env_name.to_string(),
+        .parse::<T>()
-    })
+        .map_err(|_| EnvError::FailedToParse(env_name.to_string()))
 }
 
 #[doc(hidden)]

itconfig/src/lib.rs

@@ -144,22 +144,21 @@
     unused_imports,
     unused_qualifications
 )]
+#![deny(clippy::all)]
+#![allow(clippy::needless_doctest_main)]
 
 /////////////////////////////////////////////////////////////////////////////
 
-#[macro_use]
-extern crate failure;
-
-mod enverr;
 pub mod envstr;
+mod error;
 mod getenv;
 
-pub use self::enverr::*;
+pub use self::error::*;
 pub use self::getenv::*;
 
 pub mod prelude {
-    pub use crate::enverr::*;
     pub use crate::envstr::*;
+    pub use crate::error::*;
 }
 
 #[cfg(feature = "macro")]