Make ConfigBuilder's method consuming

13 files changed, 124 insertions, 131 deletions

diff --git a/src/builder.rs b/src/builder.rs
index 8c0e82d..627ba2a 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -27,11 +27,10 @@ use crate::{config::Config, error, path::Expression, source::Source, value::Valu
 /// # use config::*;
 /// # use std::error::Error;
 /// # fn main() -> Result<(), Box<dyn Error>> {
-/// let mut builder = ConfigBuilder::default();
-///
-/// builder.set_default("default", "1")?;
-/// builder.add_source(File::new("config/settings", FileFormat::Json));
-/// builder.set_override("override", "1")?;
+/// let mut builder = ConfigBuilder::default()
+///     .set_default("default", "1")?
+///     .add_source(File::new("config/settings", FileFormat::Json))
+///     .set_override("override", "1")?;
 ///
 /// match builder.build() {
 ///     Ok(config) => {
@@ -45,18 +44,16 @@ use crate::{config::Config, error, path::Expression, source::Source, value::Valu
 /// # }
 /// ```
 ///
-/// Calls can be chained as well
+/// Calls can be not chained as well
 /// ```rust
 /// # use std::error::Error;
 /// # use config::*;
 /// # fn main() -> Result<(), Box<dyn Error>> {
 /// let mut builder = ConfigBuilder::default();
-///
-/// builder
-///     .set_default("default", "1")?
-///     .add_source(File::new("config/settings", FileFormat::Json))
-///     .add_source(File::new("config/settings.prod", FileFormat::Json))
-///     .set_override("override", "1")?;
+/// builder = builder.set_default("default", "1")?;
+/// builder = builder.add_source(File::new("config/settings", FileFormat::Json));
+/// builder = builder.add_source(File::new("config/settings.prod", FileFormat::Json));
+/// builder = builder.set_override("override", "1")?;
 /// # Ok(())
 /// # }
 /// ```
@@ -75,7 +72,7 @@ impl ConfigBuilder {
     /// # Errors
     ///
     /// Fails if `Expression::from_str(key)` fails.
-    pub fn set_default<S, T>(&mut self, key: S, value: T) -> error::Result<&mut ConfigBuilder>
+    pub fn set_default<S, T>(mut self, key: S, value: T) -> error::Result<ConfigBuilder>
     where
         S: AsRef<str>,
         T: Into<Value>,
@@ -88,7 +85,7 @@ impl ConfigBuilder {
     /// Registers new [`Source`] in this builder.
     ///
     /// Calling this method does not invoke any I/O. [`Source`] is only saved in internal register for later use.
-    pub fn add_source<T>(&mut self, source: T) -> &mut Self
+    pub fn add_source<T>(mut self, source: T) -> Self
     where
         T: Source + Send + Sync + 'static,
     {
@@ -103,7 +100,7 @@ impl ConfigBuilder {
     /// # Errors
     ///
     /// Fails if `Expression::from_str(key)` fails.
-    pub fn set_override<S, T>(&mut self, key: S, value: T) -> error::Result<&mut ConfigBuilder>
+    pub fn set_override<S, T>(mut self, key: S, value: T) -> error::Result<ConfigBuilder>
     where
         S: AsRef<str>,
         T: Into<Value>,
diff --git a/tests/datetime.rs b/tests/datetime.rs
index 1bdce3c..2b0c22d 100644
--- a/tests/datetime.rs
+++ b/tests/datetime.rs
@@ -14,9 +14,7 @@ use chrono::{DateTime, TimeZone, Utc};
 use config::*;
 
 fn make() -> Config {
-    let mut builder = Config::builder();
-
-    builder
+    Config::builder()
         .add_source(File::from_str(
             r#"
             {
@@ -58,9 +56,9 @@ fn make() -> Config {
             )
             "#,
             FileFormat::Ron,
-        ));
-
-    builder.build().unwrap()
+        ))
+        .build()
+        .unwrap()
 }
 
 #[test]
diff --git a/tests/errors.rs b/tests/errors.rs
index b47d821..54bbe95 100644
--- a/tests/errors.rs
+++ b/tests/errors.rs
@@ -10,16 +10,17 @@ use std::path::PathBuf;
 use config::*;
 
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Toml));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Toml))
+        .build()
+        .unwrap()
 }
 
 #[test]
 fn test_error_parse() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings-invalid", FileFormat::Toml));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Toml))
+        .build();
 
     let path: PathBuf = ["tests", "Settings-invalid.toml"].iter().collect();
 
@@ -120,9 +121,13 @@ inner:
     test: ABC
 "#;
 
-    let mut cfg = Config::builder();
-    cfg.add_source(File::from_str(CFG, FileFormat::Yaml));
-    let e = cfg.build().unwrap().try_into::<Outer>().unwrap_err();
+    let e = Config::builder()
+        .add_source(File::from_str(CFG, FileFormat::Yaml))
+        .build()
+        .unwrap()
+        .try_into::<Outer>()
+        .unwrap_err();
+
     if let ConfigError::Type {
         key: Some(path), ..
     } = e
diff --git a/tests/file.rs b/tests/file.rs
index 8292426..c282691 100644
--- a/tests/file.rs
+++ b/tests/file.rs
@@ -6,18 +6,18 @@ use config::*;
 
 #[test]
 fn test_file_not_required() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/NoSettings", FileFormat::Yaml).required(false));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/NoSettings", FileFormat::Yaml).required(false))
+        .build();
 
     assert!(res.is_ok());
 }
 
 #[test]
 fn test_file_required_not_found() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/NoSettings", FileFormat::Yaml));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/NoSettings", FileFormat::Yaml))
+        .build();
 
     assert!(res.is_err());
     assert_eq!(
@@ -28,10 +28,10 @@ fn test_file_required_not_found() {
 
 #[test]
 fn test_file_auto() {
-    let mut builder = Config::builder();
-    builder.add_source(File::with_name("tests/Settings-production"));
-
-    let c = builder.build().unwrap();
+    let c = Config::builder()
+        .add_source(File::with_name("tests/Settings-production"))
+        .build()
+        .unwrap();
 
     assert_eq!(c.get("debug").ok(), Some(false));
     assert_eq!(c.get("production").ok(), Some(true));
@@ -39,9 +39,9 @@ fn test_file_auto() {
 
 #[test]
 fn test_file_auto_not_found() {
-    let mut c = Config::builder();
-    c.add_source(File::with_name("tests/NoSettings"));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::with_name("tests/NoSettings"))
+        .build();
 
     assert!(res.is_err());
     assert_eq!(
@@ -52,10 +52,10 @@ fn test_file_auto_not_found() {
 
 #[test]
 fn test_file_ext() {
-    let mut builder = Config::builder();
-    builder.add_source(File::with_name("tests/Settings.json"));
-
-    let c = builder.build().unwrap();
+    let c = Config::builder()
+        .add_source(File::with_name("tests/Settings.json"))
+        .build()
+        .unwrap();
 
     assert_eq!(c.get("debug").ok(), Some(true));
     assert_eq!(c.get("production").ok(), Some(false));
diff --git a/tests/file_hjson.rs b/tests/file_hjson.rs
index 5d9f24d..4002a90 100644
--- a/tests/file_hjson.rs
+++ b/tests/file_hjson.rs
@@ -35,9 +35,10 @@ struct Settings {
 }
 
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Hjson));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Hjson))
+        .build()
+        .unwrap()
 }
 
 #[test]
@@ -66,9 +67,9 @@ fn test_file() {
 
 #[test]
 fn test_error_parse() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings-invalid", FileFormat::Hjson));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Hjson))
+        .build();
 
     let path: PathBuf = ["tests", "Settings-invalid.hjson"].iter().collect();
 
diff --git a/tests/file_ini.rs b/tests/file_ini.rs
index 1f57272..332d3ea 100644
--- a/tests/file_ini.rs
+++ b/tests/file_ini.rs
@@ -28,9 +28,10 @@ struct Settings {
 }
 
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Ini));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Ini))
+        .build()
+        .unwrap()
 }
 
 #[test]
@@ -55,9 +56,9 @@ fn test_file() {
 
 #[test]
 fn test_error_parse() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings-invalid", FileFormat::Ini));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Ini))
+        .build();
 
     let path: PathBuf = ["tests", "Settings-invalid.ini"].iter().collect();
 
diff --git a/tests/file_json.rs b/tests/file_json.rs
index 9d457e4..4563e42 100644
--- a/tests/file_json.rs
+++ b/tests/file_json.rs
@@ -35,9 +35,10 @@ struct Settings {
 }
 
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Json));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Json))
+        .build()
+        .unwrap()
 }
 
 #[test]
@@ -66,9 +67,9 @@ fn test_file() {
 
 #[test]
 fn test_error_parse() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings-invalid", FileFormat::Json));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Json))
+        .build();
 
     let path_with_extension: PathBuf = ["tests", "Settings-invalid.json"].iter().collect();
 
@@ -84,17 +85,17 @@ fn test_error_parse() {
 
 #[test]
 fn test_json_vec() {
-    let mut builder = Config::builder();
-    builder.add_source(File::from_str(
-        r#"
+    let c = Config::builder()
+        .add_source(File::from_str(
+            r#"
             {
               "WASTE": ["example_dir1", "example_dir2"]
             }
             "#,
-        FileFormat::Json,
-    ));
-
-    let c = builder.build().unwrap();
+            FileFormat::Json,
+        ))
+        .build()
+        .unwrap();
 
     let v = c.get_array("WASTE").unwrap();
     let mut vi = v.into_iter();
diff --git a/tests/file_ron.rs b/tests/file_ron.rs
index 1e5c6d3..d60c890 100644
--- a/tests/file_ron.rs
+++ b/tests/file_ron.rs
@@ -36,9 +36,10 @@ struct Settings {
 }
 
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Ron));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Ron))
+        .build()
+        .unwrap()
 }
 
 #[test]
@@ -68,9 +69,9 @@ fn test_file() {
 
 #[test]
 fn test_error_parse() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings-invalid", FileFormat::Ron));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Ron))
+        .build();
 
     let path_with_extension: PathBuf = ["tests", "Settings-invalid.ron"].iter().collect();
 
diff --git a/tests/file_toml.rs b/tests/file_toml.rs
index cee80b7..9493bbd 100644
--- a/tests/file_toml.rs
+++ b/tests/file_toml.rs
@@ -44,9 +44,10 @@ struct Settings {
 
 #[cfg(test)]
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Toml));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Toml))
+        .build()
+        .unwrap()
 }
 
 #[test]
@@ -77,9 +78,9 @@ fn test_file() {
 
 #[test]
 fn test_error_parse() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings-invalid", FileFormat::Toml));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Toml))
+        .build();
 
     let path_with_extension: PathBuf = ["tests", "Settings-invalid.toml"].iter().collect();
 
diff --git a/tests/file_yaml.rs b/tests/file_yaml.rs
index 645829a..90feefc 100644
--- a/tests/file_yaml.rs
+++ b/tests/file_yaml.rs
@@ -35,9 +35,10 @@ struct Settings {
 }
 
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Yaml));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Yaml))
+        .build()
+        .unwrap()
 }
 
 #[test]
@@ -66,9 +67,9 @@ fn test_file() {
 
 #[test]
 fn test_error_parse() {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings-invalid", FileFormat::Yaml));
-    let res = c.build();
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Yaml))
+        .build();
 
     let path_with_extension: PathBuf = ["tests", "Settings-invalid.yaml"].iter().collect();
 
diff --git a/tests/get.rs b/tests/get.rs
index 10e2927..c6030ae 100644
--- a/tests/get.rs
+++ b/tests/get.rs
@@ -31,9 +31,10 @@ struct Settings {
 }
 
 fn make() -> Config {
-    let mut c = Config::builder();
-    c.add_source(File::new("tests/Settings", FileFormat::Toml));
-    c.build().unwrap()
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Toml))
+        .build()
+        .unwrap()
 }
 
 #[test]
diff --git a/tests/merge.rs b/tests/merge.rs
index 5bb84da..9de36b2 100644
--- a/tests/merge.rs
+++ b/tests/merge.rs
@@ -5,11 +5,11 @@ extern crate config;
 use config::*;
 
 fn make() -> Config {
-    let mut builder = Config::builder();
-    builder
+    Config::builder()
         .add_source(File::new("tests/Settings", FileFormat::Toml))
-        .add_source(File::new("tests/Settings-production", FileFormat::Toml));
-    builder.build().unwrap()
+        .add_source(File::new("tests/Settings-production", FileFormat::Toml))
+        .build()
+        .unwrap()
 }
 
 #[test]
@@ -27,11 +27,8 @@ fn test_merge() {
 
 #[test]
 fn test_merge_whole_config() {
-    let mut builder1 = Config::builder();
-    let mut builder2 = Config::builder();
-
-    builder1.set_override("x", 10).unwrap();
-    builder2.set_override("y", 25).unwrap();
+    let builder1 = Config::builder().set_override("x", 10).unwrap();
+    let builder2 = Config::builder().set_override("y", 25).unwrap();
 
     let config1 = builder1.build_cloned().unwrap();
     let config2 = builder2.build_cloned().unwrap();
@@ -42,9 +39,7 @@ fn test_merge_whole_config() {
     assert_eq!(config2.get("y").ok(), Some(25));
     assert_eq!(config1.get::<()>("y").ok(), None);
 
-    builder1.add_source(config2);
-
-    let config3 = builder1.build().unwrap();
+    let config3 = builder1.add_source(config2).build().unwrap();
 
     assert_eq!(config3.get("x").ok(), Some(10));
     assert_eq!(config3.get("y").ok(), Some(25));
diff --git a/tests/set.rs b/tests/set.rs
index 956f123..4c827d8 100644
--- a/tests/set.rs
+++ b/tests/set.rs
@@ -4,11 +4,10 @@ use config::*;
 
 #[test]
 fn test_set_override_scalar() {
-    let mut builder = Config::builder();
-
-    builder.set_override("value", true).unwrap();
-
-    let config = builder.build().unwrap();
+    let config = Config::builder()
+        .set_override("value", true)
+        .and_then(|b| b.build())
+        .unwrap();
 
     assert_eq!(config.get("value").ok(), Some(true));
 }
@@ -16,17 +15,15 @@ fn test_set_override_scalar() {
 #[cfg(feature = "toml")]
 #[test]
 fn test_set_scalar_default() {
-    let mut builder = Config::builder();
-
-    builder
+    let config = Config::builder()
         .add_source(File::new("tests/Settings", FileFormat::Toml))
         .set_default("debug", false)
         .unwrap()
         .set_default("staging", false)
+        .unwrap()
+        .build()
         .unwrap();
 
-    let config = builder.build().unwrap();
-
     assert_eq!(config.get("debug").ok(), Some(true));
     assert_eq!(config.get("staging").ok(), Some(false));
 }
@@ -34,19 +31,17 @@ fn test_set_scalar_default() {
 #[cfg(feature = "toml")]
 #[test]
 fn test_set_scalar_path() {
-    let mut builder = Config::builder();
-
-    builder
+    let config = Config::builder()
         .set_override("first.second.third", true)
         .unwrap()
         .add_source(File::new("tests/Settings", FileFormat::Toml))
         .set_default("place.favorite", true)
         .unwrap()
         .set_default("place.blocked", true)
+        .unwrap()
+        .build()
         .unwrap();
 
-    let config = builder.build().unwrap();
-
     assert_eq!(config.get("first.second.third").ok(), Some(true));
     assert_eq!(config.get("place.favorite").ok(), Some(false));
     assert_eq!(config.get("place.blocked").ok(), Some(true));
@@ -55,9 +50,7 @@ fn test_set_scalar_path() {
 #[cfg(feature = "toml")]
 #[test]
 fn test_set_arr_path() {
-    let mut builder = Config::builder();
-
-    builder
+    let config = Config::builder()
         .set_override("items[0].name", "Ivan")
         .unwrap()
         .set_override("data[0].things[1].name", "foo")
@@ -68,10 +61,10 @@ fn test_set_arr_path() {
         .unwrap()
         .add_source(File::new("tests/Settings", FileFormat::Toml))
         .set_override("items[2]", "George")
+        .unwrap()
+        .build()
         .unwrap();
 
-    let config = builder.build().unwrap();
-
     assert_eq!(config.get("items[0].name").ok(), Some("Ivan".to_string()));
     assert_eq!(
         config.get("data[0].things[1].name").ok(),
@@ -85,16 +78,14 @@ fn test_set_arr_path() {
 #[cfg(feature = "toml")]
 #[test]
 fn test_set_capital() {
-    let mut builder = Config::builder();
-
-    builder
+    let config = Config::builder()
         .set_default("this", false)
         .unwrap()
         .set_override("ThAt", true)
         .unwrap()
-        .add_source(File::from_str("{\"logLevel\": 5}", FileFormat::Json));
-
-    let config = builder.build().unwrap();
+        .add_source(File::from_str("{\"logLevel\": 5}", FileFormat::Json))
+        .build()
+        .unwrap();
 
     assert_eq!(config.get("this").ok(), Some(false));
     assert_eq!(config.get("ThAt").ok(), Some(true));