Merge pull request #4 from kherge/enhancement/3

Enhancement/3

.github/workflows/test.yml

@@ -32,4 +32,4 @@ jobs:
         uses: actions-rs/cargo@v1
         with:
           command: clippy
-          args: --all-targets --all-features
+          args: --all-targets --all-features -- -D warnings

src/error.rs

@@ -68,7 +68,7 @@
 //!     No such file or directory (os error 2)
 //! ```
 
-use std::{fmt, io, process, sync};
+use std::{fmt, process};
 
 /// A trait to add context to an error result.
 ///
@@ -265,22 +265,42 @@ impl fmt::Display for Error {
     }
 }
 
-impl From<io::Error> for Error {
-    fn from(error: io::Error) -> Self {
-        Self {
-            context: None,
-            message: Some(error.to_string()),
-            status: error.raw_os_error().unwrap_or(1),
+impl<T: std::error::Error + 'static> From<T> for Error {
+    fn from(error: T) -> Self {
+        let mut context = None;
+        let mut current = &error as &dyn std::error::Error;
+        let message;
+        let mut status = 1;
+
+        // Allow for error source traversal.
+        loop {
+            // If not at the lowest level, capture the error as context.
+            if let Some(next) = current.source() {
+                context
+                    .get_or_insert_with(Vec::new)
+                    .push(current.to_string());
+
+                current = next;
+
+            // If at the lowest level, capture the message.
+            } else {
+                message = Some(current.to_string());
+
+                // If std::io::Error, capture the OS error code as the status.
+                if let Some(other) = current.downcast_ref::<std::io::Error>() {
+                    if let Some(code) = other.raw_os_error() {
+                        status = code;
+                    }
+                }
+
+                break;
+            }
         }
-    }
-}
 
-impl<T> From<sync::PoisonError<T>> for Error {
-    fn from(error: sync::PoisonError<T>) -> Self {
         Self {
-            context: None,
-            message: Some(error.to_string()),
-            status: 1,
+            context,
+            message,
+            status,
         }
     }
 }
@@ -594,6 +614,51 @@ mod test {
         );
     }
 
+    #[test]
+    fn from_error() {
+        fn generate_error() -> Result<()> {
+            fn source_error() -> Result<()> {
+                let _ = std::fs::File::open("/should/not/exist")?;
+
+                Ok(())
+            }
+
+            source_error().context(|| "The lower level message.")?;
+
+            Ok(())
+        }
+
+        let error = generate_error()
+            .context(|| "The higher level message.")
+            .unwrap_err();
+
+        assert_eq!(
+            error.context,
+            Some(vec![
+                "The lower level message.".to_string(),
+                "The higher level message.".to_string()
+            ])
+        );
+
+        #[cfg(not(windows))]
+        {
+            assert_eq!(
+                error.message,
+                Some("No such file or directory (os error 2)".to_string())
+            );
+            assert_eq!(error.status, 2);
+        }
+
+        #[cfg(windows)]
+        {
+            assert_eq!(
+                error.message,
+                Some("The system cannot find the path specified. (os error 3)".to_string())
+            );
+            assert_eq!(error.status, 3);
+        }
+    }
+
     #[test]
     fn result_context() {
         let err: Result<()> = Err(Error::default()).context(|| "The context message.");

src/io.rs

@@ -529,7 +529,7 @@ mod test {
 
             assert_eq!(vec, b"test");
         } else {
-            assert!(false, "Unexpected StreamKind.");
+            panic!("Unexpected StreamKind.");
         }
     }