fix: Add key tracking for all error types

src/error.rs

@@ -78,6 +78,21 @@ pub enum ConfigError {
         key: Option<String>,
     },
 
+    /// Custom message
+    At {
+        /// Error being extended with a path
+        error: Box<ConfigError>,
+
+        /// The URI that references the source that the value came from.
+        /// Example: `/path/to/config.json` or `Environment` or `etcd://localhost`
+        // TODO: Why is this called Origin but FileParse has a uri field?
+        origin: Option<String>,
+
+        /// The key in the configuration hash of this value (if available where the
+        /// error is generated).
+        key: Option<String>,
+    },
+
     /// Custom message
     Message(String),
 
@@ -130,7 +145,17 @@ impl ConfigError {
                 key: Some(key.into()),
             },
 
-            _ => self,
+            Self::At { origin, error, .. } => Self::At {
+                error,
+                origin,
+                key: Some(key.into()),
+            },
+
+            other => Self::At {
+                error: Box::new(other),
+                origin: None,
+                key: Some(key.into()),
+            },
         }
     }
 
@@ -157,8 +182,17 @@ impl ConfigError {
                 expected,
                 key: Some(concat(key)),
             },
+            Self::At { error, origin, key } => Self::At {
+                error,
+                origin,
+                key: Some(concat(key)),
+            },
             Self::NotFound(key) => Self::NotFound(concat(Some(key))),
-            _ => self,
+            other => Self::At {
+                error: Box::new(other),
+                origin: None,
+                key: Some(concat(None)),
+            },
         }
     }
 
@@ -217,6 +251,24 @@ impl fmt::Display for ConfigError {
                 Ok(())
             }
 
+            ConfigError::At {
+                ref error,
+                ref origin,
+                ref key,
+            } => {
+                write!(f, "{error}")?;
+
+                if let Some(ref key) = *key {
+                    write!(f, " for key `{key}`")?;
+                }
+
+                if let Some(ref origin) = *origin {
+                    write!(f, " in {origin}")?;
+                }
+
+                Ok(())
+            }
+
             ConfigError::FileParse { ref cause, ref uri } => {
                 write!(f, "{cause}")?;
 

tests/testsuite/deserialize-invalid-type.json

@@ -0,0 +1,5 @@
+{
+  "place": {
+    "name": "Torre di Pisa"
+  }
+}

tests/testsuite/deserialize-missing-field.json

@@ -0,0 +1,3 @@
+{
+    "inner": { "value": 42 }
+}