Merge pull request #2902 from ehuss/fix-missing-format

Fix error message for config.get deserialization error

crates/mdbook-core/src/config.rs

@@ -204,7 +204,7 @@ impl Config {
                 value
                     .clone()
                     .try_into()
-                    .with_context(|| "Failed to deserialize `{name}`")
+                    .with_context(|| format!("Failed to deserialize `{name}`"))
             })
             .transpose()
     }
@@ -1147,4 +1147,18 @@ mod tests {
         assert_eq!(json!(TextDirection::RightToLeft), json!("rtl"));
         assert_eq!(json!(TextDirection::LeftToRight), json!("ltr"));
     }
+
+    #[test]
+    fn get_deserialize_error() {
+        let src = r#"
+        [preprocessor.foo]
+        x = 123
+        "#;
+        let cfg = Config::from_str(src).unwrap();
+        let err = cfg.get::<String>("preprocessor.foo.x").unwrap_err();
+        assert_eq!(
+            err.to_string(),
+            "Failed to deserialize `preprocessor.foo.x`"
+        );
+    }
 }