Fix/decoder correctness (2/8)

examples/parts/arrays.rs

@@ -1,7 +1,4 @@
-use serde::{
-    Deserialize,
-    Serialize,
-};
+use serde::{Deserialize, Serialize};
 use serde_json::json;
 use toon_format::encode_default;
 

examples/parts/arrays_of_arrays.rs

@@ -1,7 +1,4 @@
-use serde::{
-    Deserialize,
-    Serialize,
-};
+use serde::{Deserialize, Serialize};
 use serde_json::json;
 use toon_format::encode_default;
 

examples/parts/decode_strict.rs

@@ -1,8 +1,5 @@
 use serde_json::Value;
-use toon_format::{
-    decode,
-    DecodeOptions,
-};
+use toon_format::{decode, DecodeOptions};
 
 pub fn decode_strict() {
     // Malformed: header says 2 rows, but only 1 provided

examples/parts/delimiters.rs

@@ -1,9 +1,5 @@
 use serde_json::json;
-use toon_format::{
-    encode,
-    Delimiter,
-    EncodeOptions,
-};
+use toon_format::{encode, Delimiter, EncodeOptions};
 
 pub fn delimiters() {
     let data = json!({

examples/parts/mixed_arrays.rs

@@ -1,7 +1,4 @@
-use serde::{
-    Deserialize,
-    Serialize,
-};
+use serde::{Deserialize, Serialize};
 use serde_json::json;
 use toon_format::encode_default;
 

examples/parts/objects.rs

@@ -1,7 +1,4 @@
-use serde::{
-    Deserialize,
-    Serialize,
-};
+use serde::{Deserialize, Serialize};
 use serde_json::json;
 use toon_format::encode_default;
 

examples/parts/round_trip.rs

@@ -1,15 +1,6 @@
-use serde::{
-    Deserialize,
-    Serialize,
-};
-use serde_json::{
-    json,
-    Value,
-};
-use toon_format::{
-    decode_default,
-    encode_default,
-};
+use serde::{Deserialize, Serialize};
+use serde_json::{json, Value};
+use toon_format::{decode_default, encode_default};
 
 #[derive(Debug, Serialize, Deserialize, PartialEq)]
 struct Product {

examples/parts/structs.rs

@@ -1,11 +1,5 @@
-use serde::{
-    Deserialize,
-    Serialize,
-};
-use toon_format::{
-    decode_default,
-    encode_default,
-};
+use serde::{Deserialize, Serialize};
+use toon_format::{decode_default, encode_default};
 
 #[derive(Debug, Serialize, Deserialize, PartialEq)]
 struct User {

examples/parts/tabular.rs

@@ -1,7 +1,4 @@
-use serde::{
-    Deserialize,
-    Serialize,
-};
+use serde::{Deserialize, Serialize};
 use serde_json::json;
 use toon_format::encode_default;
 

src/cli/main.rs

@@ -1,36 +1,17 @@
 use std::{
     fs,
-    io::{
-        self,
-        Read,
-        Write,
-    },
-    path::{
-        Path,
-        PathBuf,
-    },
+    io::{self, Read, Write},
+    path::{Path, PathBuf},
 };
 
-use anyhow::{
-    bail,
-    Context,
-    Result,
-};
+use anyhow::{bail, Context, Result};
 use clap::Parser;
 use comfy_table::Table;
 use serde::Serialize;
 use tiktoken_rs::cl100k_base;
 use toon_format::{
-    decode,
-    encode,
-    types::{
-        DecodeOptions,
-        Delimiter,
-        EncodeOptions,
-        Indent,
-        KeyFoldingMode,
-        PathExpansionMode,
-    },
+    decode, encode,
+    types::{DecodeOptions, Delimiter, EncodeOptions, Indent, KeyFoldingMode, PathExpansionMode},
 };
 
 #[derive(Parser, Debug)]

src/decode/expansion.rs

@@ -2,13 +2,7 @@ use indexmap::IndexMap;
 
 use crate::{
     constants::QUOTED_KEY_MARKER,
-    types::{
-        is_identifier_segment,
-        JsonValue as Value,
-        PathExpansionMode,
-        ToonError,
-        ToonResult,
-    },
+    types::{is_identifier_segment, JsonValue as Value, PathExpansionMode, ToonError, ToonResult},
 };
 
 pub fn should_expand_key(key: &str, mode: PathExpansionMode) -> Option<Vec<String>> {
@@ -90,7 +84,7 @@ pub fn deep_merge_value(
         }
     } else {
         target.insert(first_key.clone(), Value::Object(IndexMap::new()));
-        match target.get_mut(first_key).unwrap() {
+        match target.get_mut(first_key).expect("key was just inserted") {
             Value::Object(obj) => obj,
             _ => unreachable!(),
         }
@@ -108,10 +102,8 @@ pub fn expand_paths_in_object(
     let mut result = IndexMap::new();
 
     for (key, mut value) in obj {
-        // Expand nested objects first (depth-first)
-        if let Value::Object(nested_obj) = value {
-            value = Value::Object(expand_paths_in_object(nested_obj, mode, strict)?);
-        }
+        // Expand nested structures (arrays/objects) first (depth-first)
+        value = expand_paths_recursive(value, mode, strict)?;
 
         // Strip marker from quoted keys
         let clean_key = if key.starts_with(QUOTED_KEY_MARKER) {

src/decode/mod.rs

@@ -6,10 +6,7 @@ pub mod validation;
 
 use serde_json::Value;
 
-use crate::types::{
-    DecodeOptions,
-    ToonResult,
-};
+use crate::types::{DecodeOptions, ToonResult};
 
 /// Decode a TOON string into any deserializable type.
 ///