🐛 keep substituted values when concatenating to a substitueed array w…

…ith += #27

src/internals/internal.rs

@@ -335,6 +335,16 @@ impl HoconInternal {
                             .collect(),
                     )
                 }
+                HoconValue::PathSubstitution { ref target, .. } => {
+                    let value = concatenated_arrays
+                        .get(&target.to_path())
+                        .cloned()
+                        .unwrap_or_else(HashMap::new);
+                    concatenated_arrays
+                        .entry(full_path.clone())
+                        .or_insert(value);
+                    (item.substitute(config, &root, &full_path), full_path)
+                }
                 v => {
                     let mut checked_path: Path = vec![];
                     for item in full_path.clone() {
@@ -373,6 +383,7 @@ impl HoconInternal {
                         match (exist, first_key) {
                             (_, Some(HoconValue::Integer(0)))
                                 if path_item == HoconValue::Integer(0)
+                                    && last_path_encoutered.len() >= current_path.len()
                                     && current_path.as_slice()
                                         != &last_path_encoutered[0..current_path.len()] =>
                             {

src/internals/value.rs

@@ -63,7 +63,7 @@ impl HoconValue {
         }
     }
 
-    fn to_path(&self) -> Vec<HoconValue> {
+    pub(crate) fn to_path(&self) -> Vec<HoconValue> {
         match self {
             HoconValue::UnquotedString(s) if s == "." => vec![],
             HoconValue::UnquotedString(s) => s

tests/data/issue-27.conf

@@ -0,0 +1,9 @@
+{
+    "array1": [1, 2],
+    "v": ${array1}
+    "v" += "v3"
+
+    "w": [1, 2]
+    "w" += "w3"
+
+}

tests/snapshots/snapshot__issue-27.conf.snap

@@ -0,0 +1,5 @@
+---
+source: tests/snapshot.rs
+expression: stable_readable_display(&doc)
+---
+"{array1: [1, 2], v: [1, 2, \"v3\"], w: [1, 2, \"w3\"]}"