fix(toml_edit): reformat dotted keyed-items in TableLike::fmt

`TableLike::fmt` only reset the decor of value items, leaving dotted
keyed-items untouched. They are stored as dotted tables and dotted
inline tables, so recurse into them to reformat their key segments and
nested values as well.

Fixes #262

crates/toml_edit/src/inline_table.rs

@@ -512,16 +512,23 @@ impl<'s> IntoIterator for &'s InlineTable {
 
 fn decorate_inline_table(table: &mut InlineTable) {
     use indexmap::map::MutableKeys;
-    for (mut key, value) in table
-        .items
-        .iter_mut2()
-        .filter(|(_, value)| value.is_value())
-        .map(|(key, value)| (key.as_mut(), value.as_value_mut().unwrap()))
-    {
+    for (key, value) in table.items.iter_mut2() {
+        match value {
+            // Dotted keyed-items are stored as dotted inline tables, so reformat the
+            // key segment and recurse to cover any values nested beneath it.
+            Item::Value(Value::InlineTable(dotted)) if dotted.is_dotted() => {
+                key.leaf_decor_mut().clear();
+                key.dotted_decor_mut().clear();
+                decorate_inline_table(dotted);
+            }
+            Item::Value(value) => {
                 key.leaf_decor_mut().clear();
                 key.dotted_decor_mut().clear();
                 value.decor_mut().clear();
             }
+            _ => {}
+        }
+    }
 }
 
 /// An owned iterator type over an [`InlineTable`]'s [`Key`]/[`Value`] pairs

crates/toml_edit/src/table.rs

@@ -540,16 +540,23 @@ pub(crate) type KeyValuePairs = IndexMap<Key, Item>;
 
 fn decorate_table(table: &mut Table) {
     use indexmap::map::MutableKeys;
-    for (mut key, value) in table
-        .items
-        .iter_mut2()
-        .filter(|(_, value)| value.is_value())
-        .map(|(key, value)| (key.as_mut(), value.as_value_mut().unwrap()))
-    {
+    for (key, value) in table.items.iter_mut2() {
+        match value {
+            Item::Value(value) => {
                 key.leaf_decor_mut().clear();
                 key.dotted_decor_mut().clear();
                 value.decor_mut().clear();
             }
+            // Dotted keyed-items are stored as dotted tables, so reformat the key
+            // segment and recurse to cover any values nested beneath it.
+            Item::Table(dotted) if dotted.is_dotted() => {
+                key.leaf_decor_mut().clear();
+                key.dotted_decor_mut().clear();
+                decorate_table(dotted);
+            }
+            _ => {}
+        }
+    }
 }
 
 // `key1 = value1`

crates/toml_edit/tests/testsuite/edit.rs

@@ -1238,6 +1238,44 @@ fn test_format_array() {
     "#]]);
 }
 
+#[test]
+fn test_format_dotted_keys() {
+    given(
+        r#"
+        a . b  =  1
+        c  =  2
+        d . e . f  =  3
+        "#,
+    )
+    .running(|root| {
+        root.fmt();
+    })
+    .produces_display(str![[r#"
+a.b = 1
+c = 2
+d.e.f = 3
+        
+"#]]);
+}
+
+#[test]
+fn test_format_dotted_keys_in_inline_table() {
+    given(
+        r#"
+        a = { b . c  =  1, d  =  2 }
+        "#,
+    )
+    .running(|root| {
+        let a = root.get_mut("a").unwrap().as_inline_table_mut().unwrap();
+        a.fmt();
+    })
+    .produces_display(str![[r#"
+
+        a = { b.c = 1, d = 2 }
+        
+"#]]);
+}
+
 macro_rules! as_inline_table {
     ($entry:ident) => {{
         assert!($entry.is_value());