fix: ignore comments apply to trailing commas

src/generation/generate.rs

@@ -339,13 +339,21 @@ fn gen_comma_separated_values<'a>(
         };
         let items = ir_helpers::new_line_group({
           let is_final_node = i == nodes_count - 1;
-          let use_comma_for_last = !is_final_node
-            || match context.config.trailing_commas {
+          let use_comma_for_last = !is_final_node || {
+            let leading_comments = context.comments.get(&value.start()).map(|c| c.as_slice());
+            let trailing_commas = if has_ignore_comment(leading_comments, context) {
+              // an ignore comment also applies to the node's trailing comma
+              TrailingCommaKind::Maintain
+            } else {
+              context.config.trailing_commas
+            };
+            match trailing_commas {
               TrailingCommaKind::Always => true,
               TrailingCommaKind::Maintain => context.token_finder.get_next_token_if_comma(&value).is_some(),
               TrailingCommaKind::Jsonc => context.is_jsonc,
               TrailingCommaKind::Never => false,
-            };
+            }
+          };
           let maybe_comma = if !is_final_node {
             sc_items(COMMA_SC)
           } else if use_comma_for_last {

tests/specs/comments/Comments_IgnoreNode_TrailingCommas_Always.txt

@@ -0,0 +1,32 @@
+~~ trailingCommas: always ~~
+== should not add a trailing comma to an ignored node ==
+{
+  "tasks": {
+    // dprint-ignore
+    "foo": "echo bar"
+  },
+  "other": {
+    "foo":   "echo bar"
+  },
+  "array": [
+    1,
+    // dprint-ignore
+    [ 2,   3 ]
+  ]
+}
+
+[expect]
+{
+  "tasks": {
+    // dprint-ignore
+    "foo": "echo bar"
+  },
+  "other": {
+    "foo": "echo bar",
+  },
+  "array": [
+    1,
+    // dprint-ignore
+    [ 2,   3 ]
+  ],
+}

tests/specs/comments/Comments_IgnoreNode_TrailingCommas_Jsonc_Json.txt

@@ -0,0 +1,32 @@
+~~ trailingCommas: jsonc ~~
+== should maintain the trailing comma of an ignored node in a json file ==
+{
+  "tasks": {
+    // dprint-ignore
+    "foo": "echo bar",
+  },
+  "other": {
+    "foo":   "echo bar",
+  },
+  "array": [
+    1,
+    // dprint-ignore
+    [ 2,   3 ],
+  ]
+}
+
+[expect]
+{
+  "tasks": {
+    // dprint-ignore
+    "foo": "echo bar",
+  },
+  "other": {
+    "foo": "echo bar"
+  },
+  "array": [
+    1,
+    // dprint-ignore
+    [ 2,   3 ],
+  ]
+}

tests/specs/comments/Comments_IgnoreNode_TrailingCommas_Never.txt

@@ -0,0 +1,32 @@
+~~ trailingCommas: never ~~
+== should maintain the trailing comma of an ignored node ==
+{
+  "tasks": {
+    // dprint-ignore
+    "foo": "echo bar",
+  },
+  "other": {
+    "foo":   "echo bar",
+  },
+  "array": [
+    1,
+    // dprint-ignore
+    [ 2,   3 ],
+  ]
+}
+
+[expect]
+{
+  "tasks": {
+    // dprint-ignore
+    "foo": "echo bar",
+  },
+  "other": {
+    "foo": "echo bar"
+  },
+  "array": [
+    1,
+    // dprint-ignore
+    [ 2,   3 ],
+  ]
+}