Skip trailing comma in explicit partial application (#6949)

* Check for dotdotdot in args * Check on attribute rather than label * Add tests * Fix naming convention * Update CHANGELOG

Author: shulhi

CHANGELOG.md

@@ -23,6 +23,9 @@
  - Removed empty line at the end of `switch` statement
  - Removed empty `default` case from `switch` statement in the generated code
 
+#### :bug: Bug Fix
+- Fix issue where long layout break added a trailing comma in partial application `...`. https://github.com/rescript-lang/rescript-compiler/pull/6949
+
 # 12.0.0-alpha.1
 
 #### :rocket: New Feature

jscomp/syntax/src/res_parsetree_viewer.ml

@@ -57,6 +57,13 @@ let process_partial_app_attribute attrs =
  in
  process false [] attrs
 
+let has_partial_attribute attrs =
+ List.exists
+ (function
+ | {Location.txt = "res.partial"}, _ -> true
+ | _ -> false)
+ attrs
+
 type function_attributes_info = {async: bool; attributes: Parsetree.attributes}
 
 let process_function_attributes attrs =

jscomp/syntax/src/res_parsetree_viewer.mli

@@ -17,6 +17,8 @@ val functor_type :
 val process_partial_app_attribute :
  Parsetree.attributes -> bool * Parsetree.attributes
 
+val has_partial_attribute : Parsetree.attributes -> bool
+
 type function_attributes_info = {async: bool; attributes: Parsetree.attributes}
 
 (* determines whether a function is async and/or uncurried based on the given attributes *)

jscomp/syntax/src/res_printer.ml

@@ -4146,7 +4146,13 @@ and print_pexp_apply ~state expr cmt_tbl =
  let partial, attrs = ParsetreeViewer.process_partial_app_attribute attrs in
  let args =
  if partial then
- let dummy = Ast_helper.Exp.constant (Ast_helper.Const.int 0) in
+ let loc =
+ {Asttypes.txt = "res.partial"; Asttypes.loc = expr.pexp_loc}
+ in
+ let attr = (loc, Parsetree.PTyp (Ast_helper.Typ.any ())) in
+ let dummy =
+ Ast_helper.Exp.constant ~attrs:[attr] (Ast_helper.Const.int 0)
+ in
  args @ [(Asttypes.Labelled "...", dummy)]
  else args
  in
@@ -4730,6 +4736,18 @@ and print_arguments ~state ?(partial = false)
  in
  Doc.concat [Doc.lparen; arg_doc; Doc.rparen]
  | args ->
+ (* Avoid printing trailing comma when there is ... in function application *)
+ let has_partial_attr, printed_args =
+ List.fold_right
+ (fun arg (flag, acc) ->
+ let _, expr = arg in
+ let has_partial_attr =
+ ParsetreeViewer.has_partial_attribute expr.Parsetree.pexp_attributes
+ in
+ let doc = print_argument ~state arg cmt_tbl in
+ (flag || has_partial_attr, doc :: acc))
+ args (false, [])
+ in
  Doc.group
  (Doc.concat
  [
@@ -4738,13 +4756,9 @@ and print_arguments ~state ?(partial = false)
  (Doc.concat
  [
  Doc.soft_line;
- Doc.join
- ~sep:(Doc.concat [Doc.comma; Doc.line])
- (List.map
- (fun arg -> print_argument ~state arg cmt_tbl)
- args);
+ Doc.join ~sep:(Doc.concat [Doc.comma; Doc.line]) printed_args;
  ]);
- (if partial then Doc.nil else Doc.trailing_comma);
+ (if partial || has_partial_attr then Doc.nil else Doc.trailing_comma);
  Doc.soft_line;
  Doc.rparen;
  ])

jscomp/syntax/tests/printer/expr/apply.res

@@ -73,3 +73,37 @@ f(. {
 
 resolve(.)
 resolve(. ())
+
+let g = f(
+ a => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c
+)
+
+let g = f(
+ a => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c, 
+ ...
+)
+
+let g = f(
+ a => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(d, ...),
+ ...
+)
+
+let g = f(
+ a => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a, ...),
+ b,
+ c => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(d),
+ ...
+)
+
+
+let g = f(
+ a => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(d, ...)
+)

jscomp/syntax/tests/printer/expr/expected/apply.res.txt

@@ -93,3 +93,54 @@ f({
 
 resolve()
 resolve()
+
+let g = f(
+ a => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c,
+)
+
+let g =
+ f(
+ a =>
+ LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c,
+ ...
+ )
+
+let g =
+ f(
+ a =>
+ LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c =>
+ LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(
+ d,
+ ...
+ ),
+ ...
+ )
+
+let g =
+ f(
+ a =>
+ LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(
+ a,
+ ...
+ ),
+ b,
+ c =>
+ LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(d),
+ ...
+ )
+
+let g = f(
+ a => LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(a),
+ b,
+ c =>
+ LongModuleName.functionWithAlongNameThatWrapsTheEditorToTheNextLinexxxxxxxxxxxxxxxxxxxxxx(
+ d,
+ ...
+ ),
+)