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

@@ -12,6 +12,8 @@
 
 # 11.1.4
 
+- Fix issue where long layout break added a trailing comma in partial application `...`. https://github.com/rescript-lang/rescript-compiler/pull/6949
+
 # 11.1.3
 
 #### :bug: Bug Fix

jscomp/syntax/src/res_parsetree_viewer.ml

@@ -72,6 +72,13 @@ let processUncurriedAppAttribute attrs =
   in
   process false [] attrs
 
+let hasPartialAttribute attrs =
+  List.exists
+    (function
+      | {Location.txt = "res.partial"}, _ -> true
+      | _ -> false)
+    attrs
+
 let processPartialAppAttribute attrs =
   let rec process partialApp acc attrs =
     match attrs with

jscomp/syntax/src/res_parsetree_viewer.mli

@@ -29,6 +29,8 @@ type functionAttributesInfo = {
   attributes: Parsetree.attributes;
 }
 
+val hasPartialAttribute : Parsetree.attributes -> bool
+
 (* determines whether a function is async and/or uncurried based on the given attributes *)
 val processFunctionAttributes : Parsetree.attributes -> functionAttributesInfo
 

jscomp/syntax/src/res_printer.ml

@@ -4120,7 +4120,13 @@ and printPexpApply ~state expr cmtTbl =
     let partial, attrs = ParsetreeViewer.processPartialAppAttribute 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
@@ -4700,6 +4706,18 @@ and printArguments ~state ~dotted ?(partial = false)
     Doc.concat
       [(if dotted then Doc.text "(. " else Doc.lparen); argDoc; Doc.rparen]
   | args ->
+    (* Avoid printing trailing comma when there is ... in function application *)
+    let hasPartialAttr, printedArgs =
+      List.fold_right
+        (fun arg (flag, acc) ->
+          let _, expr = arg in
+          let hasPartialAttr =
+            ParsetreeViewer.hasPartialAttribute expr.Parsetree.pexp_attributes
+          in
+          let doc = printArgument ~state arg cmtTbl in
+          (flag || hasPartialAttr, doc :: acc))
+        args (false, [])
+    in
     Doc.group
       (Doc.concat
          [
@@ -4708,11 +4726,9 @@ and printArguments ~state ~dotted ?(partial = false)
              (Doc.concat
                 [
                   (if dotted then Doc.line else Doc.softLine);
-                  Doc.join
-                    ~sep:(Doc.concat [Doc.comma; Doc.line])
-                    (List.map (fun arg -> printArgument ~state arg cmtTbl) args);
+                  Doc.join ~sep:(Doc.concat [Doc.comma; Doc.line]) printedArgs;
                 ]);
-           (if partial then Doc.nil else Doc.trailingComma);
+           (if partial || hasPartialAttr then Doc.nil else Doc.trailingComma);
            Doc.softLine;
            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,
+      ...
+    ),
+)