fix: do not print > on new line (rescript-lang#678)

Author: ah-yu

src/res_printer.ml

@@ -113,6 +113,21 @@ let hasNestedJsxOrMoreThanOneChild expr =
   in
   loop false expr
 
+let hasTailSingleLineComment tbl loc =
+  let rec getLastElement elements =
+    match elements with
+    | [] -> None
+    | [element] -> Some element
+    | _ :: rest -> getLastElement rest
+  in
+  match Hashtbl.find_opt tbl.CommentTable.trailing loc with
+  | None -> false
+  | Some comments -> (
+    let lastComment = getLastElement comments in
+    match lastComment with
+    | None -> false
+    | Some comment -> Comment.isSingleLineComment comment)
+
 let hasCommentsInside tbl loc =
   match Hashtbl.find_opt tbl.CommentTable.inside loc with
   | None -> false
@@ -4041,8 +4056,20 @@ and printJsxExpression ~customLayout lident args cmtTbl =
                         Pexp_construct ({txt = Longident.Lident "[]"}, None);
                     }
                   when isSelfClosing ->
-                  Doc.concat [Doc.line; Doc.text "/>"]
-                | _ -> Doc.concat [Doc.softLine; Doc.greaterThan]);
+                  Doc.text "/>"
+                | _ ->
+                  (* if last trailing comment of tag is single line comment then put > on the next line
+                     <A
+                     // single line comment
+                     >
+                     </A>
+                  *)
+                  if hasTailSingleLineComment cmtTbl lident.Asttypes.loc then
+                    Doc.concat [Doc.softLine; Doc.greaterThan]
+                  else
+                    Doc.ifBreaks
+                      (Doc.lineSuffix Doc.greaterThan)
+                      Doc.greaterThan);
               ]);
          (if isSelfClosing then Doc.nil
          else
@@ -4140,6 +4167,27 @@ and printJsxChildren ~customLayout (childrenExpr : Parsetree.expression) ~sep
 
 and printJsxProps ~customLayout args cmtTbl :
     Doc.t * Parsetree.expression option =
+  (* This function was introduced because we have different formatting behavior for self-closing tags and other tags
+     we always put /> on a new line for self-closing tag when it breaks
+     <A
+      a=""
+     />
+
+     <A
+     a="">
+      <B />
+     </A>
+     we should remove this function once the format is unified
+  *)
+  let isSelfClosing children =
+    match children with
+    | {
+     Parsetree.pexp_desc = Pexp_construct ({txt = Longident.Lident "[]"}, None);
+     pexp_loc = loc;
+    } ->
+      not (hasCommentsInside cmtTbl loc)
+    | _ -> false
+  in
   let rec loop props args =
     match args with
     | [] -> (Doc.nil, None)
@@ -4151,13 +4199,42 @@ and printJsxProps ~customLayout args cmtTbl :
            Pexp_construct ({txt = Longident.Lident "()"}, None);
        } );
     ] ->
+      let doc = if isSelfClosing children then Doc.line else Doc.nil in
+      (doc, Some children)
+    | ((_, expr) as lastProp)
+      :: [
+           (Asttypes.Labelled "children", children);
+           ( Asttypes.Nolabel,
+             {
+               Parsetree.pexp_desc =
+                 Pexp_construct ({txt = Longident.Lident "()"}, None);
+             } );
+         ] ->
+      let loc =
+        match expr.Parsetree.pexp_attributes with
+        | ({Location.txt = "ns.namedArgLoc"; loc}, _) :: _attrs ->
+          {loc with loc_end = expr.pexp_loc.loc_end}
+        | _ -> expr.pexp_loc
+      in
+      let tailSingleLineCommentPresent = hasTailSingleLineComment cmtTbl loc in
+      let propDoc = printJsxProp ~customLayout lastProp cmtTbl in
       let formattedProps =
-        Doc.indent
-          (match props with
-          | [] -> Doc.nil
-          | props ->
-            Doc.concat
-              [Doc.line; Doc.group (Doc.join ~sep:Doc.line (props |> List.rev))])
+        Doc.concat
+          [
+            Doc.indent
+              (Doc.concat
+                 [
+                   Doc.line;
+                   Doc.group
+                     (Doc.join ~sep:Doc.line (propDoc :: props |> List.rev));
+                 ]);
+            (* print > on new line if last comment is single line comment *)
+            (match (isSelfClosing children, tailSingleLineCommentPresent) with
+            (* we always put /> on a new line when a self-closing tag breaks *)
+            | true, _ -> Doc.line
+            | false, true -> Doc.softLine
+            | false, false -> Doc.nil);
+          ]
       in
       (formattedProps, Some children)
     | arg :: args ->

tests/conversion/reason/expected/bracedJsx.res.txt

@@ -111,8 +111,7 @@ let make = () => {
     <div
       className=Styles.terminal
       onClick={event => (event->ReactEvent.Mouse.target)["querySelector"]("input")["focus"]()}
-      ref={containerRef->ReactDOMRe.Ref.domRef}
-    >
+      ref={containerRef->ReactDOMRe.Ref.domRef}>
       {state.history
       ->Array.mapWithIndex((index, item) =>
         <div key={j`$index`} className=Styles.line>

tests/printer/comments/expected/jsx.res.txt

@@ -31,6 +31,27 @@ module Cite = {
   <B /* comment3 */ />
 </A>
 
+<A
+  value=""
+  /* comment */>
+  <B />
+</A>
+
+<A
+// comment
+>
+  <B />
+</A>
+
+<A
+/* comment */>
+  <B />
+</A>
+
+<A /* comment */>
+  <B />
+</A>
+
 <div>
   // Must not jump inside braces
   {React.string("Hello, World!")}

tests/printer/comments/jsx.res

@@ -33,6 +33,29 @@ value=""
   <B /* comment3 */ />
 </A>
 
+<A
+  value=""
+  /* comment */
+>
+  <B/>
+</A>
+
+<A
+// comment
+>
+  <B />
+</A>
+
+<A
+/* comment */
+>
+  <B />
+</A>
+
+<A /* comment */>
+  <B />
+</A>
+
 <div>
   // Must not jump inside braces
   {React.string("Hello, World!")}

tests/printer/expr/expected/jsx.res.txt

@@ -104,8 +104,7 @@ let avatarSection =
           onMouseLeave={_ => setHoveringAdmin(false)}
           onClick={_e => {
             stopImpersonating(csrfToken)
-          }}
-        >
+          }}>
           <Avatar user={viewer} size={45} />
         </div>
       : React.nullElement}

tests/printer/other/expected/signaturePicker.res.txt

@@ -28,8 +28,7 @@ let make = () => {
     <div className="pr-2 font-bold text-gray-400 text-lg"> {"Signature"->string} </div>
     <select
       id="country"
-      className="transition duration-150 ease-in-out sm:text-sm sm:leading-5 border-none font-bold text-2xl text-gray-600 bg-transparent"
-    >
+      className="transition duration-150 ease-in-out sm:text-sm sm:leading-5 border-none font-bold text-2xl text-gray-600 bg-transparent">
       {options
       ->Belt.List.map(option =>
         <option key={option->TimeSignature.toString}>
@@ -48,8 +47,7 @@ let make = () => {
       fill="none"
       strokeLinecap="round"
       strokeLinejoin="round"
-      className="text-gray-400"
-    >
+      className="text-gray-400">
       <polyline points="6 9 12 15 18 9" />
     </svg>
   </label>