Fix fragment optional children (#704)

Author: mununki

CHANGELOG.md

@@ -48,6 +48,7 @@
 - Fix issue where certain JSX expressions would be formatted differenctly in compiler 10.1.0-rc.1 https://github.com/rescript-lang/syntax/issues/675
 - Fix issue where printing nested pipe discards await https://github.com/rescript-lang/syntax/issues/687
 - Fix issue where the JSX key type is not an optional string https://github.com/rescript-lang/syntax/pull/693
+- Fix issue where the JSX fragment withouth children build error https://github.com/rescript-lang/syntax/pull/704
 
 #### :eyeglasses: Spec Compliance
 

cli/reactjs_jsx_v4.ml

@@ -1368,24 +1368,22 @@ let expr ~config mapper expression =
           Exp.ident ~loc {loc; txt = Ldot (Lident "React", "fragment")}
       in
       let childrenExpr = transformChildrenIfList ~mapper listItems in
+      let recordOfChildren children =
+        Exp.record [(Location.mknoloc (Lident "children"), children)] None
+      in
       let args =
         [
           (nolabel, fragment);
           (match config.mode with
-          | "automatic" ->
+          | "automatic" -> (
             ( nolabel,
-              Exp.record
-                [
-                  ( Location.mknoloc @@ Lident "children",
-                    match childrenExpr with
-                    | {pexp_desc = Pexp_array children} -> (
-                      match children with
-                      | [] -> emptyRecord ~loc:Location.none
-                      | [child] -> child
-                      | _ -> childrenExpr)
-                    | _ -> childrenExpr );
-                ]
-                None )
+              match childrenExpr with
+              | {pexp_desc = Pexp_array children} -> (
+                match children with
+                | [] -> emptyRecord ~loc:Location.none
+                | [child] -> recordOfChildren child
+                | _ -> recordOfChildren childrenExpr)
+              | _ -> recordOfChildren childrenExpr ))
           | "classic" | _ -> (nolabel, childrenExpr));
         ]
       in

tests/ppx/react/expected/fragment.res.txt

@@ -0,0 +1,19 @@
+@@jsxConfig({version: 4, mode: "classic"})
+
+let _ = ReactDOM.createElement(React.fragment, [])
+let _ = ReactDOM.createElement(React.fragment, [ReactDOM.createDOMElementVariadic("div", [])])
+let _ = ReactDOM.createElement(React.fragment, [ReactDOM.createElement(React.fragment, [])])
+let _ = React.createElement(Z.make, {})
+let _ = React.createElement(Z.make, {children: ReactDOM.createDOMElementVariadic("div", [])})
+let _ = ReactDOM.createDOMElementVariadic("div", [])
+let _ = ReactDOM.createDOMElementVariadic("div", [ReactDOM.createDOMElementVariadic("div", [])])
+
+@@jsxConfig({version: 4, mode: "automatic"})
+
+let _ = React.jsx(React.jsxFragment, {})
+let _ = React.jsx(React.jsxFragment, {children: ReactDOM.jsx("div", {})})
+let _ = React.jsx(React.jsxFragment, {children: React.jsx(React.jsxFragment, {})})
+let _ = React.jsx(Z.make, {})
+let _ = React.jsx(Z.make, {children: ReactDOM.jsx("div", {})})
+let _ = ReactDOM.jsx("div", {})
+let _ = ReactDOM.jsx("div", {children: ?ReactDOM.someElement(ReactDOM.jsx("div", {}))})

tests/ppx/react/fragment.res

@@ -0,0 +1,19 @@
+@@jsxConfig({version:4, mode: "classic"})
+
+let _ = <></>
+let _ = <><div /></>
+let _ = <><></></>
+let _ = <Z />
+let _ = <Z><div /></Z>
+let _ = <div />
+let _ = <div><div /></div>
+
+@@jsxConfig({version:4, mode: "automatic"})
+
+let _ = <></>
+let _ = <><div /></>
+let _ = <><></></>
+let _ = <Z />
+let _ = <Z><div /></Z>
+let _ = <div />
+let _ = <div><div /></div>