Accept a payload on @react.componentWithProps with a deprecation warning

changes/component-with-props-payload.polish.md

@@ -0,0 +1 @@
+- Accept a payload on `@react.componentWithProps` again, as in 12.x, with a deprecation warning: it never had an effect.

compiler/syntax/src/jsx_common.ml

@@ -8,6 +8,36 @@ type jsx_config = {
   mutable has_component: bool;
 }
 
+(* The JSX transform used to ignore a payload on [@react.componentWithProps],
+   so code may carry one, such as [(: props)] copied from [@react.component].
+   The node cannot hold it, so the attribute stays for formatting to keep; take
+   it here as the component, with a deprecation warning, unless the definition
+   already has one. *)
+let take_component_with_props_payload jsx_component attributes =
+  match jsx_component with
+  | Some _ -> (jsx_component, attributes)
+  | None ->
+    let rec go seen = function
+      | [] -> (None, attributes)
+      | ((({txt; loc}, _) : attribute) as attr) :: rest -> (
+        let namespace =
+          match txt with
+          | "react.componentWithProps" -> Some Pjc_react
+          | "jsx.componentWithProps" -> Some Pjc_jsx
+          | _ -> None
+        in
+        match namespace with
+        | Some pjc_namespace
+          when Option.is_none (Ast_helper.Jsx_component.of_attribute attr) ->
+          Location.deprecated ~use:loc loc
+            (Printf.sprintf
+               "@%s takes no payload. The payload has no effect; remove it." txt);
+          ( Some {pjc_kind = Pjc_with_props; pjc_namespace; pjc_loc = loc},
+            List.rev_append seen rest )
+        | _ -> go (attr :: seen) rest)
+    in
+    go [] attributes
+
 (* [Ast_helper] takes the first [@react.component], or failing that the first
    [@react.componentWithProps], into the binding's or description's component
    node. One still among the attributes is a second annotation, or one with a
@@ -19,18 +49,17 @@ let reject_leftover_component_attrs attributes =
       match txt with
       | "react.component" | "jsx.component" | "react.componentWithProps"
       | "jsx.componentWithProps" -> (
-        match Ast_helper.Jsx_component.of_attribute attr with
-        | Some _ ->
+        match (txt, Ast_helper.Jsx_component.of_attribute attr) with
+        | ("react.component" | "jsx.component"), None ->
           Location.raise_errorf ~loc
-            "A definition can have only one JSX component annotation."
-        | None -> (
-          match txt with
-          | "react.component" | "jsx.component" ->
-            Location.raise_errorf ~loc
-              "@@%s takes no payload, or the props type to share, as in @@%s(: \
-               props)."
-              txt txt
-          | _ -> Location.raise_errorf ~loc "@@%s takes no payload." txt))
+            "@@%s takes no payload, or the props type to share, as in @@%s(: \
+             props)."
+            txt txt
+        | _ ->
+          (* [take_component_with_props_payload] has taken a lone
+             [@react.componentWithProps] whatever its payload. *)
+          Location.raise_errorf ~loc
+            "A definition can have only one JSX component annotation.")
       | _ -> ())
     attributes
 

compiler/syntax/src/jsx_v4.ml

@@ -563,6 +563,11 @@ let map_binding ~config ~empty_loc ~pstr_loc ~file_name binding =
       {expr with pexp_desc = Pexp_sequence (first, constrain_jsx_return second)}
     | _ -> jsx_element_constraint expr
   in
+  let pvb_jsx_component, pvb_attributes =
+    Jsx_common.take_component_with_props_payload binding.pvb_jsx_component
+      binding.pvb_attributes
+  in
+  let binding = {binding with pvb_jsx_component; pvb_attributes} in
   Jsx_common.reject_leftover_component_attrs binding.pvb_attributes;
   match binding.pvb_jsx_component with
   | Some {pjc_kind = Pjc_labelled core_type_of_attr} ->
@@ -948,8 +953,12 @@ let transform_structure_item ~config item =
       pstr_desc =
         Pstr_primitive ({pval_attributes; pval_type} as value_description);
     } as pstr -> (
+    let pval_jsx_component, pval_attributes =
+      Jsx_common.take_component_with_props_payload
+        value_description.pval_jsx_component pval_attributes
+    in
     Jsx_common.reject_leftover_component_attrs pval_attributes;
-    match value_description.pval_jsx_component with
+    match pval_jsx_component with
     | None -> [item]
     | Some {pjc_kind = Pjc_with_props} ->
       Jsx_common.raise_error ~loc:pstr_loc
@@ -1048,8 +1057,12 @@ let transform_signature_item ~config item =
       psig_loc;
       psig_desc = Psig_value ({pval_attributes; pval_type} as psig_desc);
     } as psig -> (
+    let pval_jsx_component, pval_attributes =
+      Jsx_common.take_component_with_props_payload psig_desc.pval_jsx_component
+        pval_attributes
+    in
     Jsx_common.reject_leftover_component_attrs pval_attributes;
-    match psig_desc.pval_jsx_component with
+    match pval_jsx_component with
     (* [@react.componentWithProps] on a signature item has always been left
        alone. *)
     | None | Some {pjc_kind = Pjc_with_props} -> [item]

tests/build_tests/super_errors/expected/react_componentWithProps_payload.res.expected

@@ -0,0 +1,11 @@
+
+  Warning number 3
+  /.../fixtures/react_componentWithProps_payload.res:12:3-27
+
+  10 │ 
+  11 │ module C = {
+  12 │   @react.componentWithProps(: props)
+  13 │   let make = (props: props) => React.string(props.label)
+  14 │ }
+
+  deprecated: @react.componentWithProps takes no payload. The payload has no effect; remove it.

tests/build_tests/super_errors/fixtures/react_componentWithProps_payload.res

@@ -0,0 +1,16 @@
+module React = {
+  type element = Jsx.element
+  type componentLike<'props, 'return> = 'props => 'return
+  type component<'props> = Jsx.component<'props>
+  external component: componentLike<'props, element> => component<'props> = "%component_identity"
+  external string: string => element = "%identity"
+}
+
+type props = {label: string}
+
+module C = {
+  @react.componentWithProps(: props)
+  let make = (props: props) => React.string(props.label)
+}
+
+let c = C.make

tests/syntax_tests/data/ppx/react/expected/sharedPropsWithProps.res.txt

@@ -1,3 +1,16 @@
+
+  Warning number 3
+  syntax_tests/data/ppx/react/sharedPropsWithProps.res:63:3-27
+
+  61 │ 
+  62 │   // The payload has no effect; it is accepted with a deprecation warni
+     │ ng.
+  63 │   @react.componentWithProps(: props)
+  64 │   let make = props => React.string(props.x)
+  65 │ }
+
+  deprecated: @react.componentWithProps takes no payload. The payload has no effect; remove it.
+
 let f = a => Promise.resolve(a + a)
 
 @@jsxConfig({version: 4})
@@ -76,3 +89,14 @@ module V4A7 = {
     \"SharedPropsWithProps$V4A7"
   })
 }
+
+module V4A8 = {
+  type props = {x: string}
+
+  // The payload has no effect; it is accepted with a deprecation warning.
+  let make = (props): React.element => React.string(props.x)
+  let make = React.component({
+    let \"SharedPropsWithProps$V4A8" = (props): React.element => make(props)
+    \"SharedPropsWithProps$V4A8"
+  })
+}

tests/syntax_tests/data/ppx/react/sharedPropsWithProps.res

@@ -55,3 +55,11 @@ module V4A7 = {
     React.int(props.count)
   }
 }
+
+module V4A8 = {
+  type props = {x: string}
+
+  // The payload has no effect; it is accepted with a deprecation warning.
+  @react.componentWithProps(: props)
+  let make = props => React.string(props.x)
+}