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Safe promises
Introduce safe promises, based on rescript-lang#5707 - Add t-first Js.Promise2 with safe bindings - Remove type check for nested promises - Add example illustrating a typical example of nested promises, and how it goes away with Js.Promise2
1 parent 0bc4815 commit 2324e1b

19 files changed

+1744
-1661
lines changed

‎jscomp/ext/warnings.ml

-4
Original file line numberDiff line numberDiff line change
@@ -84,7 +84,6 @@ type t =
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| Bs_integer_literal_overflow (* 107 *)
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| Bs_uninterpreted_delimiters of string (* 108 *)
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| Bs_toplevel_expression_unit (* 109 *)
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| Bs_nested_promise of string (* 110 *)
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(* If you remove a warning, leave a hole in the numbering. NEVER change
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the numbers of existing warnings.
@@ -150,7 +149,6 @@ let number = function
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| Bs_integer_literal_overflow -> 107
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| Bs_uninterpreted_delimiters _ -> 108
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| Bs_toplevel_expression_unit -> 109
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| Bs_nested_promise _ -> 110
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let last_warning_number = 110
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@@ -494,8 +492,6 @@ let message = function
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| Bs_uninterpreted_delimiters s -> "Uninterpreted delimiters " ^ s
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| Bs_toplevel_expression_unit ->
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"Toplevel expression is expected to have unit type."
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| Bs_nested_promise s ->
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"Expression uses nested promise type " ^ s ^ " which is unsafe."
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let sub_locs = function
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| Deprecated (_, def, use) ->

‎jscomp/ext/warnings.mli

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@@ -77,7 +77,6 @@ type t =
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| Bs_integer_literal_overflow (* 107 *)
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| Bs_uninterpreted_delimiters of string (* 108 *)
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| Bs_toplevel_expression_unit (* 109 *)
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| Bs_nested_promise of string (* 110 *)
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val parse_options : bool -> string -> unit
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‎jscomp/main/builtin_cmj_datasets.ml

+30-28
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‎jscomp/ml/typecore.ml

-35
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@@ -1865,45 +1865,10 @@ and type_expect ?in_function ?recarg env sexp ty_expected =
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type_expect_ ?in_function ?recarg env sexp ty_expected
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)
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in
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checkTypeInvariant exp;
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Cmt_format.set_saved_types
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(Cmt_format.Partial_expression exp :: previous_saved_types);
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exp
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(* NOTE: the type invariant check should have no side effects and be efficient *)
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and checkTypeInvariant exp : unit =
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let rec extractPromise t =
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match t.desc with
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| Tconstr
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(Pdot (Pdot (Pident { name = "Js" }, "Promise", _), "t", _), [ t1 ], _)
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| Tconstr (Pident { name = "promise" }, [ t1 ], _) ->
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(* Improvement: check for type aliases, if it can be done efficiently *)
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Some t1
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| Tlink t1 | Tsubst t1 | Tpoly (t1, []) -> extractPromise t1
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| _ -> None
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in
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(* Only traverse arguments of a type constructors and function types.
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This should guarantee that the traversal finished quickly. *)
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let rec findNestedPromise t =
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match t.desc with
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| Tlink t1 | Tsubst t1 | Tpoly (t1, []) -> findNestedPromise t1
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| Tconstr (_, ts, _) -> (
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match extractPromise t with
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| Some t1 -> (
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match extractPromise t1 with
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| Some _t2 ->
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let nestedType = Format.asprintf "%a" Printtyp.type_expr t in
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Location.prerr_warning exp.exp_loc
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(Bs_nested_promise nestedType)
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| None -> ts |> List.iter findNestedPromise)
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| None -> ts |> List.iter findNestedPromise)
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| Tarrow (_, t1, t2, _) ->
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findNestedPromise t1;
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findNestedPromise t2
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| _ -> ()
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in
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findNestedPromise exp.exp_type
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and type_expect_ ?in_function ?(recarg=Rejected) env sexp ty_expected =
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let loc = sexp.pexp_loc in
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(* Record the expression type before unifying it with the expected type *)

‎jscomp/others/js.ml

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@@ -249,6 +249,9 @@ module Re = Js_re
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module Promise = Js_promise
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(** Provide bindings to JS Promise *)
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module Promise2 = Js_promise2
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(** Provide bindings to JS Promise *)
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module Date = Js_date
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(** Provide bindings for JS Date *)
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‎jscomp/others/js_promise2.ml

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@@ -0,0 +1,16 @@
1+
include Js_promise
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let then_ : 'a promise -> ('a -> 'b promise) -> 'b promise =
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[%raw {|
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function(p, cont) {
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Promise.resolve(p).then(cont)
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}
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|}]
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10+
let catch_ : 'a promise -> (error -> 'a promise) -> 'a promise =
11+
[%raw
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{|
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function(p, cont) {
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Promise.resolve(p).catch(cont)
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}
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|}]

‎jscomp/others/release.ninja

+2-1
Original file line numberDiff line numberDiff line change
@@ -47,6 +47,7 @@ o others/js_obj.cmi others/js_obj.cmj : cc others/js_obj.ml | others/belt_intern
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o others/js_option.cmj : cc_cmi others/js_option.ml | others/belt_internals.cmi others/js.cmi others/js_exn.cmj others/js_option.cmi $bsc
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o others/js_option.cmi : cc others/js_option.mli | others/belt_internals.cmi others/js.cmi $bsc
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o others/js_promise.cmi others/js_promise.cmj : cc others/js_promise.ml | others/belt_internals.cmi others/js.cmi $bsc
50+
o others/js_promise2.cmi others/js_promise2.cmj : cc others/js_promise2.ml | others/belt_internals.cmi others/js.cmi others/js_promise.cmj $bsc
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o others/js_re.cmi others/js_re.cmj : cc others/js_re.ml | others/belt_internals.cmi others/js.cmi others/js.cmj $bsc
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o others/js_result.cmj : cc_cmi others/js_result.ml | others/belt_internals.cmi others/js.cmi others/js_result.cmi $bsc
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o others/js_result.cmi : cc others/js_result.mli | others/belt_internals.cmi others/js.cmi $bsc
@@ -67,7 +68,7 @@ o others/jsx.cmi others/jsx.cmj : cc others/jsx.ml | others/belt_internals.cmi o
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o others/jsxDOM.cmi others/jsxDOM.cmj : cc others/jsxDOM.ml | others/belt_internals.cmi others/js.cmi others/jsx.cmj others/jsxDOMStyle.cmj others/jsxEvent.cmj $bsc
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o others/jsxDOMStyle.cmi others/jsxDOMStyle.cmj : cc others/jsxDOMStyle.ml | others/belt_internals.cmi others/js.cmi $bsc
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o others/jsxEvent.cmi others/jsxEvent.cmj : cc others/jsxEvent.ml | others/belt_internals.cmi others/js.cmi $bsc
70-
o js_pkg : phony others/js_OO.cmi others/js_OO.cmj others/js_array.cmi others/js_array.cmj others/js_array2.cmi others/js_array2.cmj others/js_bigint.cmi others/js_bigint.cmj others/js_cast.cmi others/js_cast.cmj others/js_console.cmi others/js_console.cmj others/js_date.cmi others/js_date.cmj others/js_dict.cmi others/js_dict.cmj others/js_exn.cmi others/js_exn.cmj others/js_float.cmi others/js_float.cmj others/js_global.cmi others/js_global.cmj others/js_int.cmi others/js_int.cmj others/js_json.cmi others/js_json.cmj others/js_list.cmi others/js_list.cmj others/js_map.cmi others/js_map.cmj others/js_mapperRt.cmi others/js_mapperRt.cmj others/js_math.cmi others/js_math.cmj others/js_null.cmi others/js_null.cmj others/js_null_undefined.cmi others/js_null_undefined.cmj others/js_obj.cmi others/js_obj.cmj others/js_option.cmi others/js_option.cmj others/js_promise.cmi others/js_promise.cmj others/js_re.cmi others/js_re.cmj others/js_result.cmi others/js_result.cmj others/js_set.cmi others/js_set.cmj others/js_string.cmi others/js_string.cmj others/js_string2.cmi others/js_string2.cmj others/js_typed_array.cmi others/js_typed_array.cmj others/js_typed_array2.cmi others/js_typed_array2.cmj others/js_types.cmi others/js_types.cmj others/js_undefined.cmi others/js_undefined.cmj others/js_vector.cmi others/js_vector.cmj others/js_weakmap.cmi others/js_weakmap.cmj others/js_weakset.cmi others/js_weakset.cmj others/jsx.cmi others/jsx.cmj others/jsxDOM.cmi others/jsxDOM.cmj others/jsxDOMStyle.cmi others/jsxDOMStyle.cmj others/jsxEvent.cmi others/jsxEvent.cmj
71+
o js_pkg : phony others/js_OO.cmi others/js_OO.cmj others/js_array.cmi others/js_array.cmj others/js_array2.cmi others/js_array2.cmj others/js_bigint.cmi others/js_bigint.cmj others/js_cast.cmi others/js_cast.cmj others/js_console.cmi others/js_console.cmj others/js_date.cmi others/js_date.cmj others/js_dict.cmi others/js_dict.cmj others/js_exn.cmi others/js_exn.cmj others/js_float.cmi others/js_float.cmj others/js_global.cmi others/js_global.cmj others/js_int.cmi others/js_int.cmj others/js_json.cmi others/js_json.cmj others/js_list.cmi others/js_list.cmj others/js_map.cmi others/js_map.cmj others/js_mapperRt.cmi others/js_mapperRt.cmj others/js_math.cmi others/js_math.cmj others/js_null.cmi others/js_null.cmj others/js_null_undefined.cmi others/js_null_undefined.cmj others/js_obj.cmi others/js_obj.cmj others/js_option.cmi others/js_option.cmj others/js_promise.cmi others/js_promise.cmj others/js_promise2.cmi others/js_promise2.cmj others/js_re.cmi others/js_re.cmj others/js_result.cmi others/js_result.cmj others/js_set.cmi others/js_set.cmj others/js_string.cmi others/js_string.cmj others/js_string2.cmi others/js_string2.cmj others/js_typed_array.cmi others/js_typed_array.cmj others/js_typed_array2.cmi others/js_typed_array2.cmj others/js_types.cmi others/js_types.cmj others/js_undefined.cmi others/js_undefined.cmj others/js_vector.cmi others/js_vector.cmj others/js_weakmap.cmi others/js_weakmap.cmj others/js_weakset.cmi others/js_weakset.cmj others/jsx.cmi others/jsx.cmj others/jsxDOM.cmi others/jsxDOM.cmj others/jsxDOMStyle.cmi others/jsxDOMStyle.cmj others/jsxEvent.cmi others/jsxEvent.cmj
7172
o others/belt_Array.cmj : cc_cmi others/belt_Array.ml | others/belt.cmi others/belt_Array.cmi others/belt_internals.cmi others/js.cmi others/js.cmj others/js_math.cmj $bsc js_pkg
7273
o others/belt_Array.cmi : cc others/belt_Array.mli | others/belt.cmi others/belt_internals.cmi others/js.cmi others/js.cmj $bsc js_pkg
7374
o others/belt_Float.cmj : cc_cmi others/belt_Float.ml | others/belt.cmi others/belt_Float.cmi others/belt_internals.cmi others/js.cmi $bsc js_pkg

‎jscomp/runtime/js.ml

+3
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@@ -258,6 +258,9 @@ module Re = Js_re
258258
module Promise = Js_promise
259259
(** Provide bindings to JS promise *)
260260

261+
module Promise2 = Js_promise2
262+
(** Provide bindings to JS promise *)
263+
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module Date = Js_date
262265
(** Provide bindings for JS Date *)
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‎jscomp/test/SafePromises.js

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@@ -0,0 +1,35 @@
1+
'use strict';
2+
3+
var Js_promise2 = require("../../lib/js/js_promise2.js");
4+
5+
async function nestedPromise(xxx) {
6+
var xx = await xxx;
7+
Js_promise2.then_(xx, (function (x) {
8+
return Promise.resolve((console.log("Promise2.then_", x), undefined));
9+
}));
10+
Js_promise2.catch_(xx, (function (x) {
11+
console.log("Promise2.catch_", x);
12+
return Promise.resolve(0);
13+
}));
14+
var arg1 = function (x) {
15+
return Promise.resolve((console.log("Promise.then_", x), undefined));
16+
};
17+
xx.then(arg1);
18+
}
19+
20+
async function create(x) {
21+
console.log("create", x);
22+
return x;
23+
}
24+
25+
var xx = create(10);
26+
27+
var xxx = create(xx);
28+
29+
nestedPromise(xxx);
30+
31+
exports.nestedPromise = nestedPromise;
32+
exports.create = create;
33+
exports.xx = xx;
34+
exports.xxx = xxx;
35+
/* xx Not a pure module */

‎jscomp/test/SafePromises.res

+23
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@@ -0,0 +1,23 @@
1+
/*** Problematic example of nested promises is safe with Js.Promise2 */
2+
3+
let nestedPromise = async (xxx: promise<promise<int>>) => {
4+
let xx = await xxx
5+
6+
let _ = xx->Js.Promise2.then_(x => Js.log2("Promise2.then_", x) |> Js.Promise.resolve)
7+
let _ = xx->Js.Promise2.catch_(x => {
8+
Js.log2("Promise2.catch_", x)
9+
0 |> Js.Promise.resolve
10+
})
11+
12+
// This crashes
13+
let _ = Js.Promise.then_(x => Js.log2("Promise.then_", x) |> Js.Promise.resolve, xx)
14+
}
15+
16+
let create = async (x) => {
17+
Js.log2("create", x)
18+
x
19+
}
20+
21+
let xx = create(10)
22+
let xxx = create(xx)
23+
let _ = nestedPromise(xxx)

‎jscomp/test/build.ninja

+2-1
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