1142351 - Add console warnings for non-standard flag argument of String.prototype.{search,match,replace}.

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Tooru Fujisawa [:arai]]

Derived from bug 1108382.

Now almost all in-tree consumers of flag argument of String.prototype.{search,match,replace} are fixed.
Add deprecation warning for it, in the same way as other non-standard features.

Adding also telemetry might be needed.

Comment 1

[Tooru Fujisawa [:arai]]

Attachment: Part 1: Collect telemetry about deprecated flag argument for String.prototype.{search,match,replace}.

To make sure it's safe to remove flags argument, added telemetry for it, as Part 1.
Is there any other thing required to add telemetry item?

Almost green on try runs:
  https://treeherder.mozilla.org/#/jobs?repo=try&revision=992de148a534
    (forgot to add shell-only comment)
  https://treeherder.mozilla.org/#/jobs?repo=try&revision=c9f4dd0003d3
    (fixed above)

Comment 2

[Tooru Fujisawa [:arai]]

Attachment: Part 2: Warn about deprecated flag argument for String.prototype.{search,match,replace}.

Comment 3

[Jan de Mooij [:jandem]]

Comment on attachment 8579973 [details] [diff] [review]
Part 1: Collect telemetry about deprecated flag argument for String.prototype.{search,match,replace}.

Review of attachment 8579973 [details] [diff] [review]:
-----------------------------------------------------------------

Nice.

Comment 4

[Jan de Mooij [:jandem]]

Comment on attachment 8579974 [details] [diff] [review]
Part 2: Warn about deprecated flag argument for String.prototype.{search,match,replace}.

Review of attachment 8579974 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/jsstr.cpp
@@ +2137,5 @@
>                  cx->compartment()->addTelemetry(filename, JSCompartment::DeprecatedFlagsArgument);
>              }
>  
> +            if (!JS_ReportErrorFlagsAndNumber(cx, JSREPORT_WARNING, GetErrorMessage, nullptr,
> +                                              JSMSG_DEPRECATED_FLAGS_ARG))

Reporting a warning each time the flags argument is used will slow us down a lot and will spam the browser's console.

It'd be good to warn at most once per compartment/global. You can do something like I did in bug 1140428, or use GlobalObject::warnOnceAbout (vm/GlobalObject.h)

Comment 5

[Tooru Fujisawa [:arai]]

Attachment: Part 2: Warn about deprecated flag argument for String.prototype.{search,match,replace}.

Thank you for reviewing :D
Added `warnedAboutFlagsArgument` member to compartment.

Green on try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=7de970d52299

Comment 6

[Jan de Mooij [:jandem]]

Comment on attachment 8581029 [details] [diff] [review]
Part 2: Warn about deprecated flag argument for String.prototype.{search,match,replace}.

Review of attachment 8581029 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/js.msg
@@ +231,5 @@
>  MSG_DEF(JSMSG_CURLY_IN_COMPOUND,       0, JSEXN_SYNTAXERR, "missing } in compound statement")
>  MSG_DEF(JSMSG_DECLARATION_AFTER_EXPORT,0, JSEXN_SYNTAXERR, "missing declaration after 'export' keyword")
>  MSG_DEF(JSMSG_DECLARATION_AFTER_IMPORT,0, JSEXN_SYNTAXERR, "missing declaration after 'import' keyword")
>  MSG_DEF(JSMSG_DEPRECATED_DELETE_OPERAND, 0, JSEXN_SYNTAXERR, "applying the 'delete' operator to an unqualified name is deprecated")
> +MSG_DEF(JSMSG_DEPRECATED_FLAGS_ARG,    0, JSEXN_NONE, "flags argument of String.prototype.{search,match,replace} are deprecated")

Nit: s/are deprecated/is deprecated/

::: js/src/tests/js1_5/String/replace-flags.js
@@ +8,5 @@
> +
> +options("werror");
> +assertEq(evaluate("'aaaA'.match('a', 'i')", {catchTermination: true}), "terminated");
> +assertEq(evaluate("'aaaA'.search('a', 'i')", {catchTermination: true}), "terminated");
> +assertEq(evaluate("'aaaA'.replace('a', 'b', 'g')", {catchTermination: true}), "terminated");

Does this test still pass, if we warn only once per compartment? If not you can probably do newGlobal().evaluate(...); it'll create a new compartment.

Comment 7

[Tooru Fujisawa [:arai]]

Thank you for reviewing :)

(In reply to Jan de Mooij [:jandem] from comment #6)
> ::: js/src/tests/js1_5/String/replace-flags.js
> @@ +8,5 @@
> > +
> > +options("werror");
> > +assertEq(evaluate("'aaaA'.match('a', 'i')", {catchTermination: true}), "terminated");
> > +assertEq(evaluate("'aaaA'.search('a', 'i')", {catchTermination: true}), "terminated");
> > +assertEq(evaluate("'aaaA'.replace('a', 'b', 'g')", {catchTermination: true}), "terminated");
> 
> Does this test still pass, if we warn only once per compartment? If not you
> can probably do newGlobal().evaluate(...); it'll create a new compartment.

Yes, because JS_ReportErrorFlagsAndNumber returns false after `options("werror")`, and `cx->compartment()->warnedAboutFlagsArgument = true;` is not evaluated in that case.
is it better to do `cx->compartment()->warnedAboutFlagsArgument = true` before calling JS_ReportErrorFlagsAndNumber ?

Comment 8

[Jan de Mooij [:jandem]]

(In reply to Tooru Fujisawa [:arai] from comment #7)
> Yes, because JS_ReportErrorFlagsAndNumber returns false after
> `options("werror")`, and `cx->compartment()->warnedAboutFlagsArgument =
> true;` is not evaluated in that case.

Ah, right.

> is it better to do `cx->compartment()->warnedAboutFlagsArgument = true`
> before calling JS_ReportErrorFlagsAndNumber ?

Since this only happens with the non-standard werror option, I don't think it matters too much. Either way is fine with me.

Comment 9

[Tooru Fujisawa [:arai]]

Thanks again, I keep it as current.

https://hg.mozilla.org/integration/mozilla-inbound/rev/a7556816cb5f
https://hg.mozilla.org/integration/mozilla-inbound/rev/d802bf89d877

Comment 10

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/a7556816cb5f
https://hg.mozilla.org/mozilla-central/rev/d802bf89d877

Comment 11

[Tooru Fujisawa [:arai]]

Updated following documents:
  https://developer.mozilla.org/en-US/Firefox/Releases/39
  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace
  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/match
  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/search

match/search page says nothing about `flags`, so added only to "Firefox-specific notes".

Comment 12

[Florian Scholz (Open Web Docs)]

Thanks arai! Let's not further advertise this, now that it will be gone at some point. The notes in the compat section are enough imo.