Copy objects received from user code before passing them into user co…

…de again

The intention of this is that any getters installed on an object received
from user code are called once each, in a defined order.

Requires a few fixes to make the polyfill match the spec text.

See: #1426

polyfill/lib/ecmascript.mjs

@@ -1123,10 +1123,10 @@ export const ES = ObjectAssign({}, ES2020, {
       ['month', undefined],
       ['monthCode', undefined],
       ['nanosecond', 0],
-      ['offset', undefined],
       ['second', 0],
-      ['timeZone'],
-      ['year', undefined]
+      ['year', undefined],
+      ['offset', undefined],
+      ['timeZone']
     ];
     // Add extra fields from the calendar at the end
     fieldNames.forEach((fieldName) => {

polyfill/lib/plaindate.mjs

@@ -141,6 +141,7 @@ export class PlainDate {
     }
     let fields = ES.ToTemporalDateFields(this, fieldNames);
     fields = ES.CalendarMergeFields(calendar, fields, props);
+    fields = ES.ToTemporalDateFields(fields, fieldNames);
 
     options = ES.NormalizeOptionsObject(options);
 

polyfill/lib/plaindatetime.mjs

@@ -232,6 +232,7 @@ export class PlainDateTime {
     }
     let fields = ES.ToTemporalDateTimeFields(this, fieldNames);
     fields = ES.CalendarMergeFields(calendar, fields, props);
+    fields = ES.ToTemporalDateTimeFields(fields, fieldNames);
     const {
       year,
       month,

polyfill/lib/plainmonthday.mjs

@@ -5,8 +5,6 @@ import { DateTimeFormat } from './intl.mjs';
 import { MakeIntrinsicClass } from './intrinsicclass.mjs';
 import { ISO_MONTH, ISO_DAY, ISO_YEAR, CALENDAR, MONTH_DAY_BRAND, CreateSlots, GetSlot, SetSlot } from './slots.mjs';
 
-const ObjectAssign = Object.assign;
-
 function MonthDayToString(monthDay, showCalendar = 'auto') {
   const month = ES.ISODateTimePartString(GetSlot(monthDay, ISO_MONTH));
   const day = ES.ISODateTimePartString(GetSlot(monthDay, ISO_DAY));
@@ -88,6 +86,7 @@ export class PlainMonthDay {
     }
     let fields = ES.ToTemporalMonthDayFields(this, fieldNames);
     fields = ES.CalendarMergeFields(calendar, fields, props);
+    fields = ES.ToTemporalMonthDayFields(fields, fieldNames);
 
     options = ES.NormalizeOptionsObject(options);
     return ES.MonthDayFromFields(calendar, fields, options);
@@ -124,18 +123,28 @@ export class PlainMonthDay {
     const calendar = GetSlot(this, CALENDAR);
 
     const receiverFieldNames = ES.CalendarFields(calendar, ['day', 'monthCode']);
-    const fields = ES.ToTemporalMonthDayFields(this, receiverFieldNames);
+    let fields = ES.ToTemporalMonthDayFields(this, receiverFieldNames);
 
     const inputFieldNames = ES.CalendarFields(calendar, ['year']);
-    const entries = [['year']];
+    const inputEntries = [['year']];
     // Add extra fields from the calendar at the end
     inputFieldNames.forEach((fieldName) => {
-      if (!entries.some(([name]) => name === fieldName)) {
-        entries.push([fieldName, undefined]);
+      if (!inputEntries.some(([name]) => name === fieldName)) {
+        inputEntries.push([fieldName, undefined]);
+      }
+    });
+    const inputFields = ES.PrepareTemporalFields(item, inputEntries);
+    let mergedFields = ES.CalendarMergeFields(calendar, fields, inputFields);
+
+    const mergedFieldNames = [...new Set([...receiverFieldNames, ...inputFieldNames])];
+    const mergedEntries = [];
+    mergedFieldNames.forEach((fieldName) => {
+      if (!mergedEntries.some(([name]) => name === fieldName)) {
+        mergedEntries.push([fieldName, undefined]);
       }
     });
-    ObjectAssign(fields, ES.PrepareTemporalFields(item, entries));
-    return ES.DateFromFields(calendar, fields);
+    mergedFields = ES.PrepareTemporalFields(mergedFields, mergedEntries);
+    return ES.DateFromFields(calendar, mergedFields);
   }
   getISOFields() {
     if (!ES.IsTemporalMonthDay(this)) throw new TypeError('invalid receiver');

polyfill/lib/plainyearmonth.mjs

@@ -5,8 +5,6 @@ import { DateTimeFormat } from './intl.mjs';
 import { GetIntrinsic, MakeIntrinsicClass } from './intrinsicclass.mjs';
 import { ISO_YEAR, ISO_MONTH, ISO_DAY, YEAR_MONTH_BRAND, CALENDAR, CreateSlots, GetSlot, SetSlot } from './slots.mjs';
 
-const ObjectAssign = Object.assign;
-
 function YearMonthToString(yearMonth, showCalendar = 'auto') {
   const year = ES.ISOYearString(GetSlot(yearMonth, ISO_YEAR));
   const month = ES.ISODateTimePartString(GetSlot(yearMonth, ISO_MONTH));
@@ -113,6 +111,7 @@ export class PlainYearMonth {
     }
     let fields = ES.ToTemporalYearMonthFields(this, fieldNames);
     fields = ES.CalendarMergeFields(calendar, fields, props);
+    fields = ES.ToTemporalYearMonthFields(fields, fieldNames);
 
     options = ES.NormalizeOptionsObject(options);
 
@@ -348,18 +347,28 @@ export class PlainYearMonth {
     const calendar = GetSlot(this, CALENDAR);
 
     const receiverFieldNames = ES.CalendarFields(calendar, ['monthCode', 'year']);
-    const fields = ES.ToTemporalYearMonthFields(this, receiverFieldNames);
+    let fields = ES.ToTemporalYearMonthFields(this, receiverFieldNames);
 
     const inputFieldNames = ES.CalendarFields(calendar, ['day']);
-    const entries = [['day']];
+    const inputEntries = [['day']];
     // Add extra fields from the calendar at the end
     inputFieldNames.forEach((fieldName) => {
-      if (!entries.some(([name]) => name === fieldName)) {
-        entries.push([fieldName, undefined]);
+      if (!inputEntries.some(([name]) => name === fieldName)) {
+        inputEntries.push([fieldName, undefined]);
+      }
+    });
+    const inputFields = ES.PrepareTemporalFields(item, inputEntries);
+    let mergedFields = ES.CalendarMergeFields(calendar, fields, inputFields);
+
+    const mergedFieldNames = [...new Set([...receiverFieldNames, ...inputFieldNames])];
+    const mergedEntries = [];
+    mergedFieldNames.forEach((fieldName) => {
+      if (!mergedEntries.some(([name]) => name === fieldName)) {
+        mergedEntries.push([fieldName, undefined]);
       }
     });
-    ObjectAssign(fields, ES.PrepareTemporalFields(item, entries));
-    return ES.DateFromFields(calendar, fields, { overflow: 'reject' });
+    mergedFields = ES.PrepareTemporalFields(mergedFields, mergedEntries);
+    return ES.DateFromFields(calendar, mergedFields, { overflow: 'reject' });
   }
   getISOFields() {
     if (!ES.IsTemporalYearMonth(this)) throw new TypeError('invalid receiver');

polyfill/lib/zoneddatetime.mjs

@@ -226,6 +226,7 @@ export class ZonedDateTime {
     }
     let fields = ES.ToTemporalZonedDateTimeFields(this, fieldNames);
     fields = ES.CalendarMergeFields(calendar, fields, props);
+    fields = ES.ToTemporalZonedDateTimeFields(fields, fieldNames);
     let {
       year,
       month,

polyfill/test/PlainDate/prototype/with/copies-merge-fields-object.js

@@ -0,0 +1,30 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.with
+description: The object returned from mergeFields() is copied before being passed to dateFromFields().
+info: |
+    sec-temporal.plaindate.prototype.with steps 13–15:
+      13. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialDate_).
+      14. Set _fields_ to ? PrepareTemporalFields(_fields_, _fieldNames_, «»).
+      15. Return ? DateFromFields(_calendar_, _fields_, _options_).
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  "get day",
+  "valueOf day",
+  "get month",
+  "valueOf month",
+  "get monthCode",
+  "toString monthCode",
+  "get year",
+  "valueOf year",
+];
+
+const calendar = TemporalHelpers.calendarMergeFieldsGetters();
+const date = new Temporal.PlainDate(2021, 3, 31, calendar);
+date.with({ year: 2022 });
+
+assert.compareArray(calendar.mergeFieldsReturnOperations, expected, "getters called on mergeFields return");

polyfill/test/PlainDateTime/prototype/with/copies-merge-fields-object.js

@@ -0,0 +1,44 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.with
+description: The object returned from mergeFields() is copied before being passed to dateFromFields().
+info: |
+    sec-temporal.plaindatetime.prototype.with steps 13–15:
+      13. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialDate_).
+      14. Set _fields_ to ? PrepareTemporalFields(_fields_, _fieldNames_, «»).
+      15. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
+    sec-temporal-interprettemporaldatetimefields step 2:
+      2. Let _temporalDate_ be ? DateFromFields(_calendar_, _fields_, _options_).
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  "get day",
+  "valueOf day",
+  "get hour",
+  "valueOf hour",
+  "get microsecond",
+  "valueOf microsecond",
+  "get millisecond",
+  "valueOf millisecond",
+  "get minute",
+  "valueOf minute",
+  "get month",
+  "valueOf month",
+  "get monthCode",
+  "toString monthCode",
+  "get nanosecond",
+  "valueOf nanosecond",
+  "get second",
+  "valueOf second",
+  "get year",
+  "valueOf year",
+];
+
+const calendar = TemporalHelpers.calendarMergeFieldsGetters();
+const datetime = new Temporal.PlainDateTime(2021, 3, 31, 12, 34, 56, 987, 654, 321, calendar);
+datetime.with({ year: 2022 });
+
+assert.compareArray(calendar.mergeFieldsReturnOperations, expected, "getters called on mergeFields return");

polyfill/test/PlainMonthDay/prototype/toPlainDate/copies-merge-fields-object.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainmonthday.prototype.toplaindate
+description: The object returned from mergeFields() is copied before being passed to monthDayFromFields().
+info: |
+    sec-temporal.plainmonthday.prototype.toplaindate steps 9 and 11:
+      9. Let _mergedFields_ be ? CalendarMergeFields(_calendar_, _fields_, _inputFields_).
+      11. Set _mergedFields_ to ? PrepareTemporalFields(_mergedFields_, _mergedFieldNames_, «»).
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  "get day",
+  "valueOf day",
+  "get monthCode",
+  "toString monthCode",
+  "get year",
+  "valueOf year",
+];
+
+const calendar = TemporalHelpers.calendarMergeFieldsGetters();
+const monthday = new Temporal.PlainMonthDay(3, 31, calendar);
+monthday.toPlainDate({ year: 2000 });
+
+assert.compareArray(calendar.mergeFieldsReturnOperations, expected, "getters called on mergeFields return");

polyfill/test/PlainMonthDay/prototype/with/copies-merge-fields-object.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainmonthday.prototype.with
+description: The object returned from mergeFields() is copied before being passed to monthDayFromFields().
+info: |
+    sec-temporal.plainmonthday.prototype.with steps 13–15:
+      13. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialMonthDay_).
+      14. Set _fields_ to ? PrepareTemporalFields(_fields_, _fieldNames_, «»).
+      15. Return ? MonthDayFromFields(_calendar_, _fields_, _options_).
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  "get day",
+  "valueOf day",
+  "get month", // PlainMonthDay.month property does not exist, no valueOf
+  "get monthCode",
+  "toString monthCode",
+  "get year", // undefined, no valueOf
+];
+
+const calendar = TemporalHelpers.calendarMergeFieldsGetters();
+const monthday = new Temporal.PlainMonthDay(3, 31, calendar);
+monthday.with({ day: 1 });
+
+assert.compareArray(calendar.mergeFieldsReturnOperations, expected, "getters called on mergeFields return");

polyfill/test/PlainYearMonth/prototype/toPlainDate/copies-merge-fields-object.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainyearmonth.prototype.toplaindate
+description: The object returned from mergeFields() is copied before being passed to monthDayFromFields().
+info: |
+    sec-temporal.plainyearmonth.prototype.toplaindate steps 9 and 11:
+      9. Let _mergedFields_ be ? CalendarMergeFields(_calendar_, _fields_, _inputFields_).
+      11. Set _mergedFields_ to ? PrepareTemporalFields(_mergedFields_, _mergedFieldNames_, «»).
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  "get monthCode",
+  "toString monthCode",
+  "get year",
+  "valueOf year",
+  "get day",  // first receiver fields, then input fields
+  "valueOf day",
+];
+
+const calendar = TemporalHelpers.calendarMergeFieldsGetters();
+const yearmonth = new Temporal.PlainYearMonth(2000, 5, calendar);
+yearmonth.toPlainDate({ day: 2 });
+
+assert.compareArray(calendar.mergeFieldsReturnOperations, expected, "getters called on mergeFields return");

polyfill/test/PlainYearMonth/prototype/with/copies-merge-fields-object.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainyearmonth.prototype.with
+description: The object returned from mergeFields() is copied before being passed to monthDayFromFields().
+info: |
+    sec-temporal.plainyearmonth.prototype.with steps 13–15:
+      13. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialYearMonth_).
+      14. Set _fields_ to ? PrepareTemporalFields(_fields_, _fieldNames_, «»).
+      15. Return ? YearMonthFromFields(_calendar_, _fields_, _options_).
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  "get month",
+  "valueOf month",
+  "get monthCode",
+  "toString monthCode",
+  "get year",
+  "valueOf year",
+];
+
+const calendar = TemporalHelpers.calendarMergeFieldsGetters();
+const yearmonth = new Temporal.PlainYearMonth(2000, 5, calendar);
+yearmonth.with({ year: 2004 });
+
+assert.compareArray(calendar.mergeFieldsReturnOperations, expected, "getters called on mergeFields return");

polyfill/test/ZonedDateTime/prototype/with/copies-merge-fields-object.js

@@ -0,0 +1,47 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.with
+description: The object returned from mergeFields() is copied before being passed to dateFromFields().
+info: |
+    sec-temporal.plaindatetime.prototype.with steps 18–19 and 23:
+      18. Set _fields_ to ? CalendarMergeFields(_calendar_, _fields_, _partialDate_).
+      19. Set _fields_ to ? PrepareTemporalFields(_fields_, _fieldNames_, « *"timeZone"* »).
+      23. Let _dateTimeResult_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
+    sec-temporal-interprettemporaldatetimefields step 2:
+      2. Let _temporalDate_ be ? DateFromFields(_calendar_, _fields_, _options_).
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  "get day",
+  "valueOf day",
+  "get hour",
+  "valueOf hour",
+  "get microsecond",
+  "valueOf microsecond",
+  "get millisecond",
+  "valueOf millisecond",
+  "get minute",
+  "valueOf minute",
+  "get month",
+  "valueOf month",
+  "get monthCode",
+  "toString monthCode",
+  "get nanosecond",
+  "valueOf nanosecond",
+  "get second",
+  "valueOf second",
+  "get year",
+  "valueOf year",
+  "get offset",
+  "toString offset",
+  "get timeZone",
+];
+
+const calendar = TemporalHelpers.calendarMergeFieldsGetters();
+const datetime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UTC", calendar);
+datetime.with({ year: 2022 });
+
+assert.compareArray(calendar.mergeFieldsReturnOperations, expected, "getters called on mergeFields return");