Store strings or objects in Temporal objects' [[Calendar]] slot

In several tests involving custom calendars, we need to change the
implementation of dateFromFields/monthDayFromFields/yearMonthFromFields so
that the returned object gets the receiver as its calendar after chaining
up to the builtin implementation.

Normative PR: tc39/proposal-temporal#2482

harness/temporalHelpers.js

@@ -839,6 +839,20 @@ var TemporalHelpers = {
         super("iso8601");
       }
 
+      dateFromFields(...args) {
+        return super.dateFromFields(...args).withCalendar(this);
+      }
+
+      monthDayFromFields(...args) {
+        const { isoYear, isoMonth, isoDay } = super.monthDayFromFields(...args).getISOFields();
+        return new Temporal.PlainMonthDay(isoMonth, isoDay, this, isoYear);
+      }
+
+      yearMonthFromFields(...args) {
+        const { isoYear, isoMonth, isoDay } = super.yearMonthFromFields(...args).getISOFields();
+        return new Temporal.PlainYearMonth(isoYear, isoMonth, this, isoDay);
+      }
+
       toString() {
         return "fast-path-check";
       }
@@ -1059,13 +1073,17 @@ var TemporalHelpers = {
         return "dateadd-plain-date-instance";
       }
 
+      dateFromFields(...args) {
+        return super.dateFromFields(...args).withCalendar(this);
+      }
+
       dateAdd(date, duration, options) {
         this.dateAddCallCount++;
         assert(date instanceof Temporal.PlainDate, "dateAdd() should be called with a PlainDate instance");
         if (this.dateAddCallCount === 1 && this.specificPlainDate) {
           assert.sameValue(date, this.specificPlainDate, `dateAdd() should be called first with the specific PlainDate instance ${this.specificPlainDate}`);
         }
-        return super.dateAdd(date, duration, options);
+        return super.dateAdd(date, duration, options).withCalendar(this);
       }
     }
     return new CalendarDateAddPlainDateInstance();

test/built-ins/Temporal/Calendar/prototype/dateUntil/argument-propertybag-calendar-string.js

@@ -9,6 +9,13 @@ features: [Temporal]
 ---*/
 
 const instance = new Temporal.Calendar("iso8601");
+Object.defineProperty(instance, "dateFromFields", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateFromFields should not be looked up on receiver");
+  },
+});
 
 const calendar = "iso8601";
 

test/built-ins/Temporal/Duration/compare/relativeto-propertybag-calendar-string.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.duration.compare
+description: >
+    Builtin dateFromFields method is not observably called when the property bag
+    has a string-valued calendar property
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dateFromFieldsOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dateFromFields");
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateFromFields should not be looked up");
+  },
+});
+
+const relativeTo = { year: 2000, month: 5, day: 2, calendar: "iso8601" };
+Temporal.Duration.compare(new Temporal.Duration(), new Temporal.Duration(), { relativeTo });
+
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", dateFromFieldsOriginal);

test/built-ins/Temporal/Duration/prototype/add/relativeto-propertybag-calendar-string.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.duration.prototype.add
+description: >
+    Builtin dateFromFields method is not observably called when the property bag
+    has a string-valued calendar property
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dateFromFieldsOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dateFromFields");
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateFromFields should not be looked up");
+  },
+});
+
+const instance = new Temporal.Duration(1, 0, 0, 1);
+const relativeTo = { year: 2000, month: 5, day: 2, calendar: "iso8601" };
+instance.add(new Temporal.Duration(0, 0, 0, 0, -24), { relativeTo });
+
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", dateFromFieldsOriginal);

test/built-ins/Temporal/Duration/prototype/round/relativeto-propertybag-calendar-string.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.duration.prototype.round
+description: >
+    Builtin dateFromFields method is not observably called when the property bag
+    has a string-valued calendar property
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dateFromFieldsOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dateFromFields");
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateFromFields should not be looked up");
+  },
+});
+
+const instance = new Temporal.Duration(1, 0, 0, 0, 24);
+const relativeTo = { year: 2000, month: 5, day: 2, calendar: "iso8601" };
+instance.round({ largestUnit: "years", relativeTo });
+
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", dateFromFieldsOriginal);

test/built-ins/Temporal/Duration/prototype/subtract/relativeto-propertybag-calendar-string.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.duration.prototype.subtract
+description: >
+    Builtin dateFromFields method is not observably called when the property bag
+    has a string-valued calendar property
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dateFromFieldsOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dateFromFields");
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateFromFields should not be looked up");
+  },
+});
+
+const instance = new Temporal.Duration(1, 0, 0, 1);
+const relativeTo = { year: 2000, month: 5, day: 2, calendar: "iso8601" };
+instance.subtract(new Temporal.Duration(0, 0, 0, 0, 24), { relativeTo });
+
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", dateFromFieldsOriginal);

test/built-ins/Temporal/Duration/prototype/total/relativeto-propertybag-calendar-string.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.duration.prototype.total
+description: >
+    Builtin dateFromFields method is not observably called when the property bag
+    has a string-valued calendar property
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dateFromFieldsOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dateFromFields");
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateFromFields should not be looked up");
+  },
+});
+
+const instance = new Temporal.Duration(1, 0, 0, 0, 24);
+const relativeTo = { year: 2000, month: 5, day: 2, calendar: "iso8601" };
+instance.total({ unit: "days", relativeTo });
+
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", dateFromFieldsOriginal);

test/built-ins/Temporal/Instant/prototype/toZonedDateTimeISO/calendar-is-builtin.js

@@ -0,0 +1,13 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.instant.prototype.tozoneddatetimeiso
+description: >
+  toZonedDateTimeISO() results in a ZonedDateTime with builtin ISO calendar
+features: [Temporal]
+---*/
+
+const instance = new Temporal.Instant(0n);
+const result = instance.toZonedDateTimeISO("UTC");
+assert.sameValue(result.getISOFields().calendar, "iso8601", "calendar slot stores a string");

test/built-ins/Temporal/PlainDate/compare/argument-propertybag-calendar-string.js

@@ -4,9 +4,19 @@
 /*---
 esid: sec-temporal.plaindate.compare
 description: A calendar ID is valid input for Calendar
+includes: [temporalHelpers.js]
 features: [Temporal]
 ---*/
 
+const dateFromFieldsOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dateFromFields");
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateFromFields should not be looked up");
+  },
+});
+
 const calendar = "iso8601";
 
 const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
@@ -16,3 +26,5 @@ assert.sameValue(result1, 0, `Calendar created from string "${arg}" (first argum
 
 const result2 = Temporal.PlainDate.compare(new Temporal.PlainDate(1976, 11, 18), arg);
 assert.sameValue(result2, 0, `Calendar created from string "${arg}" (second argument)`);
+
+Object.defineProperty(Temporal.Calendar.prototype, "dateFromFields", dateFromFieldsOriginal);

test/built-ins/Temporal/PlainDate/from/argument-propertybag-calendar-string.js

@@ -13,3 +13,4 @@ const calendar = "iso8601";
 const arg = { year: 1976, monthCode: "M11", day: 18, calendar };
 const result = Temporal.PlainDate.from(arg);
 TemporalHelpers.assertPlainDate(result, 1976, 11, "M11", 18, `Calendar created from string "${calendar}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", "calendar slot stores a string");

test/built-ins/Temporal/PlainDate/prototype/add/builtin-calendar-no-observable-calls.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.add
+description: >
+  Calling the method on an instance constructed with a builtin calendar causes
+  no observable lookups or calls to calendar methods.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dateAddOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dateAdd");
+Object.defineProperty(Temporal.Calendar.prototype, "dateAdd", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dateAdd should not be looked up");
+  },
+});
+
+const instance = new Temporal.PlainDate(2000, 5, 2, "iso8601");
+instance.add(new Temporal.Duration(1));
+
+Object.defineProperty(Temporal.Calendar.prototype, "dateAdd", dateAddOriginal);

test/built-ins/Temporal/PlainDate/prototype/calendarId/builtin-calendar-no-observable-calls.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.calendarid
+description: >
+  Calling the method on an instance constructed with a builtin calendar causes
+  no observable lookups or calls to calendar methods.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const idOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "id");
+Object.defineProperty(Temporal.Calendar.prototype, "id", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("id should not be looked up");
+  },
+});
+
+const instance = new Temporal.PlainDate(2000, 5, 2, "iso8601");
+instance.calendarId;
+
+Object.defineProperty(Temporal.Calendar.prototype, "id", idOriginal);

test/built-ins/Temporal/PlainDate/prototype/day/builtin-calendar-no-observable-calls.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.day
+description: >
+  Calling the method on an instance constructed with a builtin calendar causes
+  no observable lookups or calls to calendar methods.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dayOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "day");
+Object.defineProperty(Temporal.Calendar.prototype, "day", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("day should not be looked up");
+  },
+});
+
+const instance = new Temporal.PlainDate(2000, 5, 2, "iso8601");
+instance.day;
+
+Object.defineProperty(Temporal.Calendar.prototype, "day", dayOriginal);

test/built-ins/Temporal/PlainDate/prototype/dayOfWeek/builtin-calendar-no-observable-calls.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.dayofweek
+description: >
+  Calling the method on an instance constructed with a builtin calendar causes
+  no observable lookups or calls to calendar methods.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dayOfWeekOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dayOfWeek");
+Object.defineProperty(Temporal.Calendar.prototype, "dayOfWeek", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dayOfWeek should not be looked up");
+  },
+});
+
+const instance = new Temporal.PlainDate(2000, 5, 2, "iso8601");
+instance.dayOfWeek;
+
+Object.defineProperty(Temporal.Calendar.prototype, "dayOfWeek", dayOfWeekOriginal);

test/built-ins/Temporal/PlainDate/prototype/dayOfYear/builtin-calendar-no-observable-calls.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.dayofyear
+description: >
+  Calling the method on an instance constructed with a builtin calendar causes
+  no observable lookups or calls to calendar methods.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const dayOfYearOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "dayOfYear");
+Object.defineProperty(Temporal.Calendar.prototype, "dayOfYear", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("dayOfYear should not be looked up");
+  },
+});
+
+const instance = new Temporal.PlainDate(2000, 5, 2, "iso8601");
+instance.dayOfYear;
+
+Object.defineProperty(Temporal.Calendar.prototype, "dayOfYear", dayOfYearOriginal);

test/built-ins/Temporal/PlainDate/prototype/daysInMonth/builtin-calendar-no-observable-calls.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.daysinmonth
+description: >
+  Calling the method on an instance constructed with a builtin calendar causes
+  no observable lookups or calls to calendar methods.
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const daysInMonthOriginal = Object.getOwnPropertyDescriptor(Temporal.Calendar.prototype, "daysInMonth");
+Object.defineProperty(Temporal.Calendar.prototype, "daysInMonth", {
+  configurable: true,
+  enumerable: false,
+  get() {
+    TemporalHelpers.assertUnreachable("daysInMonth should not be looked up");
+  },
+});
+
+const instance = new Temporal.PlainDate(2000, 5, 2, "iso8601");
+instance.daysInMonth;
+
+Object.defineProperty(Temporal.Calendar.prototype, "daysInMonth", daysInMonthOriginal);