Validate required methods of Temporal Calendar protocol

Checking whether an object implements the Calendar protocol is now done by
means of HasProperty operations for each of the required methods unless
the object already has the Calendar brand.

Discussion:
tc39/proposal-temporal#2104 (comment)

Corresponding normative PR:
tc39/proposal-temporal#2485

harness/temporalHelpers.js

@@ -1464,6 +1464,34 @@ var TemporalHelpers = {
    * objectName is used in the log.
    */
   calendarObserver(calls, objectName, methodOverrides = {}) {
+    function removeExtraHasPropertyChecks(objectName, calls) {
+      // Inserting the tracking calendar into the return values of methods
+      // that we chain up into the ISO calendar for, causes extra HasProperty
+      // checks, which we observe. This removes them so that we don't leak
+      // implementation details of the helper into the test code.
+      assert.sameValue(calls.pop(), `has ${objectName}.yearOfWeek`);
+      assert.sameValue(calls.pop(), `has ${objectName}.yearMonthFromFields`);
+      assert.sameValue(calls.pop(), `has ${objectName}.year`);
+      assert.sameValue(calls.pop(), `has ${objectName}.weekOfYear`);
+      assert.sameValue(calls.pop(), `has ${objectName}.monthsInYear`);
+      assert.sameValue(calls.pop(), `has ${objectName}.monthDayFromFields`);
+      assert.sameValue(calls.pop(), `has ${objectName}.monthCode`);
+      assert.sameValue(calls.pop(), `has ${objectName}.month`);
+      assert.sameValue(calls.pop(), `has ${objectName}.mergeFields`);
+      assert.sameValue(calls.pop(), `has ${objectName}.inLeapYear`);
+      assert.sameValue(calls.pop(), `has ${objectName}.id`);
+      assert.sameValue(calls.pop(), `has ${objectName}.fields`);
+      assert.sameValue(calls.pop(), `has ${objectName}.daysInYear`);
+      assert.sameValue(calls.pop(), `has ${objectName}.daysInWeek`);
+      assert.sameValue(calls.pop(), `has ${objectName}.daysInMonth`);
+      assert.sameValue(calls.pop(), `has ${objectName}.dayOfYear`);
+      assert.sameValue(calls.pop(), `has ${objectName}.dayOfWeek`);
+      assert.sameValue(calls.pop(), `has ${objectName}.day`);
+      assert.sameValue(calls.pop(), `has ${objectName}.dateUntil`);
+      assert.sameValue(calls.pop(), `has ${objectName}.dateFromFields`);
+      assert.sameValue(calls.pop(), `has ${objectName}.dateAdd`);
+    }
+
     const iso8601 = new Temporal.Calendar("iso8601");
     const trackingMethods = {
       dateFromFields(...args) {
@@ -1475,7 +1503,9 @@ var TemporalHelpers = {
         const originalResult = iso8601.dateFromFields(...args);
         // Replace the calendar in the result with the call-tracking calendar
         const {isoYear, isoMonth, isoDay} = originalResult.getISOFields();
-        return new Temporal.PlainDate(isoYear, isoMonth, isoDay, this);
+        const result = new Temporal.PlainDate(isoYear, isoMonth, isoDay, this);
+        removeExtraHasPropertyChecks(objectName, calls);
+        return result;
       },
       yearMonthFromFields(...args) {
         calls.push(`call ${objectName}.yearMonthFromFields`);
@@ -1486,7 +1516,9 @@ var TemporalHelpers = {
         const originalResult = iso8601.yearMonthFromFields(...args);
         // Replace the calendar in the result with the call-tracking calendar
         const {isoYear, isoMonth, isoDay} = originalResult.getISOFields();
-        return new Temporal.PlainYearMonth(isoYear, isoMonth, this, isoDay);
+        const result = new Temporal.PlainYearMonth(isoYear, isoMonth, this, isoDay);
+        removeExtraHasPropertyChecks(objectName, calls);
+        return result;
       },
       monthDayFromFields(...args) {
         calls.push(`call ${objectName}.monthDayFromFields`);
@@ -1497,7 +1529,9 @@ var TemporalHelpers = {
         const originalResult = iso8601.monthDayFromFields(...args);
         // Replace the calendar in the result with the call-tracking calendar
         const {isoYear, isoMonth, isoDay} = originalResult.getISOFields();
-        return new Temporal.PlainMonthDay(isoMonth, isoDay, this, isoYear);
+        const result = new Temporal.PlainMonthDay(isoMonth, isoDay, this, isoYear);
+        removeExtraHasPropertyChecks(objectName, calls);
+        return result;
       },
       dateAdd(...args) {
         calls.push(`call ${objectName}.dateAdd`);
@@ -1507,12 +1541,34 @@ var TemporalHelpers = {
         }
         const originalResult = iso8601.dateAdd(...args);
         const {isoYear, isoMonth, isoDay} = originalResult.getISOFields();
-        return new Temporal.PlainDate(isoYear, isoMonth, isoDay, this);
+        const result = new Temporal.PlainDate(isoYear, isoMonth, isoDay, this);
+        removeExtraHasPropertyChecks(objectName, calls);
+        return result;
       },
       id: "iso8601",
     };
     // Automatically generate the other methods that don't need any custom code
-    ["toString", "dateUntil", "era", "eraYear", "year", "month", "monthCode", "day", "daysInMonth", "fields", "mergeFields"].forEach((methodName) => {
+    [
+      "dateUntil",
+      "day",
+      "dayOfWeek",
+      "dayOfYear",
+      "daysInMonth",
+      "daysInWeek",
+      "daysInYear",
+      "era",
+      "eraYear",
+      "fields",
+      "inLeapYear",
+      "mergeFields",
+      "month",
+      "monthCode",
+      "monthsInYear",
+      "toString",
+      "weekOfYear",
+      "year",
+      "yearOfWeek",
+    ].forEach((methodName) => {
       trackingMethods[methodName] = function (...args) {
         calls.push(`call ${formatPropertyName(methodName, objectName)}`);
         if (methodName in methodOverrides) {

test/built-ins/Temporal/Calendar/from/calendar-object.js

@@ -3,9 +3,33 @@
 
 /*---
 esid: sec-temporal.calendar.from
-description: Converting a plain object to Temporal.Calendar gives the same object
+description: >
+  Converting an object implementing the Calendar protocol to Temporal.Calendar
+  gives the same object
 features: [Temporal]
 ---*/
 
-const custom = { id: "custom-calendar" };
+const custom = {
+  dateAdd() {},
+  dateFromFields() {},
+  dateUntil() {},
+  day() {},
+  dayOfWeek() {},
+  dayOfYear() {},
+  daysInMonth() {},
+  daysInWeek() {},
+  daysInYear() {},
+  fields() {},
+  id: "custom-calendar",
+  inLeapYear() {},
+  mergeFields() {},
+  month() {},
+  monthCode() {},
+  monthDayFromFields() {},
+  monthsInYear() {},
+  weekOfYear() {},
+  year() {},
+  yearMonthFromFields() {},
+  yearOfWeek() {},
+};
 assert.sameValue(Temporal.Calendar.from(custom), custom);

test/built-ins/Temporal/Calendar/from/calendar-wrong-type.js

@@ -15,7 +15,6 @@ const rangeErrorTests = [
   ["", "empty string"],
   [1, "number that doesn't convert to a valid ISO string"],
   [1n, "bigint"],
-  [new Temporal.TimeZone("UTC"), "time zone instance"],
 ];
 
 for (const [arg, description] of rangeErrorTests) {
@@ -24,6 +23,9 @@ for (const [arg, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
 ];
 
 for (const [arg, description] of typeErrorTests) {

test/built-ins/Temporal/Calendar/prototype/dateAdd/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/dateAdd/order-of-operations.js

@@ -9,8 +9,29 @@ features: [Temporal]
 ---*/
 
 const expected = [
-  // ToTemporalDate → GetTemporalCalendarWithISODefault
+  // ToTemporalDate → GetTemporalCalendarSlotValueWithISODefault
   "get date.calendar",
+  "has date.calendar.dateAdd",
+  "has date.calendar.dateFromFields",
+  "has date.calendar.dateUntil",
+  "has date.calendar.day",
+  "has date.calendar.dayOfWeek",
+  "has date.calendar.dayOfYear",
+  "has date.calendar.daysInMonth",
+  "has date.calendar.daysInWeek",
+  "has date.calendar.daysInYear",
+  "has date.calendar.fields",
+  "has date.calendar.id",
+  "has date.calendar.inLeapYear",
+  "has date.calendar.mergeFields",
+  "has date.calendar.month",
+  "has date.calendar.monthCode",
+  "has date.calendar.monthDayFromFields",
+  "has date.calendar.monthsInYear",
+  "has date.calendar.weekOfYear",
+  "has date.calendar.year",
+  "has date.calendar.yearMonthFromFields",
+  "has date.calendar.yearOfWeek",
   // ToTemporalDate → CalendarFields
   "get date.calendar.fields",
   "call date.calendar.fields",

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

@@ -18,7 +18,6 @@ const rangeErrorTests = [
   ["", "empty string"],
   [1, "number that doesn't convert to a valid ISO string"],
   [1n, "bigint"],
-  [new Temporal.TimeZone("UTC"), "time zone instance"],
 ];
 
 for (const [calendar, description] of rangeErrorTests) {
@@ -29,8 +28,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/dateUntil/order-of-operations.js

@@ -9,8 +9,29 @@ features: [Temporal]
 ---*/
 
 const expected = [
-  // ToTemporalDate 1 → GetTemporalCalendarWithISODefault
+  // ToTemporalDate 1 → GetTemporalCalendarSlotValueWithISODefault
   "get one.calendar",
+  "has one.calendar.dateAdd",
+  "has one.calendar.dateFromFields",
+  "has one.calendar.dateUntil",
+  "has one.calendar.day",
+  "has one.calendar.dayOfWeek",
+  "has one.calendar.dayOfYear",
+  "has one.calendar.daysInMonth",
+  "has one.calendar.daysInWeek",
+  "has one.calendar.daysInYear",
+  "has one.calendar.fields",
+  "has one.calendar.id",
+  "has one.calendar.inLeapYear",
+  "has one.calendar.mergeFields",
+  "has one.calendar.month",
+  "has one.calendar.monthCode",
+  "has one.calendar.monthDayFromFields",
+  "has one.calendar.monthsInYear",
+  "has one.calendar.weekOfYear",
+  "has one.calendar.year",
+  "has one.calendar.yearMonthFromFields",
+  "has one.calendar.yearOfWeek",
   // ToTemporalDate 1 → CalendarFields
   "get one.calendar.fields",
   "call one.calendar.fields",
@@ -30,8 +51,29 @@ const expected = [
   // ToTemporalDate 1 → CalendarDateFromFields
   "get one.calendar.dateFromFields",
   "call one.calendar.dateFromFields",
-  // ToTemporalDate 2 → GetTemporalCalendarWithISODefault
+  // ToTemporalDate 2 → GetTemporalCalendarSlotValueWithISODefault
   "get two.calendar",
+  "has two.calendar.dateAdd",
+  "has two.calendar.dateFromFields",
+  "has two.calendar.dateUntil",
+  "has two.calendar.day",
+  "has two.calendar.dayOfWeek",
+  "has two.calendar.dayOfYear",
+  "has two.calendar.daysInMonth",
+  "has two.calendar.daysInWeek",
+  "has two.calendar.daysInYear",
+  "has two.calendar.fields",
+  "has two.calendar.id",
+  "has two.calendar.inLeapYear",
+  "has two.calendar.mergeFields",
+  "has two.calendar.month",
+  "has two.calendar.monthCode",
+  "has two.calendar.monthDayFromFields",
+  "has two.calendar.monthsInYear",
+  "has two.calendar.weekOfYear",
+  "has two.calendar.year",
+  "has two.calendar.yearMonthFromFields",
+  "has two.calendar.yearOfWeek",
   // ToTemporalDate 2 → CalendarFields
   "get two.calendar.fields",
   "call two.calendar.fields",

test/built-ins/Temporal/Calendar/prototype/day/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/dayOfWeek/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/dayOfYear/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/daysInMonth/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/daysInWeek/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/daysInYear/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/inLeapYear/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/month/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];
 

test/built-ins/Temporal/Calendar/prototype/monthCode/argument-propertybag-calendar-wrong-type.js

@@ -27,8 +27,9 @@ for (const [calendar, description] of rangeErrorTests) {
 
 const typeErrorTests = [
   [Symbol(), "symbol"],
-  [{}, "plain object"],  // TypeError due to missing dateFromFields()
-  [Temporal.Calendar, "Temporal.Calendar, object"],  // ditto
+  [{}, "plain object that doesn't implement the protocol"],
+  [new Temporal.TimeZone("UTC"), "time zone instance"],
+  [Temporal.Calendar, "Temporal.Calendar, object"],
   [Temporal.Calendar.prototype, "Temporal.Calendar.prototype, object"],  // fails brand check in dateFromFields()
 ];