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Fix Android DateTimeFormat hour-cycle selection and midnight formatting #2210

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Fix Android DateTimeFormat hour-cycle selection and midnight formatting #2210

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41 changes: 41 additions & 0 deletions android/intltest/java/com/facebook/hermes/test/HermesIntlAndroidTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,47 @@ public void testDateTimeFormat() {
}
}

@Test
public void testDateTimeFormatMidnightHourCycles() {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
return;
}

try (JSRuntime rt = JSRuntime.makeHermesRuntime()) {
rt.evaluateJavaScript(
"var midnight = new Date('2026-05-29T00:54:00Z');\n"
+ "function hourAtMidnight(locale, options) {\n"
+ " var formatter = new Intl.DateTimeFormat(locale, Object.assign({\n"
+ " timeStyle: 'short', timeZone: 'UTC'\n"
+ " }, options));\n"
+ " var parts = formatter.formatToParts(midnight);\n"
+ " var hour = parts.filter(function(part) {\n"
+ " return part.type === 'hour';\n"
+ " })[0].value;\n"
+ " var dayPeriod = parts.some(function(part) {\n"
+ " return part.type === 'dayPeriod';\n"
+ " });\n"
+ " return formatter.resolvedOptions().hourCycle + ':' + Number(hour)\n"
+ " + ':' + dayPeriod;\n"
+ "}\n"
+ "var midnightResults = [\n"
+ " hourAtMidnight('en-GB', {hourCycle: 'h11'}),\n"
+ " hourAtMidnight('en-GB', {hourCycle: 'h12'}),\n"
+ " hourAtMidnight('en-US', {hourCycle: 'h23'}),\n"
+ " hourAtMidnight('en-US', {hourCycle: 'h24'}),\n"
+ " hourAtMidnight('en-GB', {hour12: true}),\n"
+ " hourAtMidnight('en-US', {hour12: false}),\n"
+ " hourAtMidnight('en-GB-u-hc-h24', {hour12: true}),\n"
+ " hourAtMidnight('ja-JP', {hour12: true})\n"
+ "].join(',');");

assertThat(rt.getGlobalStringProperty("midnightResults"))
.isEqualTo(
"h11:0:true,h12:12:true,h23:0:false,h24:24:false,"
+ "h12:12:true,h23:0:false,h12:12:true,h11:0:true");
}
}

@Test
public void testDateTimeFormatCaseInsensitivity() {
try (JSRuntime rt = JSRuntime.makeHermesRuntime()) {
Expand Down
14 changes: 3 additions & 11 deletions lib/Platform/Intl/java/com/facebook/hermes/intl/DateTimeFormat.java
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Expand Up @@ -409,17 +409,9 @@ private void initializeDateTimeFormat(List<String> locales, Map<String, Object>
}

if (!JSObjects.isUndefined(hour12)) {
if (JSObjects.getJavaBoolean(hour12)) { // true
if (hcDefault == IPlatformDateTimeFormatter.HourCycle.H11
|| hcDefault == IPlatformDateTimeFormatter.HourCycle.H23)
hc = IPlatformDateTimeFormatter.HourCycle.H11;
else hc = IPlatformDateTimeFormatter.HourCycle.H12;
} else {
if (hcDefault == IPlatformDateTimeFormatter.HourCycle.H11
|| hcDefault == IPlatformDateTimeFormatter.HourCycle.H23)
hc = IPlatformDateTimeFormatter.HourCycle.H23;
else hc = IPlatformDateTimeFormatter.HourCycle.H24;
}
hc =
mPlatformDateTimeFormatter.getPreferredHourCycle(
mResolvedLocaleObject, JSObjects.getJavaBoolean(hour12));
}
mHourCycle = hc;
}
Expand Down
3 changes: 3 additions & 0 deletions lib/Platform/Intl/java/com/facebook/hermes/intl/IPlatformDateTimeFormatter.java
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Expand Up @@ -492,6 +492,9 @@ String getDefaultCalendarName(ILocaleObject<?> mResolvedLocaleObject)

HourCycle getDefaultHourCycle(ILocaleObject<?> localeObject) throws JSRangeErrorException;

HourCycle getPreferredHourCycle(ILocaleObject<?> localeObject, boolean hour12)
throws JSRangeErrorException;

String getDefaultTimeZone(ILocaleObject<?> localeObject) throws JSRangeErrorException;

String getDefaultNumberingSystem(ILocaleObject<?> localeObject) throws JSRangeErrorException;
Expand Down
14 changes: 14 additions & 0 deletions lib/Platform/Intl/java/com/facebook/hermes/intl/PlatformDateTimeFormatterAndroid.java
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Expand Up @@ -141,6 +141,20 @@ else if (dateFormatPatternWithoutLiterals.contains(String.valueOf('H')))
return hourCycle;
}

@Override
public HourCycle getPreferredHourCycle(ILocaleObject<?> localeObject, boolean hour12)
throws JSRangeErrorException {
HourCycle defaultCycle = getDefaultHourCycle(localeObject);
if (hour12) {
return defaultCycle == HourCycle.H11 || defaultCycle == HourCycle.H23
? HourCycle.H11
: HourCycle.H12;
}
return defaultCycle == HourCycle.H11 || defaultCycle == HourCycle.H23
? HourCycle.H23
: HourCycle.H24;
}

@Override
public String getDefaultTimeZone(ILocaleObject<?> localeObject) throws JSRangeErrorException {
return Calendar.getInstance((Locale) localeObject.getLocale()).getTimeZone().getID();
Expand Down
83 changes: 83 additions & 0 deletions lib/Platform/Intl/java/com/facebook/hermes/intl/PlatformDateTimeFormatterICU.java
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Expand Up @@ -10,6 +10,7 @@
import static com.facebook.hermes.intl.IPlatformDateTimeFormatter.DateStyle.UNDEFINED;

import android.icu.text.DateFormat;
import android.icu.text.DateTimePatternGenerator;
import android.icu.text.NumberingSystem;
import android.icu.text.SimpleDateFormat;
import android.icu.util.Calendar;
Expand Down Expand Up @@ -127,6 +128,64 @@ public static String getPatternWithoutLiterals(String pattern) {

return segment.toString();
}

public static String withHourCycle(String pattern, HourCycle hourCycle) {
char hourSymbol;
switch (hourCycle) {
case H11:
hourSymbol = 'K';
break;
case H12:
hourSymbol = 'h';
break;
case H23:
hourSymbol = 'H';
break;
case H24:
hourSymbol = 'k';
break;
default:
return pattern;
}

StringBuilder result = new StringBuilder(pattern.length());
boolean inLiteral = false;
for (int i = 0; i < pattern.length(); i++) {
char c = pattern.charAt(i);
if (c == '\'') {
result.append(c);
if (i + 1 < pattern.length() && pattern.charAt(i + 1) == '\'') {
result.append(pattern.charAt(++i));
} else {
inLiteral = !inLiteral;
}
} else if (!inLiteral && (c == 'h' || c == 'H' || c == 'K' || c == 'k')) {
result.append(hourSymbol);
} else {
result.append(c);
}
}
return result.toString();
}

public static String withoutDayPeriod(String pattern) {
StringBuilder result = new StringBuilder(pattern.length());
boolean inLiteral = false;
for (int i = 0; i < pattern.length(); i++) {
char c = pattern.charAt(i);
if (c == '\'') {
result.append(c);
if (i + 1 < pattern.length() && pattern.charAt(i + 1) == '\'') {
result.append(pattern.charAt(++i));
} else {
inLiteral = !inLiteral;
}
} else if (inLiteral || (c != 'a' && c != 'b' && c != 'B')) {
result.append(c);
}
}
return result.toString();
}
}

@RequiresApi(api = Build.VERSION_CODES.N)
Expand Down Expand Up @@ -154,6 +213,21 @@ else if (dateFormatPatternWithoutLiterals.contains(String.valueOf('H')))
return hourCycle;
}

@RequiresApi(api = Build.VERSION_CODES.N)
@Override
public HourCycle getPreferredHourCycle(ILocaleObject<?> localeObject, boolean hour12)
throws JSRangeErrorException {
ULocale locale = (ULocale) localeObject.getLocaleWithoutExtensions();
String pattern =
DateTimePatternGenerator.getInstance(locale).getBestPattern(hour12 ? "hm" : "Hm");
String fields = PatternUtils.getPatternWithoutLiterals(pattern);
if (fields.indexOf('K') >= 0) return HourCycle.H11;
if (fields.indexOf('h') >= 0) return HourCycle.H12;
if (fields.indexOf('H') >= 0) return HourCycle.H23;
if (fields.indexOf('k') >= 0) return HourCycle.H24;
throw new JSRangeErrorException("No hour field in locale time pattern");
}

@RequiresApi(api = Build.VERSION_CODES.N)
@Override
public String getDefaultTimeZone(ILocaleObject<?> localeObject) throws JSRangeErrorException {
Expand Down Expand Up @@ -293,6 +367,10 @@ private static String getSkeleton(
replacePatternChars(skeletonBuffer, new char[] {'h', 'H', 'K'}, 'k');
}
}

if (hourCycle == HourCycle.H23 || hourCycle == HourCycle.H24) {
skeletonBuffer = new StringBuilder(PatternUtils.withoutDayPeriod(skeletonBuffer.toString()));
}
} else {
skeletonBuffer.append(weekDay.getSkeleonSymbol());
skeletonBuffer.append(era.getSkeleonSymbol());
Expand Down Expand Up @@ -388,6 +466,11 @@ public void configure(
mDateFormat =
DateFormat.getPatternInstance(skeleton, (ULocale) resolvedLocaleObject.getLocale());

if (hourCycle != HourCycle.UNDEFINED) {
SimpleDateFormat formatter = (SimpleDateFormat) mDateFormat;
formatter.applyPattern(PatternUtils.withHourCycle(formatter.toPattern(), hourCycle));
}

if (!JSObjects.isUndefined(timeZone) && !JSObjects.isNull(timeZone)) {
TimeZone timeZoneObject = TimeZone.getTimeZone(JSObjects.getJavaString(timeZone));
mDateFormat.setTimeZone(timeZoneObject);
Expand Down