fix: date separator missing day of month on certain Android devices

app/components/post_list/date_separator/index.tsx

@@ -2,12 +2,14 @@
 // See LICENSE.txt for license information.
 
 import React from 'react';
-import {type StyleProp, type TextStyle, View, type ViewStyle} from 'react-native';
+import {useIntl} from 'react-intl';
+import {type StyleProp, Text, type TextStyle, View, type ViewStyle} from 'react-native';
 
 import FormattedDate, {type FormattedDateFormat} from '@components/formatted_date';
 import FormattedText from '@components/formatted_text';
 import {useTheme} from '@context/theme';
 import {isSameYear, isToday, isYesterday} from '@utils/datetime';
+import {logDebug} from '@utils/log';
 import {makeStyleSheetFromTheme} from '@utils/theme';
 import {typography} from '@utils/typography';
 
@@ -38,13 +40,62 @@ const getStyleSheet = makeStyleSheetFromTheme((theme: Theme) => {
     };
 });
 
-const DATE_FORMATS = {
-    withinYear: {month: 'short', day: 'numeric'},
-    afterYear: {dateStyle: 'medium'},
-} satisfies Record<string, FormattedDateFormat>;
+const AFTER_YEAR_FORMAT: FormattedDateFormat = {dateStyle: 'medium'};
+
+/**
+ * Formats a date without the year component using dateStyle:'medium' and formatToParts.
+ * This avoids a Hermes bug where {month:'short', day:'numeric'} may omit the day
+ * on certain Android versions.
+ */
+function formatDateWithoutYear(locale: string, date: Date, timezone?: string | null): string | null {
+    try {
+        let timeZone: string | undefined;
+        if (timezone && typeof timezone === 'string') {
+            timeZone = timezone;
+        }
+
+        const parts = [...new Intl.DateTimeFormat(locale, {
+            dateStyle: 'medium',
+            ...(timeZone ? {timeZone} : {}),
+        }).formatToParts(date)];
+
+        const yearIdx = parts.findIndex((p) => p.type === 'year');
+        if (yearIdx < 0) {
+            return parts.map((p) => p.value).join('');
+        }
+
+        if (yearIdx === 0) {
+            // Year at start (e.g. ja, zh, ko, hu): remove year + following literal
+            const removeCount = parts[1]?.type === 'literal' ? 2 : 1;
+            parts.splice(0, removeCount);
+        } else if (yearIdx === parts.length - 1) {
+            // Year at end (e.g. en, de, fr): remove preceding literal + year
+            const start = parts[yearIdx - 1]?.type === 'literal' ? yearIdx - 1 : yearIdx;
+            parts.splice(start, parts.length - start);
+        } else {
+            // Year in middle (e.g. ru, uk, bg with trailing suffix): remove adjacent literals + year
+            let start = yearIdx;
+            let count = 1;
+            if (parts[yearIdx - 1]?.type === 'literal') {
+                start--;
+                count++;
+            }
+            if (parts[yearIdx + 1]?.type === 'literal') {
+                count++;
+            }
+            parts.splice(start, count);
+        }
+
+        return parts.map((p) => p.value).join('');
+    } catch (error) {
+        logDebug('Failed to format date without year', error);
+        return null;
+    }
+}
 
 const RecentDate = (props: DateSeparatorProps) => {
-    const {date, ...otherProps} = props;
+    const {date, timezone, ...otherProps} = props;
+    const {locale} = useIntl();
     const when = new Date(date);
 
     if (isToday(when)) {
@@ -65,12 +116,18 @@ const RecentDate = (props: DateSeparatorProps) => {
         );
     }
 
-    const format: FormattedDateFormat = isSameYear(when, new Date()) ? DATE_FORMATS.withinYear : DATE_FORMATS.afterYear;
+    if (isSameYear(when, new Date())) {
+        const formatted = formatDateWithoutYear(locale, when, timezone);
+        if (formatted) {
+            return <Text {...otherProps}>{formatted}</Text>;
+        }
+    }
 
     return (
         <FormattedDate
             {...otherProps}
-            format={format}
+            format={AFTER_YEAR_FORMAT}
+            timezone={timezone}
             value={date}
         />
     );