Fix asset catalog scale-to-file pairing for assets with non-standard scales

[janicduplessis]

Summary:

saveAssets filters an asset's scales through filterPlatformAssetScales, but getImageSet indexes the unfiltered asset.files, so an asset with scales [1, 1.5, 2, 3] gets the 1.5x file in its 2x catalog slot and the 2x file in its 3x slot: Assets.car ships the wrong images. An asset with no standard scale at all (only @1.5x, say) produces an imageset actool silently drops from the car, which makes the image unloadable when RCTUseAssetCatalog is on, since the catalog runtime has no filesystem fallback (#30129).

Fix, in assetCatalogIOS.js:

• Each catalog slot (1x/2x/3x) is paired with its own file.
• An asset with no valid scale maps its closest variant into the nearest valid slot, the same "closest larger" rule loose files already get, and warns in the build log. Every imageset now holds at least one rendition actool will compile.

Related: expo/expo#48525 applies the same fix to Expo CLI's mirrored implementation.

Changelog:

[IOS] [FIXED] - Asset catalog imagesets paired wrong files for assets with non-standard scales

Test Plan:

New unit tests in assetCatalogIOS-test.js: standard 1x/2x/3x pairing, mixed [1, 1.5, 2, 3] (regression for the file shift), fractional-only [1.5], and [4] clamping to the 3x slot.

yarn jest packages/community-cli-plugin/src/commands/bundle
Tests: 18 passed, 18 total

End-to-end

Bundled a test app through the real pipeline (Metro → saveAssets → actool → assetutil --info on the compiled Assets.car) with two assets: logo at scales [1, 1.5, 2, 3] (100/150/200/300 px) and star with only a @1.5x file (150 px).

Rendition in Assets.car	before	after
img_logo 1x	100 px	100 px
img_logo 2x	150 px (the 1.5x file)	200 px
img_logo 3x	200 px (the 2x file)	300 px
img_star	absent (actool dropped the @1.5x imageset)	150 px in the 2x slot, with a build-log warning

Running on an iPhone 17 Pro simulator (3x), same app built with the buggy and fixed CLI — the labeled tiles show which file the catalog actually served, and star goes from missing to rendering:

Before	After

Repro app used for the screenshots

Built private/helloworld (Release, simulator) with RCTUseAssetCatalog set to true in its Info.plist, and these assets in img/, where each file is a solid tile with its scale label and pixel size baked into the image so a screenshot shows exactly which file got served: logo.png (100px, "1x"), logo@1.5x.png (150px, "1.5x"), logo@2x.png (200px, "2x"), logo@3x.png (300px, "3x"), and star@1.5x.png (150px, "STAR") with no other variants.

// index.js
import React from 'react';
import {AppRegistry, Image, Text, View, StyleSheet} from 'react-native';

const styles = StyleSheet.create({
  root: {flex: 1, backgroundColor: '#111', alignItems: 'center', justifyContent: 'center'},
  label: {color: '#fff', fontSize: 16, marginTop: 24, marginBottom: 8, fontWeight: '600'},
  box: {width: 100, height: 100, borderWidth: 2, borderColor: '#666'},
  img: {width: 100, height: 100},
});

const App = () => (
  <View style={styles.root}>
    <Text style={styles.label}>logo.png (has 1x/1.5x/2x/3x)</Text>
    <View style={styles.box}>
      <Image style={styles.img} source={require('./img/logo.png')} />
    </View>
    <Text style={styles.label}>star.png (only @1.5x)</Text>
    <View style={styles.box}>
      <Image style={styles.img} source={require('./img/star.png')} />
    </View>
  </View>
);

AppRegistry.registerComponent('HelloWorld', () => App);

On the 3x simulator JS resolves logo to the 3x variant, so the tile that renders is the file the catalog's 3x slot actually contains: the 2x-labeled tile before the fix, the 3x tile after. star resolves to its only variant (@1.5x); before the fix its imageset is dropped by actool and the box renders empty.