Cached file should be removed on 404, and error should be added to Stream even if a cached file exists

[ltOgt]

🐛 Bug Report

Moving Baseflow/flutter_cached_network_image#898 to here.

flutter_cache_manager/flutter_cache_manager/lib/src/cache_manager.dart

Lines 137 to 157 in 32b71c1

	if (cacheFile == null || cacheFile.validTill.isBefore(DateTime.now())) {
	try {
	await for (final response
	in _webHelper.downloadFile(url, key: key, authHeaders: headers)) {
	if (response is DownloadProgress && withProgress) {
	streamController.add(response);
	}
	if (response is FileInfo) {
	streamController.add(response);
	}
	}
	} on Object catch (e) {
	cacheLogger.log(
	'CacheManager: Failed to download file from $url with error:\n$e',
	CacheManagerLogLevel.debug);
	if (cacheFile == null && streamController.hasListener) {
	streamController.addError(e);
	}
	}
	}
	streamController.close();

Currently, in CacheManager._pushFileToStream when a cacheFile exists, the cached content is emitted, and if it is outdated, a network request is made to potentially update the file, and emit the updated content.

If a 404 happens on that request, the error is not added to the stream, and the cache is not evicted.

The error is only added if no cacheFile exists.

Expected behavior

On the 404, the cache is evicted (the server is telling us the resource no longer exists) and the error is added to the stream.

Reproduction steps

See Baseflow/flutter_cached_network_image#898

Configuration

Version: 3.1.1

Platform:
Tested on macos but should affect all platforms