Update folder data even when the feed has no articles

[Eitot]

Closes #1813

Previously, if the feed had no articles at all, the finalizeFolderRefresh: method exited immediately, before applying any changes to the folder title, description, homepage or last-update string/date. Even if the feed has (currently) no articles, the feed-level data and last-refresh data ought to be updated.

[barijaona]

call to Database's setLastUpdate:forFolder: should be displaced.

[barijaona]

The last update date is displayed in the "Get Info…" window, and is useful for detecting that the feed is stale.
Therefore, we should update it only if new items are present…

[Eitot]

The label in the info panel says "last refreshed" though, implying that Vienna did refresh the feed, whether the feed was updated or not. Also, as a result of this PR, the feed data is refreshed, even if it doesn't have any (new) entries.

[barijaona]

This conversation takes an interesting turn…

First, I have to make clear that, for a folder, the only role of the lastUpdate field is to be displayed in the "Get Info…" window.
It must not be confused with lastUpdateString, which is provided by the server and is used for optimizing network access.

That being said, the word "refreshed" can have slightly different meanings. In the context, I identify at least three possible nuances:

• fetched from server;
• got some article(s);
• got some new article(s) (fresh article(s)…)

From a user point of view, I think the most interesting meaning is the third one. Current implementation in OpenReader is aligned with this latest meaning. Cf.

vienna-rss/Vienna/Sources/Fetching/OpenReader.m

Lines 640 to 655 in 196afbb

	// Here's where we add the articles to the database
	if (articleArray.count > 0) {
	[refreshedFolder resetArticleStatuses];
	NSArray *guidHistory = [dbManager guidHistoryForFolderId:refreshedFolder.itemId];
	for (Article *article in articleArray) {
	if ([refreshedFolder createArticle:article guidHistory:guidHistory] &&
	(article.status == ArticleStatusNew))
	{
	newArticlesFromFeed++;
	}
	}
	// Set the last update date for this folder.
	[dbManager setLastUpdate:[NSDate date] forFolder:refreshedFolder.itemId];
	}

I am not sure if this is what led me to modify the French translation of the "Last Refreshed" label during the development of version 3.8, in 2021 : 251861e#diff-987fbfdc228b4925f39ac4eaeae776a082dc0d34c459450200654da97f34ffd2 . I replaced "Dernier rafraîchissement" (which does not really sound French) with "Dernière actualisation" (which is closer to "Last Update").

My current opinion is that we should make Vienna consistent and adopt the OpenReader behavior mentioned beforehand:

• do not set lastUpdate anymore on 304 HTTP status :

  vienna-rss/Vienna/Sources/Fetching/RefreshManager.m

  Lines 610 to 614 in 196afbb

  	if (responseStatusCode == 304) {
  	// No modification from last check
  	[dbManager setLastUpdate:[NSDate date] forFolder:folderId];

• update it only if newArticlesFromFeed> 0

The change would constitute a first step towards implementing a solution to issue #1638

[barijaona]

Feel free to remove my latest commit if you disagree.

[Eitot]

I can't review my own PR. 😀 You can approve and merge.

[barijaona]

I can't review my own PR. 😀 You can approve and merge.

strange Github behaviors 🤣