fix: preserve RSS history across feed rollover

Jobs/RssFeedJob.cs

@@ -44,7 +44,9 @@ public async Task Execute(IJobExecutionContext context)
 
             // If nothing from this feed has ever been seen, this is an initial run: mark
             // everything seen and only post the latest entry to avoid backfilling history.
-            bool initialSeed = !entries.Any(e => seen.Contains(e.EntryId));
+            // Check all history for the feed because older seen entries may have rolled out of
+            // the feed's current response.
+            bool initialSeed = !await HasFeedHistoryAsync(db, feedUrl);
             if (initialSeed)
             {
                 RssFeedService.FeedEntry latest = entries.OrderByDescending(e => e.Published).First();
@@ -97,6 +99,9 @@ internal static async Task<bool> DispatchAsync(
         return allSucceeded;
     }
 
+    internal static Task<bool> HasFeedHistoryAsync(DB db, string feedUrl) =>
+        db.RssSeenEntries.AnyAsync(entry => entry.FeedUrl == feedUrl);
+
     private async Task<bool> SendAsync(RssSubscription sub, string content)
     {
         if (sub.Webhook == null)

Morpheus.Tests/RssFeedJobTests.cs

@@ -1,3 +1,6 @@
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+using Morpheus.Database;
 using Morpheus.Database.Models;
 using Morpheus.Jobs;
 using Morpheus.Services;
@@ -6,6 +9,28 @@ namespace Morpheus.Tests;
 
 public class RssFeedJobTests
 {
+    [Fact]
+    public async Task HasFeedHistoryAsync_WhenOlderEntryRolledOutOfFeed_ReturnsTrue()
+    {
+        await using SqliteConnection connection = new("Data Source=:memory:");
+        await connection.OpenAsync();
+        DbContextOptions<DB> options = new DbContextOptionsBuilder<DB>()
+            .UseSqlite(connection)
+            .Options;
+        await using DB db = new(options);
+        await db.Database.EnsureCreatedAsync();
+        db.RssSeenEntries.Add(new RssSeenEntry
+        {
+            FeedUrl = "https://example.com/feed",
+            EntryId = "entry-that-is-no-longer-in-the-feed"
+        });
+        await db.SaveChangesAsync();
+
+        bool hasHistory = await RssFeedJob.HasFeedHistoryAsync(db, "https://example.com/feed");
+
+        Assert.True(hasHistory);
+    }
+
     [Fact]
     public async Task DispatchAsync_WhenOneDeliveryFails_ReportsFailureAndAttemptsEverySubscriber()
     {