* replace logging different values of `postRevisioningFieldSelector()…

…` that sharing the same key `AuthorUid` of `BasePost` entities with a invoking to `Helper.LogDifferentValuesSharingTheSameKeyInEntities()` @ `AuthorRevisionSaver.Save()`

* replace logging different values of `Signature` that sharing the same key `SignatureId` of `ReplyPost` entities with a invoking to `Helper.LogDifferentValuesSharingTheSameKeyInEntities()` @ `Save()`
* turn record `ReplySignatureProjection` into class `SignatureIdAndValueEqualityComparer` that implements `EqualityComparer<ValueTuple<Nullable<uint>, Array<byte>>`
@ ReplySignatureSaver.cs
@ c#/crawler

c#/crawler/src/Helper.cs

@@ -20,4 +20,22 @@ public static byte[]? SerializedProtoBufWrapperOrNullIfEmpty<T>
 
     public static PostContentWrapper? WrapPostContent(IEnumerable<Content>? contents) =>
         contents == null ? null : new() {Value = {contents}};
+
+    public static void LogDifferentValuesSharingTheSameKeyInEntities<TLoggerCategory, TEntity, TKey, TValue>(
+        ILogger<TLoggerCategory> logger,
+        IEnumerable<TEntity> entities,
+        string keyName,
+        Func<TEntity, TKey?> keySelector,
+        Func<TEntity, TValue?> valueSelector,
+        IEqualityComparer<(TKey?, TValue?)>? keyAndValueComparer = null) => entities
+        .GroupBy(keySelector)
+        .Where(g => g.Count() > 1)
+        .Flatten2()
+        .GroupBy(p => (keySelector(p), valueSelector(p)), comparer: keyAndValueComparer)
+        .GroupBy(g => g.Key.Item1)
+        .Where(gg => gg.Count() > 1)
+        .Flatten2()
+        .ForEach(g => logger.LogWarning(
+            "Multiple entities with different value of field {} sharing the same key \"{}\": {}",
+            keyName, g.Key, SharedHelper.UnescapedJsonSerialize(g)));
 }

c#/crawler/src/Tieba/Crawl/Saver/AuthorRevisionSaver.cs

@@ -48,19 +48,11 @@ private void Save<TPost, TRevision, TValue>(
         where TRevision : AuthorRevision
     { // only takes the first of multiple post from the same author
         var uniquePosts = posts.DistinctBy(p => p.AuthorUid).ToList();
-        if (uniquePosts.Count != posts.Count) (
-                from p in posts
-                group p by p.AuthorUid into g
-                where g.Count() > 1
-                from p in g
-                group p by (p.AuthorUid, postRevisioningFieldSelector(p)) into g
-                group g by g.Key.AuthorUid into gg
-                where gg.Count() > 1
-                from g in gg
-                select g)
-            .ForEach(g => logger.LogWarning(
-                "Multiple entities with different value of revisioning field sharing the same TPost.AuthorUid {}: {}",
-                g.Key, SharedHelper.UnescapedJsonSerialize(g)));
+        if (uniquePosts.Count != posts.Count)
+            Helper.LogDifferentValuesSharingTheSameKeyInEntities(logger, posts,
+            $"{nameof(TPost)}.{nameof(BasePost.AuthorUid)}",
+            p => p.AuthorUid,
+            postRevisioningFieldSelector);
 
         SharedHelper.GetNowTimestamp(out var now);
         var existingRevisionOfExistingUsers = dbSet.AsNoTracking()

c#/crawler/src/Tieba/Crawl/Saver/ReplySignatureSaver.cs

@@ -26,20 +26,15 @@ public Action Save(CrawlerDbContext db, IEnumerable<ReplyPost> replies)
             }).ToList();
         if (signatures.Count == 0) return () => { };
         if (signatures.Count != repliesWithSignature
-                .GroupBy(r => new ReplySignatureProjection(r.SignatureId!.Value, r.Signature!))
-                .Count()) (
-                from r in repliesWithSignature
-                group r by r.SignatureId into g
-                where g.Count() > 1
-                from r in g
-                group r by new ReplySignatureProjection(r.SignatureId!.Value, r.Signature!) into g
-                group g by g.Key.SignatureId into gg
-                where gg.Count() > 1
-                from g in gg
-                select g)
-            .ForEach(g => logger.LogWarning(
-                "Multiple entities with different value of revisioning field sharing the same signature id {}: {}",
-                g.Key.SignatureId, SharedHelper.UnescapedJsonSerialize(g)));
+                .GroupBy(r => (r.SignatureId!.Value, r.Signature!),
+                    comparer: SignatureIdAndValueEqualityComparer.Instance)
+                .Count())
+            Helper.LogDifferentValuesSharingTheSameKeyInEntities(logger,
+                repliesWithSignature,
+                nameof(ReplyPost.SignatureId),
+                r => r.SignatureId,
+                r => r.Signature,
+                SignatureIdAndValueEqualityComparer.Instance);
 
         var existingSignatures = (
             from s in db.ReplySignatures.AsTracking()
@@ -63,18 +58,20 @@ join newInReply in signatures on existing.SignatureId equals newInReply.Signatur
         return locks.Dispose;
     }
 
-    private sealed record ReplySignatureProjection(uint SignatureId, byte[] Signature)
+    private class SignatureIdAndValueEqualityComparer : EqualityComparer<(uint? SignatureId, byte[]? Signature)>
     {
-        public bool Equals(ReplySignatureProjection? other) =>
-            other != null
-            && SignatureId == other.SignatureId
-            && ByteArrayEqualityComparer.Instance.Equals(Signature, other.Signature);
+        public static SignatureIdAndValueEqualityComparer Instance { get; } = new();
 
-        public override int GetHashCode()
+        public override bool Equals((uint? SignatureId, byte[]? Signature) x, (uint? SignatureId, byte[]? Signature) y) =>
+            x == y ||
+            (x.SignatureId == y.SignatureId
+             && ByteArrayEqualityComparer.Instance.Equals(x.Signature, y.Signature));
+
+        public override int GetHashCode((uint? SignatureId, byte[]? Signature) obj)
         {
             var hash = default(HashCode);
-            hash.Add(SignatureId);
-            hash.AddBytes(Signature);
+            hash.Add(obj.SignatureId);
+            hash.AddBytes(obj.Signature);
             return hash.ToHashCode();
         }
     }