* fix still saving changes and revisions for existing users whose id …

…already get locked @ `UserSaver.Save()`

+ record `MaybeExistingAndNewEntity` & method `SaveNewEntities()` to reuse parts in `(User|Post)Saver.Save()`
* rename record `ExistingAndNewEntities` to `ExistingAndNewEntity` and remove suffix `-Entity` from its props
@ SaverWithRevision.cs
@ c#/crawler

c#/crawler/src/Tieba/Crawl/Saver/Post/PostSaver.cs

@@ -28,7 +28,7 @@ protected SaverChangeSet<TPost> Save<TRevision>(
         Func<TPost, PostId> postIdSelector,
         Func<TPost, TRevision> revisionFactory,
         Func<IQueryable<TPost>, IQueryable<TPost>> postQueryTransformer,
-        Action<IEnumerable<ExistingAndNewEntities<TPost>>>? onBeforeSaveRevision = null)
+        Action<IEnumerable<ExistingAndNewEntity<TPost>>>? onBeforeSaveRevision = null)
         where TRevision : TBaseRevision
     {
         var existingPosts = postQueryTransformer(db.Set<TPost>().AsTracking()).ToList();
@@ -39,15 +39,9 @@ protected SaverChangeSet<TPost> Save<TRevision>(
             join existingPost in existingPosts
                 on postIdSelector(newPost) equals postIdSelector(existingPost) into existingPostsWithSameId
             from existingPost in existingPostsWithSameId.DefaultIfEmpty()
-            select (existingPost, newPost)).ToList();
-
-        db.Set<TPost>().AddRange(maybeExistingAndNewPosts
-            .Where(t => t.existingPost == null).Select(t => t.newPost));
-        var existingAndNewPosts = maybeExistingAndNewPosts
-            .Where(t => t.existingPost != null)
-            .Select(t => new ExistingAndNewEntities<TPost>(t.existingPost, t.newPost))
-            .ToList();
+            select new MaybeExistingAndNewEntity<TPost>(existingPost, newPost)).ToList();
 
+        var existingAndNewPosts = SaveNewEntities(db, maybeExistingAndNewPosts).ToList();
         SaveExistingEntities(db, existingAndNewPosts);
         onBeforeSaveRevision?.Invoke(existingAndNewPosts);
         SaveExistingEntityRevisions(db, revisionFactory, existingAndNewPosts);

c#/crawler/src/Tieba/Crawl/Saver/Post/ThreadSaver.cs

@@ -20,7 +20,7 @@ public override SaverChangeSet<ThreadPost> Save(CrawlerDbContext db) => Save(db,
             .Include(th => th.LatestReplier),
         existingAndNewPosts =>
             PostSaveHandlers += threadLatestReplierSaver.SaveFromThread(db,
-                existingAndNewPosts.Select(t => t.ExistingEntity).ToList()));
+                existingAndNewPosts.Select(t => t.Existing).ToList()));
 }
 public partial class ThreadSaver
 {

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

@@ -67,12 +67,24 @@ private static bool IsTimestampingFieldName(string name) => name is nameof(BaseP
 
     protected abstract NullFieldsBitMask GetRevisionNullFieldBitMask(string fieldName);
 
-    protected record ExistingAndNewEntities<TEntity>
-        (TEntity ExistingEntity, TEntity NewEntity) where TEntity : RowVersionedEntity;
+    protected record ExistingAndNewEntity<TEntity>(TEntity Existing, TEntity New) where TEntity : RowVersionedEntity;
+    protected record MaybeExistingAndNewEntity<TEntity>(TEntity? Existing, TEntity New) where TEntity : RowVersionedEntity;
+
+    protected IEnumerable<ExistingAndNewEntity<TEntity>> SaveNewEntities<TEntity>(
+        CrawlerDbContext db,
+        IReadOnlyCollection<MaybeExistingAndNewEntity<TEntity>> maybeEntities)
+        where TEntity : RowVersionedEntity
+    {
+        db.Set<TEntity>().AddRange(maybeEntities
+            .Where(entity => entity.Existing == null).Select(entity => entity.New));
+        return maybeEntities
+            .Where(entity => entity.Existing != null)
+            .Select(entity => new ExistingAndNewEntity<TEntity>(entity.Existing!, entity.New));
+    }
 
     protected void SaveExistingEntities<TEntity>(
         CrawlerDbContext db,
-        IEnumerable<ExistingAndNewEntities<TEntity>> existingAndNewEntities)
+        IEnumerable<ExistingAndNewEntity<TEntity>> existingAndNewEntities)
         where TEntity : RowVersionedEntity =>
         existingAndNewEntities.ForEach(existingAndNew =>
         {
@@ -100,7 +112,7 @@ on newNavigation.Metadata.Name equals existingNavigation.Metadata.Name
     protected void SaveExistingEntityRevisions<TEntity, TRevision>(
         CrawlerDbContext db,
         Func<TEntity, TRevision> revisionFactory,
-        IEnumerable<ExistingAndNewEntities<TEntity>> existingAndNewEntities,
+        IEnumerable<ExistingAndNewEntity<TEntity>> existingAndNewEntities,
         UserSaver.FieldChangeIgnorance? userFieldUpdateIgnorance = null,
         UserSaver.FieldChangeIgnorance? userFieldRevisionIgnorance = null)
         where TEntity : RowVersionedEntity

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

@@ -32,19 +32,14 @@ public void Save(
         var existingUsers = (from user in db.Users.AsTracking()
             where newlyLocked.Contains(user.Uid)
             select user).ToList();
-        var maybeExistingAndNewUsers = (from newUser in users.Values
+        var maybeExistingAndNewUsers = (
+            from newUser in users.IntersectByKey(newlyLocked).Values()
             join existingUser in existingUsers
                 on newUser.Uid equals existingUser.Uid into existingUsersWithSameId
             from existingUser in existingUsersWithSameId.DefaultIfEmpty()
-            select (existingUser, newUser)).ToList();
-
-        db.Users.AddRange(maybeExistingAndNewUsers
-            .Where(t => t.existingUser == null).Select(t => t.newUser));
-        var existingAndNewUsers = maybeExistingAndNewUsers
-            .Where(t => t.existingUser != null)
-            .Select(t => new ExistingAndNewEntities<User>(t.existingUser, t.newUser))
-            .ToList();
+            select new MaybeExistingAndNewEntity<User>(existingUser, newUser)).ToList();
 
+        var existingAndNewUsers = SaveNewEntities(db, maybeExistingAndNewUsers).ToList();
         SaveExistingEntities(db, existingAndNewUsers);
         SaveExistingEntityRevisions(db,
             u => new UserRevision