Refactor AssignHomographNumber to use single DB query for SecondaryOrder

Replace the two-stage approach (DB query for headword match, then
in-memory filter for SecondaryOrder) with a single DB query using
correlated subqueries on MorphTypes, matching the pattern in Sorting.cs.

Restore the original if(HomographNumber == 0) guard — explicit values
get no special handling at all; only auto-assign for new FW-Lite entries.

https://claude.ai/code/session_01FJj2v135u6KdgVxoK4tRp2

Author: claude

backend/FwLite/LcmCrdt/CrdtMiniLcmApi.cs

@@ -517,7 +517,10 @@ public async Task<Entry> CreateEntry(Entry entry, CreateEntryOptions? options =
     {
         options ??= CreateEntryOptions.Everything;
         await using var repo = await repoFactory.CreateRepoAsync();
-        await AssignHomographNumber(entry, repo);
+        if (entry.HomographNumber == 0)
+        {
+            await AssignHomographNumber(entry, repo);
+        }
         await AddChanges([
             new CreateEntryChange(entry),
             ..await entry.Senses.ToAsyncEnumerable()
@@ -623,10 +626,9 @@ private async ValueTask<bool> IsEntryDeleted(Guid id)
     }
 
     /// <summary>
-    /// Ensures homograph numbers are consistent when creating an entry.
-    /// Always queries entries in the same "homograph scope" (same headword + SecondaryOrder)
-    /// so that a lone existing entry at 0 gets promoted to 1 when a second entry arrives.
-    /// Explicit (non-zero) HomographNumbers are trusted as-is (FLEx handles correctness).
+    /// When creating a new entry whose HomographNumber is 0, find entries in the same
+    /// "homograph scope" (same headword + SecondaryOrder) and assign the next number.
+    /// If a lone existing entry has HomographNumber 0, promote it to 1.
     /// </summary>
     private async Task AssignHomographNumber(Entry entry, MiniLcmRepository repo)
     {
@@ -637,26 +639,23 @@ private async Task AssignHomographNumber(Entry entry, MiniLcmRepository repo)
         var newHeadword = entry.Headword(wsId);
         if (string.IsNullOrEmpty(newHeadword)) return;
 
-        // Get the SecondaryOrder for the new entry's MorphType (fall back to Stem's SecondaryOrder)
-        var morphTypeLookup = await repo.MorphTypes.ToDictionaryAsyncEF(m => m.Kind);
-        var stemSecondaryOrder = morphTypeLookup.TryGetValue(MorphTypeKind.Stem, out var stemMt)
-            ? stemMt.SecondaryOrder
-            : 0;
-        var newSecondaryOrder = morphTypeLookup.TryGetValue(entry.MorphType, out var mt)
-            ? mt.SecondaryOrder
-            : stemSecondaryOrder;
-
-        // Query entries with the same headword in the default vernacular WS, then filter by SecondaryOrder
-        var matchingEntries = (await repo.Entries
-                .Where(e => e.Id != entry.Id && e.Headword(wsId) == newHeadword)
-                .Select(e => new { e.Id, e.HomographNumber, e.MorphType })
-                .ToListAsyncLinqToDB())
-            .Where(e =>
-            {
-                var so = morphTypeLookup.TryGetValue(e.MorphType, out var eMt) ? eMt.SecondaryOrder : stemSecondaryOrder;
-                return so == newSecondaryOrder;
-            })
-            .ToList();
+        // Single DB query: join MorphTypes for SecondaryOrder filtering (same pattern as Sorting.cs)
+        var morphTypes = repo.MorphTypes.ToLinqToDB();
+        var stemOrder = morphTypes.Where(m => m.Kind == MorphTypeKind.Stem).Select(m => m.SecondaryOrder);
+        var newSecondaryOrder = morphTypes
+            .Where(m => m.Kind == entry.MorphType)
+            .Select(m => (int?)m.SecondaryOrder).FirstOrDefault()
+            ?? stemOrder.FirstOrDefault();
+
+        var matchingEntries = await (
+            from e in repo.Entries
+            where e.Id != entry.Id && e.Headword(wsId) == newHeadword
+            let so = morphTypes.Where(m => m.Kind == e.MorphType)
+                .Select(m => (int?)m.SecondaryOrder).FirstOrDefault()
+                ?? stemOrder.FirstOrDefault()
+            where so == newSecondaryOrder
+            select new { e.Id, e.HomographNumber }
+        ).ToListAsyncLinqToDB();
 
         if (matchingEntries.Count == 0) return;
 
@@ -671,9 +670,6 @@ private async Task AssignHomographNumber(Entry entry, MiniLcmRepository repo)
             maxHomograph = 1;
         }
 
-        // Explicit (non-zero) HomographNumber — trust it as-is
-        if (entry.HomographNumber != 0) return;
-
         entry.HomographNumber = maxHomograph + 1;
     }
 

backend/FwLite/MiniLcm.Tests/CreateEntryTestsBase.cs

@@ -152,19 +152,6 @@ public async Task CreateEntry_RespectsExplicitHomographNumber()
         entry1.HomographNumber.Should().Be(5, "explicit HomographNumber should be preserved");
     }
 
-    [Fact]
-    public async Task CreateEntry_ExplicitHomographNumber_PromotesLoneEntry()
-    {
-        var entry1 = await Api.CreateEntry(new() { LexemeForm = { { "en", "promotiontest" } } });
-        entry1.HomographNumber.Should().Be(0, "single entry should have HomographNumber 0");
-
-        var entry2 = await Api.CreateEntry(new() { LexemeForm = { { "en", "promotiontest" } }, HomographNumber = 5 });
-        entry2.HomographNumber.Should().Be(5, "explicit HomographNumber should be preserved");
-
-        entry1 = await Api.GetEntry(entry1.Id) ?? throw new NullReferenceException();
-        entry1.HomographNumber.Should().Be(1, "existing lone entry should be promoted from 0 to 1");
-    }
-
     [Fact]
     public async Task CreateEntry_DifferentSecondaryOrder_DoesNotShareHomographNumbers()
     {