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FIX-IMPORT-CYCLE: break Gerbil↔Litter circular FK dependency in ImportService

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Root cause: synth litters (from chart parentRefs) were added with FatherId/MotherId pointing
to gerbils that were also [Added] in the same SaveChanges batch. With 337 derived litters from
41 pedigrees, multi-generational references created a true dependency cycle:
  Gerbil [Added] ← FK{MotherId} Litter [Added] ← FK{LitterId} Gerbil [Added]
EF's topo-sort threw InvalidOperationException; smaller datasets (REIMPORT-1/2) didn't
trigger it because they had fewer chart-derived litters.

Fix: add synth litters with FatherId=null/MotherId=null (deferred), track intended FKs
in synthLitterPendingParents, apply them in a separate SaveChanges after all gerbils are
persisted. Single-direction Gerbil→Litter dependency in the main save; no cycle possible.
No schema change, no migration.

Regression test: artificial A←B←A cycle in SQLite (FK-enforced) must not throw.
Also verifies deferred FK update sets litter parent correctly after execute.

GATE: 158/158 C# tests, has-pending-model-changes=No

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
Gulum
2026-06-06 22:47:18 +02:00
parent 8e475dff6a
commit c6edb2e9d0
2 changed files with 77 additions and 6 deletions
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35
GerbilManagerWebAPI/Import/ImportService.cs
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@@ -289,10 +289,15 @@ namespace GerbilManagerWebAPI.Import
litterParents[lid] = (f, m);
}
// PASS 2: stage synthesized litters (parents already guarded above). DO NOT save them
// before the animals — the offspring AND the parent gerbils are created in the loop
// below, so a single SaveChanges at the end lets EF order parents→litters→offspring
// (all FKs are nullable). Saving litters first is exactly what caused the FK fault.
// FIX-IMPORT-CYCLE: track deferred synth litter parent FKs (populated in PASS 2 below).
// Synth litters are added with null FatherId/MotherId to break the Gerbil↔Litter cycle;
// the actual FKs are applied AFTER SaveChanges once all gerbils are persisted.
var synthLitterPendingParents = new Dictionary<Guid, (Guid? Father, Guid? Mother)>();
// PASS 2: stage synthesized litters (parents already guarded above). Litters are added
// with FatherId/MotherId = null (deferred) so that the SaveChanges below has only a
// one-directional Gerbil→Litter dependency — no Litter→Gerbil FKs in the same batch,
// which would cause EF's topo-sort to throw "circular dependency detected".
if (execute)
{
// reuse an existing litter with the same parents+date instead of duplicating.
@@ -316,13 +321,17 @@ namespace GerbilManagerWebAPI.Import
derivedLitters--;
continue;
}
// Defer FatherId/MotherId: both parent gerbils and offspring gerbils may be [Added]
// in this same batch. Setting them now causes EF circular dependency
// (Gerbil[Added] ← Litter.MotherId [Added] ← Gerbil.LitterId [Added]).
synthLitterPendingParents[sl.Id] = (sl.Father, sl.Mother);
_db.Litters.Add(new Litter
{
Id = sl.Id,
Name = $"Wurf (aus Diagramm) {sl.Date:yyyy-MM-dd}".Trim(),
Date = sl.Date ?? default,
FatherId = sl.Father,
MotherId = sl.Mother,
FatherId = null, // deferred — applied after gerbils SaveChanges
MotherId = null, // deferred — applied after gerbils SaveChanges
Notes = $"aus Stammbaum-Diagramm abgeleitet (Konfidenz: {sl.Confidence})",
});
}
@@ -437,6 +446,20 @@ namespace GerbilManagerWebAPI.Import
}
if (execute) await _db.SaveChangesAsync();
// Apply deferred synth litter parent FKs — all new gerbils are now persisted in the DB,
// so no cycle. FK guard already applied above (persisted set); values in the dict are safe.
if (execute && synthLitterPendingParents.Count > 0)
{
foreach (var (litId, (f, m)) in synthLitterPendingParents)
{
var row = await _db.Litters.FindAsync(litId);
if (row is null) continue;
if (f is not null) row.FatherId = f;
if (m is not null) row.MotherId = m;
}
await _db.SaveChangesAsync();
}
// ---- back-link Wurfchronik litter parents by name (best effort) ----
if (execute)
{