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AB#1922 Fix: Validate resulting cardinality for to-one associations #201

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Merged
mmgerald merged 1 commit into from
Jun 29, 2026
Merged

AB#1922 Fix: Validate resulting cardinality for to-one associations #201

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30 changes: 22 additions & 8 deletions src/Runtime.Engine/RuleEngine/GraphRuleEngine.cs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -252,11 +252,18 @@ private async Task ValidateTarget(IOctoSession session, IRepositoryDataSource re
}
}

if (changeDelta > 0)
if (changeDelta > 0 &&
(multiplicity == MultiplicitiesDto.One ||
multiplicity == MultiplicitiesDto.ZeroOrOne))
{
if (currentMultiplicity == CurrentMultiplicity.One &&
(multiplicity == MultiplicitiesDto.One ||
multiplicity == MultiplicitiesDto.ZeroOrOne))
// Validate the RESULTING cardinality after applying the batch, not just the current
// DB state. A to-one role must end up with at most one association. This is violated if:
// - one association already exists and we net-add (result >= 2)
// - the state is already corrupt (Many) and we net-add (stays > 1)
// - no association exists yet but the batch creates two or more (result >= 2)
if (currentMultiplicity == CurrentMultiplicity.One ||
currentMultiplicity == CurrentMultiplicity.Many ||
(currentMultiplicity == CurrentMultiplicity.Zero && changeDelta >= 2))
{
operationResult.AddMessage(MessageCodes.AssociationCardinalityViolationOnModification(
originFileResolver.Resolve(repositoryDataSource.TenantId), repositoryDataSource.TenantId,
Expand Down Expand Up @@ -367,11 +374,18 @@ private async Task ValidateOrigin(IOctoSession session, IRepositoryDataSource re
}
}

if (changeDelta > 0)
if (changeDelta > 0 &&
(multiplicity == MultiplicitiesDto.One ||
multiplicity == MultiplicitiesDto.ZeroOrOne))
{
if (currentMultiplicity == CurrentMultiplicity.One &&
(multiplicity == MultiplicitiesDto.One ||
multiplicity == MultiplicitiesDto.ZeroOrOne))
// Validate the RESULTING cardinality after applying the batch, not just the current
// DB state. A to-one role must end up with at most one association. This is violated if:
// - one association already exists and we net-add (result >= 2)
// - the state is already corrupt (Many) and we net-add (stays > 1)
// - no association exists yet but the batch creates two or more (result >= 2)
if (currentMultiplicity == CurrentMultiplicity.One ||
currentMultiplicity == CurrentMultiplicity.Many ||
(currentMultiplicity == CurrentMultiplicity.Zero && changeDelta >= 2))
{
operationResult.AddMessage(MessageCodes.AssociationCardinalityViolationOnModification(
originFileResolver.Resolve(repositoryDataSource.TenantId), repositoryDataSource.TenantId,
Expand Down
62 changes: 62 additions & 0 deletions tests/Runtime.Engine.Tests/RuleEngine/GraphRuleEngineTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -273,6 +273,68 @@ await engine.ValidateAsync(session, dataSource,
Assert.Equal(14, operationResult.Messages[0].MessageNumber);
}

[Fact]
public async Task ValidateAsync_CreateMultipleParentsFromEmpty_AddsError()
{
// Bug 1922: a to-one role (ParentChild outbound = Parent) must not gain multiple targets
// in a single mutation even when no association exists yet (currentMultiplicity == Zero).
// Arrange
var (engine, session, dataSource, operationResult, originFileResolver) = CreateTestObjects();
var origin = CreateEntity(TestCkIds.RtCkCountryTypeId);
var target1 = CreateEntity(TestCkIds.RtCkContinentTypeId);
var target2 = CreateEntity(TestCkIds.RtCkContinentTypeId);

SetupEntityRetrieval(dataSource, [origin, target1, target2]);
SetupEmptyAssociations(dataSource);
// Note: no SetupMultiplicity → currentMultiplicity defaults to Zero (node has no parent yet).

// Act — create two parents in one batch
await engine.ValidateAsync(session, dataSource,
[EntityUpdateInfo<RtEntity>.CreateUpdate(origin.ToRtEntityId(), origin)],
[
AssociationUpdateInfo.CreateInsert(origin.ToRtEntityId(), target1.ToRtEntityId(),
SystemCkIds.RtCkParentChildRoleId),
AssociationUpdateInfo.CreateInsert(origin.ToRtEntityId(), target2.ToRtEntityId(),
SystemCkIds.RtCkParentChildRoleId)
],
originFileResolver, operationResult);

// Assert
Assert.Single(operationResult.Messages);
Assert.True(operationResult.HasFatalErrors);
Assert.Equal(14, operationResult.Messages[0].MessageNumber);
}

[Fact]
public async Task ValidateAsync_AddParentToExistingParent_AddsError()
{
// Bug 1922: adding a second parent to a node that already has one (currentMultiplicity == One)
// must be rejected for the to-one ParentChild role.
// Arrange
var (engine, session, dataSource, operationResult, originFileResolver) = CreateTestObjects();
var origin = CreateEntity(TestCkIds.RtCkCountryTypeId);
var newParent = CreateEntity(TestCkIds.RtCkContinentTypeId);

SetupEntityRetrieval(dataSource, [origin, newParent]);
SetupEmptyAssociations(dataSource);
SetupMultiplicity(dataSource, origin, SystemCkIds.RtCkParentChildRoleId, GraphDirections.Outbound,
CurrentMultiplicity.One);

// Act — add a single additional parent without removing the existing one
await engine.ValidateAsync(session, dataSource,
[EntityUpdateInfo<RtEntity>.CreateUpdate(origin.ToRtEntityId(), origin)],
[
AssociationUpdateInfo.CreateInsert(origin.ToRtEntityId(), newParent.ToRtEntityId(),
SystemCkIds.RtCkParentChildRoleId)
],
originFileResolver, operationResult);

// Assert
Assert.Single(operationResult.Messages);
Assert.True(operationResult.HasFatalErrors);
Assert.Equal(14, operationResult.Messages[0].MessageNumber);
}

#endregion

#region Entity Deletion Tests
Expand Down