Fix NRE in AddJsonNavigationBindings when combining DbFunction with OwnsOne/OwnsMany ToJson by Copilot · Pull Request #37855 · dotnet/efcore

Copilot · 2026-03-05T06:50:05Z

CreateFunctionMapping in RelationalModel never added JSON container columns to StoreFunction, so AddJsonNavigationBindings hit a null deref when resolving the container column via IStoreFunction.FindColumn(). Tables and views already handled this via CreateContainerColumn; functions were simply missing it.

Fixes #37842

Changes

RelationalEntityTypeExtensions.cs: GetFunctionName now falls back to the ownership principal's function name for owned types — consistent with GetViewName/GetTableName which already do this via GetDefaultViewName/GetDefaultTableName
RelationalModel.cs: Restructured CreateFunctionMapping to check mappedType.GetContainerColumnName() and create the container column when non-null, falling to the property loop otherwise — matching the existing pattern in CreateTableMapping and CreateViewMapping. Also added owned JSON type processing in AddTvfs via a new AddTvfMapping helper method so that TVF-mapped entities (which lack a FunctionName annotation) get function mappings for their owned JSON types, eliminating duplicated mapping registration logic.
RelationalModelTest.cs: Add Can_use_relational_model_with_functions_and_json_owned_types using existing Order class with both OwnsOne(DateDetails).ToJson() and OwnsMany(Addresses).ToJson() on a TVF-mapped entity, asserting both JSON container and non-JSON columns to ensure no extra columns are added

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…g DbFunction with OwnsOne/OwnsMany ToJson Add JSON container column creation to CreateFunctionMapping in RelationalModel, matching how tables and views already handle JSON container columns. Pass IRelationalTypeMappingSource through AddMappedFunctions, AddTvfs and CreateFunctionMapping to enable container column creation. Co-authored-by: roji <1862641+roji@users.noreply.github.com>

roji · 2026-03-05T08:52:31Z

@copilot what was the exact cause of the regression from 9.0 to 10.0?

Copilot · 2026-03-05T08:56:05Z

@copilot what was the exact cause of the regression from 9.0 to 10.0?

In EF Core 9, AddJsonNavigationBindings looked up the JSON container column from the entity's table or view mappings (not the function mapping):

// EF Core 9
var containerColumn = (entityType.GetViewOrTableMappings().SingleOrDefault()?.Table
        ?? entityType.GetDefaultMappings().Single().Table)
    .FindColumn(containerColumnName)!;

So even when querying through a TVF, the container column was always resolved from the regular Table metadata (which had it), and only the tableAlias parameter was used for the column expression.

In EF Core 10, this was refactored to look up the container column via the tableMap dictionary — which maps the actual ITableBase in the query to its alias:

// EF Core 10
var (containerColumn, tableAlias) = tableMap
    .Select(kvp => (Column: kvp.Key.FindColumn(containerColumnName), TableAlias: kvp.Value))
    .SingleOrDefault(c => c.Column is not null);

For TVFs, the tableMap contains the IStoreFunction (not the Table). Since CreateFunctionMapping in RelationalModel.cs never added JSON container columns to StoreFunction (unlike CreateTableMapping which calls CreateContainerColumn), FindColumn() returned null → NRE.

The fix adds the missing CreateContainerColumn call to CreateFunctionMapping so the StoreFunction has the JSON container column, matching the existing table/view pattern.

roji · 2026-03-05T08:57:51Z

@AndriySvyryd this looks like a relational model (owned) JSON issue, triggered by a query change I did in 10.0. Assigning this and the issue to you for now, but let's discuss if you think query should be doing something else.

src/EFCore.Relational/Metadata/Internal/RelationalModel.cs

…nctionName ownership fallback Co-authored-by: AndriySvyryd <6539701+AndriySvyryd@users.noreply.github.com>

AndriySvyryd · 2026-03-05T20:17:27Z

test/EFCore.Relational.Tests/Metadata/RelationalModelTest.cs

+        {
+            var modelBuilder = CreateConventionModelBuilder();
+
+            modelBuilder.Entity<EntityWithJsonOwnedType>(cb =>


@copilot Try to use existing classes instead of adding EntityWithJsonOwnedType.
Also assert the non-json columns to ensure no extra ones are addded

Done in 4bfd2db. Replaced EntityWithJsonOwnedType with existing Order class using OwnsOne(c => c.DateDetails, o => o.ToJson("date_details")), removed the three custom classes and GetEntitiesWithJsonOwnedType method, and added column name assertions to verify no extra columns are present.

Co-authored-by: AndriySvyryd <6539701+AndriySvyryd@users.noreply.github.com>

Copilot

Pull request overview

Fixes a NullReferenceException when building relational models that combine table-valued DbFunctions with owned JSON types (OwnsOne/OwnsMany + ToJson), ensuring function mappings include the necessary JSON container columns and owned-type mappings.

Changes:

Pass IRelationalTypeMappingSource through function-mapping code paths and create function container columns for JSON-mapped types.
Update GetFunctionName to resolve function names from owners for owned (including JSON-mapped) entity types.
Extend TVF mapping to include owned JSON entity types and add a regression test covering the scenario.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
test/EFCore.Relational.Tests/Metadata/RelationalModelTest.cs	Adds a regression test ensuring TVFs include owned JSON container columns and don’t introduce extra columns.
src/EFCore.Relational/Metadata/Internal/RelationalModel.cs	Adds type-mapping source to function mapping, creates JSON container columns for functions, and maps owned JSON types for TVFs.
src/EFCore.Relational/Extensions/RelationalEntityTypeExtensions.cs	Updates `GetFunctionName` to inherit function names from owners for owned/JSON-mapped entity types.

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test/EFCore.Relational.Tests/Metadata/RelationalModelTest.cs

Copilot · 2026-03-05T20:48:49Z

src/EFCore.Relational/Metadata/Internal/RelationalModel.cs

+                if (ownedType.FindRuntimeAnnotationValue(RelationalAnnotationNames.FunctionMappings)
+                    is not List<FunctionMapping> ownedFunctionMappings)
+                {
+                    ownedFunctionMappings = [];
+                    ownedType.AddRuntimeAnnotation(RelationalAnnotationNames.FunctionMappings, ownedFunctionMappings);
+                }
+
+                ownedFunctionMappings.Add(ownedFunctionMapping);
+                ((StoreFunction)ownedFunctionMapping.StoreFunction).EntityTypeMappings.Add(ownedFunctionMapping);


The annotation-list initialization + mapping registration logic is duplicated (similar logic exists for the root entityType earlier in AddTvfs). Consider extracting this into a small helper to keep the mapping registration consistent and reduce copy/paste (e.g., a local function that “gets/creates function mappings list, adds mapping, and registers it on the StoreFunction”).

@copilot The annotation-list initialization + mapping registration logic is duplicated (similar logic exists for the root entityType earlier in AddTvfs). Consider extracting this into a small helper to keep the mapping registration consistent and reduce duplication

Extracted AddTvfMapping helper in e3ee4f0. The duplicated annotation-list initialization + mapping registration logic in AddTvfs is now a single method called for both the root entity and each owned JSON type.

Extracted AddTvfMapping helper in e3ee4f0.

AndriySvyryd · 2026-03-05T21:18:45Z

src/EFCore.Relational/Metadata/Internal/RelationalModel.cs

+                if (ownedType.FindRuntimeAnnotationValue(RelationalAnnotationNames.FunctionMappings)
+                    is not List<FunctionMapping> ownedFunctionMappings)
+                {
+                    ownedFunctionMappings = [];
+                    ownedType.AddRuntimeAnnotation(RelationalAnnotationNames.FunctionMappings, ownedFunctionMappings);
+                }
+
+                ownedFunctionMappings.Add(ownedFunctionMapping);
+                ((StoreFunction)ownedFunctionMapping.StoreFunction).EntityTypeMappings.Add(ownedFunctionMapping);


@copilot The annotation-list initialization + mapping registration logic is duplicated (similar logic exists for the root entityType earlier in AddTvfs). Consider extracting this into a small helper to keep the mapping registration consistent and reduce duplication

test/EFCore.Relational.Tests/Metadata/RelationalModelTest.cs

AndriySvyryd · 2026-03-05T21:19:14Z

test/EFCore.Relational.Tests/Metadata/RelationalModelTest.cs

            public string Value { get; set; }
            public int Number { get; set; }
        }
+


@copilot Remove blank line

Removed in e3ee4f0.

Co-authored-by: AndriySvyryd <6539701+AndriySvyryd@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

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Initial plan

1ddc7e7

Copilot AI assigned Copilot and roji Mar 5, 2026

Copilot started work on behalf of roji March 5, 2026 06:50 View session

Copilot AI changed the title ~~[WIP] Fix EF Core 10 regression with OwnsMany and DbFunction~~ Fix NRE in AddJsonNavigationBindings when combining DbFunction with OwnsOne/OwnsMany ToJson Mar 5, 2026

Copilot finished work on behalf of roji March 5, 2026 07:16

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src/EFCore.Relational/Metadata/Internal/RelationalModel.cs Outdated Show resolved Hide resolved

Copilot started work on behalf of AndriySvyryd March 5, 2026 18:49 View session

Address review feedback: simplify CreateFunctionMapping and fix GetFu…

1c902a7

…nctionName ownership fallback Co-authored-by: AndriySvyryd <6539701+AndriySvyryd@users.noreply.github.com>

Copilot finished work on behalf of AndriySvyryd March 5, 2026 19:05

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Copilot started work on behalf of AndriySvyryd March 5, 2026 20:36 View session

Use existing Order class in function+JSON test and assert column names

4bfd2db

Co-authored-by: AndriySvyryd <6539701+AndriySvyryd@users.noreply.github.com>

AndriySvyryd added the poachable label Mar 5, 2026

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Copilot started work on behalf of AndriySvyryd March 5, 2026 21:19 View session

Extract AddTvfMapping helper, add OwnsMany test, remove blank line

e3ee4f0

Co-authored-by: AndriySvyryd <6539701+AndriySvyryd@users.noreply.github.com>

Copilot finished work on behalf of AndriySvyryd March 5, 2026 21:33

AndriySvyryd marked this pull request as ready for review March 5, 2026 22:00

AndriySvyryd requested a review from a team as a code owner March 5, 2026 22:00

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roji approved these changes Mar 6, 2026

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roji merged commit 1b36259 into main Mar 6, 2026
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roji deleted the copilot/fix-ef-core-10-regression branch March 6, 2026 13:15

roji mentioned this pull request Mar 6, 2026

Ef core 10 regression: owned JSON combined with DbFunction #37842

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dotnet-maestro bot mentioned this pull request Mar 7, 2026

[main] Source code updates from dotnet/efcore dotnet/dotnet#5300

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github-actions bot mentioned this pull request Mar 11, 2026

[EF Sync] Sync to EF 11.0.0-preview.3.26160.112 npgsql/efcore.pg#3776

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Copilot AI commented Mar 5, 2026 •

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