fix(types): inner join type on nullable relationships

src/select-query-parser/result.ts

@@ -372,7 +372,9 @@ type ProcessEmbeddedResourceResult<
             TablesAndViews<Schema>[CurrentTableOrView],
             Resolved['relation']
           > extends true
-        ? ProcessedChildren | null
+        ? Field extends { innerJoin: true }
+          ? ProcessedChildren
+          : ProcessedChildren | null
         : ProcessedChildren
     }
   : {

test/db/01-dummy-data.sql

@@ -86,4 +86,37 @@ INSERT INTO public.cornercase (id, array_column)
 VALUES
   (1, ARRAY['test', 'one']),
   (2, ARRAY['another']),
-  (3, ARRAY['test2']);
+  (3, ARRAY['test2']);
+
+create table
+  hotel (
+    id bigint generated by default as identity primary key,
+    name text null
+  );
+
+create table
+  booking (
+    id bigint generated by default as identity primary key,
+    hotel_id bigint, -- nullable foreign key is needed to reproduce !inner supabase-js error
+    foreign key (hotel_id) references hotel (id)
+  );
+
+-- Insert sample hotels
+INSERT INTO hotel (id, name)
+VALUES
+  (1, 'Sunset Resort'),
+  (2, 'Mountain View Hotel'),
+  (3, 'Beachfront Inn'),
+  (4, NULL);
+
+-- Insert bookings with various relationship scenarios
+INSERT INTO booking (id, hotel_id)
+VALUES
+  (1, 1),                -- Valid booking for Sunset Resort
+  (2, 1),                -- Another booking for Sunset Resort (duplicate reference)
+  (3, 2),                -- Booking for Mountain View Hotel
+  (4, NULL),             -- Booking with no hotel (null reference)
+  (5, 3),                -- Booking for Beachfront Inn
+  (6, 1),                -- Third booking for Sunset Resort
+  (7, NULL),             -- Another booking with no hotel
+  (8, 4);                -- Booking for hotel with null name

test/relationships.ts

@@ -190,6 +190,10 @@ export const selectParams = {
     select:
       'msgs:messages(id, ...message_details(created_at, channel!inner(id, slug, owner:users(*))))',
   },
+  innerJoinOnNullableRelationship: {
+    from: 'booking',
+    select: 'id, hotel!inner(id, name)',
+  },
 } as const
 
 export const selectQueries = {
@@ -371,6 +375,9 @@ export const selectQueries = {
   nestedQueryWithSelectiveFieldsAndInnerJoin: postgrest
     .from(selectParams.nestedQueryWithSelectiveFieldsAndInnerJoin.from)
     .select(selectParams.nestedQueryWithSelectiveFieldsAndInnerJoin.select),
+  innerJoinOnNullableRelationship: postgrest
+    .from(selectParams.innerJoinOnNullableRelationship.from)
+    .select(selectParams.innerJoinOnNullableRelationship.select),
 } as const
 
 test('nested query with selective fields', async () => {
@@ -518,6 +525,62 @@ test('!inner relationship', async () => {
   `)
 })
 
+test('!inner relationship on nullable relation', async () => {
+  const res = await selectQueries.innerJoinOnNullableRelationship
+  expect(res).toMatchInlineSnapshot(`
+    Object {
+      "count": null,
+      "data": Array [
+        Object {
+          "hotel": Object {
+            "id": 1,
+            "name": "Sunset Resort",
+          },
+          "id": 1,
+        },
+        Object {
+          "hotel": Object {
+            "id": 1,
+            "name": "Sunset Resort",
+          },
+          "id": 2,
+        },
+        Object {
+          "hotel": Object {
+            "id": 2,
+            "name": "Mountain View Hotel",
+          },
+          "id": 3,
+        },
+        Object {
+          "hotel": Object {
+            "id": 3,
+            "name": "Beachfront Inn",
+          },
+          "id": 5,
+        },
+        Object {
+          "hotel": Object {
+            "id": 1,
+            "name": "Sunset Resort",
+          },
+          "id": 6,
+        },
+        Object {
+          "hotel": Object {
+            "id": 4,
+            "name": null,
+          },
+          "id": 8,
+        },
+      ],
+      "error": null,
+      "status": 200,
+      "statusText": "OK",
+    }
+  `)
+})
+
 test('one-to-many relationship', async () => {
   const res = await selectQueries.oneToMany.limit(1).single()
   expect(res).toMatchInlineSnapshot(`

test/select-query-parser/select.test-d.ts

@@ -85,6 +85,20 @@ type Schema = Database['public']
   expectType<TypeEqual<typeof result, typeof expected>>(true)
 }
 
+// !inner relationship on nullable relation
+{
+  const { data } = await selectQueries.innerJoinOnNullableRelationship
+  let result: Exclude<typeof data, null>
+  let expected: Array<{
+    id: number
+    hotel: {
+      id: number
+      name: string | null
+    }
+  }>
+  expectType<TypeEqual<typeof result, typeof expected>>(true)
+}
+
 // one-to-many relationship
 {
   const { data } = await selectQueries.oneToMany.limit(1).single()

test/types.ts

@@ -496,6 +496,44 @@ export type Database = {
           }
         ]
       }
+      booking: {
+        Row: {
+          hotel_id: number | null
+          id: number
+        }
+        Insert: {
+          hotel_id?: number | null
+          id?: number
+        }
+        Update: {
+          hotel_id?: number | null
+          id?: number
+        }
+        Relationships: [
+          {
+            foreignKeyName: 'booking_hotel_id_fkey'
+            columns: ['hotel_id']
+            isOneToOne: false
+            referencedRelation: 'hotel'
+            referencedColumns: ['id']
+          }
+        ]
+      }
+      hotel: {
+        Row: {
+          id: number
+          name: string | null
+        }
+        Insert: {
+          id?: number
+          name?: string | null
+        }
+        Update: {
+          id?: number
+          name?: string | null
+        }
+        Relationships: []
+      }
     }
     Views: {
       non_updatable_view: {