fix: resolve edge case with varying shapes in multiple item inserts causing undefined in parameters.

src/parser/insert-values-parser.ts

@@ -100,11 +100,13 @@ function parseRowValues(
   })
 
   let hasUndefinedOrComplexColumns = false
+  let indexedRowColumns = rowColumns.length
 
   for (const col of rowColumns) {
     const columnIdx = columns.get(col)
 
     if (isUndefined(columnIdx)) {
+      indexedRowColumns--
       continue
     }
 
@@ -117,7 +119,7 @@ function parseRowValues(
     rowValues[columnIdx] = value
   }
 
-  const hasMissingColumns = rowColumns.length < columns.size
+  const hasMissingColumns = indexedRowColumns < columns.size
 
   if (hasMissingColumns || hasUndefinedOrComplexColumns) {
     const defaultValue = DefaultInsertValueNode.create()

test/node/src/insert.test.ts

@@ -762,6 +762,42 @@ for (const dialect of DIALECTS) {
       await query.execute()
     })
 
+    // https://github.com/kysely-org/kysely/issues/1310
+    it('should insert multiple rows while falling back to default values in partial rows - different shapes edge case issue - issue #1310', async () => {
+      const query = ctx.db.insertInto('person').values([
+        {
+          gender: 'female',
+          marital_status: 'divorced', // <--- only exists here.
+          children: undefined, // <--- always undefined explicitly.
+        },
+        {
+          gender: 'female',
+          children: undefined, // <--- always undefined explicitly.
+        },
+      ])
+
+      testSql(query, dialect, {
+        postgres: {
+          sql: `insert into "person" ("gender", "marital_status") values ($1, $2), ($3, default)`,
+          parameters: ['female', 'divorced', 'female'],
+        },
+        mysql: {
+          sql: `insert into \`person\` (\`gender\`, \`marital_status\`) values (?, ?), (?, default)`,
+          parameters: ['female', 'divorced', 'female'],
+        },
+        mssql: {
+          sql: `insert into "person" ("gender", "marital_status") values (@1, @2), (@3, default)`,
+          parameters: ['female', 'divorced', 'female'],
+        },
+        sqlite: {
+          sql: `insert into "person" ("gender", "marital_status") values (?, ?), (?, null)`,
+          parameters: ['female', 'divorced', 'female'],
+        },
+      })
+
+      await query.execute()
+    })
+
     it('should insert multiple rows while falling back to default values in partial rows - undefined/missing columns', async () => {
       const query = ctx.db.insertInto('person').values([
         {