Remove unnecessary parentheses for functions

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt

@@ -2,6 +2,7 @@ package org.jetbrains.exposed.sql.vendors
 
 import org.jetbrains.exposed.exceptions.throwUnsupportedException
 import org.jetbrains.exposed.sql.*
+import org.jetbrains.exposed.sql.Function
 import org.jetbrains.exposed.sql.transactions.TransactionManager
 import java.nio.ByteBuffer
 import java.util.*
@@ -109,6 +110,7 @@ abstract class DataTypeProvider {
     /** Returns the SQL representation of the specified expression, for it to be used as a column default value. */
     open fun processForDefaultValue(e: Expression<*>): String = when {
         e is LiteralOp<*> -> "$e"
+        e is Function<*> -> "$e"
         currentDialect is MysqlDialect -> "$e"
         currentDialect is SQLServerDialect -> "$e"
         else -> "($e)"

exposed-java-time/src/test/kotlin/org/jetbrains/exposed/DefaultsTest.kt

@@ -359,4 +359,23 @@ class DefaultsTest : DatabaseTestsBase() {
             assertEquals(1, count)
         }
     }
+
+    @Test
+    fun testConsistentSchemeWithFunctionAsDefaultExpression() {
+        val foo = object : IntIdTable("foo") {
+            val name = text("name")
+            val defaultDateTime = datetime("defaultDateTime").defaultExpression(CurrentDateTime)
+        }
+
+        withDb {
+            try {
+                SchemaUtils.create(foo)
+
+                val actual = SchemaUtils.statementsRequiredToActualizeScheme(foo)
+                assertTrue(actual.isEmpty())
+            } finally {
+                SchemaUtils.drop(foo)
+            }
+        }
+    }
 }

exposed-kotlin-datetime/src/test/kotlin/org/jetbrains/exposed/sql/kotlin/datetime/DefaultsTest.kt

@@ -1,4 +1,5 @@
 @file:OptIn(ExperimentalTime::class)
+
 package org.jetbrains.exposed.sql.kotlin.datetime
 
 import kotlinx.datetime.*
@@ -24,6 +25,7 @@ import org.jetbrains.exposed.sql.vendors.OracleDialect
 import org.jetbrains.exposed.sql.vendors.SQLServerDialect
 import org.jetbrains.exposed.sql.vendors.h2Mode
 import org.junit.Test
+import org.junit.runners.model.MultipleFailureException
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
@@ -230,6 +232,7 @@ class DefaultsTest : DatabaseTestsBase() {
         fun Expression<*>.itOrNull() = when {
             currentDialectTest.isAllowedAsColumnDefault(this) ->
                 "DEFAULT ${currentDialectTest.dataTypeProvider.processForDefaultValue(this)} NOT NULL"
+
             else -> "NULL"
         }
 
@@ -352,9 +355,9 @@ class DefaultsTest : DatabaseTestsBase() {
 
         withTables(foo) {
             val d2020 = LocalDate(2020, 1, 1)
-            val dt2020 = d2020.atTime(0,0,0)
-            val dt2020m1w = d2020.minus(DateTimeUnit.WEEK).atTime(0,0,0)
-            val dt2020p1w = d2020.plus(DateTimeUnit.WEEK).atTime(0,0,0)
+            val dt2020 = d2020.atTime(0, 0, 0)
+            val dt2020m1w = d2020.minus(DateTimeUnit.WEEK).atTime(0, 0, 0)
+            val dt2020p1w = d2020.plus(DateTimeUnit.WEEK).atTime(0, 0, 0)
 
             foo.insert { it[dt] = LocalDateTime(2019, 1, 1, 1, 1) }
             foo.insert { it[dt] = dt2020 }
@@ -363,4 +366,23 @@ class DefaultsTest : DatabaseTestsBase() {
             assertEquals(1, count)
         }
     }
+
+    @Test
+    fun testConsistentSchemeWithFunctionAsDefaultExpression() {
+        val foo = object : IntIdTable("foo") {
+            val name = text("name")
+            val defaultDateTime = datetime("defaultDateTime").defaultExpression(CurrentDateTime)
+        }
+
+        withDb {
+            try {
+                SchemaUtils.create(foo)
+
+                val actual = SchemaUtils.statementsRequiredToActualizeScheme(foo)
+                assertTrue(actual.isEmpty())
+            } finally {
+                SchemaUtils.drop(foo)
+            }
+        }
+    }
 }