From afd0147e6958134a9efdb2f0f1ae470314ab5580 Mon Sep 17 00:00:00 2001
From: Tapac <fantocci@gmail.com>
Date: Tue, 24 Mar 2020 00:53:48 +0300
Subject: [PATCH] Exposed tries to create the same foreign key constraint even
 if one already exists #843

---
 .../main/kotlin/org/jetbrains/exposed/sql/Queries.kt   |  2 +-
 .../kotlin/org/jetbrains/exposed/sql/SchemaUtils.kt    |  4 ++--
 .../org/jetbrains/exposed/sql/vendors/Default.kt       | 10 ++++------
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Queries.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Queries.kt
index fa507b0813..cc9e2da6a2 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Queries.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Queries.kt
@@ -287,7 +287,7 @@ private fun checkMissingIndices(vararg tables: Table): List<Index> {
     val fKeyConstraints = currentDialect.columnConstraints(*tables).keys
     val existingIndices = currentDialect.existingIndices(*tables)
     fun List<Index>.filterFKeys() = if (isMysql)
-        filterNot { (it.table.tableName.inProperCase() to it.columns.singleOrNull()?.let { c -> tr.identity(c) }) in fKeyConstraints }
+        filterNot { it.table to it.columns.singleOrNull() in fKeyConstraints }
     else
         this
 
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SchemaUtils.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SchemaUtils.kt
index a0f4ee001f..b7399869a5 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SchemaUtils.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SchemaUtils.kt
@@ -149,10 +149,10 @@ object SchemaUtils {
                     for (column in table.columns) {
                         val foreignKey = column.foreignKey
                         if (foreignKey != null) {
-                            val existingConstraint = existingColumnConstraint[table.tableName.inProperCase() to identity(column)]?.firstOrNull()
+                            val existingConstraint = existingColumnConstraint[table to column]?.firstOrNull()
                             if (existingConstraint == null) {
                                 statements.addAll(createFKey(column))
-                            } else if (existingConstraint.targetTable != foreignKey.targetTable
+                            } else if (existingConstraint.target.table != foreignKey.target.table
                                     || foreignKey.deleteRule != existingConstraint.deleteRule
                                     || foreignKey.updateRule != existingConstraint.updateRule) {
                                 statements.addAll(existingConstraint.dropStatement())
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt
index a19dbb289d..a469a4d1e7 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt
@@ -7,8 +7,6 @@ import java.nio.ByteBuffer
 import java.util.*
 import java.util.concurrent.ConcurrentHashMap
 
-internal typealias TableAndColumnName = Pair<String, String>
-
 /**
  * Provides definitions for all the supported SQL data types.
  * By default, definitions from the SQL standard are provided but if a vendor doesn't support a specific type, or it is
@@ -523,7 +521,7 @@ interface DatabaseDialect {
     fun tableColumns(vararg tables: Table): Map<Table, List<ColumnMetadata>> = emptyMap()
 
     /** Returns a map with the foreign key constraints of all the defined columns in each of the specified [tables]. */
-    fun columnConstraints(vararg tables: Table): Map<TableAndColumnName, List<ForeignKeyConstraint>> = emptyMap()
+    fun columnConstraints(vararg tables: Table): Map<Pair<Table, Column<*>>, List<ForeignKeyConstraint>> = emptyMap()
 
     /** Returns a map with all the defined indices in each of the specified [tables]. */
     fun existingIndices(vararg tables: Table): Map<Table, List<Index>> = emptyMap()
@@ -613,15 +611,15 @@ abstract class VendorDialect(
     override fun tableColumns(vararg tables: Table): Map<Table, List<ColumnMetadata>> =
         TransactionManager.current().connection.metadata { columns(*tables) }
 
-    override fun columnConstraints(vararg tables: Table): Map<Pair<String, String>, List<ForeignKeyConstraint>> {
-        val constraints = HashMap<Pair<String, String>, MutableList<ForeignKeyConstraint>>()
+    override fun columnConstraints(vararg tables: Table): Map<Pair<Table, Column<*>>, List<ForeignKeyConstraint>> {
+        val constraints = HashMap<Pair<Table, Column<*>>, MutableList<ForeignKeyConstraint>>()
 
         val tablesToLoad = tables.filter { !columnConstraintsCache.containsKey(it.nameInDatabaseCase()) }
 
         fillConstraintCacheForTables(tablesToLoad)
         tables.forEach { table ->
             columnConstraintsCache[table.nameInDatabaseCase()].orEmpty().forEach {
-                constraints.getOrPut(it.fromTable to it.fromColumn) { arrayListOf() }.add(it)
+                constraints.getOrPut(it.from.table to it.from) { arrayListOf() }.add(it)
             }
 
         }