fix: EXPOSED-244 [PostgreSQL] Collate option on column not recognized

exposed-core/api/exposed-core.api

@@ -2071,6 +2071,7 @@ public abstract class org/jetbrains/exposed/sql/StringColumnType : org/jetbrains
 	public synthetic fun <init> (Ljava/lang/String;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun equals (Ljava/lang/Object;)Z
 	protected final fun escape (Ljava/lang/String;)Ljava/lang/String;
+	protected final fun escapeAndQuote (Ljava/lang/String;)Ljava/lang/String;
 	public final fun getCollate ()Ljava/lang/String;
 	public fun hashCode ()I
 	public fun nonNullValueToString (Ljava/lang/Object;)Ljava/lang/String;

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

@@ -546,6 +546,12 @@ abstract class StringColumnType(
     /** Returns the specified [value] with special characters escaped. */
     protected fun escape(value: String): String = value.map { charactersToEscape[it] ?: it }.joinToString("")
 
+    /** Returns the specified [value] with special characters escaped and wrapped in quotations, if necessary. */
+    protected fun escapeAndQuote(value: String): String = when (currentDialect) {
+        is PostgreSQLDialect -> "\"${escape(value)}\""
+        else -> escape(value)
+    }
+
     override fun valueFromDB(value: Any): Any = when (value) {
         is Clob -> value.characterStream.readText()
         is ByteArray -> String(value)
@@ -597,7 +603,7 @@ open class CharColumnType(
     override fun sqlType(): String = buildString {
         append("CHAR($colLength)")
         if (collate != null) {
-            append(" COLLATE ${escape(collate)}")
+            append(" COLLATE ${escapeAndQuote(collate)}")
         }
     }
 
@@ -643,7 +649,7 @@ open class VarCharColumnType(
     override fun sqlType(): String = buildString {
         append(preciseType())
         if (collate != null) {
-            append(" COLLATE ${escape(collate)}")
+            append(" COLLATE ${escapeAndQuote(collate)}")
         }
     }
 
@@ -689,7 +695,7 @@ open class TextColumnType(
     override fun sqlType(): String = buildString {
         append(preciseType())
         if (collate != null) {
-            append(" COLLATE ${escape(collate)}")
+            append(" COLLATE ${escapeAndQuote(collate)}")
         }
     }
 

exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/types/CharColumnType.kt

@@ -3,6 +3,8 @@ package org.jetbrains.exposed.sql.tests.shared.types
 import org.jetbrains.exposed.dao.id.IntIdTable
 import org.jetbrains.exposed.sql.*
 import org.jetbrains.exposed.sql.tests.DatabaseTestsBase
+import org.jetbrains.exposed.sql.tests.TestDB
+import org.jetbrains.exposed.sql.tests.shared.assertEqualLists
 import org.jetbrains.exposed.sql.tests.shared.assertEquals
 import org.junit.Test
 
@@ -23,4 +25,39 @@ class CharColumnType : DatabaseTestsBase() {
             assertEquals('A', result?.get(CharTable.charColumn))
         }
     }
+
+    @Test
+    fun testCharColumnWithCollate() {
+        val collateOption = when (TestDB.enabledDialects().first()) {
+            TestDB.POSTGRESQL, TestDB.POSTGRESQLNG -> "C"
+            TestDB.SQLITE -> "binary"
+            TestDB.SQLSERVER -> "latin1_general_bin"
+            else -> "utf8mb4_bin"
+        }
+
+        val tester = object : Table("tester") {
+            val letter = char("letter", 1, collate = collateOption)
+        }
+
+        // H2 only allows collation for the entire database using SET COLLATION
+        // Oracle only allows collation if MAX_STRING_SIZE=EXTENDED, which can only be set in upgrade mode
+        // Oracle -> https://docs.oracle.com/en/database/oracle/oracle-database/12.2/refrn/MAX_STRING_SIZE.html#
+        withDb(excludeSettings = TestDB.allH2TestDB + TestDB.ORACLE) {
+            try {
+                SchemaUtils.create(tester)
+
+                val letters = listOf("a", "A", "b", "B")
+                tester.batchInsert(letters) { ch ->
+                    this[tester.letter] = ch
+                }
+
+                // one of the purposes of collation is to determine ordering rules of stored character data types
+                val expected = letters.sortedBy { it.single().code } // [A, B, a, b]
+                val actual = tester.selectAll().orderBy(tester.letter).map { it[tester.letter] }
+                assertEqualLists(expected, actual)
+            } finally {
+                SchemaUtils.drop(tester)
+            }
+        }
+    }
 }