From 50848d672b60581242003ff65ef9c078aa72f058 Mon Sep 17 00:00:00 2001
From: Tapac <fantocci@gmail.com>
Date: Thu, 27 Feb 2020 01:14:18 +0300
Subject: [PATCH] QueryAlias.get(original: Expression<T>) lose query's alias
 #633

---
 .../kotlin/org/jetbrains/exposed/sql/Alias.kt | 16 ++++++----
 .../exposed/sql/tests/shared/AliasesTests.kt  | 31 +++++++++++++++++++
 2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt
index e75849d7..75451eb2 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt
@@ -67,15 +67,17 @@ class QueryAlias(val query: Query, val alias: String): ColumnSet() {
     override val columns: List<Column<*>>
         get() = query.set.source.columns.filter { it in query.set.fields }.map { it.clone() }
 
-    private fun <T:Any?> Column<T>.clone() = Column<T>(table.alias(alias), name, columnType)
+    @Suppress("UNCHECKED_CAST")
+    operator fun <T : Any?> get(original: Column<T>): Column<T> =
+        query.set.source.columns.find { it == original }?.clone() as? Column<T>
+            ?: error("Column not found in original table")
 
     @Suppress("UNCHECKED_CAST")
-    operator fun <T: Any?> get(original: Column<T>): Column<T> = query.set.source.columns.find { it == original }?.
-            let { it.clone() as? Column<T> } ?: error("Column not found in original table")
-
-    @Suppress("UNCHECKED_CAST")
-    operator fun <T: Any?> get(original: Expression<T>): Expression<T> = (query.set.fields.find { it == original } as? ExpressionAlias<T>)?.aliasOnlyExpression()
+    operator fun <T : Any?> get(original: Expression<T>): Expression<T> {
+        val expressionAlias = query.set.fields.find { it == original } as? ExpressionAlias<T>
             ?: error("Field not found in original table fields")
+        return expressionAlias.delegate.alias("$alias.${expressionAlias.alias}").aliasOnlyExpression()
+    }
 
     override fun join(otherTable: ColumnSet, joinType: JoinType, onColumn: Expression<*>?, otherColumn: Expression<*>?, additionalConstraint: (SqlExpressionBuilder.()->Op<Boolean>)? ) : Join =
             Join (this, otherTable, joinType, onColumn, otherColumn, additionalConstraint)
@@ -89,6 +91,8 @@ class QueryAlias(val query: Query, val alias: String): ColumnSet() {
     override infix fun fullJoin(otherTable: ColumnSet): Join = Join (this, otherTable, JoinType.FULL)
 
     override infix fun crossJoin(otherTable: ColumnSet) : Join = Join (this, otherTable, JoinType.CROSS)
+
+    private fun <T:Any?> Column<T>.clone() = Column<T>(table.alias(alias), name, columnType)
 }
 
 fun <T:Table> T.alias(alias: String) = Alias(this, alias)
diff --git a/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/AliasesTests.kt b/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/AliasesTests.kt
index cb0431fe..b4670490 100644
--- a/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/AliasesTests.kt
+++ b/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/AliasesTests.kt
@@ -110,4 +110,35 @@ class AliasesTests : DatabaseTestsBase() {
             assertEquals(false, entityFromAlias.b1)
         }
     }
+
+    @Test
+    fun `test aliased expression with aliased query`() {
+        withTables(EntityTestsData.XTable) {
+            val dataToInsert = listOf(true, true, false, true)
+            EntityTestsData.XTable.batchInsert(dataToInsert) {
+                this[EntityTestsData.XTable.b1] = it
+            }
+            val aliasedExpression = EntityTestsData.XTable.id.max().alias("maxId")
+            val aliasedQuery = EntityTestsData.XTable.
+                slice(EntityTestsData.XTable.b1, aliasedExpression).
+                selectAll().
+                groupBy(EntityTestsData.XTable.b1).
+                alias("maxBoolean")
+
+            val aliasedBool = aliasedQuery[EntityTestsData.XTable.b1]
+            val expressionToCheck = aliasedQuery[aliasedExpression]
+            assertEquals("maxBoolean.maxId", expressionToCheck.toString())
+
+            val resultQuery = aliasedQuery.
+                leftJoin(EntityTestsData.XTable, { this[aliasedExpression]}, { id }).
+                slice(aliasedBool, expressionToCheck).
+                selectAll()
+
+            val result = resultQuery.map {
+                it[aliasedBool] to it[expressionToCheck]!!.value
+            }
+
+            assertEqualCollections(listOf(true to 4, false to 3), result)
+        }
+    }
 }
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