Implemented workaround for Sql2o ID type misdetection bug. Closes #8

src/main/kotlin/com/github/vokorm/DB.kt

@@ -14,7 +14,9 @@ import org.sql2o.converters.ConvertersProvider
 import org.sql2o.quirks.NoQuirks
 import org.sql2o.quirks.Quirks
 import org.sql2o.quirks.QuirksProvider
+import org.sql2o.reflection.PojoMetadata
 import java.io.Closeable
+import java.sql.ResultSet
 import java.sql.Timestamp
 import java.time.Instant
 import java.time.LocalDate
@@ -166,7 +168,47 @@ private class MysqlUuidConverter : Converter<UUID> {
  * Works around MySQL drivers not able to convert [UUID] to [ByteArray].
  * See https://github.com/mvysny/vok-orm/issues/8 for more details.
  */
-class MysqlQuirks : NoQuirks(mapOf(UUID::class.java to MysqlUuidConverter()))
+class MysqlQuirks : NoQuirks(mapOf(UUID::class.java to MysqlUuidConverter())) {
+
+    override fun <E : Any?> converterOf(ofClass: Class<E>): Converter<E>? {
+        if (Entity::class.java.isAssignableFrom(ofClass)) {
+            currentEntity.set(ofClass)
+        }
+        return super.converterOf(ofClass)
+    }
+
+    override fun getRSVal(rs: ResultSet, idx: Int): Any? {
+        val rsval: Any? = super.getRSVal(rs, idx)
+        // here the issue is that Sql2o may misdetect the type of the ID column as Object
+        // that is because there are two setId() methods on every Entity:
+        // 1. setId(Object); and
+        // 2. setId(T);
+        // depending on the order of methods in Java reflection, Sql2o may pick the incorrect one
+        // and may store it into its PojoMetadata.
+        // I failed to hook into PojoMetadata and fix the type there.
+        //
+        // This is just a dumb workaround: I'll simply run the converter myself.
+        if (rsval != null) {
+            val e = currentEntity.get()!!
+            val isIdColumn = e.entityMeta.idProperty.dbColumnName == getColumnName(rs.metaData, idx)
+            if (isIdColumn) {
+                val metadata = PojoMetadata(e, false, false, mapOf(), true)!!
+                val isIdTypeMisdetected = metadata.getPropertySetter(e.entityMeta.idProperty.name).type == Object::class.java
+                if (isIdTypeMisdetected) {
+                    val converter = converterOf(e.entityMeta.idProperty.valueType)
+                    if (converter != null) {
+                        return converter.convert(rsval)
+                    }
+                }
+            }
+        }
+        return rsval
+    }
+
+    companion object {
+        private val currentEntity = ThreadLocal<Class<*>>()
+    }
+}
 
 /**
  * Provides specialized quirks for MySQL. See [MysqlQuirks] for more details.

src/test/kotlin/com/github/vokorm/Databases.kt

@@ -69,14 +69,17 @@ data class EntityWithAliasedId(
 /**
  * A table demoing natural person with government-issued ID (birth number, social security number, etc).
  */
-data class NaturalPerson(override var id: String? = null, var name: String) : Entity<String> {
+data class NaturalPerson(override var id: String? = null, var name: String, var bytes: ByteArray) : Entity<String> {
     companion object : Dao<NaturalPerson>
 }
 
 /**
  * Demoes app-generated UUID ids.
+ *
+ * Warning: do NOT add any additional fields in here, since that would mysteriously make the compiler generate
+ * `void setId(UUID)` instead of `void setId(Object)` and we wouldn't test the metadata hook that fixes this issue.
  */
-data class LogRecord(override var id: UUID?, var text: String, var bytes: ByteArray) : Entity<UUID> {
+data class LogRecord(override var id: UUID?, var text: String) : Entity<UUID> {
     companion object : Dao<LogRecord>
 }
 
@@ -104,8 +107,8 @@ private fun DynaNodeGroup.usingDockerizedPosgresql() {
                 maritalStatus varchar(200)
                  )""")
             ddl("""create table if not exists EntityWithAliasedId(myid bigserial primary key, name varchar(400) not null)""")
-            ddl("""create table if not exists NaturalPerson(id varchar(10) primary key, name varchar(400) not null)""")
-            ddl("""create table if not exists LogRecord(id UUID primary key, text varchar(400) not null, bytes bytea not null)""")
+            ddl("""create table if not exists NaturalPerson(id varchar(10) primary key, name varchar(400) not null, bytes bytea not null)""")
+            ddl("""create table if not exists LogRecord(id UUID primary key, text varchar(400) not null)""")
         }
     }
 
@@ -146,8 +149,8 @@ fun DynaNodeGroup.usingDockerizedMysql() {
                 maritalStatus varchar(200)
                  )""")
             ddl("""create table if not exists EntityWithAliasedId(myid bigint primary key auto_increment, name varchar(400) not null)""")
-            ddl("""create table if not exists NaturalPerson(id varchar(10) primary key, name varchar(400) not null)""")
-            ddl("""create table if not exists LogRecord(id binary(16) primary key, text varchar(400) not null, bytes binary(16) not null)""")
+            ddl("""create table if not exists NaturalPerson(id varchar(10) primary key, name varchar(400) not null, bytes binary(16) not null)""")
+            ddl("""create table if not exists LogRecord(id binary(16) primary key, text varchar(400) not null)""")
         }
     }
 
@@ -190,8 +193,8 @@ fun DynaNodeGroup.usingH2Database() {
                 maritalStatus varchar
                  )""")
             ddl("""create table EntityWithAliasedId(myid bigint primary key auto_increment, name varchar not null)""")
-            ddl("""create table if not exists NaturalPerson(id varchar(10) primary key, name varchar(400) not null)""")
-            ddl("""create table if not exists LogRecord(id UUID primary key, text varchar(400) not null, bytes binary(16) not null)""")
+            ddl("""create table NaturalPerson(id varchar(10) primary key, name varchar(400) not null, bytes binary(16) not null)""")
+            ddl("""create table LogRecord(id UUID primary key, text varchar(400) not null)""")
         }
     }
     afterEach {
@@ -229,8 +232,8 @@ private fun DynaNodeGroup.usingDockerizedMariaDB() {
                  )"""
             )
             ddl("""create table if not exists EntityWithAliasedId(myid bigint primary key auto_increment, name varchar(400) not null)""")
-            ddl("""create table if not exists NaturalPerson(id varchar(10) primary key, name varchar(400) not null)""")
-            ddl("""create table if not exists LogRecord(id binary(16) primary key, text varchar(400) not null, bytes binary(16) not null)""")
+            ddl("""create table if not exists NaturalPerson(id varchar(10) primary key, name varchar(400) not null, bytes binary(16) not null)""")
+            ddl("""create table if not exists LogRecord(id binary(16) primary key, text varchar(400) not null)""")
         }
     }
 

src/test/kotlin/com/github/vokorm/MappingTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN")
+
 package com.github.vokorm
 
 import com.github.mvysny.dynatest.DynaTest
@@ -122,52 +124,51 @@ class MappingTest : DynaTest({
         }
         group("NaturalPerson") {
             test("save fails") {
-                val p = NaturalPerson(id = "12345678", name = "Albedo")
+                val p = NaturalPerson(id = "12345678", name = "Albedo", bytes = byteArrayOf(5))
                 expectThrows(IllegalStateException::class, message = "We expected to update only one row but we updated 0 - perhaps there is no row with id 12345678?") {
                     p.save()
                 }
             }
             test("Save") {
-                val p = NaturalPerson(id = "12345678", name = "Albedo")
+                val p = NaturalPerson(id = "12345678", name = "Albedo", bytes = byteArrayOf(5))
                 p.create()
                 expectList("Albedo") { NaturalPerson.findAll().map { it.name } }
                 p.name = "Rubedo"
                 p.save()
                 expectList("Rubedo") { NaturalPerson.findAll().map { it.name } }
-                NaturalPerson(id = "aaa", name = "Nigredo").create()
+                NaturalPerson(id = "aaa", name = "Nigredo", bytes = byteArrayOf(5)).create()
                 expectList("Rubedo", "Nigredo") { NaturalPerson.findAll().map { it.name } }
             }
             test("delete") {
-                val p = NaturalPerson(id = "foo", name = "Albedo")
+                val p = NaturalPerson(id = "foo", name = "Albedo", bytes = byteArrayOf(5))
                 p.create()
                 p.delete()
                 expectList() { NaturalPerson.findAll() }
             }
         }
         group("LogRecord") {
             test("save fails") {
-                val p = LogRecord(id = UUID.randomUUID(), text = "foo", bytes = byteArrayOf(5))
+                val p = LogRecord(id = UUID.randomUUID(), text = "foo")
                 expectThrows(IllegalStateException::class, message = "We expected to update only one row but we updated 0 - perhaps there is no row with id") {
                     p.save()
                 }
             }
             test("Save") {
-                val p = LogRecord(id = UUID.randomUUID(), text = "Albedo", bytes = byteArrayOf(5))
+                val p = LogRecord(id = UUID.randomUUID(), text = "Albedo")
                 p.create()
                 expectList("Albedo") { LogRecord.findAll().map { it.text } }
                 p.text = "Rubedo"
                 p.save()
                 expectList("Rubedo") { LogRecord.findAll().map { it.text } }
-                LogRecord(id = UUID.randomUUID(), text = "Nigredo", bytes = byteArrayOf(5)).create()
+                LogRecord(id = UUID.randomUUID(), text = "Nigredo").create()
                 expect(setOf("Rubedo", "Nigredo")) { LogRecord.findAll().map { it.text } .toSet() }
             }
             test("delete") {
-                val p = LogRecord(id = UUID.randomUUID(), text = "foo", bytes = byteArrayOf(5))
+                val p = LogRecord(id = UUID.randomUUID(), text = "foo")
                 p.create()
                 p.delete()
                 expectList() { LogRecord.findAll() }
             }
         }
     }
 })
-