From f3bf1e7e73e6c1ee72f108098287aabde93ec8a5 Mon Sep 17 00:00:00 2001
From: Lukas Eder <lukas.eder@gmail.com>
Date: Wed, 14 Jul 2021 16:16:56 +0200
Subject: [PATCH] [jOOQ/jOOQ#12189] Db2 cannot handle scalar subqueries in
 JSON_OBJECT in the presence of a MULTISET ad-hoc converter

---
 jOOQ/src/main/java/org/jooq/impl/ConvertedDataType.java | 4 ++++
 jOOQ/src/main/java/org/jooq/impl/JSONEntryImpl.java     | 4 ++++
 jOOQ/src/main/java/org/jooq/impl/Tools.java             | 5 +++++
 3 files changed, 13 insertions(+)

diff --git a/jOOQ/src/main/java/org/jooq/impl/ConvertedDataType.java b/jOOQ/src/main/java/org/jooq/impl/ConvertedDataType.java
index c7ca9484b1..6104c51f83 100644
--- a/jOOQ/src/main/java/org/jooq/impl/ConvertedDataType.java
+++ b/jOOQ/src/main/java/org/jooq/impl/ConvertedDataType.java
@@ -228,5 +228,9 @@ final class ConvertedDataType<T, U> extends AbstractDataTypeX<U> {
     public final <X> DataType<X> asConvertedDataType(Converter<? super U, X> converter) {
         return super.asConvertedDataType(new ChainedConverterBinding(getBinding(), converter));
     }
+
+    final DataType<T> delegate() {
+        return delegate instanceof ConvertedDataType ? ((ConvertedDataType) delegate).delegate() : delegate;
+    }
 }
 
diff --git a/jOOQ/src/main/java/org/jooq/impl/JSONEntryImpl.java b/jOOQ/src/main/java/org/jooq/impl/JSONEntryImpl.java
index 2f20dbbf49..73b8150eac 100644
--- a/jOOQ/src/main/java/org/jooq/impl/JSONEntryImpl.java
+++ b/jOOQ/src/main/java/org/jooq/impl/JSONEntryImpl.java
@@ -63,6 +63,7 @@ import static org.jooq.impl.Names.N_JSON_QUERY;
 import static org.jooq.impl.SQLDataType.VARCHAR;
 import static org.jooq.impl.Tools.combine;
 import static org.jooq.impl.Tools.emulateMultiset;
+import static org.jooq.impl.Tools.isScalarSubquery;
 import static org.jooq.impl.Tools.BooleanDataKey.DATA_MULTISET_CONTENT;
 
 import java.util.Set;
@@ -241,6 +242,9 @@ final class JSONEntryImpl<T> extends AbstractQueryPart implements JSONEntry<T>,
     }
 
     static final boolean isJSON(Scope scope, DataType<?> t) {
+        if (t instanceof ConvertedDataType)
+            t = ((ConvertedDataType<?, ?>) t).delegate();
+
         return t.isJSON()
             || t.isRecord() && (TRUE.equals(scope.data(DATA_MULTISET_CONTENT)) && emulateMultisetWithJSON(scope))
             || t.isMultiset() && emulateMultisetWithJSON(scope);
diff --git a/jOOQ/src/main/java/org/jooq/impl/Tools.java b/jOOQ/src/main/java/org/jooq/impl/Tools.java
index 73f47c6c88..8a23f5ac12 100644
--- a/jOOQ/src/main/java/org/jooq/impl/Tools.java
+++ b/jOOQ/src/main/java/org/jooq/impl/Tools.java
@@ -5409,6 +5409,11 @@ final class Tools {
         return result != null ? result : table;
     }
 
+    static final boolean isScalarSubquery(Field<?> field) {
+        // TODO: Replace other instanceof checks by this one
+        return uncoerce(field) instanceof ScalarSubquery;
+    }
+
     static final Field<?> uncoerce(Field<?> field) {
         return field instanceof Coerce ? ((Coerce<?>) field).field : field;
     }