Supports the PostgreSQL domain

src/pgduckdb_types.cpp

@@ -808,7 +808,9 @@ numeric_typmod_scale(int32 typmod) {
 
 duckdb::LogicalType
 ConvertPostgresToBaseDuckColumnType(Form_pg_attribute &attribute) {
-	switch (attribute->atttypid) {
+	/* If it's a domain, look at the base type instead */
+	auto type_id = getBaseType(attribute->atttypid);
+	switch (type_id) {
 	case BOOLOID:
 	case BOOLARRAYOID:
 		return duckdb::LogicalTypeId::BOOLEAN;
@@ -867,7 +869,7 @@ ConvertPostgresToBaseDuckColumnType(Form_pg_attribute &attribute) {
 	case REGCLASSARRAYOID:
 		return duckdb::LogicalTypeId::UINTEGER;
 	default:
-		return duckdb::LogicalType::USER("UnsupportedPostgresType (Oid=" + std::to_string(attribute->atttypid) + ")");
+		return duckdb::LogicalType::USER("UnsupportedPostgresType (Oid=" + std::to_string(type_id) + ")");
 	}
 }
 

test/regression/expected/domain.out

@@ -0,0 +1,31 @@
+create domain domainvarchar varchar(5);
+create domain domainint4 int4;
+create domain domaintext text;
+create table basictest
+           ( testint4 domainint4
+           , testtext domaintext
+           , testvarchar domainvarchar
+           );
+INSERT INTO basictest values ('88', 'haha', 'short');      -- Good
+INSERT INTO basictest values ('88', 'haha', 'short text'); -- Bad varchar
+ERROR:  value too long for type character varying(5)
+INSERT INTO basictest values ('888', 'haha', 'short');
+select * from basictest;
+ testint4 | testtext | testvarchar 
+----------+----------+-------------
+       88 | haha     | short
+      888 | haha     | short
+(2 rows)
+
+select testtext || testvarchar as concat, testint4 + 12 as sum
+from basictest;
+  concat   | sum 
+-----------+-----
+ hahashort | 100
+ hahashort | 900
+(2 rows)
+
+drop table basictest;
+drop domain domainvarchar restrict;
+drop domain domainint4 restrict;
+drop domain domaintext;

test/regression/schedule

@@ -26,3 +26,4 @@ test: transaction_errors
 test: secrets
 test: prepare
 test: function
+test: domain

test/regression/sql/domain.sql

@@ -0,0 +1,23 @@
+create domain domainvarchar varchar(5);
+create domain domainint4 int4;
+create domain domaintext text;
+
+create table basictest
+           ( testint4 domainint4
+           , testtext domaintext
+           , testvarchar domainvarchar
+           );
+
+INSERT INTO basictest values ('88', 'haha', 'short');      -- Good
+INSERT INTO basictest values ('88', 'haha', 'short text'); -- Bad varchar
+INSERT INTO basictest values ('888', 'haha', 'short');
+
+select * from basictest;
+
+select testtext || testvarchar as concat, testint4 + 12 as sum
+from basictest;
+
+drop table basictest;
+drop domain domainvarchar restrict;
+drop domain domainint4 restrict;
+drop domain domaintext;