fix: let sqlc output nullable array

Close #1851

This remove 2 assumptions from the code:
- type cast are no longer always non null
- postgres can output nullable array

Author: babariviere

internal/codegen/golang/postgresql_type.go

@@ -36,7 +36,7 @@ func parseIdentifierString(name string) (*plugin.Identifier, error) {
 
 func postgresType(req *plugin.GenerateRequest, options *opts.Options, col *plugin.Column) string {
 	columnType := sdk.DataType(col.Type)
-	notNull := col.NotNull || col.IsArray
+	notNull := col.NotNull
 	driver := parseDriver(options.SqlPackage)
 	emitPointersForNull := driver.IsPGX() && options.EmitPointersForNullTypes
 

internal/endtoend/testdata/unnest_null/postgresql/pgx/v4/go/db.go

@@ -0,0 +1,9 @@
+-- name: CreateMemories :many
+INSERT INTO memories (vampire_id)
+SELECT
+    unnest(sqlc.narg(vamprie_id)::uuid[]) AS vampire_id
+RETURNING
+    *;
+
+-- name: GetVampireIDs :many
+SELECT vampires.id::uuid FROM unnest(sqlc.narg(vampire_id)::uuid[]) AS vampires (id);

internal/endtoend/testdata/unnest_null/postgresql/pgx/v4/go/models.go

@@ -0,0 +1,10 @@
+CREATE TABLE vampires (
+    id uuid PRIMARY KEY DEFAULT gen_random_uuid ()
+);
+
+CREATE TABLE memories (
+    id uuid PRIMARY KEY DEFAULT gen_random_uuid (),
+    is_vampire uuid REFERENCES vampires (id),
+    created_at timestamp NOT NULL DEFAULT NOW(),
+    updated_at timestamp
+);

internal/endtoend/testdata/unnest_null/postgresql/pgx/v4/go/querier.go

@@ -0,0 +1,14 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "postgresql",
+      "sql_package": "pgx/v4",
+      "name": "querytest",
+      "schema": "schema.sql",
+      "queries": "query.sql",
+      "emit_interface": true
+    }
+  ]
+}