FIX: If a query that uses returning-clause support fails, the error was dropped. (#59)

Author: scouten

lib/sqlitex/statement.ex

@@ -348,12 +348,12 @@ defmodule Sqlitex.Statement do
 
     with {:ok, _} = db_exec(db, "CREATE TEMP TABLE #{temp_table} (#{temp_fields})"),
          {:ok, _} = db_exec(db, trigger),
-         _ = :esqlite3.fetchall(statement),
+         result = :esqlite3.fetchall(statement),
          {:ok, rows} = db_exec(db, "SELECT #{column_names} FROM #{temp_table}"),
          {:ok, _} = db_exec(db, "DROP TRIGGER IF EXISTS #{trigger_name}"),
          {:ok, _} = db_exec(db, "DROP TABLE IF EXISTS #{temp_table}")
     do
-      rows
+      if is_list(result), do: rows, else: result
     end
   catch
     e ->

test/statement_test.exs

@@ -59,4 +59,19 @@ defmodule StatementTest do
     rows = Sqlitex.Statement.fetch_all!(stmt, :raw_list)
     assert rows == [[1], [2], [3]]
   end
+
+  test "RETURNING pseudo-syntax doesn't mask error when query fails" do
+    {:ok, db} = Sqlitex.open(":memory:")
+
+    Sqlitex.exec(db, "CREATE TABLE x(id INTEGER PRIMARY KEY AUTOINCREMENT, str)")
+    Sqlitex.exec(db, "CREATE UNIQUE INDEX x_str ON x(str)")
+
+    Sqlitex.exec(db, "INSERT INTO x(str) VALUES ('x'),('y'),('z')")
+
+    stmt = Sqlitex.Statement.prepare!(db, "INSERT INTO x(str) VALUES ('x') "
+                                          <> ";--RETURNING ON INSERT x,id")
+
+    result = Sqlitex.Statement.fetch_all(stmt, :raw_list)
+    assert result == {:error, {:constraint, 'UNIQUE constraint failed: x.str'}}
+  end
 end