parser: preserve empty lines in SQL statements (#372)

sql_parser.go

@@ -29,6 +29,7 @@ type stateMachine parserState
 func (s *stateMachine) Get() parserState {
 	return parserState(*s)
 }
+
 func (s *stateMachine) Set(new parserState) {
 	verboseInfo("StateMachine: %v => %v", *s, new)
 	*s = stateMachine(new)
@@ -65,6 +66,7 @@ func parseSQLMigration(r io.Reader, direction bool) (stmts []string, useTx bool,
 	stateMachine := stateMachine(start)
 	useTx = true
 
+	firstLineFound := false
 	for scanner.Scan() {
 		line := scanner.Text()
 		if verbose {
@@ -76,6 +78,7 @@ func parseSQLMigration(r io.Reader, direction bool) (stmts []string, useTx bool,
 
 			switch cmd {
 			case "+goose Up":
+				firstLineFound = true
 				switch stateMachine.Get() {
 				case start:
 					stateMachine.Set(gooseUp)
@@ -85,6 +88,7 @@ func parseSQLMigration(r io.Reader, direction bool) (stmts []string, useTx bool,
 				continue
 
 			case "+goose Down":
+				firstLineFound = true
 				switch stateMachine.Get() {
 				case gooseUp, gooseStatementEndUp:
 					stateMachine.Set(gooseDown)
@@ -94,6 +98,7 @@ func parseSQLMigration(r io.Reader, direction bool) (stmts []string, useTx bool,
 				continue
 
 			case "+goose StatementBegin":
+				firstLineFound = true
 				switch stateMachine.Get() {
 				case gooseUp, gooseStatementEndUp:
 					stateMachine.Set(gooseStatementBeginUp)
@@ -105,6 +110,7 @@ func parseSQLMigration(r io.Reader, direction bool) (stmts []string, useTx bool,
 				continue
 
 			case "+goose StatementEnd":
+				firstLineFound = true
 				switch stateMachine.Get() {
 				case gooseStatementBeginUp:
 					stateMachine.Set(gooseStatementEndUp)
@@ -125,8 +131,8 @@ func parseSQLMigration(r io.Reader, direction bool) (stmts []string, useTx bool,
 			}
 		}
 
-		// Ignore empty lines.
-		if matchEmptyLines.MatchString(line) {
+		// Ignore empty lines until first line is found.
+		if !firstLineFound && matchEmptyLines.MatchString(line) {
 			verboseInfo("StateMachine: ignore empty line")
 			continue
 		}

sql_parser_test.go

@@ -74,6 +74,25 @@ func TestSplitStatements(t *testing.T) {
 	}
 }
 
+func TestKeepEmptyLines(t *testing.T) {
+	stmts, _, err := parseSQLMigration(strings.NewReader(emptyLineSQL), true)
+	if err != nil {
+		t.Errorf("Failed to parse SQL migration. %v", err)
+	}
+	expected := `INSERT INTO post (id, title, body)
+VALUES ('id_01', 'my_title', '
+this is an insert statement including empty lines.
+
+empty (blank) lines can be meaningful.
+
+leave the lines to keep the text syntax.
+');
+`
+	if stmts[0] != expected {
+		t.Errorf("incorrect stmts. got %v, want %v", stmts, expected)
+	}
+}
+
 func TestUseTransactions(t *testing.T) {
 	t.Parallel()
 
@@ -138,6 +157,20 @@ SELECT 4;           -- 4th stmt
 DROP TABLE post;    -- 1st stmt
 `
 
+var emptyLineSQL = `-- +goose Up
+INSERT INTO post (id, title, body)
+VALUES ('id_01', 'my_title', '
+this is an insert statement including empty lines.
+
+empty (blank) lines can be meaningful.
+
+leave the lines to keep the text syntax.
+');
+
+-- +goose Down
+TRUNCATE TABLE post; 
+`
+
 var functxt = `-- +goose Up
 CREATE TABLE IF NOT EXISTS histories (
 	id                BIGSERIAL  PRIMARY KEY,