internal/dinosql: ignore golang-migrate rollbacks (#320)

Author: treuherz

docs/migrations.md

@@ -5,6 +5,7 @@ sqlc will ignore rollback statements when parsing migration SQL files. The follo
 - [goose](https://github.com/pressly/goose)
 - [sql-migrate](https://github.com/rubenv/sql-migrate)
 - [tern](https://github.com/jackc/tern)
+- [golang-migrate](https://github.com/golang-migrate/migrate)
 
 ## goose
 
@@ -67,4 +68,32 @@ type Comment struct {
 	ID     int32 
 	Text   string 
 }
-```
+```
+
+## golang-migrate
+
+In `20060102.up.sql`:
+
+```sql
+CREATE TABLE post (
+    id    int NOT NULL,
+    title text,
+    body  text,
+    PRIMARY KEY(id)
+);
+```
+
+In `20060102.down.sql`:
+```sql
+DROP TABLE post;
+```
+
+```go
+package db
+
+type Post struct {
+	ID    int
+	Title sql.NullString
+	Body  sql.NullString
+}
+```

internal/dinosql/migrations_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 )
 
 const inputGoose = `
@@ -57,3 +58,23 @@ func TestRemoveRollback(t *testing.T) {
 		t.Errorf("tern migration mismatch:\n%s", diff)
 	}
 }
+
+func TestRemoveGolangMigrateRollback(t *testing.T) {
+	want := []string{
+		// make sure we let through golang-migrate files that aren't rollbacks
+		"testdata/migrations/1.up.sql",
+		// make sure we let through other sql files
+		"testdata/migrations/2.sql",
+		"testdata/migrations/foo.sql",
+	}
+
+	got, err := ReadSQLFiles("./testdata/migrations")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	less := func(a, b string) bool { return a < b }
+	if diff := cmp.Diff(want, got, cmpopts.SortSlices(less)); diff != "" {
+		t.Errorf("golang-migrate filtering mismatch: \n %s", diff)
+	}
+}

internal/dinosql/parser.go

@@ -86,6 +86,10 @@ func ReadSQLFiles(path string) ([]string, error) {
 		if strings.HasPrefix(filepath.Base(filename), ".") {
 			continue
 		}
+		// Remove golang-migrate rollback files.
+		if strings.HasSuffix(filename, ".down.sql") {
+			continue
+		}
 		sql = append(sql, filename)
 	}
 	return sql, nil