fix: check for single import

Signed-off-by: jolheiser <john.olheiser@gmail.com>

format/format.go

@@ -8,13 +8,18 @@ import (
 )
 
 var (
-	importRe     = regexp.MustCompile(`(?ms)import \(([^)]+)\)`)
-	otherRe      = regexp.MustCompile(`^(?:var|const|func)\s`)
-	ErrNoImports = errors.New("no imports found")
+	importRe       = regexp.MustCompile(`(?ms)^import \(([^)]+)\)`)
+	singleImportRe = regexp.MustCompile(`(?ms)^import "[^"]+"`)
+	otherRe        = regexp.MustCompile(`^(?:var|const|func)\s`)
+	ErrNoImports   = errors.New("no imports found")
 )
 
 // Source formats a given src's imports
 func Source(src []byte, module string) ([]byte, error) {
+	if singleImportRe.Match(src) {
+		return src, nil
+	}
+
 	importStart := importRe.FindIndex(src)
 	if importStart == nil {
 		return nil, fmt.Errorf("could not find imports: %w", ErrNoImports)

format/format_test.go

@@ -22,6 +22,9 @@ func TestSource(t *testing.T) {
 	formatted, err := Source(before, module)
 	assert.NoErr(err)                          // Should be able to format before block
 	assert.True(bytes.Equal(formatted, after)) // Formatted should match after block
+
+	_, err = Source(singleImport, module)
+	assert.NoErr(err) // Should not get an error for single import
 }
 
 var (
@@ -34,6 +37,11 @@ func main() {
 	s := "import \"fmt\""
 	_ = s
 }`)
+	singleImport = []byte(`package main
+
+import "fmt"
+
+func main() {}`)
 	before = []byte(`package main
 
 import (