writeUniqueFile writes content to _test.go, or _N_test.go when that already exists, and never overwrites: --record paths are user-controlled, so silently clobbering an unrelated *_test.go would be destructive.
(base string, content []byte)
| 33 | // user-controlled, so silently clobbering an unrelated *_test.go would be |
| 34 | // destructive. |
| 35 | func writeUniqueFile(base string, content []byte) (string, error) { |
| 36 | for n := 1; n <= 100; n++ { |
| 37 | path := base + "_test.go" |
| 38 | if n > 1 { |
| 39 | path = fmt.Sprintf("%s_%d_test.go", base, n) |
| 40 | } |
| 41 | f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600) |
| 42 | if os.IsExist(err) { |
| 43 | continue |
| 44 | } |
| 45 | if err != nil { |
| 46 | return "", err |
| 47 | } |
| 48 | // Remove on failure: a leftover empty file would permanently occupy |
| 49 | // this O_EXCL slot on every subsequent --record run. |
| 50 | if _, err := f.Write(content); err != nil { |
| 51 | f.Close() |
| 52 | os.Remove(path) |
| 53 | return "", err |
| 54 | } |
| 55 | if err := f.Close(); err != nil { |
| 56 | os.Remove(path) |
| 57 | return "", err |
| 58 | } |
| 59 | return path, nil |
| 60 | } |
| 61 | return "", fmt.Errorf("no available file name for %s_test.go", base) |
| 62 | } |