nodejs/node · error

suffix already set\n

Error message

suffix already set\n

What it means

`-S SUFFIX` overrides the default `.br` suffix used when generating output file names. The parser latches it via `suffix_set`; a second `-S` is rejected to keep the output name unambiguous.

Source

Thrown at deps/brotli/c/tools/brotli.c:500

          if (comment_set) {
            fprintf(stderr, "comment already set\n");
            return COMMAND_INVALID;
          }
          params->comment_len = MAX_COMMENT_LEN;
          if (!ParseBase64(argv[i], params->comment, &params->comment_len)) {
            fprintf(stderr, "invalid base64-encoded comment\n");
            return COMMAND_INVALID;
          }
          comment_set = BROTLI_TRUE;
        } else if (c == 'D') {
          if (params->dictionary_path) {
            fprintf(stderr, "dictionary path already set\n");
            return COMMAND_INVALID;
          }
          params->dictionary_path = argv[i];
        } else if (c == 'S') {
          if (suffix_set) {
            fprintf(stderr, "suffix already set\n");
            return COMMAND_INVALID;
          }
          suffix_set = BROTLI_TRUE;
          params->suffix = argv[i];
        }
      }
    } else {  /* Double-dash. */
      arg = &arg[2];
      if (strcmp("best", arg) == 0) {
        if (quality_set) {
          fprintf(stderr, "quality already set\n");
          return COMMAND_INVALID;
        }
        quality_set = BROTLI_TRUE;
        params->quality = 11;
      } else if (strcmp("concatenated", arg) == 0) {
        if (concatenated_set) {
          fprintf(stderr, "argument -K / --concatenated already set\n");

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Pass `-S` exactly once with the desired suffix.
2. Drop any wrapper-injected `-S` when the user supplies one.

Example fix

# before
brotli -S .br -S .brotli in
# after
brotli -S .brotli in

# bash: at most one suffix setter
s=$(printf '%s\n' "$@" | grep -cE '^(-S|--suffix=.*)$')
if [ "$s" -gt 1 ]; then echo "multiple suffix flags" >&2; exit 2; fi
brotli "$@"

# bash
if ! brotli "$@"; then rc=$?; echo "brotli exit $rc; dedupe suffix flags" >&2; exit "$rc"; fi

When it happens

Trigger: `brotli -S .br -S .brotli in`, or `-S` combined with `--suffix=...`.

Common situations: Cross-platform scripts that set a default suffix colliding with an explicit one; migrating suffix conventions.

Related errors

• argument -K / --concatenated already set\n
• quality already set\n
• write to standard output already set (-o)\n
• lgwin parameter already set\n
• comment already set\n

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/ac5251403d8a1b5c. Report an issue: GitHub.