nodejs/node · error

command already set when parsing --test\n

Error message

command already set when parsing --test\n

What it means

The brotli CLI allows exactly one operation per invocation: compress (default), `--decompress`/`-d`, or `--test`/`-t`. The parser tracks this with `command_set`; encountering `--test` after any prior command returns COMMAND_INVALID rather than silently shadowing the earlier one.

Source

Thrown at deps/brotli/c/tools/brotli.c:577

        params->junk_source = BROTLI_TRUE;
      } else if (strcmp("squash", arg) == 0) {
        if (squash_set) {
          fprintf(stderr, "argument --squash / -s already set\n");
          return COMMAND_INVALID;
        }
        squash_set = BROTLI_TRUE;
        params->reject_uncompressible = BROTLI_TRUE;
        continue;
      } else if (strcmp("stdout", arg) == 0) {
        if (output_set) {
          fprintf(stderr, "write to standard output already set\n");
          return COMMAND_INVALID;
        }
        output_set = BROTLI_TRUE;
        params->write_to_stdout = BROTLI_TRUE;
      } else if (strcmp("test", arg) == 0) {
        if (command_set) {
          fprintf(stderr, "command already set when parsing --test\n");
          return COMMAND_INVALID;
        }
        command_set = BROTLI_TRUE;
        command = COMMAND_TEST_INTEGRITY;
      } else if (strcmp("verbose", arg) == 0) {
        if (params->verbosity > 0) {
          fprintf(stderr, "argument --verbose / -v already set\n");
          return COMMAND_INVALID;
        }
        params->verbosity = 1;
      } else if (strcmp("version", arg) == 0) {
        /* Don't parse further. */
        return COMMAND_VERSION;
      } else {
        /* key=value */
        const char* value = strchr(arg, '=');
        size_t key_len;
        if (!value || value[1] == 0) {

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Split into two invocations: one to decompress, a separate `brotli --test` for integrity checking.
2. If only verifying integrity, remove the prior command flag (`--decompress`/`-z`).
3. If only decompressing, remove `--test`.

Example fix

# before
brotli -d --test archive.br
# after (two steps)
brotli -d archive.br -o archive
brotli --test archive.br

# Allow at most one command-mode flag.
cmds=0
for a in "$@"; do
  case "$a" in
    --decompress|-d|--test|-t|-z) cmds=$((cmds+1));;
  esac
done
[ "$cmds" -gt 1 ] && { echo 'multiple command modes' >&2; exit 2; }

When it happens

Trigger: Invoking `brotli --decompress --test file.br`, `brotli -z --test file`, or `brotli --test --test file.br`; aliasing brotli with `-d` and then adding `--test`.

Common situations: CI jobs that combine a verification step (`--test`) with a decompression step in one command; users coming from `gzip -t` expecting to chain modes; copy-paste concatenation of two how-to snippets.

Related errors

• command already set when parsing --decompress\n
• write to standard output already set (--output)\n
• too many options passed
• quality already set
• write to standard output already set

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/7353309ebb3481da. Report an issue: GitHub.