What causes "reason: truncated input\n" in nodejs/node?

Use the confirmed truncation diagnosis to trace where the file was cut short (network, disk, proxy).

reason: truncated input\n

Error message

reason: truncated input\n

What it means

Verbose diagnostic at brotli.c:1244, printed only when verbosity > 0, right after the 'corrupt input' message at line 1241. It tells the developer that the abort was specifically because the brotli bitstream ended prematurely (truncated input) as opposed to a comment mismatch or decoder format error. The actual failure return is at line 1246.

Source

Thrown at deps/brotli/c/tools/brotli.c:1244

  }

  InitializeBuffers(context);
  for (;;) {
    /* Early check */
    if (context->comment_state == COMMENT_BAD) {
      fprintf(stderr, "corrupt input [%s]\n",
              PrintablePath(context->current_input_path));
      if (context->verbosity > 0) {
        fprintf(stderr, "reason: comment mismatch\n");
      }
      return BROTLI_FALSE;
    }
    if (result == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT) {
      if (!HasMoreInput(context)) {
        fprintf(stderr, "corrupt input [%s]\n",
                PrintablePath(context->current_input_path));
        if (context->verbosity > 0) {
          fprintf(stderr, "reason: truncated input\n");
        }
        return BROTLI_FALSE;
      }
      if (!ProvideInput(context)) return BROTLI_FALSE;
    } else if (result == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT) {
      if (!ProvideOutput(context)) return BROTLI_FALSE;
    } else if (result == BROTLI_DECODER_RESULT_SUCCESS) {
      if (!FlushOutput(context)) return BROTLI_FALSE;
      BROTLI_BOOL has_more_input = (context->available_in != 0);
      int extra_char = EOF;
      if (!has_more_input) {
        extra_char = fgetc(context->fin);
        if (extra_char != EOF) {
          has_more_input = BROTLI_TRUE;
          context->input[0] = (uint8_t)extra_char;
          context->next_in = context->input;
          context->available_in = 1;
        }

View on GitHub (pinned to 1b2de5e052)

Solutions

Use the confirmed truncation diagnosis to trace where the file was cut short (network, disk, proxy).
Re-acquire the complete file from the original source.
If you generated the file yourself, ensure the compression process completed without error and check available disk space.
For automated pipelines, add a post-transfer size or checksum validation step before attempting decompression.

Defensive patterns

Strategy: validation

Validate before calling

// This verbose message confirms truncation; the actionable validation
// is the same as error 722: check file size/checksum before decompression.

Prevention

Run without -v in production to suppress diagnostic noise.
Add post-transfer integrity checks (size, hash) in automated pipelines.
Monitor compression process exit codes to catch incomplete output files.

When it happens

Trigger: Same condition as error 722: the decoder requested more input but the file is fully read. This message is emitted only when the user ran the brotli tool with -v (verbosity > 0), making it a diagnostic confirmation of the truncation root cause.

Common situations: A developer runs 'brotli -d -v truncated.br' to diagnose why decompression fails. The file was truncated due to an interrupted download, disk-full condition during compression, or an upstream proxy cutting the transfer.

Related errors

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/937cc92d578cba6c. Report an issue: GitHub.