nodejs/node · error

dictionary [%s] is larger than maximum allowed: %d\n

Error message

dictionary [%s] is larger than maximum allowed: %d\n

What it means

The dictionary file size exceeds `kMaxDictionarySize`, which is `BROTLI_MAX_DISTANCE - BROTLI_MAX_BACKWARD_LIMIT(24)` (approximately 16 MiB minus 16 MiB = implementation-dependent; effectively the raw dictionary must fit within the encoder's maximum backward distance window). The message prints the offending path and the maximum allowed size in bytes.

Source

Thrown at deps/brotli/c/tools/brotli.c:909

  if (context->dictionary_path == NULL) return BROTLI_TRUE;
  f = fopen(context->dictionary_path, "rb");
  if (f == NULL) {
    fprintf(stderr, "failed to open dictionary file [%s]: %s\n",
            PrintablePath(context->dictionary_path), strerror(errno));
    return BROTLI_FALSE;
  }

  file_size_64 = FileSize(context->dictionary_path);
  if (file_size_64 == -1) {
    fprintf(stderr, "could not get size of dictionary file [%s]",
            PrintablePath(context->dictionary_path));
    fclose(f);
    return BROTLI_FALSE;
  }

  if (file_size_64 > kMaxDictionarySize) {
    fprintf(stderr, "dictionary [%s] is larger than maximum allowed: %d\n",
            PrintablePath(context->dictionary_path), kMaxDictionarySize);
    fclose(f);
    return BROTLI_FALSE;
  }
  context->dictionary_size = (size_t)file_size_64;

  buffer = (uint8_t*)malloc(context->dictionary_size);
  if (!buffer) {
    fprintf(stderr, "could not read dictionary: out of memory\n");
    fclose(f);
    return BROTLI_FALSE;
  }
  bytes_read = fread(buffer, sizeof(uint8_t), context->dictionary_size, f);
  if (bytes_read != context->dictionary_size) {
    free(buffer);
    fprintf(stderr, "failed to read dictionary [%s]: %s\n",
            PrintablePath(context->dictionary_path), strerror(errno));
    fclose(f);

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Trim or retrain the dictionary to be at most `kMaxDictionarySize` bytes.
2. Verify you are pointing at the correct dictionary file, not a large data file.
3. Check the value of `BROTLI_MAX_DISTANCE` and `BROTLI_MAX_BACKWARD_LIMIT(24)` in the build's headers to know the exact limit.

#include <sys/stat.h>
#include <stdint.h>
#include <stdbool.h>

// BROTLI_MAX_DISTANCE is typically 0x3FFFFFFF (16 MiB window).
// The effective raw dict limit is implementation-dependent.
// Use a conservative 16 MiB ceiling for pre-validation:
#define SAFE_MAX_DICT (16 * 1024 * 1024)

bool dictionary_within_limit(const char *path) {
    struct stat st;
    if (stat(path, &st) != 0) return false;
    return (int64_t)st.st_size <= SAFE_MAX_DICT;
}

When it happens

Trigger: Supplying a dictionary file larger than the brotli encoder's maximum raw dictionary size. The limit is a compile-time constant derived from brotli's distance-coding parameters, not a user-configurable value.

Common situations: Using a large pre-trained dictionary for domain-specific compression (e.g. a web text corpus) that exceeds the limit; accidentally pointing `--dictionary` at a large data file instead of the intended small dictionary.

Related errors

• quality already set
• dictionary path already set\n
• failed to open dictionary file [%s]: %s\n
• could not get size of dictionary file [%s]
• could not read dictionary: out of memory\n

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/8ed31fc82c7ac83a. Report an issue: GitHub.