What causes "could not get size of dictionary file [%s]" in nodejs/node?

Ensure the dictionary path points to a regular file with a determinate size.

could not get size of dictionary file [%s]

Error message

could not get size of dictionary file [%s]

What it means

`FileSize()` returned -1 for the dictionary file, meaning `fopen` + `stat`/`fseek` to determine size failed even though the file was just opened successfully for reading. Note this message has no trailing newline — a minor formatting inconsistency in the tool.

Source

Thrown at deps/brotli/c/tools/brotli.c:902

static BROTLI_BOOL ReadDictionary(Context* context, Command command) {
  static const int kMaxDictionarySize =
      BROTLI_MAX_DISTANCE - BROTLI_MAX_BACKWARD_LIMIT(24);
  FILE* f;
  int64_t file_size_64;
  uint8_t* buffer;
  size_t bytes_read;

  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;

View on GitHub (pinned to 1b2de5e052)

Solutions

Ensure the dictionary path points to a regular file with a determinate size.
Materialize the dictionary to a plain file first: `cat pipe > /tmp/dict.bin && brotli --dictionary=/tmp/dict.bin input.txt`.

Defensive patterns

Strategy: validation

Validate before calling

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

bool dictionary_has_size(const char *path) {
    struct stat st;
    if (stat(path, &st) != 0) return false;
    if (!S_ISREG(st.st_mode)) return false; // reject pipes, devices, dirs
    return st.st_size > 0;
}

Prevention

Ensure the dictionary path points to a regular file, not a pipe or device.
Pre-copy dictionary content to a plain file before passing to brotli.
Verify the file type with `file <dict_path>` before use.

When it happens

Trigger: The file is a special file (FIFO, device, socket) where `stat` reports a size of 0 or fseek/ftell fails; the file was deleted between the successful open and the `FileSize` call (race condition); a procfs/sysfs pseudo-file.

Common situations: Pointing `--dictionary` at `/dev/stdin`, a named pipe, or a FUSE filesystem that does not implement seek; transient filesystem on a network mount.

Related errors

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/a69e5cfb1f79e50f. Report an issue: GitHub.