PVS-Studio warning V595 for TortoiseGIT

void free_decoration(struct decoration *n)
{
  unsigned int i;
  struct object_decoration *hash = n->hash;
  if (n == NULL || n->hash == NULL)
    return;
  ....
}

This suspicious code was found in TortoiseGIT project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'n' pointer was utilized before it was verified against nullptr. Check lines: 41, 43. decorate.c 41

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