Error: EISDIR: illegal operation on a directory, read

[taoyuan]

The error shows sometimes.

Error: EISDIR: illegal operation on a directory, read

To dig this, we can get the trace to the original call site, through setting the NODE_DEBUG environment variable according to https://nodejs.org/api/fs.html#fs_file_system:

$ cat script.js
function bad() {
  require('fs').readFile('/');
}
bad();

$ env NODE_DEBUG=fs node script.js
fs.js:88
        throw backtrace;
        ^
Error: EISDIR: illegal operation on a directory, read
    <stack trace.>