Exit Code 4 in CI: What It Means and How to Fix It
Exit code 4 is application-defined, with no universal meaning.
Like exit 3, code 4 is whatever the tool that returned it decides.
What it means
A tool-specific error.
Common causes
- A specific failure class in the producing tool.
- A custom
exit 4.
How to fix it
Consult the tool’s docs; for example flake8 uses exit codes to signal different result classes.
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