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Python

What is a CalledProcessError?

← Errors

subprocess.CalledProcessError is raised when a subprocess called with check=True exits with a non-zero return code. It carries the return code, command, and optionally stdout/stderr so you can diagnose what went wrong.

Why it happens

  • •The subprocess command exits with a non-zero status code and check=True is set.
  • •An external tool (git, docker, npm) fails due to a configuration or environment issue.
  • •The command is not found or lacks execute permission.
  • •The subprocess is terminated by a signal (negative return code).

Examples

Python

Code that triggers the error

import subprocess
subprocess.run(["git", "push"], check=True)

Error output

subprocess.CalledProcessError: Command '['git', 'push']' returned non-zero exit status 1

How to fix it

Use check=False and inspect result.returncode manually for more control. Always set capture_output=True with text=True so you can read stderr on failure. Log the full command, return code, and stderr output to diagnose the root cause.

Fixed code

import subprocess

result = subprocess.run(
    ["git", "push"],
    capture_output=True,
    text=True,
)
if result.returncode != 0:
    print("Push failed:", result.stderr)

Related errors

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