← 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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