I/O operation on a closed file detected PTC-W0021
Bug risk
Major
4 years ago
—
4 years old
Trying to perform I/O operation on a closed file
99 document = ""
100 for command in commands:
101 with os.popen(f"{ACTIVATE}{PYTHON3}{command} --help ") as stream:
102 text = stream.read()103 text = re.sub("```", "", text)
104 document = command_template.format(text=text, command=command)
105 with open("docs/commands.md", "w") as stream:
Description
The I/O operation is being performed on a resource that is closed.
This will lead to a runtime error.
It is recommended to perform I/O operation on files inside with blocks, as the file is automatically closed when the scope of with ends.
Bad practice
This is a very visible case of an I/O operation on a closed resource.
fp = open(resource_path, "w")
# do some operations on fp
fp.close()
# some code
fp.write("This will throw an error!")
Recommended
It is best to use a with statement context maneger here. Using with, you don't need to worry about closing the resource when you're done using it.
with open(resource_path, "w") as fp:
# Do some operations on fp
...
References:
- Python Docs -
withstatements. - Python Docs -
withstatement context managers.