Should use a ‘with’ statement¶
ID: py/should-use-with Kind: problem Security severity: Severity: recommendation Precision: very-high Tags: - quality - maintainability - readability Query suites: - python-code-quality.qls - python-security-and-quality.qls Click to see the query in the CodeQL repository
The with statement was introduced by PEP343 to allow standard uses of try-finally statements to be factored out. Using this simplification makes code easier to read.
Recommendation¶
Review the code and determine whether or not the try-finally is used only to ensure that a resource is closed. If the only purpose is to ensure that a resource is closed, then replace the try-finally statement with a with statement.
Example¶
The following code shows examples of different ways of ensuring that a file is always closed, even when an error is generated. In the second example, the try-finally block is replaced by a simpler with statement.
f = open("filename") try: # Method of ensuring file closure f.write(...) finally: f.close() with open("filename") as f: # Simpler method of ensuring file closure f.write(...) References¶
Python Language Reference: The with statement.
Python Standard Library: Context manager .
Python PEP 343: The “with” Statement.