Differential D7910 Diff 24640 arcanist/linter/PythonMutableDefaultLinter.php

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				<?php

				/**
				* Make sure we don't use mutable default arguments
				* https://docs.python-guide.org/writing/gotchas/#mutable-default-arguments
				*/
				final class PythonMutableDefaultLinter extends ArcanistLinter {

				const MUTABLE_DEFAULT_FOUND = 1;

				public function getInfoName() {
				return 'lint-python-mutable-default';
				}

				public function getInfoDescription() {
				return pht('Make sure we don\'t use mutable default arguments '.
				'in python.');
				}

				public function getLinterName() {
				return 'PYTHON_MUTABLE_DEFAULT';
				}

				public function getLinterConfigurationName() {
				return 'lint-python-mutable-default';
				}

				public function getLintSeverityMap() {
				return array(
				self::MUTABLE_DEFAULT_FOUND => ArcanistLintSeverity::SEVERITY_WARNING,
				);
				}

				public function getLintNameMap() {
				return array(
				self::MUTABLE_DEFAULT_FOUND => pht('Mutable default arguments should '.
				'generally not be used in python.'),
				);
				}

				public function lintPath($path) {
				$path = Filesystem::resolvePath($path, $this->getProjectRoot());
				$fileContent = Filesystem::readFile($path);

				// Match all function definitions containing list, dict or set literals
				// used as default arguments.
				$pattern = "/[ ]def \w+$[\w, \n=\($\"']+=\s(\[\|\{)[^:]+:/";
				if (preg_match_all($pattern, $fileContent, $matches,
				PREG_OFFSET_CAPTURE)) {
				foreach ($matches[1] as $match) {
				list($fullLine, $offset) = $match;

				$this->raiseLintAtOffset(
				$offset,
				self::MUTABLE_DEFAULT_FOUND,
				pht('Found mutable default argument in function.'),
				$fullLine,
				null);
				}
				}
				}
				}