Avoid rescuing the Exception
class. Perhaps you meant to rescue StandardError
? Open
rescue Exception => err
_log.warn("#{err.message}, deleting #{log_uri} from FTP")
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Checks for rescue
blocks targeting the Exception class.
Example:
# bad
begin
do_something
rescue Exception
handle_exception
end
Example:
# good
begin
do_something
rescue ArgumentError
handle_exception
end
Remove unnecessary existence check File.exist?
. Open
FileUtils.rm_f(local_file) if File.exist?(local_file)
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Checks for non-atomic file operation. And then replace it with a nearly equivalent and atomic method.
These can cause problems that are difficult to reproduce, especially in cases of frequent file operations in parallel, such as test runs with parallel_rspec.
For examples: creating a directory if there is none, has the following problems
An exception occurs when the directory didn't exist at the time of exist?
,
but someone else created it before mkdir
was executed.
Subsequent processes are executed without the directory that should be there
when the directory existed at the time of exist?
,
but someone else deleted it shortly afterwards.
Safety:
This cop is unsafe, because autocorrection change to atomic processing. The atomic processing of the replacement destination is not guaranteed to be strictly equivalent to that before the replacement.
Example:
# bad - race condition with another process may result in an error in `mkdir`
unless Dir.exist?(path)
FileUtils.mkdir(path)
end
# good - atomic and idempotent creation
FileUtils.mkdir_p(path)
# bad - race condition with another process may result in an error in `remove`
if File.exist?(path)
FileUtils.remove(path)
end
# good - atomic and idempotent removal
FileUtils.rm_f(path)