Style-FetchEnvVar.md

Pattern: Use of ENV[] instead of ENV.fetch

Issue: -

Description

This rule suggests ENV.fetch for the replacement of ENV[]. ENV[] silently fails and returns nil when the environment variable is unset, which may cause unexpected behaviors when the developer forgets to set it. On the other hand, ENV.fetch raises KeyError or returns the explicitly specified default value.

Examples

# bad
ENV['X']
ENV['X'] || z
x = ENV['X']

# good
ENV.fetch('X')
ENV.fetch('X', nil) || z
x = ENV.fetch('X')

# also good
!ENV['X']
ENV['X'].some_method # (e.g. `.nil?`)

Configurable attributes

Name	Default value	Configurable values
AllowedVars	[]	Array

Further Reading

• RuboCop - Style/FetchEnvVar