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use-if

Summary: Use the if keyword

Category: Idiomatic

Notice: Rule made obsolete by OPA 1.0​

Since Regal v0.30.0, this rule is only enabled for projects explicitly configured to target versions of OPA before 1.0. Consult the documentation on Regal's configuration for information on how to best work with older versions of OPA and Rego.

Since OPA v1.0, this rule is no longer needed simply because the Rego v1 syntax is made mandatory, and the use of if is now enforced before all rule bodies.

Avoid

package policy

import future.keywords.in

is_admin {
    "admin" in input.user.roles
}

Prefer

package policy

import future.keywords.if
import future.keywords.in

is_admin if {
    "admin" in input.user.roles
}

# alternatively

is_admin if "admin" in input.user.roles

Rationale​

The if keyword helps communicate what Rego rules really are — conditional assignments. Using if in other words makes the rule read the same way in English as it will be interpreted by OPA, i.e:

rule := "some value" if some_condition

OPA version 1.0, which is planned for 2024, will make the if keyword mandatory. This rule helps you get ahead of the curve and start using it today.

Note: don't forget to import future.keywords.if! Or from OPA v0.59.0 and onwards, import rego.v1.

Tip: When either of the imports mentioned above are found in a Rego file, the if keyword will be inserted automatically at any applicable location by the opa fmt tool.

Configuration Options​

This linter rule provides the following configuration options:

rules:
  idiomatic:
    use-if:
      # one of "error", "warning", "ignore"
      level: error

Community​

If you think you've found a problem with this rule or its documentation, would like to suggest improvements, new rules, or just talk about Regal in general, please join us in the #regal channel in the Styra Community Slack!