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import-shadows-builtin

Summary: Import shadows built-in namespace

Category: Imports

Avoid

package policy

# Shadows the built-in `print` function
import data.print

# Shadows the built-in `http.send` function
import input.attributes.http

Prefer To either use different names for your packages, or use import aliases to avoid shadowing built-ins.

package policy

# Using a different package name
import data.printer

# Using an alias
import input.attributes.http as http_attributes

Rationale​

OPA will not complain about an import shadowing the name or the "namespace" (i.e. array in array.slice) until a conflicting built-in function is used in the same policy. Preventing this to happen in the first place is a better option!

Why does this happen? The OPA compiler rewrites any import used in a policy, so that the shorthand form expands to its longer form. Provided a simple policy like this:

package policy

import rego.v1

import data.http

allow if {
    http.send({"method": "GET", "url": "https://example.com"})
}

The compiler will go ahead and rewrite the http.send call using the import:

allow if {
    data.http.send({"method": "GET", "url": "https://example.com"})
}

This is obviously not what the policy author intended.

Configuration Options​

This linter rule provides the following configuration options:

rules:
  imports:
    import-shadows-builtin:
      # 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!