SCANOSS Replace Rule

The replace rule allows you to substitute matched components with alternative definitions in your scan results. This is particularly useful for standardizing component versions or updating license information.

This rule follows the core matching system described in Rule Matching, using the same path and PURL matching behavior.

Properties

Property	Type	Description
path	string	File path pattern for matching (inherited from base rules)
purl	string	Package URL for component matching (inherited from base rules)
replace_with	string	Package URL to use as replacement
license	string	License identifier to apply to the replaced component

Component Creation Behavior

When replacing components, the system handles two special cases:

1. New Component Creation

If the replace_with PURL doesn’t exist in the current scan results:

• A minimal component will be created using the replacement PURL
• The new component includes:
  • Package URL name and version from replace_with
  • License if specified in the rule
  • Other context-specific properties (TBD)

2. Existing Component Reference

If the replace_with PURL exists in the current scan results:

• The replacement will use information from the existing component
• Component properties will be copied from the matching component
• Additional properties may be updated based on the rule (TBD)

Example

Here’s an example that demonstrates replacing component versions and licenses:

{
  "bom": {
    "replace": [
      {
        "path": "lib/jquery/",
        "purl": "pkg:github/jquery/jquery@3.2.1",
        "replace_with": "pkg:github/jquery/jquery@3.5.0",
        "license": "MIT"
      }
    ]
  }
}

This configuration:

1. Matches components that:

   • Have a path starting with “lib/jquery/”
   • Use PURL “pkg:github/jquery/jquery@3.2.1”

2. Replaces matches with:

   • Updated PURL “pkg:github/jquery/jquery@3.5.0”
   • MIT license

Note: When the replacement PURL doesn’t exist in scan results, a new minimal component is created. This ensures continuity while maintaining accurate component tracking.

Advanced Usage

You can use replace rules to:

1. Standardize Component Versions

   • Update all instances of a component to a specific version
   • Ensure consistency across your project

2. Update License Information

   • Correct or update license information for specific components
   • Apply standard licenses to matched components

3. Component Migration

   • Move from one package ecosystem to another