[BUG] new Range(comparator).test() throws TypeError for a prerelease version #908

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

When a Range is constructed from a Comparator object, range.options is never set. Testing a prerelease version against that range then throws instead of returning a boolean. satisfies(version, comparator) goes through the same path and throws too.

Cause: in classes/range.js (v7.8.5), the range instanceof Comparator branch (L21-27) returns before this.options = options (L29). test() passes this.options (L210) to testSet, which reads options.includePrerelease (L550).

(Found by an AI system I use; a search of the tracker found nothing covering it.)

Expected Behavior

The same result as for the equivalent string range: true for 1.0.0-beta against >=1.0.0-alpha. Or, if a Comparator argument is not supported, a clear error at construction. The README does not document it either way.

Steps To Reproduce

1. npm i semver@7.8.5
2. Run:

   const semver = require('semver')
   const r = new semver.Range(new semver.Comparator('>=1.0.0-alpha'))
   console.log(new semver.Range('>=1.0.0-alpha').test('1.0.0-beta'))  // true
   console.log(r.options)                                            // undefined
   console.log(r.test('1.0.0-beta'))

3. See error:

   TypeError: Cannot read properties of undefined (reading 'includePrerelease')
       at testSet (.../semver/classes/range.js:550:45)
       at Range.test (.../semver/classes/range.js:210:11)
   

Same on 7.7.3, where the lines are range.js:530 and :207.

Environment

• npm: n/a (library called directly from node)
• Node: v24.12.0
• OS: Windows 11 Pro
• platform: x64 desktop
• semver: 7.8.5 (latest) and 7.7.3