Merge pull request #7109 from CodeMonk/pkg_version_fix

Fix for when version is nil

Library/Homebrew/pkg_version.rb

@@ -36,7 +36,10 @@ class PkgVersion
   def <=>(other)
     return unless other.is_a?(PkgVersion)
 
-    (version <=> other.version).nonzero? || revision <=> other.revision
+    version_comparison = (version <=> other.version)
+    return if version_comparison.nil?
+
+    version_comparison.nonzero? || revision <=> other.revision
   end
   alias eql? ==
 

Library/Homebrew/test/pkg_version_spec.rb

@@ -54,6 +54,11 @@ describe PkgVersion do
   describe "#<=>" do
     it "returns nil if the comparison fails" do
       expect(described_class.new(Version.create("1.0"), 0) <=> Object.new).to be nil
+      expect(Object.new <=> described_class.new(Version.create("1.0"), 0)).to be nil
+      expect(Object.new <=> described_class.new(Version.create("1.0"), 0)).to be nil
+      expect(described_class.new(Version.create("1.0"), 0) <=> nil).to be nil
+      # This one used to fail due to dereferencing a null `self`
+      expect(described_class.new(nil, 0) <=> described_class.new(Version.create("1.0"), 0)).to be nil
     end
   end