Fix key base equality and spaceship operators

CHANGELOG.md

@@ -12,6 +12,7 @@
 **Fixes and enhancements:**
 
 - Fix signature has expired error if payload is a string [#555](https://github.com/jwt/ruby-jwt/pull/555) - [@GobinathAL](https://github.com/GobinathAL).
+- Fix key base equality and spaceship operators [#569](https://github.com/jwt/ruby-jwt/pull/569) - [@magneland](https://github.com/magneland).
 - Your contribution here
 
 ## [v2.7.1](https://github.com/jwt/ruby-jwt/tree/v2.8.0) (2023-06-09)

lib/jwt/jwk/key_base.rb

@@ -38,12 +38,14 @@ def []=(key, value)
       end
 
       def ==(other)
-        self[:kid] == other[:kid]
+        other.is_a?(::JWT::JWK::KeyBase) && self[:kid] == other[:kid]
       end
 
       alias eql? ==
 
       def <=>(other)
+        return nil unless other.is_a?(::JWT::JWK::KeyBase)
+
         self[:kid] <=> other[:kid]
       end
 

spec/jwk/hmac_spec.rb

@@ -82,4 +82,68 @@
       end
     end
   end
+
+  describe '#==' do
+    it 'is equal to itself' do
+      other = jwk
+      expect(jwk == other).to eq true
+    end
+
+    it 'is equal to a clone of itself' do
+      other = jwk.clone
+      expect(jwk == other).to eq true
+    end
+
+    it 'is not equal to nil' do
+      other = nil
+      expect(jwk == other).to eq false
+    end
+
+    it 'is not equal to boolean true' do
+      other = true
+      expect(jwk == other).to eq false
+    end
+
+    it 'is not equal to a non-key' do
+      other = Object.new
+      expect(jwk == other).to eq false
+    end
+
+    it 'is not equal to a different key' do
+      other = described_class.new('other-key')
+      expect(jwk == other).to eq false
+    end
+  end
+
+  describe '#<=>' do
+    it 'is equal to itself' do
+      other = jwk
+      expect(jwk <=> other).to eq 0
+    end
+
+    it 'is equal to a clone of itself' do
+      other = jwk.clone
+      expect(jwk <=> other).to eq 0
+    end
+
+    it 'is not comparable to nil' do
+      other = nil
+      expect(jwk <=> other).to eq nil
+    end
+
+    it 'is not comparable to boolean true' do
+      other = true
+      expect(jwk <=> other).to eq nil
+    end
+
+    it 'is not comparable to a non-key' do
+      other = Object.new
+      expect(jwk <=> other).to eq nil
+    end
+
+    it 'is not equal to a different key' do
+      other = described_class.new('other-key')
+      expect(jwk <=> other).not_to eq 0
+    end
+  end
 end