Consider all dependency versions in Job.vulnerable?

common/lib/dependabot/dependency.rb

@@ -106,6 +106,15 @@ def display_name
       display_name_builder.call(name)
     end
 
+    # Returns all detected versions of the dependency. Only ecosystems that
+    # support this feature will return more than the current version.
+    def all_versions
+      all_versions = metadata[:all_versions]
+      return [version].compact unless all_versions
+
+      all_versions.filter_map(&:version)
+    end
+
     def ==(other)
       other.instance_of?(self.class) && to_h == other.to_h
     end

common/spec/dependabot/dependency_spec.rb

@@ -303,5 +303,71 @@
       )
       expect(dependency.to_h.keys).not_to include("metadata")
     end
+
+    it "isn't utilized by the equality operator" do
+      dependency1 = described_class.new(
+        name: "dep",
+        requirements: [],
+        package_manager: "dummy",
+        metadata: { foo: 42 }
+      )
+      dependency2 = described_class.new(
+        name: "dep",
+        requirements: [],
+        package_manager: "dummy",
+        metadata: { foo: 43 }
+      )
+      expect(dependency1).to eq(dependency2)
+    end
+  end
+
+  describe "#all_versions" do
+    it "returns an empty array by default" do
+      dependency = described_class.new(
+        name: "dep",
+        requirements: [],
+        package_manager: "dummy"
+      )
+
+      expect(dependency.all_versions).to eq([])
+    end
+
+    it "returns the dependency version if all_version metadata isn't present" do
+      dependency = described_class.new(
+        name: "dep",
+        requirements: [],
+        package_manager: "dummy",
+        version: "1.0.0"
+      )
+
+      expect(dependency.all_versions).to eq(["1.0.0"])
+    end
+
+    it "returns all_version metadata if present" do
+      dependency = described_class.new(
+        name: "dep",
+        requirements: [],
+        package_manager: "dummy",
+        version: "1.0.0",
+        metadata: {
+          all_versions: [
+            described_class.new(
+              name: "dep",
+              requirements: [],
+              package_manager: "dummy",
+              version: "1.0.0"
+            ),
+            described_class.new(
+              name: "dep",
+              requirements: [],
+              package_manager: "dummy",
+              version: "2.0.0"
+            )
+          ]
+        }
+      )
+
+      expect(dependency.all_versions).to eq(["1.0.0", "2.0.0"])
+    end
   end
 end

npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker.rb

@@ -118,7 +118,6 @@ def conflicting_dependencies
           dependency: dependency,
           target_version: lowest_security_fix_version
         )
-        return conflicts unless defined?(@vulnerability_audit)
 
         vulnerable = [vulnerability_audit].select do |hash|
           !hash["fix_available"] && hash["explanation"]
@@ -144,10 +143,8 @@ def vulnerability_audit
       def vulnerable_versions
         @vulnerable_versions ||=
           begin
-            all_versions = Set.new([
-              dependency.version,
-              *dependency.metadata.fetch(:all_versions, []).filter_map(&:version)
-            ]).filter_map { |v| version_class.new(v) if version_class.correct?(v) }
+            all_versions = dependency.all_versions.
+                           filter_map { |v| version_class.new(v) if version_class.correct?(v) }
 
             all_versions.select do |v|
               security_advisories.any? { |advisory| advisory.vulnerable?(v) }

updater/lib/dependabot/job.rb

@@ -112,8 +112,9 @@ def vulnerable?(dependency)
         version_class_for_package_manager(dependency.package_manager)
       return false unless version_class.correct?(dependency.version)
 
-      version = version_class.new(dependency.version)
-      security_advisories.any? { |a| a.vulnerable?(version) }
+      all_versions = dependency.all_versions.
+                     filter_map { |v| version_class.new(v) if version_class.correct?(v) }
+      security_advisories.any? { |a| all_versions.any? { |v| a.vulnerable?(v) } }
     end
 
     def security_fix?(dependency)

updater/spec/dependabot/job_spec.rb

@@ -158,6 +158,53 @@
 
         it { is_expected.to eq(true) }
       end
+
+      context "for a security fix that doesn't apply" do
+        let(:security_advisories) do
+          [
+            {
+              "dependency-name" => "business",
+              "affected-versions" => ["> 1.8.0"],
+              "patched-versions" => [],
+              "unaffected-versions" => []
+            }
+          ]
+        end
+
+        it { is_expected.to eq(false) }
+      end
+
+      context "for a security fix that doesn't apply to some versions" do
+        let(:security_advisories) do
+          [
+            {
+              "dependency-name" => "business",
+              "affected-versions" => ["> 1.8.0"],
+              "patched-versions" => [],
+              "unaffected-versions" => []
+            }
+          ]
+        end
+
+        it "should be allowed" do
+          dependency.metadata[:all_versions] = [
+            Dependabot::Dependency.new(
+              name: dependency_name,
+              package_manager: "bundler",
+              version: "1.8.0",
+              requirements: []
+            ),
+            Dependabot::Dependency.new(
+              name: dependency_name,
+              package_manager: "bundler",
+              version: "1.9.0",
+              requirements: []
+            )
+          ]
+
+          is_expected.to eq(true)
+        end
+      end
     end
 
     context "and a dependency whitelist that includes the dependency" do