Selecting the correct requirement based on the given marker condition.

python/lib/dependabot/python/file_parser.rb

@@ -294,10 +294,39 @@ def group_from_filename(filename)
 
       def blocking_marker?(dep)
         return false if dep["markers"] == "None"
-        return true if dep["markers"].include?("<")
-        return false if dep["markers"].include?(">")
 
-        dep["requirement"]&.include?("<")
+        marker = dep["markers"]
+        version = python_raw_version
+
+        if marker.include?("python_version")
+          !marker_satisfied?(marker, version)
+        else
+          return true if dep["markers"].include?("<")
+          return false if dep["markers"].include?(">")
+
+          dep["requirement"]&.include?("<")
+        end
+      end
+
+      def marker_satisfied?(marker, python_version)
+        return true if marker == "None"
+
+        operator, version = marker.match(/([<>=!]=?)\s*"?([\d.]+)"?/).captures
+
+        case operator
+        when "<"
+          Gem::Version.new(python_version) < Gem::Version.new(version)
+        when "<="
+          Gem::Version.new(python_version) <= Gem::Version.new(version)
+        when ">"
+          Gem::Version.new(python_version) > Gem::Version.new(version)
+        when ">="
+          Gem::Version.new(python_version) >= Gem::Version.new(version)
+        when "=="
+          Gem::Version.new(python_version) == Gem::Version.new(version)
+        else
+          false
+        end
       end
 
       def setup_file_dependencies

python/spec/dependabot/python/file_parser_spec.rb

@@ -106,6 +106,10 @@
     end
 
     context "with markers" do
+      before do
+        allow(parser).to receive(:python_raw_version).and_return("2.6")
+      end
+
       context "when including a < in the marker" do
         let(:requirements_fixture_name) { "markers.txt" }
 
@@ -116,10 +120,10 @@
 
           expect(dependency).to be_a(Dependabot::Dependency)
           expect(dependency.name).to eq("distro")
-          expect(dependency.version).to eq("1.3.0")
+          expect(dependency.version).to eq("1.0.4")
           expect(dependency.requirements).to eq(
             [{
-              requirement: "==1.3.0",
+              requirement: "==1.0.4",
               file: "requirements.txt",
               groups: ["dependencies"],
               source: nil