Change default python package prefix to match the major version of python.

.github/workflows/ruby.yml

@@ -9,6 +9,7 @@ jobs:
   test:
     runs-on: ubuntu-24.04
     strategy:
+      fail-fast: false
       matrix:
         ruby-version: ['2.7', '3.0', '3.1', '3.4']
     steps:

lib/fpm/package/python.rb

@@ -375,11 +375,15 @@ def explore_environment
 
       logger.info("Setting default python executable", :name => default_python)
       attributes[:python_bin] = default_python
+    end
 
-      if !attributes[:python_package_name_prefix_given?]
-        attributes[:python_package_name_prefix] = default_python
-        logger.info("Setting package name prefix", :name => default_python)
+    if !attributes[:python_package_name_prefix_given?]
+      major = nil
+      execmd([attributes[:python_bin], "-c", "import sys; print(sys.version_info[0])"], :stdin => false, :stderr => false) do |stdout|
+        major = stdout.readline.chomp
       end
+      attributes[:python_package_name_prefix] = "python#{major}"
+      logger.info("Setting package name prefix based on python major version #{major}", :name => attributes[:python_package_name_prefix])
     end
 
     if attributes[:python_internal_pip?]

spec/fpm/package/python_spec.rb

@@ -38,6 +38,11 @@ def easy_install_default(python_bin, option)
     #subject.attributes[:python_bin] = find_python
   end
 
+
+  let(:python_major) do 
+    `#{subject.attributes[:python_bin]} -c "import sys; print(sys.version_info[0])"`.chomp
+  end
+
   let (:example_dir) do
     File.expand_path("../../fixtures/python/", File.dirname(__FILE__))
   end
@@ -56,9 +61,11 @@ def easy_install_default(python_bin, option)
       end
 
       context "and :python_package_name_prefix is nil/default" do
-        it "should prefix the package name based on detected python-bin name" do
+        it "should prefix the package name based on detected python-bin version" do
           subject.input(example_dir)
-          insist { subject.name } == "#{subject.attributes[:python_bin]}-Example"
+          reject { subject.attributes[:python_package_name_prefix_given?] }
+          insist { subject.attributes[:python_package_name_prefix] } == "python#{python_major}"
+          insist { subject.name } == "python#{python_major}-Example"
         end
       end
 
@@ -99,7 +106,7 @@ def easy_install_default(python_bin, option)
         it "should prefix the package based on the version of python" do
           subject.input(example_dir)
           insist { subject.attributes[:python_package_name_prefix_given?] }.nil?
-          insist { subject.name } == "#{subject.attributes[:python_bin]}-example"
+          insist { subject.name } == "python#{python_major}-example"
         end
       end