Add helm regexps

Item 1.1 of https://gitlab.com/gitlab-org/gitlab/-/issues/18997#note_530270349

lib/gitlab/regex.rb

@@ -125,6 +125,18 @@ module Gitlab
         @debian_component_regex ||= %r{#{debian_distribution_regex}}.freeze
       end
 
+      def helm_channel_regex
+        @helm_channel_regex ||= %r{\A[-\.\_a-zA-Z0-9]+\z}.freeze
+      end
+
+      def helm_package_regex
+        @helm_package_regex ||= %r{#{helm_channel_regex}}.freeze
+      end
+
+      def helm_version_regex
+        @helm_version_regex ||= %r{#{prefixed_semver_regex}}.freeze
+      end
+
       def unbounded_semver_regex
         # See the official regex: https://semver.org/#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string
 

spec/lib/gitlab/regex_spec.rb

@@ -628,6 +628,50 @@ RSpec.describe Gitlab::Regex do
     it { is_expected.not_to match('hé') }
   end
 
+  describe '.helm_channel_regex' do
+    subject { described_class.helm_channel_regex }
+
+    it { is_expected.to match('release') }
+    it { is_expected.to match('my-repo') }
+    it { is_expected.to match('my-repo42') }
+
+    # Do not allow empty
+    it { is_expected.not_to match('') }
+
+    # Do not allow Unicode
+    it { is_expected.not_to match('hé') }
+  end
+
+  describe '.helm_package_regex' do
+    subject { described_class.helm_package_regex }
+
+    it { is_expected.to match('release') }
+    it { is_expected.to match('my-repo') }
+    it { is_expected.to match('my-repo42') }
+
+    # Do not allow empty
+    it { is_expected.not_to match('') }
+
+    # Do not allow Unicode
+    it { is_expected.not_to match('hé') }
+
+    it { is_expected.not_to match('my/../repo') }
+    it { is_expected.not_to match('me%2f%2e%2e%2f') }
+  end
+
+  describe '.helm_version_regex' do
+    subject { described_class.helm_version_regex }
+
+    it { is_expected.to match('v1.2.3') }
+    it { is_expected.to match('v1.2.3-beta') }
+    it { is_expected.to match('v1.2.3-alpha.3') }
+    it { is_expected.not_to match('v1') }
+    it { is_expected.not_to match('v1.2') }
+    it { is_expected.not_to match('v1./2.3') }
+    it { is_expected.not_to match('v../../../../../1.2.3') }
+    it { is_expected.not_to match('v%2e%2e%2f1.2.3') }
+  end
+
   describe '.semver_regex' do
     subject { described_class.semver_regex }