Update RubyGems to 3.0.3 on Ruby 2.6.1

2.6/alpine3.8/Dockerfile

@@ -13,6 +13,7 @@ RUN mkdir -p /usr/local/etc \
 ENV RUBY_MAJOR 2.6
 ENV RUBY_VERSION 2.6.1
 ENV RUBY_DOWNLOAD_SHA256 47b629808e9fd44ce1f760cdf3ed14875fc9b19d4f334e82e2cf25cb2898f2f2
+ENV RUBYGEMS_VERSION 3.0.3
 
 # some of ruby's build scripts are written in ruby
 #   we purge system ruby later to make sure our final image uses what we just built
@@ -100,6 +101,9 @@ RUN set -ex \
 	&& apk del --no-network .ruby-builddeps \
 	&& cd / \
 	&& rm -r /usr/src/ruby \
+# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
+	&& ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))' \
+	&& gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/ \
 # rough smoke test
 	&& ruby --version && gem --version && bundle --version
 

2.6/alpine3.9/Dockerfile

@@ -13,6 +13,7 @@ RUN mkdir -p /usr/local/etc \
 ENV RUBY_MAJOR 2.6
 ENV RUBY_VERSION 2.6.1
 ENV RUBY_DOWNLOAD_SHA256 47b629808e9fd44ce1f760cdf3ed14875fc9b19d4f334e82e2cf25cb2898f2f2
+ENV RUBYGEMS_VERSION 3.0.3
 
 # some of ruby's build scripts are written in ruby
 #   we purge system ruby later to make sure our final image uses what we just built
@@ -100,6 +101,9 @@ RUN set -ex \
 	&& apk del --no-network .ruby-builddeps \
 	&& cd / \
 	&& rm -r /usr/src/ruby \
+# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
+	&& ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))' \
+	&& gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/ \
 # rough smoke test
 	&& ruby --version && gem --version && bundle --version
 

2.6/stretch/Dockerfile

@@ -10,6 +10,7 @@ RUN mkdir -p /usr/local/etc \
 ENV RUBY_MAJOR 2.6
 ENV RUBY_VERSION 2.6.1
 ENV RUBY_DOWNLOAD_SHA256 47b629808e9fd44ce1f760cdf3ed14875fc9b19d4f334e82e2cf25cb2898f2f2
+ENV RUBYGEMS_VERSION 3.0.3
 
 # some of ruby's build scripts are written in ruby
 #   we purge system ruby later to make sure our final image uses what we just built
@@ -55,6 +56,9 @@ RUN set -ex \
 	&& apt-get purge -y --auto-remove $buildDeps \
 	&& cd / \
 	&& rm -r /usr/src/ruby \
+# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
+	&& ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))' \
+	&& gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/ \
 # rough smoke test
 	&& ruby --version && gem --version && bundle --version
 

2.6/stretch/slim/Dockerfile

@@ -23,6 +23,7 @@ RUN mkdir -p /usr/local/etc \
 ENV RUBY_MAJOR 2.6
 ENV RUBY_VERSION 2.6.1
 ENV RUBY_DOWNLOAD_SHA256 47b629808e9fd44ce1f760cdf3ed14875fc9b19d4f334e82e2cf25cb2898f2f2
+ENV RUBYGEMS_VERSION 3.0.3
 
 # some of ruby's build scripts are written in ruby
 #   we purge system ruby later to make sure our final image uses what we just built
@@ -87,6 +88,9 @@ RUN set -ex \
 	\
 	&& cd / \
 	&& rm -r /usr/src/ruby \
+# make sure bundled "rubygems" is older than RUBYGEMS_VERSION (https://github.com/docker-library/ruby/issues/246)
+	&& ruby -e 'exit(Gem::Version.create(ENV["RUBYGEMS_VERSION"]) > Gem::Version.create(Gem::VERSION))' \
+	&& gem update --system "$RUBYGEMS_VERSION" && rm -r /root/.gem/ \
 # rough smoke test
 	&& ruby --version && gem --version && bundle --version
 

update.sh

@@ -20,7 +20,7 @@ latest_gem_version() {
 # https://github.com/docker-library/ruby/issues/246
 rubygems='3.0.3'
 declare -A newEnoughRubygems=(
-	[2.6]=1 # 3.0.1+
+#	[2.6]=1 # 2.6.1 => gems 3.0.1
 )
 # TODO once all versions are in this family of "new enough", remove RUBYGEMS_VERSION code entirely