[rubygems/rubygems] Use the server checksum, then calculate from gem on disk if possible

1. Use the checksum provided by the server if provided: provides security
knowing if the gem you downloaded matches the gem on the server

2. Calculate the checksum from the gem on disk: provides security knowing
if the gem has changed between installs

3. In some cases, neither is possible in which case we don't put anything
in the checksum and we maintain functionality as it is today

Add the checksums to specs in the index if we already have them

Prior to checksums, we didn't lose any information when overwriting specs
in the index with stubs. But now when we overwrite EndpointSpecifications
or RemoteSpecifications with more generic specs, we could lose checksum
info. This manually sets checksum info so we keep it in the index.

https://github.com/rubygems/rubygems/commit/de00a4f153

1 files changed, 1 insertions, 0 deletions

diff --git a/spec/bundler/install/yanked_spec.rb b/spec/bundler/install/yanked_spec.rb
index 930e3c4791..bc84e25417 100644
--- a/spec/bundler/install/yanked_spec.rb
+++ b/spec/bundler/install/yanked_spec.rb
@@ -161,6 +161,7 @@ RSpec.context "when resolving a bundle that includes yanked gems, but unlocking
         foo
 
       CHECKSUMS
+        #{checksum_for_repo_gem(gem_repo4, "bar", "2.0.0")}
 
       BUNDLED WITH
          #{Bundler::VERSION}