Merge #7473

7473: Cleanup some unnecessary code r=deivid-rodriguez a=deivid-rodriguez

### What was the end-user problem that led to this PR?

The problem was #7460 is very big so I want to extract these changes to a separate PR, so that we're more aware of them.

### What was your diagnosis of the problem?

My diagnosis was that this code can be removed. In particular, in the `GemRemoteFetcher` class there was the following comment

https://github.com/bundler/bundler/blob/25595896eb0f8dfd004d941093bf1d8f4a39aeeb/lib/bundler/gem_remote_fetcher.rb#L9-L10

After having a look, I think the comment would make sense if where it says "gemstash", it actually meant "bundler". That would make sense to me since this is about fetching remote specs, so I would assume it's the client side running it.

Assuming this is the correct interpretation, we can remove the code since our minimum supported rubygems version is 2.5.2, and this code was included in rubygems in 2.5.0.

### What is your fix for the problem, implemented in this PR?

My fix is to remove the `GemRemoteFetcher` class, plus simplify other related code.


Co-authored-by: David Rodríguez <deivid.rodriguez@riseup.net>

lib/bundler.rb

@@ -50,7 +50,6 @@ module Bundler
   autoload :FeatureFlag,            File.expand_path("bundler/feature_flag", __dir__)
   autoload :GemHelper,              File.expand_path("bundler/gem_helper", __dir__)
   autoload :GemHelpers,             File.expand_path("bundler/gem_helpers", __dir__)
-  autoload :GemRemoteFetcher,       File.expand_path("bundler/gem_remote_fetcher", __dir__)
   autoload :GemVersionPromoter,     File.expand_path("bundler/gem_version_promoter", __dir__)
   autoload :Graph,                  File.expand_path("bundler/graph", __dir__)
   autoload :Index,                  File.expand_path("bundler/index", __dir__)

lib/bundler/rubygems_integration.rb

@@ -247,12 +247,6 @@ def ext_lock
       EXT_LOCK
     end
 
-    def fetch_prerelease_specs
-      fetch_specs(false, true)
-    rescue Gem::RemoteFetcher::FetchError
-      {} # if we can't download them, there aren't any
-    end
-
     def with_build_args(args)
       ext_lock.synchronize do
         old_args = build_args
@@ -502,8 +496,8 @@ def stub_rubygems(specs)
       end
     end
 
-    def fetch_specs(source, remote, name)
-      path = source + "#{name}.#{Gem.marshal_version}.gz"
+    def fetch_specs(remote, name)
+      path = remote.uri.to_s + "#{name}.#{Gem.marshal_version}.gz"
       fetcher = gem_remote_fetcher
       fetcher.headers = { "X-Gemfile-Source" => remote.original_uri.to_s } if remote.original_uri
       string = fetcher.fetch_path(path)
@@ -514,10 +508,8 @@ def fetch_specs(source, remote, name)
     end
 
     def fetch_all_remote_specs(remote)
-      source = remote.uri.is_a?(URI) ? remote.uri : URI.parse(source.to_s)
-
-      specs = fetch_specs(source, remote, "specs")
-      pres = fetch_specs(source, remote, "prerelease_specs") || []
+      specs = fetch_specs(remote, "specs")
+      pres = fetch_specs(remote, "prerelease_specs") || []
 
       specs.concat(pres)
     end
@@ -535,7 +527,7 @@ def gem_remote_fetcher
       require "resolv"
       proxy = configuration[:http_proxy]
       dns = Resolv::DNS.new
-      Bundler::GemRemoteFetcher.new(proxy, dns)
+      Gem::RemoteFetcher.new(proxy, dns)
     end
 
     def gem_from_path(path, policy = nil)

spec/bundler/rubygems_integration_spec.rb

@@ -67,7 +67,7 @@
   end
 
   describe "#fetch_all_remote_specs" do
-    let(:uri) { URI("https://example.com") }
+    let(:uri) { "https://example.com" }
     let(:fetcher) { double("gem_remote_fetcher") }
     let(:specs_response) { Marshal.dump(["specs"]) }
     let(:prerelease_specs_response) { Marshal.dump(["prerelease_specs"]) }