Avoid fetching the full index to get all dependency names

3 files changed, 42 insertions, 2 deletions

diff --git a/lib/bundler/source/rubygems.rb b/lib/bundler/source/rubygems.rb
index 8644c05d64..465aec6136 100644
--- a/lib/bundler/source/rubygems.rb
+++ b/lib/bundler/source/rubygems.rb
@@ -249,9 +249,9 @@ module Bundler
         return unless api_fetchers.any?
 
         unmet_dependency_names = unmet_dependency_names.call
-        Bundler.ui.debug "#{self}: 2x check for #{unmet_dependency_names}"
+        return if !unmet_dependency_names.nil? && unmet_dependency_names.empty?
 
-        return if unmet_dependency_names && unmet_dependency_names.empty?
+        Bundler.ui.debug "Double checking for #{unmet_dependency_names || "all specs (due to the size of the request)"} in #{self}"
 
         fetch_names(api_fetchers, unmet_dependency_names, index, override_dupes)
       end
diff --git a/spec/install/gems/compact_index_spec.rb b/spec/install/gems/compact_index_spec.rb
index 9fc5b1f90a..ad1abe2e89 100644
--- a/spec/install/gems/compact_index_spec.rb
+++ b/spec/install/gems/compact_index_spec.rb
@@ -363,6 +363,30 @@ The checksum of /versions does not match the checksum provided by the server! So
     expect(the_bundle).to include_gems "back_deps 1.0"
   end
 
+  it "does not fetch every spec if the index of gems is large when doing back deps & everything is the compact index" do
+    build_repo4 do
+      build_gem "back_deps" do |s|
+        s.add_dependency "foo"
+      end
+      build_gem "missing"
+      # need to hit the limit
+      1.upto(Bundler::Source::Rubygems::API_REQUEST_LIMIT) do |i|
+        build_gem "gem#{i}"
+      end
+
+      FileUtils.rm_rf Dir[gem_repo4("gems/foo-*.gem")]
+    end
+
+    install_gemfile! <<-G, :artifice => "compact_index_extra_api_missing"
+      source "#{source_uri}"
+      source "#{source_uri}/extra" do
+        gem "back_deps"
+      end
+    G
+
+    expect(the_bundle).to include_gem "back_deps 1.0"
+  end
+
   it "uses the endpoint if all sources support it" do
     gemfile <<-G
       source "#{source_uri}"
diff --git a/spec/support/artifice/compact_index_extra_api_missing.rb b/spec/support/artifice/compact_index_extra_api_missing.rb
new file mode 100644
index 0000000000..d11793fc2b
--- /dev/null
+++ b/spec/support/artifice/compact_index_extra_api_missing.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+require File.expand_path("../compact_index_extra_api", __FILE__)
+
+Artifice.deactivate
+
+class CompactIndexExtraAPIMissing < CompactIndexExtraApi
+  get "/extra/fetch/actual/gem/:id" do
+    if params[:id] == "missing-1.0.gemspec.rz"
+      halt 404
+    else
+      File.read("#{gem_repo2}/quick/Marshal.4.8/#{params[:id]}")
+    end
+  end
+end
+
+Artifice.activate_with(CompactIndexExtraAPIMissing)