[CompactIndex] Fall back when the versions checksum mismatchesseg-checksum-mismatch-error

4 files changed, 33 insertions, 1 deletions

diff --git a/lib/bundler/fetcher/compact_index.rb b/lib/bundler/fetcher/compact_index.rb
index c1beee6c75..3d24a9d728 100644
--- a/lib/bundler/fetcher/compact_index.rb
+++ b/lib/bundler/fetcher/compact_index.rb
@@ -61,6 +61,9 @@ module Bundler
       def available?
         # Read info file checksums out of /versions, so we can know if gems are up to date
         fetch_uri.scheme != "file" && compact_index_client.update_and_parse_checksums!
+      rescue CompactIndexClient::Updater::MisMatchedChecksumError => e
+        Bundler.ui.warn(e.message)
+        nil
       end
       compact_index_request :available?
 
diff --git a/lib/bundler/vendor/compact_index_client/lib/compact_index_client/updater.rb b/lib/bundler/vendor/compact_index_client/lib/compact_index_client/updater.rb
index e447d7a2b8..630318a9be 100644
--- a/lib/bundler/vendor/compact_index_client/lib/compact_index_client/updater.rb
+++ b/lib/bundler/vendor/compact_index_client/lib/compact_index_client/updater.rb
@@ -56,7 +56,7 @@ class Bundler::CompactIndexClient
 
     def etag_for(path)
       sum = checksum_for_file(path)
-      sum ? '"' << sum << '"' : nil
+      sum ? %("#{sum}") : nil
     end
 
     def checksum_for_file(path)
diff --git a/spec/install/gems/compact_index_spec.rb b/spec/install/gems/compact_index_spec.rb
index 13645f0ae6..c00e73523b 100644
--- a/spec/install/gems/compact_index_spec.rb
+++ b/spec/install/gems/compact_index_spec.rb
@@ -139,6 +139,20 @@ describe "compact index api" do
     should_be_installed "rack 1.0.0"
   end
 
+  it "falls back when the versions endpoint has a checksum mismatch" do
+    gemfile <<-G
+      source "#{source_uri}"
+      gem "rack"
+    G
+
+    bundle! :install, :verbose => true, :artifice => "compact_index_checksum_mismatch"
+    expect(out).to include("Fetching gem metadata from #{source_uri}")
+    expect(out).to include <<-'WARN'
+The checksum of /versions does not match the checksum provided by the server! Something is wrong (local checksum is "\"d41d8cd98f00b204e9800998ecf8427e\"", was expecting "\"123\"").
+    WARN
+    should_be_installed "rack 1.0.0"
+  end
+
   it "handles host redirects" do
     gemfile <<-G
       source "#{source_uri}"
diff --git a/spec/support/artifice/compact_index_checksum_mismatch.rb b/spec/support/artifice/compact_index_checksum_mismatch.rb
new file mode 100644
index 0000000000..4ac328736c
--- /dev/null
+++ b/spec/support/artifice/compact_index_checksum_mismatch.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+require File.expand_path("../compact_index", __FILE__)
+
+Artifice.deactivate
+
+class CompactIndexChecksumMismatch < CompactIndexAPI
+  get "/versions" do
+    headers "ETag" => quote("123")
+    headers "Surrogate-Control" => "max-age=2592000, stale-while-revalidate=60"
+    content_type "text/plain"
+    body ""
+  end
+end
+
+Artifice.activate_with(CompactIndexChecksumMismatch)