Ignore ENV["BUNDLE_GEMFILE"] if it's empty

Fixes #3678.

2 files changed, 14 insertions, 1 deletions

diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index bc03b015ad..5ddb6f12db 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -17,7 +17,7 @@ module Bundler
       super
 
       custom_gemfile = options[:gemfile] || Bundler.settings[:gemfile]
-      ENV["BUNDLE_GEMFILE"] = File.expand_path(custom_gemfile) if custom_gemfile
+      ENV["BUNDLE_GEMFILE"] = File.expand_path(custom_gemfile) if custom_gemfile && !custom_gemfile.empty?
 
       Bundler.settings[:retry] = options[:retry] if options[:retry]
 
diff --git a/spec/bundler/cli_spec.rb b/spec/bundler/cli_spec.rb
index 32eecbc49d..1d5ee7b072 100644
--- a/spec/bundler/cli_spec.rb
+++ b/spec/bundler/cli_spec.rb
@@ -24,4 +24,17 @@ describe "bundle executable" do
     expect(exitstatus).to be_zero if exitstatus
     expect(out).to eq("Hello, world")
   end
+
+  context "when ENV['BUNDLE_GEMFILE'] is set to an empty string" do
+    it "ignores it" do
+      gemfile bundled_app("Gemfile"), <<-G
+        source "file://#{gem_repo1}"
+        gem 'rack'
+      G
+
+      bundle :install, :env => { "BUNDLE_GEMFILE" => "" }
+
+      should_be_installed "rack 1.0.0"
+    end
+  end
 end