Auto merge of #5186 - bundler:seg-bundle-gem-invalid-constant, r=indirect

[CLI::Gem] Fail gracefully on an invalid constant name

Closes #5185.

2 files changed, 32 insertions, 4 deletions

diff --git a/lib/bundler/cli/gem.rb b/lib/bundler/cli/gem.rb
index 4dc0dbdb6b..955989659c 100644
--- a/lib/bundler/cli/gem.rb
+++ b/lib/bundler/cli/gem.rb
@@ -202,10 +202,23 @@ module Bundler
       if name =~ /^\d/
         Bundler.ui.error "Invalid gem name #{name} Please give a name which does not start with numbers."
         exit 1
-      elsif constant_array.inject(Object) {|c, s| (c.const_defined?(s) && c.const_get(s)) || break }
-        Bundler.ui.error "Invalid gem name #{name} constant #{constant_array.join("::")} is already in use. Please choose another gem name."
-        exit 1
       end
+
+      constant_name = constant_array.join("::")
+
+      existing_constant = constant_array.inject(Object) do |c, s|
+        defined = begin
+          c.const_defined?(s)
+        rescue NameError
+          Bundler.ui.error "Invalid gem name #{name} -- `#{constant_name}` is an invalid constant name"
+          exit 1
+        end
+        (defined && c.const_get(s)) || break
+      end
+
+      return unless existing_constant
+      Bundler.ui.error "Invalid gem name #{name} constant #{constant_name} is already in use. Please choose another gem name."
+      exit 1
     end
 
     def open_editor(editor, file)
diff --git a/spec/commands/newgem_spec.rb b/spec/commands/newgem_spec.rb
index 6e80aa7a60..26dd3b4d96 100644
--- a/spec/commands/newgem_spec.rb
+++ b/spec/commands/newgem_spec.rb
@@ -17,7 +17,7 @@ describe "bundle gem" do
   end
 
   def execute_bundle_gem(gem_name, flag = "", to_remove_push_guard = true)
-    bundle "gem #{gem_name} #{flag}"
+    bundle! "gem #{gem_name} #{flag}"
     remove_push_guard(gem_name) if to_remove_push_guard
     # reset gemspec cache for each test because of commit 3d4163a
     Bundler.clear_gemspec_cache
@@ -733,6 +733,21 @@ describe "bundle gem" do
 
       expect(bundled_app("a--a/a--a.gemspec")).to exist
     end
+
+    it "fails gracefully with a ." do
+      bundle "gem foo.gemspec"
+      expect(out).to end_with("Invalid gem name foo.gemspec -- `Foo.gemspec` is an invalid constant name")
+    end
+
+    it "fails gracefully with a ^" do
+      bundle "gem ^"
+      expect(out).to end_with("Invalid gem name ^ -- `^` is an invalid constant name")
+    end
+
+    it "fails gracefully with a space" do
+      bundle "gem 'foo bar'"
+      expect(out).to end_with("Invalid gem name foo bar -- `Foo bar` is an invalid constant name")
+    end
   end
 
   describe "#ensure_safe_gem_name" do