Raise user friendly errors in case of Cyclic Dependency

Fixes #2506

4 files changed, 49 insertions, 16 deletions

diff --git a/lib/bundler.rb b/lib/bundler.rb
index ea5673a32a..b0cf21a49d 100644
--- a/lib/bundler.rb
+++ b/lib/bundler.rb
@@ -50,21 +50,22 @@ module Bundler
     end
   end
 
-  class GemfileNotFound     < BundlerError; status_code(10) ; end
-  class GemNotFound         < BundlerError; status_code(7)  ; end
-  class GemfileError        < BundlerError; status_code(4)  ; end
-  class InstallError        < BundlerError; status_code(5)  ; end
-  class InstallHookError    < BundlerError; status_code(6)  ; end
-  class PathError           < BundlerError; status_code(13) ; end
-  class GitError            < BundlerError; status_code(11) ; end
-  class DeprecatedError     < BundlerError; status_code(12) ; end
-  class GemspecError        < BundlerError; status_code(14) ; end
-  class InvalidOption       < BundlerError; status_code(15) ; end
-  class ProductionError     < BundlerError; status_code(16) ; end
-  class HTTPError           < BundlerError; status_code(17) ; end
-  class RubyVersionMismatch < BundlerError; status_code(18) ; end
-  class SecurityError       < BundlerError; status_code(19) ; end
-  class LockfileError       < BundlerError; status_code(20) ; end
+  class GemfileNotFound     < BundlerError;   status_code(10) ; end
+  class GemNotFound         < BundlerError;   status_code(7)  ; end
+  class GemfileError        < BundlerError;   status_code(4)  ; end
+  class InstallError        < BundlerError;   status_code(5)  ; end
+  class InstallHookError    < BundlerError;   status_code(6)  ; end
+  class PathError           < BundlerError;   status_code(13) ; end
+  class GitError            < BundlerError;   status_code(11) ; end
+  class DeprecatedError     < BundlerError;   status_code(12) ; end
+  class GemspecError        < BundlerError;   status_code(14) ; end
+  class InvalidOption       < BundlerError;   status_code(15) ; end
+  class ProductionError     < BundlerError;   status_code(16) ; end
+  class HTTPError           < BundlerError;   status_code(17) ; end
+  class RubyVersionMismatch < BundlerError;   status_code(18) ; end
+  class SecurityError       < BundlerError;   status_code(19) ; end
+  class LockfileError       < BundlerError;   status_code(20) ; end
+  class CyclicDependencyError < BundlerError; status_code(21) ; end
 
   # Internal errors, should be rescued
   class VersionConflict  < BundlerError
diff --git a/lib/bundler/spec_set.rb b/lib/bundler/spec_set.rb
index 2cdffdc83f..202993e441 100644
--- a/lib/bundler/spec_set.rb
+++ b/lib/bundler/spec_set.rb
@@ -109,7 +109,12 @@ module Bundler
 
     def sorted
       rake = @specs.find { |s| s.name == 'rake' }
-      @sorted ||= ([rake] + tsort).compact.uniq
+      begin
+        @sorted ||= ([rake] + tsort).compact.uniq
+      rescue TSort::Cyclic
+        raise CyclicDependencyError.new("Bundler has detected cyclic dependencies and can't" +
+            " proceed, update your Gemfile by removing cyclic dependency and rerun bundler.")
+      end
     end
 
     def lookup
diff --git a/spec/resolver/basic_spec.rb b/spec/resolver/basic_spec.rb
index d675f4435f..ce72eead87 100644
--- a/spec/resolver/basic_spec.rb
+++ b/spec/resolver/basic_spec.rb
@@ -23,4 +23,14 @@ describe "Resolving" do
     dep "my_app"
     should_resolve_as %w(activemodel-3.2.11 builder-3.0.4 grape-0.2.6 my_app-1.0.0)
   end
+
+  it "should throw error in case of circular dependencies" do
+    @index = a_circular_index
+    dep "circular_app"
+
+    got = resolve
+    expect {
+      got = got.map { |s| s.full_name }.sort
+    }.to raise_error(Bundler::CyclicDependencyError)
+  end
 end
diff --git a/spec/support/indexes.rb b/spec/support/indexes.rb
index 2ca67a637a..d49f576768 100644
--- a/spec/support/indexes.rb
+++ b/spec/support/indexes.rb
@@ -130,5 +130,22 @@ module Spec
         end
       end
     end
+
+    def a_circular_index
+      build_index do
+        gem("foo", '0.2.6') do
+          dep "bar", ">= 0"
+        end
+
+        gem("bar", "1.0.0") do
+          dep "foo", ">= 0"
+        end
+
+        gem("circular_app", '1.0.0') do
+          dep "foo", ">= 0"
+          dep "bar", ">= 0"
+        end
+      end
+    end
   end
 end