Merge pull request #2564 from bundler/detect-cyclic-dependency

Raise user friendly errors in case of Cyclic Dependency

4 files changed, 61 insertions, 16 deletions

diff --git a/lib/bundler.rb b/lib/bundler.rb
index 5ab56154ae..cfc645b75e 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..1746f6d0df 100644
--- a/lib/bundler/spec_set.rb
+++ b/lib/bundler/spec_set.rb
@@ -109,7 +109,22 @@ 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 => error
+        cgems = extract_circular_gems(error)
+        raise CyclicDependencyError, "Your Gemfile requires gems that depend" \
+          " depend on each other, creating an infinite loop. Please remove" \
+          " either gem '#{cgems[1]}' or gem '#{cgems[0]}' and try again."
+      end
+    end
+
+    def extract_circular_gems(error)
+      if Bundler.current_ruby.mri? && Bundler.current_ruby.on_19?
+        error.message.scan(/(\w+) \([^)]/).flatten
+      else
+        error.message.scan(/@name="(.*?)"/).flatten
+      end
     end
 
     def lookup
diff --git a/spec/resolver/basic_spec.rb b/spec/resolver/basic_spec.rb
index d675f4435f..22dc2f0fbe 100644
--- a/spec/resolver/basic_spec.rb
+++ b/spec/resolver/basic_spec.rb
@@ -23,4 +23,15 @@ 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, /please remove either gem 'foo' or gem 'bar'/i)
+  end
+
 end
diff --git a/spec/support/indexes.rb b/spec/support/indexes.rb
index 2ca67a637a..418f7f32db 100644
--- a/spec/support/indexes.rb
+++ b/spec/support/indexes.rb
@@ -130,5 +130,23 @@ module Spec
         end
       end
     end
+
+    def a_circular_index
+      build_index do
+        gem "rack", "1.0.1"
+        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