6 files changed, 28 insertions, 2 deletions
diff --git a/lib/bundler/endpoint_specification.rb b/lib/bundler/endpoint_specification.rb
index 4f5377d3cc..5e14f03265 100644
--- a/lib/bundler/endpoint_specification.rb
+++ b/lib/bundler/endpoint_specification.rb
@@ -91,6 +91,13 @@ module Bundler
     end
 
     def __swap__(spec)
+      without_type = proc {|d| Gem::Dependency.new(d.name, d.requirements_list.sort) }
+      if (extra_deps = spec.runtime_dependencies.map(&without_type).-(dependencies.map(&without_type))) && extra_deps.any?
+        Bundler.ui.debug "#{full_name} from #{remote} has corrupted API dependencies (API returned #{dependencies}, real spec has (#{spec.runtime_dependencies}))"
+        raise APIResponseMismatchError,
+          "Downloading #{full_name} revealed dependencies not in the API (#{extra_deps.map(&:to_s).join(", ")})." \
+          "\nInstalling with `--full-index` should fix the problem."
+      end
       @remote_specification = spec
     end
 
diff --git a/lib/bundler/errors.rb b/lib/bundler/errors.rb
index ecd9260ea0..9ef1286936 100644
--- a/lib/bundler/errors.rb
+++ b/lib/bundler/errors.rb
@@ -54,6 +54,7 @@ module Bundler
   class PluginError < BundlerError; status_code(29); end
   class SudoNotPermittedError < BundlerError; status_code(30); end
   class ThreadCreationError < BundlerError; status_code(33); end
+  class APIResponseMismatchError < BundlerError; status_code(34); end
   class GemfileEvalError < GemfileError; end
   class MarshalError < StandardError; end
 
diff --git a/lib/bundler/installer/gem_installer.rb b/lib/bundler/installer/gem_installer.rb
index b6eb221389..0589d14e40 100644
--- a/lib/bundler/installer/gem_installer.rb
+++ b/lib/bundler/installer/gem_installer.rb
@@ -16,7 +16,7 @@ module Bundler
       Bundler.ui.debug "#{worker}:  #{spec.name} (#{spec.version}) from #{spec.loaded_from}"
       generate_executable_stubs
       return true, post_install_message
-    rescue Bundler::InstallHookError, Bundler::SecurityError
+    rescue Bundler::InstallHookError, Bundler::SecurityError, APIResponseMismatchError
       raise
     rescue Errno::ENOSPC
       return false, out_of_space_message
diff --git a/lib/bundler/lazy_specification.rb b/lib/bundler/lazy_specification.rb
index ed21a9aad4..adafa42342 100644
--- a/lib/bundler/lazy_specification.rb
+++ b/lib/bundler/lazy_specification.rb
@@ -72,7 +72,14 @@ module Bundler
       @specification = if source.is_a?(Source::Gemspec) && source.gemspec.name == name
         source.gemspec.tap {|s| s.source = source }
       else
-        source.specs.search(search_object).last
+        search = source.specs.search(search_object).last
+        if search && search.platform != platform && !search.runtime_dependencies.-(dependencies.reject {|d| d.type == :development }).empty?
+          Bundler.ui.warn "Unable to use the platform-specific (#{search.platform}) version of #{name} (#{version}) " \
+            "because it has different dependencies from the #{platform} version. " \
+            "To use the platform-specific version of the gem, run `bundle config specific_platform true` and install again."
+          search = source.specs.search(self).last
+        end
+        search
       end
     end
 
diff --git a/lib/bundler/remote_specification.rb b/lib/bundler/remote_specification.rb
index 944ff1adbd..e5f9c78b00 100644
--- a/lib/bundler/remote_specification.rb
+++ b/lib/bundler/remote_specification.rb
@@ -49,6 +49,13 @@ module Bundler
     # once the remote gem is downloaded, the backend specification will
     # be swapped out.
     def __swap__(spec)
+      without_type = proc {|d| Gem::Dependency.new(d.name, d.requirements_list) }
+      if (extra_deps = spec.runtime_dependencies.map(&without_type).-(dependencies.map(&without_type))) && extra_deps.any?
+        Bundler.ui.debug "#{full_name} from #{remote} has corrupted API dependencies (API returned #{dependencies}, real spec has (#{spec.runtime_dependencies}))"
+        raise APIResponseMismatchError,
+          "Downloading #{full_name} revealed dependencies not in the API (#{extra_deps.map(&without_type).map(&:to_s).join(", ")})." \
+          "\nInstalling with `--full-index` should fix the problem."
+      end
       @_remote_specification = spec
     end
 
diff --git a/lib/bundler/source/rubygems/remote.rb b/lib/bundler/source/rubygems/remote.rb
index 92f8a40588..b49e645506 100644
--- a/lib/bundler/source/rubygems/remote.rb
+++ b/lib/bundler/source/rubygems/remote.rb
@@ -30,6 +30,10 @@ module Bundler
           end
         end
 
+        def to_s
+          "rubygems remote at #{anonymized_uri}"
+        end
+
       private
 
         def apply_auth(uri, auth)