Improve error messages for podspec dependencies

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 ##### Enhancements
 
+* Better error messages, if unallowed version requirement is specified in Podspec.  
+  [Wolfgang Lutz][https://github.com/lutzifer]  
+  [#466](https://github.com/CocoaPods/Core/pull/474)
+
 * DSL for `scheme` support.  
   [Dimitris Koutsogiorgas](https://github.com/dnkoutso)
   [#7577](https://github.com/CocoaPods/CocoaPods/issues/7577)

lib/cocoapods-core/specification/dsl.rb

@@ -677,8 +677,21 @@ def dependency(*args)
           end
         end
         unless version_requirements.all? { |req| req.is_a?(String) }
-          raise Informative, 'Unsupported version requirements'
+          version_requirements.each do |requirement|
+            if requirement.is_a?(Hash)
+              if !requirement[:path].nil?
+                raise Informative, 'Podspecs cannot specify the source of dependencies. The `:path` option is not supported.'\
+                                   ' `:path` can be used in the Podfile instead to override global dependencies.'
+              elsif !requirement[:git].nil?
+                raise Informative, 'Podspecs cannot specify the source of dependencies. The `:git` option is not supported.'\
+                                   ' `:git` can be used in the Podfile instead to override global dependencies.'
+              end
+            end
+          end
+
+          raise Informative, "Unsupported version requirements. #{version_requirements.inspect} is not valid."
         end
+
         attributes_hash['dependencies'] ||= {}
         attributes_hash['dependencies'][name] = version_requirements
       end

spec/specification/dsl_spec.rb

@@ -240,7 +240,19 @@ module Pod
         it 'raises if the requirements are not supported' do
           should.raise Informative do
             @spec.dependency('SVProgressHUD', :head)
-          end.message.should.match /Unsupported version requirements/
+          end.message.should.match /Unsupported version requirements. \[\:head\] is not valid/
+        end
+
+        it 'raises if the requirements specify :git' do
+          should.raise Informative do
+            @spec.dependency('SVProgressHUD', :git => 'AnyPath')
+          end.message.should.match /Podspecs cannot specify the source of dependencies. The `:git` option is not supported.\.*/
+        end
+
+        it 'raises if the requirements specify :path' do
+          should.raise Informative do
+            @spec.dependency('SVProgressHUD', :path => 'AnyPath')
+          end.message.should.match /Podspecs cannot specify the source of dependencies. The `:path` option is not supported.\.*/
         end
 
         it 'raises when attempting to assign a value to dependency' do