Changes warning message to be more explanatory. Adds one more spec.

Previous message was not covering the case where there are only pre-release versions between two stable versions, and user specifies version requirements for the pod such that only possibilities satisfying version requirements are pre-release versions. New message format also includes version requirements set by user in order to give a more explanatory output.

CHANGELOG.md

@@ -8,13 +8,12 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
 
 ##### Bug Fixes
 
-* Use watchsimulator when validating pods with the watchOS platform.  
 * Give a meaningful message for the case where there is no available stable version for a pod,
   and user do not explicitly specify the required version.
   [Muhammed Yavuz Nuzumlalı](https://github.com/manuyavuz)
   [#4197](https://github.com/CocoaPods/CocoaPods/issues/4197)
 
-* Use watchsimulator when validatng PodSpecs with watchOS compatibility.  
+* Use watchsimulator when validating pods with the watchOS platform.
   [Thomas Kollbach](https://github.com/toto)
   [#4130](https://github.com/CocoaPods/CocoaPods/issues/4130)
   

lib/cocoapods/resolver.rb

@@ -390,9 +390,14 @@ module Pod
               conflict.requirement.head?)
               )
             # Conflict was caused by not specifying an explicit version for the requirement #[name],
-            # and there is no available stable version for the requirement.
-            message = "There is no corresponding stable version for `#{name}`. " \
-            "You should explicitly specify the version in order to install a pre-release version of `#{name}`"
+            # and there is no available stable version satisfying constraints for the requirement.
+            message = "There are only pre-release versions available satisfying the following requirements:\n"
+            conflict.requirements.values.flatten.each do |r|
+              unless search_for(r).empty?
+                message << "\n\t'#{name}', '#{r.requirement}'\n"
+              end
+            end
+            message << "\nYou should explicitly specify the version in order to install a pre-release version"
           elsif !conflict.existing
             conflict.requirements.values.flatten.each do |r|
               unless search_for(r).empty?

spec/unit/resolver_spec.rb

@@ -642,15 +642,28 @@ module Pod
         specs.should == ['AFNetworking (1.2.1)']
       end
 
-      it 'raises when there is no explicit version specified and there are only pre-release versions' do
+      it 'raises when no constraints are specified and only pre-release versions are available' do
         podfile = Podfile.new do
           platform :ios
           pod 'PrereleaseMonkey'
         end
         resolver = Resolver.new(config.sandbox, podfile, empty_graph, SourcesManager.all)
         e = lambda { resolver.resolve }.should.raise Informative
-        e.message.should.match(/There is no corresponding stable version for `PrereleaseMonkey`/)
-        e.message.should.match(/You should explicitly specify the version in order to install a pre-release version of `PrereleaseMonkey`/)
+        e.message.should.match(/There are only pre-release versions available satisfying the following requirements/)
+        e.message.should.match(/PrereleaseMonkey.*>= 0/)
+        e.message.should.match(/You should explicitly specify the version in order to install a pre-release version/)
+      end
+
+      it 'raises when no explicit version is specified and only pre-release versions satisfy constraints' do
+        podfile = Podfile.new do
+          platform :ios
+          pod 'AFNetworking', '< 1.0', '> 0.10.1'
+        end
+        resolver = Resolver.new(config.sandbox, podfile, empty_graph, SourcesManager.all)
+        e = lambda { resolver.resolve }.should.raise Informative
+        e.message.should.match(/There are only pre-release versions available satisfying the following requirements/)
+        e.message.should.match(/AFNetworking.*< 1\.0, > 0\.10\.1/)
+        e.message.should.match(/You should explicitly specify the version in order to install a pre-release version/)
       end
 
       it 'resolves when there is explicit pre-release version specified and there are only pre-release versions' do