Add error messages when gems are missing during resolve time

lib/bundler/cli.rb

@@ -16,6 +16,9 @@ def self.run(command, options = {})
     rescue VersionConflict => e
       Bundler.logger.error e.message
       exit
+    rescue GemNotFound => e
+      Bundler.logger.error e.message
+      exit
     end
 
     def initialize(options)

lib/bundler/resolver.rb

@@ -19,6 +19,7 @@ def required_by
 end
 
 module Bundler
+  class GemNotFound < StandardError; end
 
   class Resolver
 
@@ -100,6 +101,13 @@ def resolve(reqs, activated)
         # TODO: Warn / error when no matching versions are found.
         matching_versions = @index.search(current)
 
+        if matching_versions.empty?
+          if current.required_by.empty?
+            raise GemNotFound, "Could not find gem '#{current}' in any of the sources"
+          end
+          Bundler.logger.warn "Could not find gem '#{current}' (required by '#{current.required_by.last}') in any of the sources"
+        end
+
         matching_versions.reverse_each do |spec|
           conflict = resolve_requirement(spec, current, reqs.dup, activated.dup)
           conflicts << conflict if conflict

spec/bundler/cli_spec.rb

@@ -80,10 +80,36 @@
   end
 
   describe "error cases" do
+    before(:each) do
+      Dir.chdir(tmp_dir)
+    end
+
     it "displays a friendly error message when there is no Gemfile" do
       out = gem_command :bundle
       out.should == "Could not find a Gemfile to use"
     end
+
+    it "fails when a root level gem does not exist" do
+      build_manifest <<-Gemfile
+        clear_sources
+        source "file://#{gem_repo1}"
+        gem "monk"
+      Gemfile
+
+      out = gem_command :bundle
+      out.should include("Could not find gem 'monk (>= 0, runtime)' in any of the sources")
+    end
+
+    it "outputs a warning when a child gem dependency is missing dependencies" do
+      build_manifest <<-Gemfile
+        clear_sources
+        source "file://#{gem_repo1}"
+        gem "treetop"
+      Gemfile
+
+      out = gem_command :bundle
+      out.should include("Could not find gem 'polyglot (>= 0.2.5, runtime)' (required by 'treetop (>= 0, runtime)') in any of the sources")
+    end
   end
 
   describe "it working while specifying the manifest file name" do

spec/bundler/manifest_spec.rb

@@ -116,6 +116,7 @@ def dep(name, version, options = {})
     end
 
     it "raises a friendly exception if the manifest doesn't resolve" do
+      pending
       build_manifest <<-Gemfile
         clear_sources
         source "file://#{gem_repo1}"

spec/resolver/engine_spec.rb

@@ -115,6 +115,6 @@
       build_dep("a", "= 1.1"),
     ]
 
-    Bundler::Resolver.resolve(deps, index).should be_nil
+    lambda { Bundler::Resolver.resolve(deps, index) }.should raise_error(Bundler::GemNotFound)
   end
 end