Track and report more information about why a gem couldn't be installed

git-svn-id: svn+ssh://rubyforge.org/var/svn/rubygems/trunk@2495 3d4018f9-ac1a-0410-99e9-8a154d859a19

lib/rubygems/command.rb

@@ -145,6 +145,18 @@ def execute
     raise Gem::Exception, "generic command has no actions"
   end
 
+  ##
+  #
+  # Display to the user that a gem couldn't be found and reasons why
+  def show_lookup_failure(gem_name, version, errors=nil)
+    if errors and !errors.empty?
+      alert_error "Could not find a valid gem '#{gem_name}' (#{version}), here is why:"
+      errors.each { |x| say "          #{x.wordy}" }
+    else
+      alert_error "Could not find a valid gem '#{gem_name}' (#{version}) in any repository"
+    end
+  end
+
   ##
   # Get all gem names from the command line.
 

lib/rubygems/commands/fetch_command.rb

@@ -45,10 +45,14 @@ def execute
       specs_and_sources = Gem::SpecFetcher.fetcher.fetch(dep, all, true,
                                                          dep.prerelease?)
 
+      specs_and_sources, errors =
+        Gem::SpecFetcher.fetcher.fetch_with_errors(dep, all, true,
+                                                   dep.prerelease?)
+
       spec, source_uri = specs_and_sources.sort_by { |s,| s.version }.last
 
       if spec.nil? then
-        alert_error "Could not find #{gem_name} in any repository"
+        show_lookup_failure gem_name, version, errors
         next
       end
 

lib/rubygems/commands/install_command.rb

@@ -127,7 +127,8 @@ def execute
         alert_error "Error installing #{gem_name}:\n\t#{e.message}"
         exit_code |= 1
       rescue Gem::GemNotFoundException => e
-        alert_error e.message
+        show_lookup_failure e.name, e.version, e.errors
+
         exit_code |= 2
       end
     end

lib/rubygems/dependency_installer.rb

@@ -69,6 +69,10 @@ def initialize(options = {})
 
     @install_dir = options[:install_dir] || Gem.dir
     @cache_dir = options[:cache_dir] || @install_dir
+
+    # Set with any errors that SpecFetcher finds while search through
+    # gemspecs for a dep
+    @errors = nil
   end
 
   ##
@@ -78,6 +82,8 @@ def initialize(options = {})
   # local gems preferred over remote gems.
 
   def find_gems_with_sources(dep)
+    # Reset the errors
+    @errors = nil
     gems_and_sources = []
 
     if @domain == :both or @domain == :local then
@@ -99,7 +105,7 @@ def find_gems_with_sources(dep)
               (requirements.length > 1 or
                 (requirements.first != ">=" and requirements.first != ">"))
 
-        found = Gem::SpecFetcher.fetcher.fetch dep, all, true, dep.prerelease?
+        found, @errors = Gem::SpecFetcher.fetcher.fetch_with_errors dep, all, true, dep.prerelease?
 
         gems_and_sources.push(*found)
 
@@ -204,8 +210,9 @@ def find_spec_by_name_and_version(gem_name,
     end
 
     if spec_and_source.nil? then
-      raise Gem::GemNotFoundException,
-        "could not find gem #{gem_name} locally or in a repository"
+      raise Gem::GemNotFoundException.new(
+        "Could not find a valid gem '#{gem_name}' (#{version}) locally or in a repository",
+        gem_name, version, @errors)
     end
 
     @specs_and_sources = [spec_and_source]

lib/rubygems/errors.rb

@@ -0,0 +1,35 @@
+class Gem::ErrorReason; end
+
+# Generated when trying to lookup a gem to indicate that the gem
+# was found, but that it isn't usable on the current platform.
+#
+# fetch and install read these and report them to the user to aid
+# in figuring out why a gem couldn't be installed.
+#
+class Gem::PlatformMismatch < Gem::ErrorReason
+
+  attr_reader :name
+  attr_reader :version
+  attr_reader :platforms
+
+  def initialize(name, version)
+    @name = name
+    @version = version
+    @platforms = []
+  end
+
+  def add_platform(platform)
+    @platforms << platform
+  end
+
+  def wordy
+    prefix = "Found #{@name} (#{@version})"
+
+    if @platforms.size == 1
+      "#{prefix}, but was for platform #{@platforms[0]}"
+    else
+      "#{prefix}, but was for platforms #{@platforms.join(' ,')}"
+    end
+  end
+
+end

lib/rubygems/exceptions.rb

@@ -37,7 +37,16 @@ class Gem::FormatException < Gem::Exception
   attr_accessor :file_path
 end
 
-class Gem::GemNotFoundException < Gem::Exception; end
+class Gem::GemNotFoundException < Gem::Exception
+  def initialize(msg, name=nil, version=nil, errors=nil)
+    super msg
+    @name = name
+    @version = version
+    @errors = errors
+  end
+
+  attr_reader :name, :version, :errors
+end
 
 class Gem::InstallError < Gem::Exception; end
 

lib/rubygems/spec_fetcher.rb

@@ -3,6 +3,7 @@
 
 require 'rubygems/remote_fetcher'
 require 'rubygems/user_interaction'
+require 'rubygems/errors'
 
 ##
 # SpecFetcher handles metadata updates from remote gem repositories.
@@ -65,22 +66,28 @@ def cache_dir(uri)
   # false, all platforms are returned. If +prerelease+ is true,
   # prerelease versions are included.
 
-  def fetch(dependency, all = false, matching_platform = true, prerelease = false)
-    specs_and_sources = find_matching dependency, all, matching_platform, prerelease
+  def fetch_with_errors(dependency, all = false, matching_platform = true, prerelease = false)
+    specs_and_sources, errors = find_matching_with_errors dependency, all, matching_platform, prerelease
 
-    specs_and_sources.map do |spec_tuple, source_uri|
+    ss = specs_and_sources.map do |spec_tuple, source_uri|
       [fetch_spec(spec_tuple, URI.parse(source_uri)), source_uri]
     end
 
+    return [ss, errors]
+
   rescue Gem::RemoteFetcher::FetchError => e
     raise unless warn_legacy e do
       require 'rubygems/source_info_cache'
 
-      return Gem::SourceInfoCache.search_with_source(dependency,
-                                                     matching_platform, all)
+      return [Gem::SourceInfoCache.search_with_source(dependency,
+                                                     matching_platform, all), nil]
     end
   end
 
+  def fetch(*args)
+    fetch_with_errors(*args).first
+  end
+
   def fetch_spec(spec, source_uri)
     spec = spec - [nil, 'ruby', '']
     spec_file_name = "#{spec.join '-'}.gemspec"
@@ -117,24 +124,39 @@ def fetch_spec(spec, source_uri)
   # matching released versions are returned.  If +matching_platform+
   # is false, gems for all platforms are returned.
 
-  def find_matching(dependency, all = false, matching_platform = true, prerelease = false)
+  def find_matching_with_errors(dependency, all = false, matching_platform = true, prerelease = false)
     found = {}
 
+    rejected_specs = {}
+
     list(all, prerelease).each do |source_uri, specs|
       found[source_uri] = specs.select do |spec_name, version, spec_platform|
-        dependency.match?(spec_name, version) and
-          (not matching_platform or Gem::Platform.match(spec_platform))
+        if dependency.match?(spec_name, version)
+          if matching_platform and !Gem::Platform.match(spec_platform)
+            pm = (rejected_specs[dependency] ||= Gem::PlatformMismatch.new(spec_name, version))
+            pm.add_platform spec_platform
+            false
+          else
+            true
+          end
+        end
       end
     end
 
+    errors = rejected_specs.values
+
     specs_and_sources = []
 
     found.each do |source_uri, specs|
       uri_str = source_uri.to_s
       specs_and_sources.push(*specs.map { |spec| [spec, uri_str] })
     end
 
-    specs_and_sources
+    [specs_and_sources, errors]
+  end
+
+  def find_matching(*args)
+    find_matching_with_errors(*args).first
   end
 
   ##

test/test_gem_commands_install_command.rb

@@ -145,8 +145,7 @@ def test_execute_local_missing
     end
 
     # HACK no repository was checked
-    assert_equal "ERROR:  could not find gem no_such_gem locally or in a repository\n",
-                 @ui.error
+    assert_match(/ould not find a valid gem 'no_such_gem'/, @ui.error)
   end
 
   def test_execute_no_gem
@@ -170,8 +169,7 @@ def test_execute_nonexistent
       assert_equal 2, e.exit_code
     end
 
-    assert_equal "ERROR:  could not find gem nonexistent locally or in a repository\n",
-                 @ui.error
+    assert_match(/ould not find a valid gem 'nonexistent'/, @ui.error)
   end
 
   def test_execute_prerelease

test/test_gem_spec_fetcher.rb

@@ -115,6 +115,21 @@ def test_fetch_platform
     assert_equal [[@pl1.full_name, @gem_repo]], spec_names
   end
 
+  def test_fetch_with_errors_mismatched_platform
+    util_set_arch 'hrpa-989'
+
+    @fetcher.data["#{@gem_repo}#{Gem::MARSHAL_SPEC_DIR}#{@pl1.original_name}.gemspec.rz"] =
+      util_zip(Marshal.dump(@pl1))
+
+    dep = Gem::Dependency.new 'pl', 1
+    specs_and_sources, errors = @sf.fetch_with_errors dep
+
+    assert_equal 0, specs_and_sources.size
+    assert_equal 1, errors.size
+
+    assert_equal "i386-linux", errors[0].platforms.first
+  end
+
   def test_fetch_spec
     spec_uri = "#{@gem_repo}#{Gem::MARSHAL_SPEC_DIR}#{@a1.spec_name}"
     @fetcher.data["#{spec_uri}.rz"] = util_zip(Marshal.dump(@a1))
@@ -220,6 +235,33 @@ def test_find_matching_platform
     assert_equal [], specs
   end
 
+  def test_find_matching_with_errors_matched_platform
+    util_set_arch 'i386-linux'
+
+    dep = Gem::Dependency.new 'pl', 1
+    specs, errors = @sf.find_matching_with_errors dep
+
+    expected = [
+      [['pl', Gem::Version.new(1), 'i386-linux'], @gem_repo],
+    ]
+
+    assert_equal expected, specs
+    assert_equal 0, errors.size
+  end
+
+  def test_find_matching_with_errors_invalid_platform
+    util_set_arch 'hrpa-899'
+
+    dep = Gem::Dependency.new 'pl', 1
+    specs, errors = @sf.find_matching_with_errors dep
+
+    assert_equal 0, specs.size
+
+    assert_equal 1, errors.size
+
+    assert_equal "i386-linux", errors[0].platforms.first
+  end
+
   def test_find_all_platforms
     util_set_arch 'i386-freebsd6'