[rubygems/rubygems] Add gem sources --prepend and --append for finer source control

--append adds a source to the end, moving it to the end if it already exists.
--prepend adds or moves a source to the beginning.

This allows idempotent sorting of gem sources without removing and adding.

ruby/rubygems@d9a0567c65

Author: martinemde

lib/rubygems/commands/sources_command.rb

@@ -18,6 +18,14 @@ def initialize
       options[:add] = value
     end
 
+    add_option "--append SOURCE_URI", "Append source (can be used multiple times)" do |value, options|
+      options[:append] = value
+    end
+
+    add_option "-p", "--prepend SOURCE_URI", "Prepend source (can be used multiple times)" do |value, options|
+      options[:prepend] = value
+    end
+
     add_option "-l", "--list", "List sources" do |value, options|
       options[:list] = value
     end
@@ -26,8 +34,7 @@ def initialize
       options[:remove] = value
     end
 
-    add_option "-c", "--clear-all",
-               "Remove all sources (clear the cache)" do |value, options|
+    add_option "-c", "--clear-all", "Remove all sources (clear the cache)" do |value, options|
       options[:clear_all] = value
     end
 
@@ -68,6 +75,60 @@ def add_source(source_uri) # :nodoc:
     end
   end
 
+  def append_source(source_uri) # :nodoc:
+    check_rubygems_https source_uri
+
+    source = Gem::Source.new source_uri
+
+    check_typo_squatting(source)
+
+    begin
+      source.load_specs :released
+      was_present = Gem.sources.include?(source)
+      Gem.sources.append source
+      Gem.configuration.write
+
+      if was_present
+        say "#{source_uri} moved to end of sources"
+      else
+        say "#{source_uri} added to sources"
+      end
+    rescue Gem::URI::Error, ArgumentError
+      say "#{source_uri} is not a URI"
+      terminate_interaction 1
+    rescue Gem::RemoteFetcher::FetchError => e
+      say "Error fetching #{Gem::Uri.redact(source.uri)}:\n\t#{e.message}"
+      terminate_interaction 1
+    end
+  end
+
+  def prepend_source(source_uri) # :nodoc:
+    check_rubygems_https source_uri
+
+    source = Gem::Source.new source_uri
+
+    check_typo_squatting(source)
+
+    begin
+      source.load_specs :released
+      was_present = Gem.sources.include?(source)
+      Gem.sources.prepend source
+      Gem.configuration.write
+
+      if was_present
+        say "#{source_uri} moved to top of sources"
+      else
+        say "#{source_uri} added to sources"
+      end
+    rescue Gem::URI::Error, ArgumentError
+      say "#{source_uri} is not a URI"
+      terminate_interaction 1
+    rescue Gem::RemoteFetcher::FetchError => e
+      say "Error fetching #{Gem::Uri.redact(source.uri)}:\n\t#{e.message}"
+      terminate_interaction 1
+    end
+  end
+
   def check_typo_squatting(source)
     if source.typo_squatting?("rubygems.org")
       question = <<-QUESTION.chomp
@@ -147,14 +208,20 @@ def description # :nodoc:
 of them in your list.  https://rubygems.org is recommended as it brings the
 protections of an SSL connection to gem downloads.
 
-To add a source use the --add argument:
+To add a private gem source use the --prepend argument to insert it before
+the default source. This is usually the best place for private gem sources:
 
-    $ gem sources --add https://my.private.source
+    $ gem sources --prepend https://my.private.source
     https://my.private.source added to sources
 
 RubyGems will check to see if gems can be installed from the source given
 before it is added.
 
+To add or move a source after all other sources, use --append:
+
+    $ gem sources --append https://rubygems.org
+    https://rubygems.org moved to end of sources
+
 To remove a source use the --remove argument:
 
     $ gem sources --remove https://my.private.source/
@@ -182,6 +249,8 @@ def list # :nodoc:
 
   def list? # :nodoc:
     !(options[:add] ||
+      options[:prepend] ||
+      options[:append] ||
       options[:clear_all] ||
       options[:remove] ||
       options[:update])
@@ -190,11 +259,13 @@ def list? # :nodoc:
   def execute
     clear_all if options[:clear_all]
 
-    source_uri = options[:add]
-    add_source source_uri if source_uri
+    add_source options[:add] if options[:add]
+
+    prepend_source options[:prepend] if options[:prepend]
+
+    append_source options[:append] if options[:append]
 
-    source_uri = options[:remove]
-    remove_source source_uri if source_uri
+    remove_source options[:remove] if options[:remove]
 
     update if options[:update]
 

lib/rubygems/source_list.rb

@@ -59,6 +59,42 @@ def <<(obj)
     src
   end
 
+  ##
+  # Prepends +obj+ to the beginning of the source list which may be a Gem::Source, Gem::URI or URI
+  # Moves +obj+ to the beginning of the list if already present.
+  # String.
+
+  def prepend(obj)
+    src = case obj
+          when Gem::Source
+            obj
+          else
+            Gem::Source.new(obj)
+    end
+
+    @sources.delete(src) if @sources.include?(src)
+    @sources.unshift(src)
+    src
+  end
+
+  ##
+  # Appends +obj+ to the end of the source list, moving it if already present.
+  # +obj+ may be a Gem::Source, Gem::URI or URI String.
+  # Moves +obj+ to the end of the list if already present.
+
+  def append(obj)
+    src = case obj
+          when Gem::Source
+            obj
+          else
+            Gem::Source.new(obj)
+    end
+
+    @sources.delete(src) if @sources.include?(src)
+    @sources << src
+    src
+  end
+
   ##
   # Replaces this SourceList with the sources in +other+  See #<< for
   # acceptable items in +other+.