Merge #3017

3017: Refactor remote fetcher r=hsbt a=deivid-rodriguez

# Description:

In rubygems/bundler#7460 I'm vendoring the `uri` library inside `bundler` to add support for using the `uri` version inside Gemfile's just like any other gem. However, that was not the only thing needed since `bundler/setup` also touches some code from this class in rubygems.

So the initial approach I took was to duplicate all the code inside bundler, replacing all reference to `URI` with `Bundler::URI` (the vendored namespace). Like in rubygems/bundler@3bcc579.

However, this is ugly and hard to maintain so in this PR I'm refactoring this class so that it is enough to override only one method in the `bundler` subclass, like this: https://github.com/bundler/bundler/blob/aa3a25d30383a16e002dd94c209a6078746204a7/lib/bundler/gem_remote_fetcher.rb 

# Tasks:

- [x] Describe the problem / feature
- [ ] Write tests
- [x] Write code to solve the problem
- [ ] Get code review from coworkers / friends

I will abide by the [code of conduct](https://github.com/rubygems/rubygems/blob/master/CODE_OF_CONDUCT.md).


Co-authored-by: David Rodríguez <deivid.rodriguez@riseup.net>

Manifest.txt

@@ -495,6 +495,8 @@ lib/rubygems/test_utilities.rb
 lib/rubygems/text.rb
 lib/rubygems/uninstaller.rb
 lib/rubygems/uri_formatter.rb
+lib/rubygems/uri_parser.rb
+lib/rubygems/uri_parsing.rb
 lib/rubygems/user_interaction.rb
 lib/rubygems/util.rb
 lib/rubygems/util/licenses.rb

lib/rubygems/remote_fetcher.rb

@@ -4,6 +4,7 @@
 require 'rubygems/request/connection_pools'
 require 'rubygems/s3_uri_signer'
 require 'rubygems/uri_formatter'
+require 'rubygems/uri_parsing'
 require 'rubygems/user_interaction'
 require 'resolv'
 require 'rubygems/deprecate'
@@ -17,26 +18,29 @@ class Gem::RemoteFetcher
   include Gem::UserInteraction
   extend Gem::Deprecate
 
+  include Gem::UriParsing
+
   ##
   # A FetchError exception wraps up the various possible IO and HTTP failures
   # that could happen while downloading from the internet.
 
   class FetchError < Gem::Exception
 
+    include Gem::UriParsing
+
     ##
     # The URI which was being accessed when the exception happened.
 
     attr_accessor :uri
 
     def initialize(message, uri)
       super message
-      begin
-        uri = URI(uri)
-        uri.password = 'REDACTED' if uri.password
-        @uri = uri.to_s
-      rescue URI::InvalidURIError, ArgumentError
-        @uri = uri
-      end
+
+      uri = parse_uri(uri)
+
+      uri.password = 'REDACTED' if uri.respond_to?(:password) && uri.password
+
+      @uri = uri.to_s
     end
 
     def to_s # :nodoc:
@@ -107,7 +111,7 @@ def download_to_cache(dependency)
 
     spec, source = found.max_by { |(s,_)| s.version }
 
-    download spec, source.uri.to_s
+    download spec, source.uri
   end
 
   ##
@@ -130,18 +134,7 @@ def download(spec, source_uri, install_dir = Gem.dir)
 
     FileUtils.mkdir_p cache_dir rescue nil unless File.exist? cache_dir
 
-    # Always escape URI's to deal with potential spaces and such
-    # It should also be considered that source_uri may already be
-    # a valid URI with escaped characters. e.g. "{DESede}" is encoded
-    # as "%7BDESede%7D". If this is escaped again the percentage
-    # symbols will be escaped.
-    unless source_uri.is_a?(URI::Generic)
-      begin
-        source_uri = URI.parse(source_uri)
-      rescue
-        source_uri = URI.parse(URI::DEFAULT_PARSER.escape(source_uri.to_s))
-      end
-    end
+    source_uri = parse_uri(source_uri)
 
     scheme = source_uri.scheme
 
@@ -159,7 +152,7 @@ def download(spec, source_uri, install_dir = Gem.dir)
           remote_gem_path = source_uri + "gems/#{gem_file_name}"
 
           self.cache_update_path remote_gem_path, local_gem_path
-        rescue Gem::RemoteFetcher::FetchError
+        rescue FetchError
           raise if spec.original_platform == spec.platform
 
           alternate_name = "#{spec.original_name}.gem"
@@ -236,7 +229,7 @@ def fetch_http(uri, last_modified = nil, head = false, depth = 0)
       unless location = response['Location']
         raise FetchError.new("redirecting but no redirect location was given", uri)
       end
-      location = URI.parse response['Location']
+      location = parse_uri location
 
       if https?(uri) && !https?(location)
         raise FetchError.new("redirecting to non-https resource: #{location}", uri)
@@ -254,9 +247,7 @@ def fetch_http(uri, last_modified = nil, head = false, depth = 0)
   # Downloads +uri+ and returns it as a String.
 
   def fetch_path(uri, mtime = nil, head = false)
-    uri = URI.parse uri unless URI::Generic === uri
-
-    raise ArgumentError, "bad uri: #{uri}" unless uri
+    uri = parse_uri uri
 
     unless uri.scheme
       raise ArgumentError, "uri scheme is invalid: #{uri.scheme.inspect}"
@@ -268,21 +259,19 @@ def fetch_path(uri, mtime = nil, head = false)
       begin
         data = Gem::Util.gunzip data
       rescue Zlib::GzipFile::Error
-        raise FetchError.new("server did not return a valid file", uri.to_s)
+        raise FetchError.new("server did not return a valid file", uri)
       end
     end
 
     data
-  rescue FetchError
-    raise
   rescue Timeout::Error
-    raise UnknownHostError.new('timed out', uri.to_s)
+    raise UnknownHostError.new('timed out', uri)
   rescue IOError, SocketError, SystemCallError,
          *(OpenSSL::SSL::SSLError if defined?(OpenSSL)) => e
     if e.message =~ /getaddrinfo/
-      raise UnknownHostError.new('no such name', uri.to_s)
+      raise UnknownHostError.new('no such name', uri)
     else
-      raise FetchError.new("#{e.class}: #{e}", uri.to_s)
+      raise FetchError.new("#{e.class}: #{e}", uri)
     end
   end
 

lib/rubygems/request.rb

@@ -19,6 +19,7 @@ def self.create_with_proxy(uri, request_class, last_modified, proxy) # :nodoc:
   end
 
   def self.proxy_uri(proxy) # :nodoc:
+    require "uri"
     case proxy
     when :no_proxy then nil
     when URI::HTTP then proxy
@@ -173,6 +174,7 @@ def self.get_proxy_from_env(scheme = 'http')
         :no_proxy : get_proxy_from_env('http')
     end
 
+    require "uri"
     uri = URI(Gem::UriFormatter.new(env_proxy).normalize)
 
     if uri and uri.user.nil? and uri.password.nil?

lib/rubygems/source.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 autoload :FileUtils, 'fileutils'
-autoload :URI, 'uri'
 
 require "rubygems/text"
 ##

lib/rubygems/uri_formatter.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 require 'cgi'
-require 'uri'
 
 ##
 # The UriFormatter handles URIs from user-input and escaping.

lib/rubygems/uri_parser.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+##
+# The UriParser handles parsing URIs.
+#
+
+class Gem::UriParser
+
+  ##
+  # Parses the #uri, raising if it's invalid
+
+  def parse!(uri)
+    raise URI::InvalidURIError unless uri
+
+    # Always escape URI's to deal with potential spaces and such
+    # It should also be considered that source_uri may already be
+    # a valid URI with escaped characters. e.g. "{DESede}" is encoded
+    # as "%7BDESede%7D". If this is escaped again the percentage
+    # symbols will be escaped.
+    begin
+      URI.parse(uri)
+    rescue URI::InvalidURIError
+      URI.parse(URI::DEFAULT_PARSER.escape(uri))
+    end
+  end
+
+  ##
+  # Parses the #uri, returning the original uri if it's invalid
+
+  def parse(uri)
+    parse!(uri)
+  rescue URI::InvalidURIError
+    uri
+  end
+
+end

lib/rubygems/uri_parsing.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "rubygems/uri_parser"
+
+module Gem::UriParsing
+
+  def parse_uri(source_uri)
+    return source_uri unless source_uri.is_a?(String)
+
+    uri_parser.parse(source_uri)
+  end
+
+  private :parse_uri
+
+  def uri_parser
+    require "uri"
+
+    Gem::UriParser.new
+  end
+
+  private :uri_parser
+
+end

test/rubygems/test_remote_fetch_error.rb

@@ -5,7 +5,7 @@ class TestRemoteFetchError < Gem::TestCase
 
   def test_password_redacted
     error = Gem::RemoteFetcher::FetchError.new('There was an error fetching', 'https://user:secret@gemsource.org')
-    refute_match error.to_s, 'secret'
+    refute_match 'secret', error.to_s
   end
 
   def test_invalid_url