[WIP] brew search freezes on some GitHub API responses

Library/Homebrew/cask/lib/hbc/system_command.rb

@@ -81,31 +81,16 @@ def each_output_line(&b)
 
       write_input_to(raw_stdin)
       raw_stdin.close_write
-      each_line_from [raw_stdout, raw_stderr], &b
 
+      ::Utils::IOSelector
+        .each_line_from(stdout: raw_stdout, stderr: raw_stderr, &b)
       @processed_status = raw_wait_thr.value
     end
 
     def write_input_to(raw_stdin)
       [*options[:input]].each { |line| raw_stdin.print line }
     end
 
-    def each_line_from(sources)
-      loop do
-        readable_sources = IO.select(sources)[0]
-        readable_sources.delete_if(&:eof?).first(1).each do |source|
-          type = ((source == sources[0]) ? :stdout : :stderr)
-          begin
-            yield(type, source.readline_nonblock || "")
-          rescue IO::WaitReadable, EOFError
-            next
-          end
-        end
-        break if readable_sources.empty?
-      end
-      sources.each(&:close_read)
-    end
-
     def result
       Result.new(command,
                  processed_output[:stdout],

Library/Homebrew/test/spec_helper.rb

@@ -3,6 +3,7 @@
 require "rspec/its"
 require "rspec/wait"
 require "set"
+require "English"
 
 if ENV["HOMEBREW_TESTS_COVERAGE"]
   require "simplecov"
@@ -20,6 +21,7 @@
 require "tap"
 
 require "test/support/helper/shutup"
+require "test/support/helper/fake_curl"
 require "test/support/helper/fixtures"
 require "test/support/helper/formula"
 require "test/support/helper/mktmpdir"
@@ -42,6 +44,7 @@
   config.order = :random
 
   config.include(Test::Helper::Shutup)
+  config.include(Test::Helper::FakeCurl)
   config.include(Test::Helper::Fixtures)
   config.include(Test::Helper::Formula)
   config.include(Test::Helper::MkTmpDir)

Library/Homebrew/test/support/helper/fake_curl.rb

@@ -0,0 +1,25 @@
+require_relative "./mktmpdir"
+
+module Test
+  module Helper
+    module FakeCurl
+      def with_fake_curl(shell_command)
+        saved_value = ENV["HOMEBREW_CURL"]
+
+        begin
+          mktmpdir do |path|
+            fake_curl_path = path/"fake_curl"
+            File.open(fake_curl_path, "w") do |file|
+              file.write("#! #{`which bash`}\n#{shell_command}\n")
+            end
+            FileUtils.chmod 0755, fake_curl_path
+            ENV["HOMEBREW_CURL"] = fake_curl_path
+          end
+          return yield
+        ensure
+          ENV["HOMEBREW_CURL"] = saved_value
+        end
+      end
+    end
+  end
+end

Library/Homebrew/test/utils/curl_spec.rb

@@ -0,0 +1,137 @@
+require "utils/curl"
+
+describe "in `utils/curl`" do
+  before(:example) { ENV["HOMEBREW_CURL"] = "" }
+
+  describe "the `curl_args` method" do
+    let(:saved_travis_env) { ENV["TRAVIS"] }
+    before(:example) { ENV["TRAVIS"] = "1" }
+
+    describe "given no options" do
+      subject { curl_args }
+
+      it { is_expected.to be_an(Array) }
+
+      its(:size) { is_expected.to eq(8) }
+
+      it { is_expected.to start_with("/usr/bin/curl") }
+
+      it {
+        is_expected.to contain_exactly(
+          "/usr/bin/curl",
+          "--remote-time",
+          "--location",
+          "--user-agent",
+          HOMEBREW_USER_AGENT_CURL,
+          "--progress-bar",
+          "--fail",
+          "--silent",
+        )
+      }
+    end
+
+    describe "with the `user_agent` option set to `:browser`" do
+      subject { curl_args(user_agent: :browser) }
+
+      it { is_expected.to be_an(Array) }
+
+      its(:size) { is_expected.to eq(8) }
+
+      it { is_expected.to start_with("/usr/bin/curl") }
+
+      it {
+        is_expected.to contain_exactly(
+          "/usr/bin/curl",
+          "--remote-time",
+          "--location",
+          "--user-agent",
+          HOMEBREW_USER_AGENT_FAKE_SAFARI,
+          "--progress-bar",
+          "--fail",
+          "--silent",
+        )
+      }
+    end
+
+    describe "with the `show_output` option enabled" do
+      subject { curl_args(show_output: true) }
+
+      it { is_expected.to be_an(Array) }
+
+      its(:size) { is_expected.to eq(5) }
+
+      it { is_expected.to start_with("/usr/bin/curl") }
+
+      it {
+        is_expected.to contain_exactly(
+          "/usr/bin/curl",
+          "--remote-time",
+          "--location",
+          "--user-agent",
+          HOMEBREW_USER_AGENT_CURL,
+        )
+      }
+    end
+
+    after(:example) { ENV["TRAVIS"] = saved_travis_env }
+  end
+
+  describe "the `curl_output` method" do
+    describe "when curl outputs something on STDOUT only" do
+      subject { with_fake_curl("seq 1 5") { curl_output } }
+
+      it { is_expected.to be_an(Array) }
+      its(:size) { is_expected.to eq(3) }
+
+      its([0]) { is_expected.to eq([1, 2, 3, 4, 5, nil].join("\n")) }
+      its([1]) { is_expected.to be_empty }
+      its([2]) { is_expected.to be_a_success }
+    end
+
+    describe "when curl outputs something on STDERR only" do
+      subject { with_fake_curl("seq 1 5 >&2") { curl_output } }
+
+      it { is_expected.to be_an(Array) }
+      its(:size) { is_expected.to eq(3) }
+
+      its([0]) { is_expected.to be_empty }
+      its([1]) { is_expected.to eq([1, 2, 3, 4, 5, nil].join("\n")) }
+      its([2]) { is_expected.to be_a_success }
+    end
+
+    describe "when curl outputs something on STDOUT and STDERR" do
+      subject {
+        with_fake_curl(<<-EOF.undent) { curl_output }
+          for i in $(seq 1 2 5); do
+            echo $i; echo $(($i + 1)) >&2
+          done
+        EOF
+      }
+
+      it { is_expected.to be_an(Array) }
+      its(:size) { is_expected.to eq(3) }
+
+      its([0]) { is_expected.to eq([1, 3, 5, nil].join("\n")) }
+      its([1]) { is_expected.to eq([2, 4, 6, nil].join("\n")) }
+      its([2]) { is_expected.to be_a_success }
+    end
+
+    describe "with a very long STDERR output" do
+      let(:shell_command) {
+        <<-EOF.undent
+          for i in $(seq 1 2 100000); do
+            echo $i; echo $(($i + 1)) >&2
+          done
+        EOF
+      }
+
+      it "returns without deadlocking" do
+        wait(15).for {
+          with_fake_curl(shell_command) { curl_output }
+        }.to end_with(an_object_satisfying(&:success?))
+      end
+    end
+  end
+
+  after(:example) { ENV["HOMEBREW_CURL"] = "" }
+end