github: produce better curl error messages. (#441)

* global: add RUBY_TWO global variable.

* test-bot: use RUBY_TWO global variable.

* github: produce better curl error messages.

If we don't know why curl has failed then ensure that the error messages
that it produced are included as part of the user output.

2 files changed, 18 insertions, 7 deletions

diff --git a/Library/Homebrew/utils/curl.rb b/Library/Homebrew/utils/curl.rb
index a1653d46c..db3534542 100644
--- a/Library/Homebrew/utils/curl.rb
+++ b/Library/Homebrew/utils/curl.rb
@@ -1,4 +1,5 @@
 require "pathname"
+require "open3"
 
 def curl_args(extra_args=[])
   curl = Pathname.new ENV["HOMEBREW_CURL"]
@@ -19,6 +20,15 @@ def curl(*args)
 end
 
 def curl_output(*args)
-  curl_args = curl_args(args) - ["--fail"]
-  Utils.popen_read_text(*curl_args)
+  curl_args = curl_args(args)
+  curl_args -= ["--fail"]
+  if RUBY_TWO
+    curl_args -= ["--silent"]
+    Open3.popen3(*curl_args) do |_, stdout, stderr, wait_thread|
+      [stdout.read, stderr.read, wait_thread.value]
+    end
+  else
+    output = Utils.popen_read_text(*curl_args)
+    [output, nil, $?]
+  end
 end
diff --git a/Library/Homebrew/utils/github.rb b/Library/Homebrew/utils/github.rb
index 36f6257f7..c5dbedd6c 100644
--- a/Library/Homebrew/utils/github.rb
+++ b/Library/Homebrew/utils/github.rb
@@ -146,7 +146,8 @@ module GitHub
 
       args += ["--dump-header", "#{headers_tmpfile.path}"]
 
-      output, _, http_code = curl_output(url.to_s, *args).rpartition("\n")
+      output, errors, status = curl_output(url.to_s, *args)
+      output, _, http_code = output.rpartition("\n")
       output, _, http_code = output.rpartition("\n") if http_code == "000"
       headers = headers_tmpfile.read
     ensure
@@ -159,8 +160,8 @@ module GitHub
     end
 
     begin
-      if !http_code.start_with?("2") && !$?.success?
-        raise_api_error(output, http_code, headers)
+      if !http_code.start_with?("2") && !status.success?
+        raise_api_error(output, errors, http_code, headers)
       end
       json = Utils::JSON.load output
       if block_given?
@@ -173,7 +174,7 @@ module GitHub
     end
   end
 
-  def raise_api_error(output, http_code, headers)
+  def raise_api_error(output, errors, http_code, headers)
     meta = {}
     headers.lines.each do |l|
       key, _, value = l.delete(":").partition(" ")
@@ -197,7 +198,7 @@ module GitHub
       raise HTTPNotFoundError, output
     else
       error = Utils::JSON.load(output)["message"] rescue nil
-      error ||= output
+      error ||= "curl failed! #{errors}"
       raise Error, error
     end
   end