Respect git "core.commentchar" setting

The comment char is read from git config if it exists, but defaults to
"#" as before.

Fixes #530

features/pull_request.feature

@@ -155,6 +155,27 @@ Feature: hub pull-request
     Then the output should contain exactly "https://github.com/mislav/coral/pull/12\n"
     And the file ".git/PULLREQ_EDITMSG" should not exist
 
+  Scenario: Text editor with custom commentchar
+    Given git "core.commentchar" is set to "/"
+    And the text editor adds:
+      """
+      # Dat title
+
+      / This line is commented out.
+
+      Dem body.
+      """
+    Given the GitHub API server:
+      """
+      post('/repos/mislav/coral/pulls') {
+        assert :title => '# Dat title',
+               :body  => 'Dem body.'
+        json :html_url => "the://url"
+      }
+      """
+    When I successfully run `hub pull-request`
+    Then the output should contain exactly "the://url\n"
+
   Scenario: Failed pull request preserves previous message
     Given the text editor adds:
       """

lib/hub/commands.rb

@@ -232,14 +232,14 @@ module Hub
             [format, base_branch, remote_branch]
         end
 
-        options[:title], options[:body] = pullrequest_editmsg(commit_summary) { |msg, initial_message|
+        options[:title], options[:body] = pullrequest_editmsg(commit_summary) { |msg, initial_message, cc|
           initial_message ||= default_message
           msg.puts initial_message if initial_message
           msg.puts ""
-          msg.puts "# Requesting a pull to #{base_project.owner}:#{options[:base]} from #{options[:head]}"
-          msg.puts "#"
-          msg.puts "# Write a message for this pull request. The first block"
-          msg.puts "# of text is the title and the rest is description."
+          msg.puts "#{cc} Requesting a pull to #{base_project.owner}:#{options[:base]} from #{options[:head]}"
+          msg.puts "#{cc}"
+          msg.puts "#{cc} Write a message for this pull request. The first block"
+          msg.puts "#{cc} of text is the title and the rest is description."
         }
       end
 
@@ -1072,17 +1072,18 @@ help
 
     def pullrequest_editmsg(changes)
       message_file = pullrequest_editmsg_file
+      cc = git_commentchar
 
       if valid_editmsg_file?(message_file)
-        title, body = read_editmsg(message_file)
+        title, body = read_editmsg(message_file, cc)
         previous_message = [title, body].compact.join("\n\n") if title
       end
 
       File.open(message_file, 'w') { |msg|
-        yield msg, previous_message
+        yield msg, previous_message, cc
         if changes
-          msg.puts "#\n# Changes:\n#"
-          msg.puts changes.gsub(/^/, '# ').gsub(/ +$/, '')
+          msg.puts "#{cc}\n#{cc} Changes:\n#{cc}"
+          msg.puts changes.gsub(/^/, "#{cc} ").gsub(/ +$/, '')
         end
       }
 
@@ -1097,7 +1098,7 @@ help
         abort "error using text editor for pull request message"
       end
 
-      title, body = read_editmsg(message_file)
+      title, body = read_editmsg(message_file, cc)
       abort "Aborting due to empty pull request title" unless title
       [title, body]
     end
@@ -1118,11 +1119,11 @@ help
       File.join(git_dir, 'PULLREQ_EDITMSG')
     end
 
-    def read_editmsg(file)
+    def read_editmsg(file, commentchar)
       title, body = '', ''
       File.open(file, 'r') { |msg|
         msg.each_line do |line|
-          next if line.index('#') == 0
+          next if line.index(commentchar) == 0
           ((title.empty? and line =~ /\S/) ? title : body) << line
         end
       }

lib/hub/context.rb

@@ -504,6 +504,12 @@ module Hub
       end
     end
 
+    def git_commentchar
+      if str = git_config('core.commentchar') then str[0,1]
+      else '#'
+      end
+    end
+
     module System
       # Cross-platform web browser command; respects the value set in $BROWSER.
       #