From 64e0dfa5306aebdedeb65f2a6db95f4d2314f143 Mon Sep 17 00:00:00 2001
From: Robert Speicher <rspeicher@gmail.com>
Date: Tue, 22 Sep 2015 18:26:51 -0400
Subject: [PATCH] Prevent double-prefixing of help page paths

Prior, because the link "api/README.md" was matched twice, the first
link became "help/help/api/README.md". Now we do a negative lookahead to
make sure the link doesn't start with `help/`.

This fix is still not ideal, see TODO note.
---
 app/controllers/help_controller.rb | 18 ++++++++++++++++++
 app/views/help/index.html.haml     |  6 +-----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/app/controllers/help_controller.rb b/app/controllers/help_controller.rb
index ad00948da5..7283c4f4a4 100644
--- a/app/controllers/help_controller.rb
+++ b/app/controllers/help_controller.rb
@@ -4,6 +4,8 @@ class HelpController < ApplicationController
   layout 'help'
 
   def index
+    @help_index = File.read(Rails.root.join('doc', 'README.md'))
+    prefix_help_links!(@help_index)
   end
 
   def show
@@ -57,6 +59,22 @@ class HelpController < ApplicationController
     params
   end
 
+  # Prefix links in a Markdown document with `help/` unless they already have
+  # been
+  #
+  # TODO (rspeicher): This should be a pipeline filter that only gets included
+  # for help pages, and it should operate on the Nokogiri doc to be more robust.
+  #
+  # text - Markdown String
+  #
+  # Modifies `text` in-place
+  def prefix_help_links!(text)
+    # Match text inside a Markdown link unless it already starts with `help/`
+    #
+    # See http://rubular.com/r/nwwhzH6Z8X
+    text.gsub!(%r{(\]\()(?!help\/)([^\)\(]+)(\))}x, '\1help/\2\3')
+  end
+
   PATH_SEPS = Regexp.union(*[::File::SEPARATOR, ::File::ALT_SEPARATOR].compact)
 
   # Taken from ActionDispatch::FileHandler
diff --git a/app/views/help/index.html.haml b/app/views/help/index.html.haml
index f492aaf4c0..ab7ed1b5d9 100644
--- a/app/views/help/index.html.haml
+++ b/app/views/help/index.html.haml
@@ -27,11 +27,7 @@
   .col-md-8
     .documentation-index
       = preserve do
-        - readme_text = File.read(Rails.root.join("doc", "README.md"))
-        - text = readme_text.dup
-        - readme_text.scan(/\]\(([^(]+)\)/) { |match| text.gsub!(match.first, "help/#{match.first}") }
-        = markdown text
-
+        = markdown(@help_index)
   .col-md-4
     .panel.panel-default
       .panel-heading