Blog.permalink option being ignored

I’m setting up a new Middleman project for a personal site. Rather than keeping all articles at the top of the “source” directory, I’d like to move all articles to “source/articles”. However, I don’t want Middleman to generate article in the permalink, so I configured as so:

activate :blog do |blog|
  blog.paginate = true
  blog.prefix = nil
  blog.permalink = "{title}.html"
  blog.sources = "articles/{title}.html.md"
end

I know I’m being overly explicit with blog.prefix = nil but middleman seems to insist on generating the “articles” slug in the permalinks, anyway.

Output from /__middleman/sitemap/

example-article.html
Path	        articles/example-article.html
Build Path	articles/example-article/index.html
URL	        /articles/example-article/
Source File	source/articles/example-article.html.md
Data	        #<Hashie::Mash date=#<Date: 2012-01-01 ((2455928j,0s,0n),+0s,2299161j)> tags="example" title="Example Article">

test-article.html
Path	        articles/test-article.html
Build Path	articles/test-article/index.html
URL	        /articles/test-article/
Source File	source/articles/test-article.html.md
Data	        #<Hashie::Mash date=#<Date: 2016-01-22 ((2457410j,0s,0n),+0s,2299161j)> title="Test Article">

Using :title instead of {title} seems to have no impact, either.

Figured it out! Although my source files ended with .md stripping that extension out from blog.sources did the trick.

This works now:

activate :blog do |blog|
  blog.paginate = true
  blog.permalink = "{title}.html"
  blog.sources = "articles/{title}.html"
end