Add support for path dependent markdown autolink (#1187)

Author: calvin-kargo

lib/ex_doc/autolink.ex

@@ -105,10 +105,11 @@ defmodule ExDoc.Autolink do
          uri <- URI.parse(href),
          nil <- uri.host,
          true <- is_binary(uri.path),
-         true <- uri.path == Path.basename(uri.path),
          ".md" <- Path.extname(uri.path) do
-      if uri.path in config.extras do
-        without_ext = String.trim_trailing(uri.path, ".md")
+      md_file = Path.basename(uri.path)
+
+      if md_file in config.extras do
+        without_ext = String.trim_trailing(md_file, ".md")
         fragment = (uri.fragment && "#" <> uri.fragment) || ""
         HTML.text_to_id(without_ext) <> config.ext <> fragment
       else

test/ex_doc/autolink_test.exs

@@ -202,6 +202,8 @@ defmodule ExDoc.AutolinkTest do
 
       assert autolink(~m"[Foo](Foo Bar.md#baz)", opts) == ~m"[Foo](foo-bar.html#baz)"
 
+      assert autolink(~m"[Foo](../guide/Foo Bar.md)", opts) == ~m"[Foo](foo-bar.html)"
+
       assert_unchanged(~m"[Foo](http://example.com/foo.md)", opts)
 
       assert_unchanged(~m"[Foo](#baz)", opts)