switch to a safe version of </>

Tags.hs

@@ -14,7 +14,7 @@ import qualified Data.Yaml as Y
 import Lens.Micro
 import Lens.Micro.Aeson
 import Lens.Micro.Mtl
-import System.FilePath ((</>), joinPath, splitDirectories, takeFileName)
+import System.FilePath (joinPath, splitDirectories, takeFileName)
 
 import AesonUtils
 import Types

Utils.hs

@@ -28,7 +28,7 @@ import System.Directory
   , doesDirectoryExist
   , getDirectoryContents
   )
-import System.FilePath ((</>), splitDirectories, takeDirectory)
+import System.FilePath (splitDirectories, takeDirectory)
 import Text.Pandoc.Definition
 import qualified Text.Pandoc.Walk
 import Types
@@ -96,6 +96,16 @@ unAbsolute = dropWhile (== '/')
 withPandocBlocks :: ([Block] -> [Block]) -> Pandoc -> Pandoc
 withPandocBlocks f (Pandoc meta blocks) = Pandoc meta (f blocks)
 
+infixr 5 </>
+
+a </> b@('/':_) =
+  error
+    $ "internal error: unchecked concatenation of absolute path: "
+        ++ a
+        ++ " </> "
+        ++ b
+a </> b = (System.FilePath.</>) a b
+
 -- | Get all contents of a directory. (Interned from Hakyll.)
 getRecursiveContents ::
      (FilePath -> IO Bool) -- ^ Ignore this file/directory

reploy.hs

@@ -306,7 +306,7 @@ installRedirect target' from = do
   target <- rootedPageLink target'
   tname <- use redirectTemplate
   templ <- use $ templates . to (M.! fromString tname)
-  file <- indexFilename from
+  file <- indexFilename (unAbsolute from)
   checkTarget file
   io $ do
     putStrLn $ "@ -> " ++ file ++ " -> " ++ target