assets: report an error in ob run when referenced file doesn't exist

ChangeLog.md

@@ -21,6 +21,7 @@ This project's release branch is `master`. This log is written from the perspect
   * [#903](https://github.com/obsidiansystems/obelisk/pull/903): Added support for a file which allows users to specify global variables and namespaces in JS, that should not be used by the Google Closure Compiler during minification of the GHCJS produced JS. See the [FAQ](FAQ.md).
 * Static Assets
   * [#922](https://github.com/obsidiansystems/obelisk/pull/922): Serve .wasm files with the correct MIME type
+  * Add a warning to ob run when `static` is called with a path to a file that doesn't exist
 
 ## v1.0.0.0 - 2022-01-04
 

lib/asset/manifest/src/Obelisk/Asset/TH.hs

@@ -12,8 +12,10 @@ module Obelisk.Asset.TH
 
 import Obelisk.Asset.Gather
 
+import Control.Monad
 import Language.Haskell.TH
 import Language.Haskell.TH.Syntax
+import System.Directory
 import System.FilePath.Posix
 
 -- | Produces the hashed path of a file
@@ -31,7 +33,11 @@ staticPrefix :: FilePath
 staticPrefix = "/static"
 
 staticAssetRaw :: FilePath -> Q Exp
-staticAssetRaw fp = returnQ $ LitE $ StringL $ staticPrefix </> fp
+staticAssetRaw fp = do
+  exists <- runIO $ doesFileExist $ "static.out/" <> fp
+  when (not exists) $
+    fail $ "The file " <> fp <> " was not found in static.out"
+  returnQ $ LitE $ StringL $ staticPrefix </> fp
 
 staticAssetHashed :: FilePath -> FilePath -> Q Exp
 staticAssetHashed root fp = do