Fixes #187 - copying files from ext that do not exist.

waspc/src/Generator/FileDraft/CopyFileDraft.hs

@@ -2,6 +2,8 @@ module Generator.FileDraft.CopyFileDraft
        ( CopyFileDraft(..)
        ) where
 
+import Control.Monad (when)
+
 import StrongPath (Path, Abs, Rel, File, (</>))
 import qualified StrongPath as SP
 import Generator.Common (ProjectRootDir)
@@ -19,6 +21,14 @@ data CopyFileDraft = CopyFileDraft
 instance Writeable CopyFileDraft where
     write absDstDirPath draft = do
         createDirectoryIfMissing True (SP.toFilePath $ SP.parent absDraftDstPath)
-        copyFile (SP.toFilePath $ _srcPath draft) (SP.toFilePath $ absDraftDstPath)
+
+        -- NOTE(matija): we had cases (e.g. tmp Vim files) where file initially existed
+        -- when the filedraft was created but then got deleted before this function was invoked.
+        -- That would make this function crash, so here we make a check to make sure the given
+        -- file exists.
+        fileExists <- doesFileExist (SP.toFilePath $ _srcPath draft)
+        when fileExists
+             (copyFile (SP.toFilePath $ _srcPath draft) (SP.toFilePath $ absDraftDstPath))
+
       where
           absDraftDstPath = absDstDirPath </> (_dstPath draft)

waspc/src/Generator/FileDraft/WriteableMonad.hs

@@ -46,10 +46,15 @@ class (Monad m) => WriteableMonad m where
         -> Aeson.Value  -- ^ JSON to be provided as template data.
         -> m Text
 
+    doesFileExist
+        :: FilePath
+        -> m Bool
+
 instance WriteableMonad IO where
     createDirectoryIfMissing = System.Directory.createDirectoryIfMissing
     copyFile = System.Directory.copyFile
     writeFileFromText = Data.Text.IO.writeFile
     getTemplateFileAbsPath = Templates.getTemplateFileAbsPath
     getTemplatesDirAbsPath = Templates.getTemplatesDirAbsPath
     compileAndRenderTemplate = Templates.compileAndRenderTemplate
+    doesFileExist = System.Directory.doesFileExist

waspc/test/Generator/MockWriteableMonad.hs

@@ -61,6 +61,9 @@ instance WriteableMonad MockWriteableMonad where
         (_, config) <- get
         return $ (compileAndRenderTemplate_impl config) path json
 
+    doesFileExist path = MockWriteableMonad (return True)
+
+
 modifyLogs :: MonadState (a, b) m => (a -> a) -> m ()
 modifyLogs f = modify (\(logs, config) -> (f logs, config))