Fix bash completion for --print-default-data-file.

Previously this looked in the filesystem, even if pandoc
was compiled with `embed_data_files` (and sometimes it looked
in a nonexistent build directory).  Now the bash completion
script just includes a hard-coded list of data file names.
See #4549.

data/bash_completion.tpl

@@ -4,7 +4,7 @@
 
 _pandoc()
 {
-    local cur prev opts lastc informats outformats datadir
+    local cur prev opts lastc informats outformats datafiles
     COMPREPLY=()
     cur="${COMP_WORDS[COMP_CWORD]}"
     prev="${COMP_WORDS[COMP_CWORD-1]}"
@@ -14,7 +14,7 @@ _pandoc()
     informats="%s"
     outformats="%s"
     highlight_styles="%s"
-    datadir="%s"
+    datafiles="%s"
 
     case "${prev}" in
          --from|-f|--read|-r)
@@ -34,7 +34,7 @@ _pandoc()
              return 0
              ;;
          --print-default-data-file)
-             COMPREPLY=( $(compgen -W "reference.odt reference.docx $(find ${datadir} | sed -e 's/.*\/data\///')" -- ${cur}) )
+             COMPREPLY=( $(compgen -W "${datafiles}" -- ${cur}) )
              return 0
              ;;
          --wrap)

src/Text/Pandoc/App.hs

@@ -66,7 +66,11 @@ import Data.Yaml (decode)
 import qualified Data.Yaml as Yaml
 import GHC.Generics
 import Network.URI (URI (..), parseURI)
+#ifdef EMBED_DATA_FILES
+import Text.Pandoc.Data (dataFiles)
+#else
 import Paths_pandoc (getDataDir)
+#endif
 import Data.Aeson.Encode.Pretty (encodePretty', Config(..), keyOrder,
          defConfig, Indent(..), NumberFormat(..))
 import Skylighting (Style, Syntax (..), defaultSyntaxMap, parseTheme,
@@ -1475,7 +1479,7 @@ options =
     , Option "" ["bash-completion"]
                  (NoArg
                   (\_ -> do
-                     ddir <- getDataDir
+                     datafiles <- getDataFileNames
                      tpl <- runIOorExplode $
                               UTF8.toString <$>
                                 readDefaultDataFile "bash_completion.tpl"
@@ -1487,7 +1491,7 @@ options =
                          (unwords readersNames)
                          (unwords writersNames)
                          (unwords $ map fst highlightingStyles)
-                         ddir
+                         (unwords datafiles)
                      exitSuccess ))
                  "" -- "Print bash completion script"
 
@@ -1561,6 +1565,16 @@ options =
 
     ]
 
+getDataFileNames :: IO [FilePath]
+getDataFileNames = do
+#ifdef EMBED_DATA_FILES
+  let allDataFiles = map fst dataFiles
+#else
+  allDataFiles <- filter (\x -> x /= "." && x /= "..") <$>
+                      (getDataDir >>= getDirectoryContents)
+#endif
+  return $ "reference.docx" : "reference.odt" : "reference.pptx" : allDataFiles
+
 -- Returns usage message
 usageMessage :: String -> [OptDescr (Opt -> IO Opt)] -> String
 usageMessage programName = usageInfo (programName ++ " [OPTIONS] [FILES]")