Disable citations extension in writers if `--citeproc` is used.

Otherwise we get undesirable results, as the format's native
citation mechanism is used instead of (or in addition to) the
citeproc-generated citations. Closes #10662.

2 files changed, 7 insertions, 2 deletions

diff --git a/src/Text/Pandoc/App/OutputSettings.hs b/src/Text/Pandoc/App/OutputSettings.hs
index 38cd35455..3824ecbda 100644
--- a/src/Text/Pandoc/App/OutputSettings.hs
+++ b/src/Text/Pandoc/App/OutputSettings.hs
@@ -38,6 +38,7 @@ import System.FilePath
 import System.IO (stdout)
 import Text.Pandoc.Chunks (PathTemplate(..))
 import Text.Pandoc
+import Text.Pandoc.Filter (Filter(CiteprocFilter))
 import Text.Pandoc.App.Opt (Opt (..))
 import Text.Pandoc.App.CommandLineOptions (engines)
 import Text.Pandoc.Format (FlavoredFormat (..), applyExtensionsDiff,
@@ -121,7 +122,7 @@ optToOutputSettings scriptingEngine opts = do
                      then getAndCompile (tp <.> T.unpack format)
                      else throwError e)
 
-  (writer, writerExts, mtemplate) <-
+  (writer, writerExts', mtemplate) <-
     if "lua" `T.isSuffixOf` format
     then do
       let path = T.unpack format
@@ -150,6 +151,10 @@ optToOutputSettings scriptingEngine opts = do
         tmpl <- processCustomTemplate (compileDefaultTemplate format)
         return (w, wexts, tmpl)
 
+  -- see #10662:
+  let writerExts = if CiteprocFilter `elem` optFilters opts
+                      then disableExtension Ext_citations writerExts'
+                      else writerExts'
 
   let addSyntaxMap existingmap f = do
         res <- liftIO (parseSyntaxDefinition f)
diff --git a/src/Text/Pandoc/Filter.hs b/src/Text/Pandoc/Filter.hs
index 7b51f7239..36700d5f6 100644
--- a/src/Text/Pandoc/Filter.hs
+++ b/src/Text/Pandoc/Filter.hs
@@ -41,7 +41,7 @@ import Control.Monad (foldM, when)
 data Filter = LuaFilter FilePath
             | JSONFilter FilePath
             | CiteprocFilter -- built-in citeproc
-            deriving (Show, Generic)
+            deriving (Show, Generic, Eq)
 
 instance FromJSON Filter where
  parseJSON node =