From 019f5d1c9d31cbfeccc85648e9263b923980a580 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Tue, 15 Oct 2024 11:52:32 -0700
Subject: [PATCH] RST reader: fix linked substitutions.

E.g. `|Python|_`.

Closes #6588.
---
 src/Text/Pandoc/Readers/RST.hs | 12 +++++++++---
 test/command/6588.md           | 10 ++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)
 create mode 100644 test/command/6588.md

diff --git a/src/Text/Pandoc/Readers/RST.hs b/src/Text/Pandoc/Readers/RST.hs
index 1860b14fe507..c2a4f098ac99 100644
--- a/src/Text/Pandoc/Readers/RST.hs
+++ b/src/Text/Pandoc/Readers/RST.hs
@@ -212,11 +212,11 @@ resolveReferences x@(Link _ ils (s,_))
           return $ Note (B.toList contents)
   | Just ref <- T.stripPrefix "##SUBST##" s = do
           substTable <- stateSubstitutions <$> getState
-          let key = toKey $ stripFirstAndLast ref
+          let key@(Key key') = toKey $ stripFirstAndLast ref
           case M.lookup key substTable of
                Nothing     -> do
                  pos <- getPosition
-                 logMessage $ ReferenceNotFound (tshow key) pos
+                 logMessage $ ReferenceNotFound (tshow key') pos
                  return x
                Just target -> case
                  B.toList target of
@@ -1711,7 +1711,13 @@ autoLink = autoURI <|> autoEmail
 subst :: PandocMonad m => RSTParser m Inlines
 subst = try $ do
   (_,ref) <- withRaw $ enclosed (char '|') (char '|') inline
-  pure $ B.linkWith nullAttr ("##SUBST##" <> ref) "" (B.text ref)
+  let substlink = B.linkWith nullAttr ("##SUBST##" <> ref) "" (B.text ref)
+  reflink <- option False (True <$ char '_')
+  if reflink
+     then do
+       let linkref = T.drop 1 $ T.dropEnd 1 ref
+       return $ B.linkWith nullAttr ("##REF##" <> linkref) "" substlink
+     else return substlink
 
 note :: PandocMonad m => RSTParser m Inlines
 note = try $ do
diff --git a/test/command/6588.md b/test/command/6588.md
new file mode 100644
index 000000000000..efd3a68512b8
--- /dev/null
+++ b/test/command/6588.md
@@ -0,0 +1,10 @@
+```
+% pandoc -f rst
+I recommend you try |Python|_.
+
+.. |Python| replace:: Python, *the* best language around
+.. _Python: http://www.python.org/
+^D
+<p>I recommend you try <a href="http://www.python.org/"><span>Python,
+<em>the</em> best language around</span></a>.</p>
+```