JATS writer: fix illegal use of p inside p.

Closes #11809.

src/Text/Pandoc/Writers/JATS.hs

@@ -366,12 +366,13 @@ blockToJATS opts (Div (ident,_,kvs) bs) = do
                      [(k,v) | (k,v) <- kvs, k `elem` ["specific-use",
                                                       "content-type"]]
   let boxed_attr = [(k,v) | (k,v) <- kvs, k `elem` ["orientation", "position"]]
-  let attr = generic_attr <> boxed_attr
+  let isPlain Plain{} = True
+      isPlain _ = False
   return $
-    if null attr
+    if null generic_attr && null boxed_attr
     then contents
     else -- The contents must be wrapped in an appropriate element.
-      let element = if null boxed_attr
+      let element = if null boxed_attr && all isPlain bs
                     then "p"
                     else "boxed-text"
       in inTags True element (generic_attr <> boxed_attr) contents

test/command/11809.md

@@ -0,0 +1,35 @@
+```
+% pandoc -f markdown -t jats
+::: {#d .warn}
+hi
+:::
+^D
+<boxed-text id="d">
+  <p>hi</p>
+</boxed-text>
+
+```
+
+```
+% pandoc -f html -t jats
+<div id="d">
+hi
+</div>
+^D
+<p id="d">
+  <p>hi</p>
+</p>
+
+```
+
+```
+% pandoc -f html -t jats
+<div class="foo">
+hi
+</div>
+^D
+<p>hi</p>
+
+```
+
+