Avoid putting a frame around speaker notes in beamer.

If speaker notes (a Div with class 'notes') occur right
after a section heading, but above slide level, the
resulting `\note{..}` caommand should not be wrapped in
a frame, as that will cause a spurious blank slide.

Closes #7857.

src/Text/Pandoc/Writers/LaTeX.hs

@@ -235,10 +235,13 @@ elementToBeamer slideLevel (Div (ident,"section":dclasses,dkvs)
              isSlide _                         = False
          let (titleBs, slideBs) = break isSlide ys
          return $
-           if null titleBs
-              then Div (ident,"section":dclasses,dkvs) xs
-              else Div (ident,"section":dclasses,dkvs)
-                    (h : Div ("","slide":dclasses,dkvs) (h:titleBs) : slideBs)
+           case titleBs of
+              [] -> Div (ident,"section":dclasses,dkvs) xs
+              [Div (_,"notes":_,_) _] ->  -- see #7857, don't create frame
+                    -- just for speaker notes after section heading
+                    Div (ident,"section":dclasses,dkvs) xs
+              _  -> Div (ident,"section":dclasses,dkvs)
+                     (h : Div ("","slide":dclasses,dkvs) (h:titleBs) : slideBs)
   | otherwise
     = return $ Div (ident,"slide":dclasses,dkvs) xs
 elementToBeamer _ x = return x

test/command/7857.md

@@ -0,0 +1,22 @@
+```
+% pandoc --slide-level=2 -t beamer
+# section
+
+::: notes
+my note
+:::
+
+## slide
+
+ok
+^D
+\hypertarget{section}{%
+\section{section}\label{section}}
+
+\note{my note}
+
+\begin{frame}{slide}
+\protect\hypertarget{slide}{}
+ok
+\end{frame}
+```