Fix for bug in parsing `\include` in markdown.

Starting in 2.2.2, everything after an `\input` (or `\include`)
in a markdown file would be parsed as raw LaTeX.
This commit fixes the issue and adds a regression test.

Closes #4781.

2 files changed, 32 insertions, 1 deletions

diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index c15312cd8..1dd31d402 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -286,6 +286,12 @@ rawLaTeXBlock :: (PandocMonad m, HasMacros s, HasReaderOptions s)
 rawLaTeXBlock = do
   lookAhead (try (char '\\' >> letter))
   snd <$> (rawLaTeXParser False macroDef blocks
+      <|> (rawLaTeXParser True
+             (do choice (map controlSeq
+                   ["include", "input", "subfile", "usepackage"])
+                 skipMany opt
+                 braced
+                 return mempty) blocks)
       <|> rawLaTeXParser True
            (environment <|> blockCommand)
            (mconcat <$> (many (block <|> beginOrEndCommand))))
@@ -308,7 +314,10 @@ rawLaTeXInline :: (PandocMonad m, HasMacros s, HasReaderOptions s)
                => ParserT String s m String
 rawLaTeXInline = do
   lookAhead (try (char '\\' >> letter))
-  snd <$> rawLaTeXParser True (inlineEnvironment <|> inlineCommand') inlines
+  snd <$> (  rawLaTeXParser True
+              (mempty <$ (controlSeq "input" >> skipMany opt >> braced))
+              inlines
+        <|> rawLaTeXParser True (inlineEnvironment <|> inlineCommand') inlines)
 
 inlineCommand :: PandocMonad m => ParserT String ParserState m Inlines
 inlineCommand = do
diff --git a/test/command/4781.md b/test/command/4781.md
new file mode 100644
index 000000000..7dc973c7c
--- /dev/null
+++ b/test/command/4781.md
@@ -0,0 +1,22 @@
+```
+% pandoc -t native
+Markdown parsed *here*
+
+\include{command/bar}
+
+*But not here*
+^D
+[Para [Str "Markdown",Space,Str "parsed",Space,Emph [Str "here"]]
+,RawBlock (Format "latex") "\\include{command/bar}"
+,Para [Emph [Str "But",Space,Str "not",Space,Str "here"]]]
+```
+
+```
+% pandoc -t native
+*here* \input{command/bar}
+
+*But not here*
+^D
+[Para [Emph [Str "here"],Space,RawInline (Format "tex") "\\input{command/bar}"]
+,Para [Emph [Str "But",Space,Str "not",Space,Str "here"]]]
+```