Fix handling of property drawers containing only whitespace.

src/parser/paragraph.rs

@@ -1,6 +1,8 @@
 use nom::branch::alt;
+use nom::character::complete::space1;
 use nom::combinator::consumed;
 use nom::combinator::eof;
+use nom::combinator::opt;
 use nom::combinator::recognize;
 use nom::combinator::verify;
 use nom::multi::many1;
@@ -13,6 +15,7 @@ use super::org_source::OrgSource;
 use super::util::blank_line;
 use super::util::get_consumed;
 use super::util::maybe_consume_trailing_whitespace_if_not_exiting;
+use super::util::org_line_ending;
 use crate::context::parser_with_context;
 use crate::context::ContextElement;
 use crate::context::ExitClass;
@@ -72,6 +75,57 @@ where
     ))
 }
 
+#[cfg_attr(
+    feature = "tracing",
+    tracing::instrument(ret, level = "debug", skip(context))
+)]
+pub(crate) fn empty_paragraph<'b, 'g, 'r, 's>(
+    context: RefContext<'b, 'g, 'r, 's>,
+    input: OrgSource<'s>,
+) -> Res<OrgSource<'s>, Paragraph<'s>> {
+    // If it is just a single newline then source, contents, and post-blank are "\n".
+    // If it has multiple newlines then contents is the first "\n" and post-blank is all the new lines.
+    // If there are any spaces on the first line then post-blank excludes the first line.
+
+    let exit_matcher = parser_with_context!(exit_matcher_parser)(context);
+
+    let (remaining, first_line_with_spaces) =
+        opt(recognize(tuple((space1, org_line_ending))))(input)?;
+
+    let post_blank_begin = remaining;
+
+    if let Some(first_line_with_spaces) = first_line_with_spaces {
+        let (remaining, _additional_lines) =
+            recognize(many_till(blank_line, exit_matcher))(remaining)?;
+        let post_blank = get_consumed(post_blank_begin, remaining);
+        let source = get_consumed(input, remaining);
+        Ok((
+            remaining,
+            Paragraph::of_text_full(
+                Into::<&str>::into(source),
+                Into::<&str>::into(first_line_with_spaces),
+                Some(Into::<&str>::into(first_line_with_spaces)),
+                Some(Into::<&str>::into(post_blank)),
+            ),
+        ))
+    } else {
+        let (remaining, first_line) = blank_line(remaining)?;
+        let (remaining, _additional_lines) =
+            recognize(many_till(blank_line, exit_matcher))(remaining)?;
+        let post_blank = get_consumed(post_blank_begin, remaining);
+        let source = get_consumed(input, remaining);
+        Ok((
+            remaining,
+            Paragraph::of_text_full(
+                Into::<&str>::into(source),
+                Into::<&str>::into(first_line),
+                Some(Into::<&str>::into(first_line)),
+                Some(Into::<&str>::into(post_blank)),
+            ),
+        ))
+    }
+}
+
 #[cfg_attr(
     feature = "tracing",
     tracing::instrument(ret, level = "debug", skip(context))
@@ -99,6 +153,7 @@ mod tests {
     use crate::context::List;
     use crate::parser::element_parser::element;
     use crate::parser::org_source::OrgSource;
+    use crate::parser::paragraph::empty_paragraph;
     use crate::types::StandardProperties;
 
     #[test]
@@ -115,4 +170,17 @@ mod tests {
         assert_eq!(first_paragraph.get_source(), "foo bar baz\n\n");
         assert_eq!(second_paragraph.get_source(), "lorem ipsum");
     }
+
+    #[test]
+    fn paragraph_whitespace() {
+        let input = OrgSource::new("\n");
+        let global_settings = GlobalSettings::default();
+        let initial_context = ContextElement::document_context();
+        let initial_context = Context::new(&global_settings, List::new(&initial_context));
+        let paragraph_matcher = bind_context!(empty_paragraph, &initial_context);
+        let (remaining, paragraph) = paragraph_matcher(input).expect("Parse paragraph");
+        assert_eq!(Into::<&str>::into(remaining), "");
+        assert_eq!(paragraph.get_source(), "\n");
+        assert_eq!(paragraph.get_contents(), Some("\n"));
+    }
 }