From 31c782499e9c8dc9e790314a561a34504b27a347 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Thu, 21 Sep 2023 23:00:28 -0400
Subject: [PATCH] Do not match text markup end with empty contents.

---
 src/parser/org_source.rs  |  4 ++++
 src/parser/text_markup.rs | 21 ++++++++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/parser/org_source.rs b/src/parser/org_source.rs
index 41348124..f38b85da 100644
--- a/src/parser/org_source.rs
+++ b/src/parser/org_source.rs
@@ -59,6 +59,10 @@ impl<'s> OrgSource<'s> {
         self.end - self.start
     }
 
+    pub(crate) fn get_byte_offset(&self) -> usize {
+        self.start
+    }
+
     pub(crate) fn get_preceding_character(&self) -> Option<char> {
         self.preceding_character
     }
diff --git a/src/parser/text_markup.rs b/src/parser/text_markup.rs
index 5cae3f69..a32c4c11 100644
--- a/src/parser/text_markup.rs
+++ b/src/parser/text_markup.rs
@@ -182,7 +182,7 @@ fn _text_markup_object<'b, 'g, 'r, 's, 'c>(
     let (remaining, open) = tag(marker_symbol)(remaining)?;
     let (remaining, _peek_not_whitespace) =
         peek(verify(anychar, |c| !c.is_whitespace() && *c != '\u{200B}'))(remaining)?;
-    let text_markup_end_specialized = text_markup_end(open.into());
+    let text_markup_end_specialized = text_markup_end(open.into(), remaining.get_byte_offset());
     let contexts = [
         ContextElement::ContextObject(marker_symbol),
         ContextElement::ExitMatcherNode(ExitMatcherNode {
@@ -244,7 +244,7 @@ fn _text_markup_string<'b, 'g, 'r, 's, 'c>(
     let (remaining, open) = tag(marker_symbol)(remaining)?;
     let (remaining, _peek_not_whitespace) =
         peek(verify(anychar, |c| !c.is_whitespace() && *c != '\u{200B}'))(remaining)?;
-    let text_markup_end_specialized = text_markup_end(open.into());
+    let text_markup_end_specialized = text_markup_end(open.into(), remaining.get_byte_offset());
     let contexts = [
         ContextElement::ContextObject(marker_symbol),
         ContextElement::ExitMatcherNode(ExitMatcherNode {
@@ -315,8 +315,13 @@ fn post<'b, 'g, 'r, 's>(
     Ok((remaining, ()))
 }
 
-fn text_markup_end<'c>(marker_symbol: &'c str) -> impl ContextMatcher + 'c {
-    move |context, input: OrgSource<'_>| _text_markup_end(context, input, marker_symbol)
+fn text_markup_end<'c>(
+    marker_symbol: &'c str,
+    contents_start_offset: usize,
+) -> impl ContextMatcher + 'c {
+    move |context, input: OrgSource<'_>| {
+        _text_markup_end(context, input, marker_symbol, contents_start_offset)
+    }
 }
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
@@ -324,7 +329,13 @@ fn _text_markup_end<'b, 'g, 'r, 's, 'c>(
     context: RefContext<'b, 'g, 'r, 's>,
     input: OrgSource<'s>,
     marker_symbol: &'c str,
+    contents_start_offset: usize,
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
+    if input.get_byte_offset() == contents_start_offset {
+        return Err(nom::Err::Error(CustomError::MyError(MyError(
+            "Text markup cannot be empty".into(),
+        ))));
+    }
     not(preceded_by_whitespace(false))(input)?;
     let (remaining, _marker) = terminated(
         tag(marker_symbol),
@@ -424,7 +435,7 @@ fn _rematch_text_markup_object<'b, 'g, 'r, 's, 'x>(
     let (remaining, _) = pre(context, input)?;
     let (remaining, open) = tag(marker_symbol)(remaining)?;
     let (remaining, _peek_not_whitespace) = peek(not(multispace1))(remaining)?;
-    let text_markup_end_specialized = text_markup_end(open.into());
+    let text_markup_end_specialized = text_markup_end(open.into(), remaining.get_byte_offset());
     let parser_context = ContextElement::ExitMatcherNode(ExitMatcherNode {
         class: ExitClass::Gamma,
         exit_matcher: &text_markup_end_specialized,