From ba55e0df4f7f100f8c03245096002ca024d7989e Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sun, 8 Oct 2023 13:23:12 -0400
Subject: [PATCH] Remove all whitespace from search option if it contains any
 line breaks and handle triple+ slashes for file links.

---
 src/compare/diff.rs      |  2 +-
 src/parser/angle_link.rs |  8 +++++++
 src/types/object.rs      | 46 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/src/compare/diff.rs b/src/compare/diff.rs
index c4a39679..2f26f224 100644
--- a/src/compare/diff.rs
+++ b/src/compare/diff.rs
@@ -3044,7 +3044,7 @@ fn compare_angle_link<'b, 's>(
         ),
         (
             EmacsField::Required(":search-option"),
-            |r| r.search_option,
+            |r| r.get_search_option(),
             compare_property_quoted_string
         )
     )? {
diff --git a/src/parser/angle_link.rs b/src/parser/angle_link.rs
index 46a55fac..cffa5338 100644
--- a/src/parser/angle_link.rs
+++ b/src/parser/angle_link.rs
@@ -1,13 +1,17 @@
 use nom::branch::alt;
 use nom::bytes::complete::tag;
+use nom::bytes::complete::take;
 use nom::bytes::complete::take_until;
 use nom::combinator::consumed;
+use nom::combinator::flat_map;
 use nom::combinator::map;
 use nom::combinator::map_parser;
 use nom::combinator::opt;
 use nom::combinator::peek;
 use nom::combinator::recognize;
 use nom::combinator::rest;
+use nom::combinator::verify;
+use nom::multi::many1_count;
 use nom::sequence::tuple;
 
 use super::org_source::OrgSource;
@@ -114,6 +118,10 @@ fn parse_file_angle_link<'b, 'g, 'r, 's>(
         )),
         |(_, application, _)| application,
     )(input)?;
+    let (remaining, _) = opt(flat_map(
+        peek(map(verify(many1_count(tag("/")), |c| *c >= 3), |c| c - 1)),
+        take,
+    ))(remaining)?;
     let (remaining, path) = alt((take_until("::"), rest))(remaining)?;
     let (remaining, search_option) = opt(map(tuple((tag("::"), rest)), |(_, search_option)| {
         search_option
diff --git a/src/types/object.rs b/src/types/object.rs
index 1eb54ab2..9b52c535 100644
--- a/src/types/object.rs
+++ b/src/types/object.rs
@@ -738,6 +738,12 @@ enum PathState {
     HasLineBreak(String),
 }
 
+enum SearchOptionState {
+    Normal,
+    HasWhitespace(usize),
+    HasLineBreak(String),
+}
+
 impl<'s> AngleLink<'s> {
     /// Remove line breaks but preserve multiple consecutive spaces.
     pub fn get_path(&self) -> Cow<'s, str> {
@@ -761,4 +767,44 @@ impl<'s> AngleLink<'s> {
             PathState::HasLineBreak(ret) => Cow::Owned(ret),
         }
     }
+
+    /// Remove all whitespace but only if search_option contains a line break.
+    pub fn get_search_option(&self) -> Option<Cow<'s, str>> {
+        self.search_option.map(|search_option| {
+            let mut state = SearchOptionState::Normal;
+            for (offset, c) in search_option.char_indices() {
+                match (&mut state, c) {
+                    (SearchOptionState::Normal, '\n') => {
+                        let mut ret = String::with_capacity(search_option.len());
+                        ret.push_str(&search_option[..offset]);
+                        state = SearchOptionState::HasLineBreak(ret);
+                    }
+                    (SearchOptionState::Normal, ' ' | '\t') => {
+                        state = SearchOptionState::HasWhitespace(offset);
+                    }
+                    (SearchOptionState::Normal, _) => {}
+                    (SearchOptionState::HasWhitespace(first_whitespace_offset), '\n') => {
+                        let mut ret = String::with_capacity(search_option.len());
+                        ret.push_str(&search_option[..*first_whitespace_offset]);
+                        for c in search_option[*first_whitespace_offset..offset].chars() {
+                            if !c.is_ascii_whitespace() {
+                                ret.push(c);
+                            }
+                        }
+                        state = SearchOptionState::HasLineBreak(ret);
+                    }
+                    (SearchOptionState::HasWhitespace(_), _) => {}
+                    (SearchOptionState::HasLineBreak(_), ' ' | '\t' | '\r' | '\n') => {}
+                    (SearchOptionState::HasLineBreak(ret), _) => {
+                        ret.push(c);
+                    }
+                }
+            }
+            match state {
+                SearchOptionState::Normal => Cow::Borrowed(search_option),
+                SearchOptionState::HasWhitespace(_) => Cow::Borrowed(search_option),
+                SearchOptionState::HasLineBreak(ret) => Cow::Owned(ret),
+            }
+        })
+    }
 }