Fixed loss of error state when mapping errors

zesterer · Dec 17, 2024 · 773aef0 · 773aef0
1 parent f0a8694
commit 773aef0
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Showing 3 changed files with 42 additions and 4 deletions.
diff --git a/src/combinator.rs b/src/combinator.rs
@@ -2596,12 +2596,15 @@ where
     where
         Self: Sized,
     {
+        let old_alt = inp.take_alt();
         let res = self.parser.go::<M>(inp);
 
         if res.is_err() {
-            let mut e = inp.take_alt();
-            e.err = (self.mapper)(e.err);
-            inp.errors.alt = Some(e);
+            let mut new_alt = inp.take_alt();
+            new_alt.err = (self.mapper)(new_alt.err);
+
+            inp.errors.alt = Some(old_alt);
+            inp.add_alt_err(&new_alt.pos, new_alt.err);
         }
 
         res

diff --git a/src/input.rs b/src/input.rs
@@ -1729,7 +1729,14 @@ impl<'src, 'parse, I: Input<'src>, E: ParserExtra<'src, I>> InputRef<'src, 'pars
 
         // Prioritize errors before choosing whether to generate the alt (avoids unnecessary error creation)
         self.errors.alt = Some(match self.errors.alt.take() {
-            Some(alt) => match I::cursor_location(&alt.pos).cmp(&I::cursor_location(at)) {
+            Some(alt) => match {
+                println!(
+                    "Add alt alt = {}, at = {}",
+                    I::cursor_location(&alt.pos),
+                    I::cursor_location(at)
+                );
+                I::cursor_location(&alt.pos).cmp(&I::cursor_location(at))
+            } {
                 Ordering::Equal => {
                     Located::at(alt.pos, alt.err.merge_expected_found(expected, found, span))
                 }

diff --git a/src/lib.rs b/src/lib.rs
@@ -3597,4 +3597,32 @@ mod tests {
             )]),
         );
     }
+
+    #[test]
+    #[allow(dead_code)]
+    fn map_err_missed_info() {
+        use crate::error::Error;
+
+        fn zero<'src>() -> impl Parser<'src, &'src str, (), extra::Err<Rich<'src, char>>> {
+            just("-")
+                .or_not()
+                .then(just("0").map_err(move |e: Rich<_>| {
+                    Error::<&str>::expected_found(
+                        vec![Some('n'.into())],
+                        e.found().map(|i| From::from(*i)),
+                        e.span().clone(),
+                    )
+                }))
+                .ignored()
+        }
+
+        assert_eq!(
+            zero().parse("_0").into_result(),
+            Err(vec![<Rich<char> as Error::<&str>>::expected_found(
+                vec![Some('-'.into()), Some('n'.into())],
+                Some('_'.into()),
+                (0..1).into(),
+            )]),
+        );
+    }
 }