merge span (#4031)

crates/nu-protocol/src/dataframe/compute_between.rs

@@ -21,7 +21,7 @@ pub fn compute_between_dataframes(
     if let (UntaggedValue::DataFrame(lhs), UntaggedValue::DataFrame(rhs)) =
         (&left.value, &right.value)
     {
-        let operation_span = left.tag.span.until(right.tag.span);
+        let operation_span = right.tag.span.merge(left.tag.span);
         match (lhs.is_series(), rhs.is_series()) {
             (true, true) => {
                 let lhs = &lhs

crates/nu-source/src/meta.rs

@@ -605,6 +605,16 @@ impl Span {
         Span::new(self.start, other.end)
     }
 
+    pub fn merge(&self, other: impl Into<Span>) -> Span {
+        let other = other.into();
+
+        if other.end < self.start {
+            other.until(self)
+        } else {
+            self.until(other)
+        }
+    }
+
     /// Returns a new Span by merging a later Span with the current Span.
     ///
     /// If the given Span is of the None variant,