From 1d580ec1996e75bb9be4c1c880871d0dd2718ad4 Mon Sep 17 00:00:00 2001
From: Marko Grujic <markoog@gmail.com>
Date: Thu, 14 Nov 2024 08:39:54 +0100
Subject: [PATCH] Fix negative decimal e-notation parsing (#6729)

---
 arrow-cast/src/parse.rs | 28 ++++++++++++++++++++++------
 arrow-select/src/zip.rs |  2 +-
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/arrow-cast/src/parse.rs b/arrow-cast/src/parse.rs
index e332e5bbaaec..4bd94c13fe8d 100644
--- a/arrow-cast/src/parse.rs
+++ b/arrow-cast/src/parse.rs
@@ -841,19 +841,20 @@ pub fn parse_decimal<T: DecimalType>(
     let base = T::Native::usize_as(10);
 
     let bs = s.as_bytes();
-    let (bs, negative) = match bs.first() {
-        Some(b'-') => (&bs[1..], true),
-        Some(b'+') => (&bs[1..], false),
-        _ => (bs, false),
+    let (signed, negative) = match bs.first() {
+        Some(b'-') => (true, true),
+        Some(b'+') => (true, false),
+        _ => (false, false),
     };
 
-    if bs.is_empty() {
+    if bs.is_empty() || signed && bs.len() == 1 {
         return Err(ArrowError::ParseError(format!(
             "can't parse the string value {s} to decimal"
         )));
     }
 
-    let mut bs = bs.iter().enumerate();
+    // Iterate over the raw input bytes, skipping the sign if any
+    let mut bs = bs.iter().enumerate().skip(signed as usize);
 
     let mut is_e_notation = false;
 
@@ -2679,6 +2680,21 @@ mod tests {
                 0i128,
                 15,
             ),
+            (
+                "-1e3",
+                -1000000000i128,
+                6,
+            ),
+            (
+                "+1e3",
+                1000000000i128,
+                6,
+            ),
+            (
+                "-1e31",
+                -10000000000000000000000000000000000000i128,
+                6,
+            ),
         ];
         for (s, i, scale) in edge_tests_128 {
             let result_128 = parse_decimal::<Decimal128Type>(s, 38, scale);
diff --git a/arrow-select/src/zip.rs b/arrow-select/src/zip.rs
index 1f317dfd45c6..acb31dfa3bc2 100644
--- a/arrow-select/src/zip.rs
+++ b/arrow-select/src/zip.rs
@@ -53,7 +53,7 @@ pub fn zip(
             "all arrays should have the same length".into(),
         ));
     }
-    if truthy_is_scalar && truthy.len() != 1 {
+    if falsy_is_scalar && falsy.len() != 1 {
         return Err(ArrowError::InvalidArgumentError(
             "scalar arrays must have 1 element".into(),
         ));