(datafusion) branch main updated: fix: lazy case else expression evaluation (#17311)

[adriangb]

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adriangb pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/datafusion.git


The following commit(s) were added to refs/heads/main by this push:
     new c62d67186f fix: lazy case else expression evaluation (#17311)
c62d67186f is described below

commit c62d67186fd034eca461304bedda5d2313ca62d3
Author: Chen Chongchen <chenkov...@qq.com>
AuthorDate: Tue Aug 26 23:32:10 2025 +0800

    fix: lazy case else expression evaluation (#17311)
---
 datafusion/physical-expr/src/expressions/case.rs | 14 ++++++++------
 datafusion/sqllogictest/test_files/case.slt      | 10 ++++++++++
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/datafusion/physical-expr/src/expressions/case.rs 
b/datafusion/physical-expr/src/expressions/case.rs
index 1a74e78f10..5fa5144ecd 100644
--- a/datafusion/physical-expr/src/expressions/case.rs
+++ b/datafusion/physical-expr/src/expressions/case.rs
@@ -323,12 +323,14 @@ impl CaseExpr {
         }
 
         if let Some(e) = self.else_expr() {
-            // keep `else_expr`'s data type and return type consistent
-            let expr = try_cast(Arc::clone(e), &batch.schema(), 
return_type.clone())?;
-            let else_ = expr
-                .evaluate_selection(batch, &remainder)?
-                .into_array(batch.num_rows())?;
-            current_value = zip(&remainder, &else_, &current_value)?;
+            if remainder.true_count() > 0 {
+                // keep `else_expr`'s data type and return type consistent
+                let expr = try_cast(Arc::clone(e), &batch.schema(), 
return_type.clone())?;
+                let else_ = expr
+                    .evaluate_selection(batch, &remainder)?
+                    .into_array(batch.num_rows())?;
+                current_value = zip(&remainder, &else_, &current_value)?;
+            }
         }
 
         Ok(ColumnarValue::Array(current_value))
diff --git a/datafusion/sqllogictest/test_files/case.slt 
b/datafusion/sqllogictest/test_files/case.slt
index 21913005e2..69f80f4593 100644
--- a/datafusion/sqllogictest/test_files/case.slt
+++ b/datafusion/sqllogictest/test_files/case.slt
@@ -482,3 +482,13 @@ SELECT v, CASE WHEN v < 0 THEN 10/0 ELSE 1 END FROM 
(VALUES (1), (2)) t(v)
 
 statement ok
 drop table t
+
+query I
+SELECT case when true then 1 / 1 else 1 / 0 end;
+----
+1
+
+query I
+SELECT case when false then 1 / 0 else 1 / 1 end;
+----
+1


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