refactor to use mem take

Author: ptravers

src/compute/src/render/reduce.rs

@@ -2345,24 +2345,22 @@ mod monoids {
             }
         }
 
-        // WARNING: Panics if self and source are of different `ReductionMonoid` enum entries.
         fn clone_from(&mut self, source: &Self) {
             use ReductionMonoid::*;
-            match (self, source) {
-                (Min(row), Min(source_row)) => {
-                    row.clone_from(source_row);
-                }
-                (Max(row), Max(source_row)) => {
-                    row.clone_from(source_row);
-                }
-                // FIXME(ptravers): not sure what we want to do here we can't overwrite
-                // without having owned access to the Row in dest. I don't see a way to
-                // achieve that without a clone. Is it better to panic or clone? I would lean
-                // clone for safety but I don't know how likely it is to hit the sad case
-                // in practice?
-                (dest, src) => soft_panic_or_log!(
-                    "Mismatched monoid variants in clone_from! destination: {dest:?} source: {src:?}",
-                ),
+
+            let mut row = match std::mem::take(self) {
+                Min(row) | Max(row) => row,
+            };
+
+            let source_row = match source {
+                Min(row) | Max(row) => row,
+            };
+
+            row.clone_from(source_row);
+
+            match source {
+                Min(_) => *self = Min(row),
+                Max(_) => *self = Max(row),
             }
         }
     }