Fix CAST(interval day to second as varchar)

Summary: CAST expression used to handle INTERVAL DAY TO SECOND values as BIGINT. This allowed invalid casts (e.g. from varchar, to double, etc.) and produced incorrect results when casting to varchar. Casting 1 second interval used to return '1000' instead of '0 00:00:01.000'. Fixes facebookincubator#9384 Differential Revision: D55796600
mbasmanova · Apr 5, 2024 · b34a61e · b34a61e
1 parent 60aa8f8
commit b34a61e
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diff --git a/velox/expression/CastExpr.cpp b/velox/expression/CastExpr.cpp
@@ -159,6 +159,7 @@ VectorPtr CastExpr::castFromDate(
       auto* resultFlatVector = castResult->as<FlatVector<StringView>>();
       applyToSelectedNoThrowLocal(context, rows, castResult, [&](int row) {
         try {
+          // TODO Optimize to avoid creating an intermediate string.
           auto output = DATE()->toString(inputFlatVector->valueAt(row));
           auto writer = exec::StringWriter<>(resultFlatVector, row);
           writer.resize(output.size());
@@ -247,6 +248,49 @@ VectorPtr CastExpr::castToDate(
   }
 }
 
+VectorPtr CastExpr::castFromIntervalDayTime(
+    const SelectivityVector& rows,
+    const BaseVector& input,
+    exec::EvalCtx& context,
+    const TypePtr& toType) {
+  VectorPtr castResult;
+  context.ensureWritable(rows, toType, castResult);
+  (*castResult).clearNulls(rows);
+
+  auto* inputFlatVector = input.as<SimpleVector<int64_t>>();
+  switch (toType->kind()) {
+    case TypeKind::VARCHAR: {
+      auto* resultFlatVector = castResult->as<FlatVector<StringView>>();
+      applyToSelectedNoThrowLocal(context, rows, castResult, [&](int row) {
+        try {
+          // TODO Optimize to avoid creating an intermediate string.
+          auto output =
+              INTERVAL_DAY_TIME()->valueToString(inputFlatVector->valueAt(row));
+          auto writer = exec::StringWriter<>(resultFlatVector, row);
+          writer.resize(output.size());
+          std::memcpy(writer.data(), output.data(), output.size());
+          writer.finalize();
+        } catch (const VeloxException& ue) {
+          if (!ue.isUserError()) {
+            throw;
+          }
+          VELOX_USER_FAIL(
+              makeErrorMessage(input, row, toType) + " " + ue.message());
+        } catch (const std::exception& e) {
+          VELOX_USER_FAIL(
+              makeErrorMessage(input, row, toType) + " " + e.what());
+        }
+      });
+      return castResult;
+    }
+    default:
+      VELOX_UNSUPPORTED(
+          "Cast from {} to {} is not supported",
+          INTERVAL_DAY_TIME()->toString(),
+          toType->toString());
+  }
+}
+
 namespace {
 void propagateErrorsOrSetNulls(
     bool setNullInResultAtError,
@@ -677,6 +721,13 @@ void CastExpr::applyPeeled(
     result = castFromDate(rows, input, context, toType);
   } else if (toType->isDate()) {
     result = castToDate(rows, input, context, fromType);
+  } else if (fromType->isIntervalDayTime()) {
+    result = castFromIntervalDayTime(rows, input, context, toType);
+  } else if (toType->isIntervalDayTime()) {
+    VELOX_UNSUPPORTED(
+        "Cast from {} to {} is not supported",
+        fromType->toString(),
+        toType->toString());
   } else if (toType->isShortDecimal()) {
     result = applyDecimal<int64_t>(rows, input, context, fromType, toType);
   } else if (toType->isLongDecimal()) {

diff --git a/velox/expression/CastExpr.h b/velox/expression/CastExpr.h
@@ -189,6 +189,12 @@ class CastExpr : public SpecialForm {
       exec::EvalCtx& context,
       const TypePtr& fromType);
 
+  VectorPtr castFromIntervalDayTime(
+      const SelectivityVector& rows,
+      const BaseVector& input,
+      exec::EvalCtx& context,
+      const TypePtr& toType);
+
   template <typename TInput, typename TOutput>
   void applyDecimalCastKernel(
       const SelectivityVector& rows,

diff --git a/velox/expression/tests/CastExprTest.cpp b/velox/expression/tests/CastExprTest.cpp
@@ -2582,5 +2582,35 @@ TEST_F(CastExprTest, skipCastEvaluation) {
     assertEqualVectors(result, expected);
   }
 }
+
+TEST_F(CastExprTest, intervalDayTimeToVarchar) {
+  auto data = makeRowVector({
+      makeFlatVector<int64_t>(
+          {kMillisInDay,
+           kMillisInHour,
+           kMillisInMinute,
+           kMillisInSecond,
+           5 * kMillisInDay + 14 * kMillisInHour + 20 * kMillisInMinute +
+               52 * kMillisInSecond + 88},
+          INTERVAL_DAY_TIME()),
+  });
+
+  auto result = evaluate("cast(c0 as varchar)", data);
+  auto expected = makeFlatVector<std::string>({
+      "1 00:00:00.000",
+      "0 01:00:00.000",
+      "0 00:01:00.000",
+      "0 00:00:01.000",
+      "5 14:20:52.088",
+  });
+
+  assertEqualVectors(result, expected);
+
+  // Reverse cast is not supported.
+  VELOX_ASSERT_THROW(
+      evaluate("cast('5 14:20:52.088' as interval day to second)", data),
+      "Cast from VARCHAR to INTERVAL DAY TO SECOND is not supported");
+}
+
 } // namespace
 } // namespace facebook::velox::test