From 9f040d4c5130be7376ab7abdbf23f4ebc7e07516 Mon Sep 17 00:00:00 2001
From: Andreas Chatzistergiou
 <93710326+andreaschat-db@users.noreply.github.com>
Date: Thu, 21 Mar 2024 18:57:32 +0100
Subject: [PATCH] [Spark] Current Date/Time resolution in constraints (#2766)

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#### Which Delta project/connector is this regarding?
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- [x] Spark
- [ ] Standalone
- [ ] Flink
- [ ] Kernel
- [ ] Other (fill in here)

## Description

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- Describe what this PR changes.
- Describe why we need the change.

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Heading towards the removal of codegenFallback from Date/Time
expressions (https://github.com/apache/spark/pull/44261), delta
constraints need to resolve current_datetime expressions during the
analysis of the invariants. The proposed changes work for both Spark 3.5
and Spark master.

## How was this patch tested?

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Existing tests. In particular, `CheckConstaintsSuite` covers constraints
with `current_timestamp()` expressions. Added an extra test to cover
`current_date()`.

## Does this PR introduce _any_ user-facing changes?

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No.
---
 .../constraints/DeltaInvariantCheckerExec.scala      | 12 +++++++++++-
 .../sql/delta/schema/CheckConstraintsSuite.scala     | 12 +++++++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/spark/src/main/scala/org/apache/spark/sql/delta/constraints/DeltaInvariantCheckerExec.scala b/spark/src/main/scala/org/apache/spark/sql/delta/constraints/DeltaInvariantCheckerExec.scala
index b3c9985692..0a1e063eff 100644
--- a/spark/src/main/scala/org/apache/spark/sql/delta/constraints/DeltaInvariantCheckerExec.scala
+++ b/spark/src/main/scala/org/apache/spark/sql/delta/constraints/DeltaInvariantCheckerExec.scala
@@ -27,10 +27,12 @@ import org.apache.spark.sql.SparkSession
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.analysis._
 import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.catalyst.optimizer
 import org.apache.spark.sql.catalyst.optimizer.ReplaceExpressions
 import org.apache.spark.sql.catalyst.plans.logical.{LogicalPlan, UnaryNode}
 import org.apache.spark.sql.catalyst.plans.physical.Partitioning
 import org.apache.spark.sql.catalyst.rules.RuleExecutor
+import org.apache.spark.sql.delta.util.AnalysisHelper
 import org.apache.spark.sql.execution.{SparkPlan, SparkStrategy, UnaryExecNode}
 import org.apache.spark.sql.types.StructType
 
@@ -71,9 +73,17 @@ case class DeltaInvariantCheckerExec(
     if (constraints.isEmpty) return child.execute()
     val invariantChecks =
       DeltaInvariantCheckerExec.buildInvariantChecks(child.output, constraints, session)
-    val boundRefs = invariantChecks.map(_.withBoundReferences(child.output))
+
+    // Resolve current_date()/current_time() expressions.
+    // We resolve currentTime for all invariants together to make sure we use the same timestamp.
+    val invariantsFakePlan = AnalysisHelper.FakeLogicalPlan(invariantChecks, Nil)
+    val newInvariantsPlan = optimizer.ComputeCurrentTime(invariantsFakePlan)
+    val localOutput = child.output
 
     child.execute().mapPartitionsInternal { rows =>
+      val boundRefs = newInvariantsPlan.expressions
+        .asInstanceOf[Seq[CheckDeltaInvariant]]
+        .map(_.withBoundReferences(localOutput))
       val assertions = UnsafeProjection.create(boundRefs)
       rows.map { row =>
         assertions(row)
diff --git a/spark/src/test/scala/org/apache/spark/sql/delta/schema/CheckConstraintsSuite.scala b/spark/src/test/scala/org/apache/spark/sql/delta/schema/CheckConstraintsSuite.scala
index ef67d70138..8799ed020c 100644
--- a/spark/src/test/scala/org/apache/spark/sql/delta/schema/CheckConstraintsSuite.scala
+++ b/spark/src/test/scala/org/apache/spark/sql/delta/schema/CheckConstraintsSuite.scala
@@ -277,18 +277,20 @@ class CheckConstraintsSuite extends QueryTest
     }
   }
 
-  testQuietly("constraint with analyzer-evaluated expressions") {
+  for (expression <- Seq("year(current_date())", "unix_timestamp()"))
+  testQuietly(s"constraint with analyzer-evaluated expressions. Expression: $expression") {
     withTestTable { table =>
-      // We use current_timestamp() as the most convenient analyzer-evaluated expression - of course
-      // in a realistic use case it'd probably not be right to add a constraint on a
+      // We use current_timestamp()/current_date() as the most convenient
+      // analyzer-evaluated expressions - of course in a realistic use case
+      // it'd probably not be right to add a constraint on a
       // nondeterministic expression.
       sql(s"ALTER TABLE $table ADD CONSTRAINT maxWithAnalyzerEval " +
-        s"CHECK (num < unix_timestamp())")
+        s"CHECK (num < $expression)")
       val e = intercept[InvariantViolationException] {
         sql(s"INSERT INTO $table VALUES (${Int.MaxValue}, 'data')")
       }
       errorContains(e.getMessage,
-        "maxwithanalyzereval (num < unix_timestamp()) violated by row")
+        s"maxwithanalyzereval (num < $expression) violated by row")
     }
   }