cloud-fan commented on a change in pull request #28490:
URL: https://github.com/apache/spark/pull/28490#discussion_r481119430
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
##########
@@ -1325,25 +1325,54 @@ class Analyzer(
*
* Note : In this routine, the unresolved attributes are resolved from the
input plan's
* children attributes.
+ *
+ * @param e The expression need to be resolved.
+ * @param q The LogicalPlan whose children are used to resolve
expression's attribute.
+ * @param trimAlias When true, we will trim Struct field alias. When
isTopLevel = true,
+ * we won't trim top-level Struct field alias.
+ * @return resolved Expression.
*/
- private def resolveExpressionTopDown(e: Expression, q: LogicalPlan):
Expression = {
- if (e.resolved) return e
- e match {
- case f: LambdaFunction if !f.bound => f
- case u @ UnresolvedAttribute(nameParts) =>
- // Leave unchanged if resolution fails. Hopefully will be resolved
next round.
- val result =
- withPosition(u) {
- q.resolveChildren(nameParts, resolver)
- .orElse(resolveLiteralFunction(nameParts, u, q))
- .getOrElse(u)
+ private def resolveExpressionTopDown(
+ e: Expression,
+ q: LogicalPlan,
+ trimAlias: Boolean = false): Expression = {
+
+ // Explain for param trimAlias and isTopLevel:
+ // 1. trimAlias = false:
+ // We won't trim Struct Field alias.
+ // 2. trimAlias = true && isTopLevel = false:
+ // We will trim all Struct field alias.
+ // 3. trimAlias = true && isTopLevel = true
+ // Trim unnecessary alias of `GetStructField`. Note that, we cannot
trim the alias of
+ // top-level `GetStructField`, as we should resolve
`UnresolvedAttribute` to a named
+ // expression. The caller side can trim the alias of top-level
`GetStructField` if needed.
+ def innerResolve(
+ e: Expression,
+ isTopLevel: Boolean): Expression = {
Review comment:
nit: we can put the above 3 lines into one line
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