morrySnow commented on code in PR #67718:
URL: https://github.com/apache/doris/pull/67718#discussion_r3987959139
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fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/AccessPathExpressionCollector.java:
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@@ -321,7 +322,17 @@ public Void visitAlias(Alias alias, CollectorContext
context) {
@Override
public Void visitCast(Cast cast, CollectorContext context) {
+ // TRY_CAST semantics cover the WHOLE value: for a composite type any
element
+ // conversion failure makes the entire cast NULL (or, for a plain cast
under
+ // strict mode, raises an error). Narrowing the read/type to only the
fields an
+ // outer expression accesses would drop the conversion attempts of the
other
+ // fields and silently change the result (e.g. element_at(try_cast(s as
+ // struct<a:int,b:int>), 'a') must still fail when only field b is
unparsable).
+ // Plain Cast over nested types is pruned field-by-field on purpose;
TryCast is
+ // not, so do not translate a narrowed access path through a TryCast.
Falling
+ // through to the fresh context below reads the whole child value.
if (!context.accessPathBuilder.isEmpty()
+ && !(cast instanceof TryCast)
Review Comment:
加一个visitTryCast，而不是在visitCast里面处理TryCast
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