Merge pull request ClickHouse#55749 from ClickHouse/backport/23.9/55602

Backport ClickHouse#55602 to 23.9: Fix crash in QueryNormalizer with cyclic aliases
azat · Oct 18, 2023 · 6f8349c · 6f8349c
2 parents dbc5fb8 + a9dc274
commit 6f8349c
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diff --git a/src/Interpreters/QueryNormalizer.cpp b/src/Interpreters/QueryNormalizer.cpp
@@ -68,6 +68,10 @@ class RestoreAliasOnExitScope
 
 void QueryNormalizer::visit(ASTIdentifier & node, ASTPtr & ast, Data & data)
 {
+    /// We do handle cycles via tracking current_asts
+    /// but in case of bug in that tricky logic we need to prevent stack overflow
+    checkStackSize();
+
     auto & current_asts = data.current_asts;
     String & current_alias = data.current_alias;
 

diff --git a/tests/queries/0_stateless/02896_cyclic_aliases_crash.reference b/tests/queries/0_stateless/02896_cyclic_aliases_crash.reference
@@ -0,0 +1 @@
+1	2	3
diff --git a/tests/queries/0_stateless/02896_cyclic_aliases_crash.sql b/tests/queries/0_stateless/02896_cyclic_aliases_crash.sql
@@ -0,0 +1,17 @@
+
+SET max_ast_depth = 10_000_000;
+
+SELECT
+    val,
+    val + 1 as prev,
+    val + prev as val
+FROM ( SELECT 1 as val )
+; -- { serverError CYCLIC_ALIASES, TOO_DEEP_RECURSION }
+
+
+SELECT
+    val,
+    val + 1 as prev,
+    val + prev as val2
+FROM ( SELECT 1 as val )
+;