fix(presto): iterate over copy in eliminate_semi_and_anti_joins (#7455)

When a SELECT has multiple SEMI or ANTI joins,
eliminate_semi_and_anti_joins iterates over the joins list while
calling join.pop(), which mutates the list mid-iteration. This
causes every other SEMI/ANTI join to be skipped, leaving bare
ANTI JOIN / SEMI JOIN syntax in the generated SQL — invalid for
dialects like Presto/Trino that rely on this transform.

Fix: iterate over list(...) so removals don't shift unvisited
elements. Same approach as PR #4364 which fixed the identical
pattern in unnest_to_explode.

Made-with: Cursor

Author: Evgeniy-Sinyak

sqlglot/transforms.py

@@ -606,7 +606,7 @@ def epoch_cast_to_ts(expression: exp.Expr) -> exp.Expr:
 def eliminate_semi_and_anti_joins(expression: exp.Expr) -> exp.Expr:
     """Convert SEMI and ANTI joins into equivalent forms that use EXIST instead."""
     if isinstance(expression, exp.Select):
-        for join in expression.args.get("joins") or []:
+        for join in list(expression.args.get("joins") or []):
             on = join.args.get("on")
             if on and join.kind in ("SEMI", "ANTI"):
                 subquery = exp.select("1").from_(join.this).where(on)

tests/test_transforms.py

@@ -5,6 +5,7 @@
     eliminate_distinct_on,
     eliminate_join_marks,
     eliminate_qualify,
+    eliminate_semi_and_anti_joins,
     eliminate_window_clause,
     inherit_struct_field_names,
     remove_precision_parameterized_types,
@@ -279,6 +280,33 @@ def test_eliminate_join_marks(self):
                 AssertionError, eliminate_join_marks, parse_one(script, dialect=dialect)
             )
 
+    def test_eliminate_semi_and_anti_joins(self):
+        self.validate(
+            eliminate_semi_and_anti_joins,
+            "SELECT t1.id FROM t1 JOIN t2 ON t1.id = t2.id ANTI JOIN t3 ON t1.id = t3.id",
+            "SELECT t1.id FROM t1 JOIN t2 ON t1.id = t2.id WHERE NOT EXISTS(SELECT 1 FROM t3 WHERE t1.id = t3.id)",
+        )
+        self.validate(
+            eliminate_semi_and_anti_joins,
+            "SELECT t1.id FROM t1 JOIN t2 ON t1.id = t2.id SEMI JOIN t3 ON t1.id = t3.id",
+            "SELECT t1.id FROM t1 JOIN t2 ON t1.id = t2.id WHERE EXISTS(SELECT 1 FROM t3 WHERE t1.id = t3.id)",
+        )
+        self.validate(
+            eliminate_semi_and_anti_joins,
+            "SELECT t1.id FROM t1 ANTI JOIN t2 ON t1.id = t2.id ANTI JOIN t3 ON t1.id = t3.id",
+            "SELECT t1.id FROM t1 WHERE NOT EXISTS(SELECT 1 FROM t2 WHERE t1.id = t2.id) AND NOT EXISTS(SELECT 1 FROM t3 WHERE t1.id = t3.id)",
+        )
+        self.validate(
+            eliminate_semi_and_anti_joins,
+            "SELECT t1.id FROM t1 ANTI JOIN t2 ON t1.id = t2.id ANTI JOIN t3 ON t1.id = t3.id ANTI JOIN t4 ON t1.id = t4.id",
+            "SELECT t1.id FROM t1 WHERE (NOT EXISTS(SELECT 1 FROM t2 WHERE t1.id = t2.id) AND NOT EXISTS(SELECT 1 FROM t3 WHERE t1.id = t3.id)) AND NOT EXISTS(SELECT 1 FROM t4 WHERE t1.id = t4.id)",
+        )
+        self.validate(
+            eliminate_semi_and_anti_joins,
+            "SELECT t1.id FROM t1 SEMI JOIN t2 ON t1.id = t2.id SEMI JOIN t3 ON t1.id = t3.id",
+            "SELECT t1.id FROM t1 WHERE EXISTS(SELECT 1 FROM t2 WHERE t1.id = t2.id) AND EXISTS(SELECT 1 FROM t3 WHERE t1.id = t3.id)",
+        )
+
     def test_eliminate_window_clause(self):
         self.validate(
             eliminate_window_clause,