Adding upstream version 15.0.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

sqlglot/transforms.py

@@ -3,7 +3,7 @@ from __future__ import annotations
 import typing as t
 
 from sqlglot import expressions as exp
-from sqlglot.helper import find_new_name
+from sqlglot.helper import find_new_name, name_sequence
 
 if t.TYPE_CHECKING:
     from sqlglot.generator import Generator
@@ -63,16 +63,17 @@ def eliminate_distinct_on(expression: exp.Expression) -> exp.Expression:
         distinct_cols = expression.args["distinct"].pop().args["on"].expressions
         outer_selects = expression.selects
         row_number = find_new_name(expression.named_selects, "_row_number")
-        window = exp.Window(
-            this=exp.RowNumber(),
-            partition_by=distinct_cols,
-        )
+        window = exp.Window(this=exp.RowNumber(), partition_by=distinct_cols)
         order = expression.args.get("order")
+
         if order:
             window.set("order", order.pop().copy())
+
         window = exp.alias_(window, row_number)
         expression.select(window, copy=False)
+
         return exp.select(*outer_selects).from_(expression.subquery()).where(f'"{row_number}" = 1')
+
     return expression
 
 
@@ -93,7 +94,7 @@ def eliminate_qualify(expression: exp.Expression) -> exp.Expression:
         for select in expression.selects:
             if not select.alias_or_name:
                 alias = find_new_name(taken, "_c")
-                select.replace(exp.alias_(select.copy(), alias))
+                select.replace(exp.alias_(select, alias))
                 taken.add(alias)
 
         outer_selects = exp.select(*[select.alias_or_name for select in expression.selects])
@@ -102,8 +103,9 @@ def eliminate_qualify(expression: exp.Expression) -> exp.Expression:
         for expr in qualify_filters.find_all((exp.Window, exp.Column)):
             if isinstance(expr, exp.Window):
                 alias = find_new_name(expression.named_selects, "_w")
-                expression.select(exp.alias_(expr.copy(), alias), copy=False)
+                expression.select(exp.alias_(expr, alias), copy=False)
                 column = exp.column(alias)
+
                 if isinstance(expr.parent, exp.Qualify):
                     qualify_filters = column
                 else:
@@ -123,6 +125,7 @@ def remove_precision_parameterized_types(expression: exp.Expression) -> exp.Expr
     """
     for node in expression.find_all(exp.DataType):
         node.set("expressions", [e for e in node.expressions if isinstance(e, exp.DataType)])
+
     return expression
 
 
@@ -147,6 +150,7 @@ def unnest_to_explode(expression: exp.Expression) -> exp.Expression:
                             alias=exp.TableAlias(this=alias.this, columns=[column]),  # type: ignore
                         ),
                     )
+
     return expression
 
 
@@ -156,7 +160,10 @@ def explode_to_unnest(expression: exp.Expression) -> exp.Expression:
         from sqlglot.optimizer.scope import build_scope
 
         taken_select_names = set(expression.named_selects)
-        taken_source_names = set(build_scope(expression).selected_sources)
+        scope = build_scope(expression)
+        if not scope:
+            return expression
+        taken_source_names = set(scope.selected_sources)
 
         for select in expression.selects:
             to_replace = select
@@ -226,6 +233,7 @@ def remove_target_from_merge(expression: exp.Expression) -> exp.Expression:
                 else node,
                 copy=False,
             )
+
     return expression
 
 
@@ -242,12 +250,20 @@ def remove_within_group_for_percentiles(expression: exp.Expression) -> exp.Expre
     return expression
 
 
-def unqualify_pivot_columns(expression: exp.Expression) -> exp.Expression:
-    if isinstance(expression, exp.Pivot):
-        expression.args["field"].transform(
-            lambda node: exp.column(node.output_name) if isinstance(node, exp.Column) else node,
-            copy=False,
-        )
+def add_recursive_cte_column_names(expression: exp.Expression) -> exp.Expression:
+    if isinstance(expression, exp.With) and expression.recursive:
+        next_name = name_sequence("_c_")
+
+        for cte in expression.expressions:
+            if not cte.args["alias"].columns:
+                query = cte.this
+                if isinstance(query, exp.Union):
+                    query = query.this
+
+                cte.args["alias"].set(
+                    "columns",
+                    [exp.to_identifier(s.alias_or_name or next_name()) for s in query.selects],
+                )
 
     return expression