feat(parser): support CALLED ON NULL INPUT function property (#7792)

* feat(parser): parse CALLED ON NULL INPUT as a property instead of Command

* ruff order imports

* refactor

Co-authored-by: Giorgos Michas <geomichas96@gmail.com>

* fix test

* Update tests/dialects/test_snowflake.py

Co-authored-by: Giorgos Michas <geomichas96@gmail.com>

* update test

---------

Co-authored-by: Giorgos Michas <geomichas96@gmail.com>

Author: eruditmorina

sqlglot/expressions/properties.py

@@ -5,8 +5,8 @@
 import typing as t
 from enum import auto
 
+from sqlglot.expressions.core import ColumnConstraintKind, Expression, Literal, convert
 from sqlglot.helper import AutoName
-from sqlglot.expressions.core import Expression, ColumnConstraintKind, Literal, convert
 
 
 class Property(Expression):
@@ -63,6 +63,10 @@ class BlockCompressionProperty(Property):
     }
 
 
+class CalledOnNullInputProperty(Property):
+    arg_types = {}
+
+
 class CatalogProperty(Property):
     arg_types = {}
 

sqlglot/generator.py

@@ -149,6 +149,7 @@ class Generator:
         exp.CaseSpecificColumnConstraint: lambda _, e: (
             f"{'NOT ' if e.args.get('not_') else ''}CASESPECIFIC"
         ),
+        exp.CalledOnNullInputProperty: lambda *_: "CALLED ON NULL INPUT",
         exp.Ceil: lambda self, e: self.ceil_floor(e),
         exp.CharacterSetColumnConstraint: lambda self, e: f"CHARACTER SET {self.sql(e, 'this')}",
         exp.CharacterSetProperty: lambda self, e: (
@@ -677,6 +678,7 @@ class Generator:
         exp.AutoRefreshProperty: exp.Properties.Location.POST_SCHEMA,
         exp.BackupProperty: exp.Properties.Location.POST_SCHEMA,
         exp.BlockCompressionProperty: exp.Properties.Location.POST_NAME,
+        exp.CalledOnNullInputProperty: exp.Properties.Location.POST_SCHEMA,
         exp.CatalogProperty: exp.Properties.Location.POST_CREATE,
         exp.CharacterSetProperty: exp.Properties.Location.POST_SCHEMA,
         exp.ChecksumProperty: exp.Properties.Location.POST_NAME,

sqlglot/parser.py

@@ -4,7 +4,9 @@
 import logging
 import re
 import typing as t
+from builtins import type as Type
 from collections import defaultdict
+from collections.abc import Sequence
 
 from sqlglot import exp
 from sqlglot.errors import (
@@ -17,20 +19,17 @@
 )
 from sqlglot.expressions import apply_index_offset
 from sqlglot.helper import ensure_list, i64, seq_get
-from sqlglot.trie import new_trie
 from sqlglot.time import format_time
 from sqlglot.tokens import Token, Tokenizer, TokenType
-from sqlglot.trie import TrieResult, in_trie
-from collections.abc import Sequence
-from builtins import type as Type
+from sqlglot.trie import TrieResult, in_trie, new_trie
 
 if t.TYPE_CHECKING:
-    from sqlglot.expressions import ExpOrStr
-    from sqlglot._typing import E, BuilderArgs
-    from sqlglot.dialects.dialect import Dialect, DialectType
-
     from re import Pattern
 
+    from sqlglot._typing import BuilderArgs, E
+    from sqlglot.dialects.dialect import Dialect, DialectType
+    from sqlglot.expressions import ExpOrStr
+
     T = t.TypeVar("T")
     TCeilFloor = t.TypeVar("TCeilFloor", exp.Ceil, exp.Floor)
 
@@ -1236,6 +1235,7 @@ class Parser:
             exp.BackupProperty(this=self._parse_var(any_token=True))
         ),
         "BLOCKCOMPRESSION": lambda self: self._parse_blockcompression(),
+        "CALLED": lambda self: self._parse_called_on_null_input_property(),
         "CHARSET": lambda self, **kwargs: self._parse_character_set(**kwargs),
         "CHARACTER SET": lambda self, **kwargs: self._parse_character_set(**kwargs),
         "CHECKSUM": lambda self: self._parse_checksum(),
@@ -2900,6 +2900,13 @@ def _parse_settings_property(self) -> exp.SettingsProperty:
             exp.SettingsProperty(expressions=self._parse_csv(self._parse_assignment))
         )
 
+    def _parse_called_on_null_input_property(self) -> exp.CalledOnNullInputProperty | None:
+        if not self._match_text_seq("ON", "NULL", "INPUT"):
+            self._retreat(self._index - 1)
+            return None
+
+        return self.expression(exp.CalledOnNullInputProperty())
+
     def _parse_volatile_property(self) -> exp.VolatileProperty | exp.StabilityProperty:
         if self._index >= 2:
             pre_volatile_token = self._tokens[self._index - 2]

tests/dialects/test_postgres.py

@@ -1292,8 +1292,8 @@ def test_ddl(self):
         )
         self.validate_identity(
             "CREATE FUNCTION add(integer, integer) RETURNS integer AS 'select $1 + $2;' LANGUAGE SQL IMMUTABLE CALLED ON NULL INPUT",
-            check_command_warning=True,
-        )
+            "CREATE FUNCTION add(integer, integer) RETURNS INT LANGUAGE SQL IMMUTABLE CALLED ON NULL INPUT AS 'select $1 + $2;'",
+        ).assert_is(exp.Create)
         self.validate_identity(
             "CREATE CONSTRAINT TRIGGER my_trigger AFTER INSERT OR DELETE OR UPDATE OF col_a, col_b ON public.my_table DEFERRABLE INITIALLY DEFERRED FOR EACH ROW EXECUTE FUNCTION DO_STH()"
         )

tests/dialects/test_snowflake.py

@@ -4322,7 +4322,7 @@ def test_ddl(self):
         )
         self.validate_identity(
             """CREATE OR REPLACE FUNCTION ibis_udfs.public.object_values("obj" OBJECT) RETURNS ARRAY LANGUAGE JAVASCRIPT RETURNS NULL ON NULL INPUT AS ' return Object.values(obj) '"""
-        )
+        ).assert_is(exp.Create)
         self.validate_identity(
             """CREATE OR REPLACE FUNCTION ibis_udfs.public.object_values("obj" OBJECT) RETURNS ARRAY LANGUAGE JAVASCRIPT STRICT AS ' return Object.values(obj) '"""
         )
@@ -4427,7 +4427,9 @@ def test_user_defined_functions(self):
                 "snowflake": "CREATE FUNCTION a() RETURNS INT IMMUTABLE AS 'SELECT 1'",
             },
         )
-
+        self.validate_identity(
+            "CREATE FUNCTION a(x DOUBLE) RETURNS DOUBLE LANGUAGE SQL CALLED ON NULL INPUT AS ' x * 2 '"
+        ).assert_is(exp.Create)
         self.validate_identity(
             "CREATE OR REPLACE FUNCTION repro_fn() RETURNS INT LANGUAGE PYTHON HANDLER = 'fn' RUNTIME_VERSION='3.11' PACKAGES=() AS '\\ndef fn():\\n    return 1\\n'"
         )

tests/fixtures/identity.sql

@@ -632,6 +632,7 @@ CREATE FUNCTION a.b(x INT) RETURNS INT AS RETURN x + 1
 CREATE FUNCTION a.b(x TEXT) RETURNS TEXT CONTAINS SQL AS RETURN x
 CREATE FUNCTION a.b(x TEXT) RETURNS TEXT LANGUAGE SQL MODIFIES SQL DATA AS RETURN x
 CREATE FUNCTION a.b(x TEXT) LANGUAGE SQL READS SQL DATA RETURNS TEXT AS RETURN x
+CREATE FUNCTION a(x INT) RETURNS INT LANGUAGE SQL CALLED ON NULL INPUT AS 'SELECT 1'
 CREATE FUNCTION a.b.c()
 CREATE INDEX abc ON t(a)
 CREATE INDEX "abc" ON t(a)