Add presto unsupported warning, tests

Author: treysp

sqlglot/dialects/bigquery.py

@@ -360,7 +360,7 @@ class BigQuery(Dialect):
 
     # https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/string_functions#initcap
     INITCAP_SUPPORTS_CUSTOM_DELIMITERS = True
-    INITCAP_DEFAULT_DELIMITER_CHARS = ' \t\n\r\f\v\\[\\](){}/|\<>!?@"^#$&~_,.:;*%+\\-'
+    INITCAP_DEFAULT_DELIMITER_CHARS = ' \t\n\r\f\v\\[\\](){}/|<>!?@"^#$&~_,.:;*%+\\-'
 
     # https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#case_sensitivity
     NORMALIZATION_STRATEGY = NormalizationStrategy.CASE_INSENSITIVE

sqlglot/dialects/presto.py

@@ -45,6 +45,12 @@
 
 
 def _initcap_sql(self: Presto.Generator, expression: exp.Initcap) -> str:
+    delimiters = expression.expression
+    if delimiters and not (
+        delimiters.is_string and delimiters.this == self.dialect.INITCAP_DEFAULT_DELIMITER_CHARS
+    ):
+        self.unsupported("INITCAP does not support custom delimiters")
+
     regex = r"(\w)(\w*)"
     return f"REGEXP_REPLACE({self.sql(expression, 'this')}, '{regex}', x -> UPPER(x[1]) || LOWER(x[2]))"
 

tests/dialects/test_dialect.py

@@ -4325,6 +4325,11 @@ def duckdb_regex_literal_sql(delimiters: str) -> str:
             escaped_literal = "".join(REGEX_LITERAL_ESCAPES.get(ch, ch) for ch in delimiters)
             return exp.Literal.string(escaped_literal).sql("duckdb")
 
+        # None delimiters arg doesn't error
+        with self.subTest("Testing INITCAP with None delimiters arg"):
+            self.assertEqual(exp.Initcap(this=exp.Literal.string("col")).sql(), "INITCAP('col')")
+            self.assertEqual(exp.Initcap(this=exp.column("col")).sql(), "INITCAP(col)")
+
         # default delimiters not present in roundtrip
         for dialect in delimiter_chars:
             with self.subTest(
@@ -4439,6 +4444,8 @@ def escape_expression_sql(sql: str) -> str:
 
     def test_initcap_custom_delimiter_warning(self):
         expression = parse_one("INITCAP(col, '_')", read="bigquery")
-        with self.assertLogs(generator_logger, level="WARNING") as cm:
-            expression.sql("postgres")
-        self.assertIn("INITCAP does not support custom delimiters", cm.output[0])
+        for dialect in ("postgres", "presto"):
+            with self.subTest(f"INITCAP unsupported custom delimiters warning for {dialect}"):
+                with self.assertLogs(generator_logger, level="WARNING") as cm:
+                    expression.sql(dialect)
+                self.assertIn("INITCAP does not support custom delimiters", cm.output[0])

tests/dialects/test_presto.py

@@ -1367,3 +1367,11 @@ def test_bit_aggs(self):
                 "oracle": "BITWISE_XOR_AGG(x)",
             },
         )
+
+    def test_initcap(self):
+        self.validate_all(
+            "INITCAP(col)",
+            write={
+                "presto": "REGEXP_REPLACE(col, '(\w)(\w*)', x -> UPPER(x[1]) || LOWER(x[2]))",
+            },
+        )