SNOW-3259059: Avoid server-side bug by using CHR(34) instead of lit('"') in concat

CHANGELOG.md

@@ -10,6 +10,8 @@
 
 #### Bug Fixes
 
+- Fixed a Snowflake platform compatibility issue (SNOW-3259059) where `concat(lit('"'), ...)` could lose the leading quote through some `EXCEPT` / chained set-operation plans by lowering that literal to `CHR(34)` in generated SQL.
+
 #### Improvements
 
 - Restored the following query improvements that were reverted in 1.47.0 due to bugs:

src/snowflake/snowpark/functions.py

@@ -3712,6 +3712,22 @@ def collation(e: ColumnOrName, _emit_ast: bool = True) -> Column:
     return _call_function("collation", c, _emit_ast=_emit_ast)
 
 
+def _rewrite_concat_arg_if_double_quote_string_literal(
+    c: Column, *, _emit_ast: bool
+) -> Column:
+    # SNOW-3259059: Some Snowflake releases (10.7.1–10.9.2 per JIRA) dropped CONCAT's leading
+    # lit('"') through EXCEPT / chained set-op plans. CHR(34) is the same VARCHAR character in SQL
+    # without that specific single-character literal form.
+    expr = c._expression
+    if (
+        isinstance(expr, Literal)
+        and isinstance(expr.datatype, StringType)
+        and expr.value == '"'
+    ):
+        return _call_function("chr", lit(34, _emit_ast=_emit_ast), _emit_ast=_emit_ast)
+    return c
+
+
 @publicapi
 def concat(*cols: ColumnOrName, _emit_ast: bool = True) -> Column:
     """Concatenates one or more strings, or concatenates one or more binary values. If any of the values is null, the result is also null.
@@ -3726,7 +3742,12 @@ def concat(*cols: ColumnOrName, _emit_ast: bool = True) -> Column:
         --------------------------
         <BLANKLINE>
     """
-    columns = [_to_col_if_str(c, "concat") for c in cols]
+    columns = [
+        _rewrite_concat_arg_if_double_quote_string_literal(
+            _to_col_if_str(c, "concat"), _emit_ast=_emit_ast
+        )
+        for c in cols
+    ]
     return _call_function("concat", *columns, _emit_ast=_emit_ast)
 
 

tests/integ/test_function.py

@@ -378,6 +378,32 @@ def test_concat(session, col_a, col_b, col_c):
     assert res[0][0] == "123"
 
 
+@pytest.mark.skipif(
+    "config.getoption('local_testing_mode', default=False)",
+    reason="Local testing replaces plan SQL with MOCK_TEST_FAKE_QUERY(); CHR(34) assertion needs real SQL.",
+)
+def test_concat_rewrites_lit_double_quote_to_chr_sql(session):
+    df = session.create_dataframe([["fn"]], schema=["a"])
+    out = df.select(concat(lit('"'), col("a")).alias("q"))
+    sql = out.queries["queries"][0].upper()
+    assert "CHR(34)" in sql
+    assert "CONCAT(" in sql
+    rows = out.collect()
+    assert len(rows) == 1 and rows[0][0] == '"fn'
+
+
+@pytest.mark.skipif(
+    "config.getoption('local_testing_mode', default=False)",
+    reason="Local testing replaces plan SQL with MOCK_TEST_FAKE_QUERY(); literal SQL assertions need real SQL.",
+)
+def test_concat_preserves_other_string_literals_sql(session):
+    df = session.create_dataframe([["x"]], schema=["a"])
+    out = df.select(concat(lit("##"), col("a")).alias("q"))
+    sql = out.queries["queries"][0]
+    assert "##" in sql
+    assert "CHR(34)" not in sql.upper()
+
+
 @pytest.mark.parametrize(
     "col_a, col_b, col_c", [("a", "b", "c"), (col("a"), col("b"), col("c"))]
 )