From dd5eda9be20248b092088e122f7b224be21d40a9 Mon Sep 17 00:00:00 2001
From: neatninja <manan81140@gmail.com>
Date: Fri, 2 Oct 2026 23:21:04 +0530
Subject: [PATCH] fix(dialect): convert JSON test values to NULL and valid JSON

transform_values wrapped every JSON value in PARSE_JSON('{value}'), so a
column left out of a unit test's input rows became PARSE_JSON('None') and
DuckDB failed with "Malformed JSON". Dicts were rendered with Python's repr,
and quotes in the value broke the SQL string. None now becomes NULL, dicts
and lists are serialized with json.dumps, and the value is passed as an
escaped string literal.

Signed-off-by: neatninja <manan81140@gmail.com>
---
 sqlmesh/core/dialect.py    |  7 ++++++-
 tests/core/test_dialect.py | 20 ++++++++++++++++++++
 tests/core/test_test.py    | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/sqlmesh/core/dialect.py b/sqlmesh/core/dialect.py
index bcfb300ba1..d9beff52b1 100644
--- a/sqlmesh/core/dialect.py
+++ b/sqlmesh/core/dialect.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import functools
+import json
 import logging
 import re
 import sys
@@ -1649,7 +1650,11 @@ def _transform_value(value: t.Any, dtype: exp.DataType) -> t.Any:
             return exp.Struct(expressions=expressions)
 
         if dtype.is_type(exp.DataType.Type.JSON):
-            return exp.func("PARSE_JSON", f"'{value}'")
+            if value is None or isinstance(value, exp.Null):
+                return exp.null()
+            if isinstance(value, (dict, list, tuple, bool, int, float)):
+                value = json.dumps(value)
+            return exp.func("PARSE_JSON", exp.Literal.string(str(value)))
 
         return exp.convert(value)
 
diff --git a/tests/core/test_dialect.py b/tests/core/test_dialect.py
index 8d19ffee36..5ce35ff51d 100644
--- a/tests/core/test_dialect.py
+++ b/tests/core/test_dialect.py
@@ -1116,6 +1116,26 @@ def test_select_from_values_for_batch_range_json():
     )
 
 
+def test_select_from_values_for_batch_range_json_values():
+    values = [
+        (1, None),
+        (2, {"name": "O'Brien", "tags": ["a"]}),
+        (3, '{"name": "O\'Brien"}'),
+    ]
+    columns_to_types = {
+        "id": exp.DataType.build("int"),
+        "json_col": exp.DataType.build("json"),
+    }
+
+    assert select_from_values_for_batch_range(values, columns_to_types, 0, len(values)).sql() == (
+        "SELECT CAST(id AS INT) AS id, CAST(json_col AS JSON) AS json_col "
+        "FROM (VALUES (1, CAST(NULL AS JSON)), "
+        """(2, PARSE_JSON('{"name": "O''Brien", "tags": ["a"]}')), """
+        """(3, PARSE_JSON('{"name": "O''Brien"}'))) """
+        "AS t(id, json_col)"
+    )
+
+
 def test_select_from_values_that_include_null():
     values = [(1, exp.null())]
     columns_to_types = {
diff --git a/tests/core/test_test.py b/tests/core/test_test.py
index 0fbe8e926c..b6a3fa8d21 100644
--- a/tests/core/test_test.py
+++ b/tests/core/test_test.py
@@ -1254,6 +1254,38 @@ def test_empty_rows(sushi_context: Context) -> None:
     )
 
 
+def test_json_column_missing_from_input_rows(sushi_context: Context) -> None:
+    _check_successful_or_raise(
+        _create_test(
+            body=load_yaml(
+                """
+test_a:
+  model: a
+  inputs:
+    b:
+      columns:
+        id: int
+        payload: json
+      rows:
+        - id: 1
+  outputs:
+    query:
+      - id: 1
+        payload_is_null: true
+                """
+            ),
+            test_name="test_a",
+            model=sushi_context.upsert_model(
+                _create_model(
+                    "SELECT id, payload IS NULL AS payload_is_null FROM b",
+                    default_catalog="memory",
+                )
+            ),
+            context=Context(config=Config(model_defaults=ModelDefaultsConfig(dialect="duckdb"))),
+        ).run()
+    )
+
+
 @pytest.mark.parametrize("full_model_without_ctes", ["snowflake"], indirect=True)
 def test_normalization(full_model_without_ctes: SqlModel) -> None:
     normalized_body = _create_test(