Fix: make jinja-based model rendering more lenient (#5300)

Author: georgesittas

sqlmesh/core/renderer.py

@@ -549,6 +549,11 @@ def render(
             expressions = [e for e in expressions if not isinstance(e, exp.Semicolon)]
 
             if not expressions:
+                # We assume that if there are no expressions, then the model contains dynamic Jinja SQL
+                # and we thus treat it similar to models with adapter calls to match dbt's behavior.
+                if isinstance(self._expression, d.JinjaQuery):
+                    return None
+
                 raise ConfigError(f"Failed to render query at '{self._path}':\n{self._expression}")
 
             if len(expressions) > 1:

tests/fixtures/dbt/sushi_test/models/dynamic_graph_model.sql

@@ -0,0 +1,8 @@
+
+{% if execute %}
+    {% for dataset, nodes in graph.nodes.values() | selectattr("resource_type", "equalto", "model") | groupby('schema')  %}
+        {% if loop.first %}
+            SELECT 1 AS c
+        {% endif %}
+    {% endfor %}
+{% endif %}