Handle ephemeral models better

macros/cross_db_utils/_is_ephemeral.sql

@@ -0,0 +1,15 @@
+{% macro _is_ephemeral(obj, macro) %}
+    {%- if obj.is_cte -%}
+        {% if obj.name.startswith('__dbt__CTE__') %}
+            {% set model_name = obj.name[12:] %}
+        {% else %}
+            {% set model_name = obj.name %}
+        {%- endif -%}
+        {% set error_message %}
+The `{{ macro }}` macro cannot be used with ephemeral models, as it relies on the information schema.
+
+`{{ model_name }}` is an ephemeral model. Consider making it a view or table instead.
+        {% endset %}
+        {%- do exceptions.raise_compiler_error(error_message) -%}
+    {%- endif -%}
+{% endmacro %}

macros/schema_tests/equality.sql

@@ -8,6 +8,15 @@
 
 -- setup
 {%- do dbt_utils._is_relation(model, 'test_equality') -%}
+
+{#-
+If the compare_cols arg is provided, we can run this test without querying the
+information schema — this allows the model to be an ephemeral model
+-#}
+{%- if not kwargs.get('compare_columns', None) -%}
+    {%- do dbt_utils._is_ephemeral(model, 'test_equality') -%}
+{%- endif -%}
+
 {% set compare_model = kwargs.get('compare_model', kwargs.get('arg')) %}
 {% set compare_columns = kwargs.get('compare_columns', adapter.get_columns_in_relation(model) | map(attribute='quoted') ) %}
 {% set compare_cols_csv = compare_columns | join(', ') %}

macros/sql/nullcheck_table.sql

@@ -1,9 +1,10 @@
 {% macro nullcheck_table(relation) %}
 
   {%- do dbt_utils._is_relation(relation, 'nullcheck_table') -%}
+  {%- do dbt_utils._is_ephemeral(relation, 'nullcheck_table') -%}
   {% set cols = adapter.get_columns_in_relation(relation) %}
 
   select {{ dbt_utils.nullcheck(cols) }}
   from {{relation}}
-  
+
 {% endmacro %}

macros/sql/star.sql

@@ -1,6 +1,7 @@
 {% macro star(from, relation_alias=False, except=[]) -%}
 
     {%- do dbt_utils._is_relation(from, 'star') -%}
+    {%- do dbt_utils._is_ephemeral(from, 'star') -%}
 
     {#-- Prevent querying of db in parsing mode. This works because this macro does not create any new refs. #}
     {%- if not execute -%}
@@ -9,6 +10,7 @@
 
     {%- set include_cols = [] %}
     {%- set cols = adapter.get_columns_in_relation(from) -%}
+
     {%- for col in cols -%}
 
         {%- if col.column not in except -%}

macros/sql/union.sql

@@ -20,6 +20,7 @@
         {%- do relation_columns.update({relation: []}) -%}
 
         {%- do dbt_utils._is_relation(relation, 'union_relations') -%}
+        {%- do dbt_utils._is_ephemeral(relation, 'union_relations') -%}
         {%- set cols = adapter.get_columns_in_relation(relation) -%}
         {%- for col in cols -%}
 

macros/sql/unpivot.sql

@@ -36,6 +36,7 @@ Arguments:
   {%- do table_columns.update({relation: []}) %}
 
   {%- do dbt_utils._is_relation(relation, 'unpivot') -%}
+  {%- do dbt_utils._is_ephemeral(relation, 'unpivot') -%}
   {%- set cols = adapter.get_columns_in_relation(relation) %}
 
   {%- for col in cols -%}