FEAT: new columns in snapshots for adapters w/o bools (#4871)

* FEAT: new columns in snapshots for adapters w/o bools

* trigger gha workflow

* using changie to make changelog

* updating to be on par with main

Co-authored-by: swanderz <swanson.anders@gmail.com>

.changes/unreleased/Under the Hood-20220316-100305.yaml

@@ -0,0 +1,8 @@
+kind: Under the Hood
+body: Enable more dialects to snapshot sources with added columns, even those that
+  don't support boolean datatypes
+time: 2022-03-16T10:03:05.96768-05:00
+custom:
+  Author: McKnight-42
+  Issue: "4488"
+  PR: "4871"

CHANGELOG.md

@@ -33,6 +33,7 @@
 - Initial conversion of tests to pytest ([#4690](https://github.com/dbt-labs/dbt-core/issues/4690), [#4691](https://github.com/dbt-labs/dbt-core/pull/4691))
 - Fix errors in Windows for tests/functions ([#4781](https://github.com/dbt-labs/dbt-core/issues/4781), [#4767](https://github.com/dbt-labs/dbt-core/pull/4767))
 
+
 Contributors:
 - [@NiallRees](https://github.com/NiallRees) ([#4447](https://github.com/dbt-labs/dbt-core/pull/4447))
 - [@alswang18](https://github.com/alswang18) ([#4644](https://github.com/dbt-labs/dbt-core/pull/4644))

core/dbt/include/global_project/macros/materializations/snapshots/helpers.sql

@@ -22,6 +22,13 @@
     {# no-op #}
 {% endmacro %}
 
+{% macro get_true_sql() %}
+  {{ adapter.dispatch('get_true_sql', 'dbt')() }}
+{% endmacro %}
+
+{% macro default__get_true_sql() %}
+    {{ return('TRUE') }}
+{% endmacro %}
 
 {% macro snapshot_staging_table(strategy, source_sql, target_relation) -%}
   {{ adapter.dispatch('snapshot_staging_table', 'dbt')(strategy, source_sql, target_relation) }}

core/dbt/include/global_project/macros/materializations/snapshots/strategies.sql

@@ -157,7 +157,7 @@
     {%- set row_changed_expr -%}
     (
     {%- if column_added -%}
-        TRUE
+        {{ get_true_sql() }}
     {%- else -%}
     {%- for col in check_cols -%}
         {{ snapshotted_rel }}.{{ col }} != {{ current_rel }}.{{ col }}