Add a special as_text filter to the native env (#2384)

CHANGELOG.md

@@ -23,6 +23,7 @@
 - schema.yml files are now fully rendered in a context that is aware of vars declared in from dbt_project.yml files ([#2269](https://github.com/fishtown-analytics/dbt/issues/2269), [#2357](https://github.com/fishtown-analytics/dbt/pull/2357))
 - Sources from dependencies can be overridden in schema.yml files ([#2287](https://github.com/fishtown-analytics/dbt/issues/2287), [#2357](https://github.com/fishtown-analytics/dbt/pull/2357))
 - Implement persist_docs for both `relation` and `comments` on postgres and redshift, and extract them when getting the catalog. ([#2333](https://github.com/fishtown-analytics/dbt/issues/2333), [#2378](https://github.com/fishtown-analytics/dbt/pull/2378))
+- Added a filter named `as_text` to the native environment rendering code that allows users to mark a value as always being a string ([#2384](https://github.com/fishtown-analytics/dbt/issues/2384), [#2395](https://github.com/fishtown-analytics/dbt/pull/2395))
 
 ### Fixes
 - When a jinja value is undefined, give a helpful error instead of failing with cryptic "cannot pickle ParserMacroCapture" errors ([#2110](https://github.com/fishtown-analytics/dbt/issues/2110), [#2184](https://github.com/fishtown-analytics/dbt/pull/2184))

core/dbt/clients/jinja.py

@@ -8,7 +8,7 @@
 from contextlib import contextmanager
 from itertools import chain, islice
 from typing import (
-    List, Union, Set, Optional, Dict, Any, Iterator, Type, NoReturn
+    List, Union, Set, Optional, Dict, Any, Iterator, Type, NoReturn, Tuple
 )
 
 import jinja2
@@ -104,6 +104,13 @@ class NativeSandboxEnvironment(MacroFuzzEnvironment):
     code_generator_class = jinja2.nativetypes.NativeCodeGenerator
 
 
+class TextMarker(str):
+    """A special native-env marker that indicates that a value is text and is
+    not to be evaluated. Use this to prevent your numbery-strings from becoming
+    numbers!
+    """
+
+
 def quoted_native_concat(nodes):
     """This is almost native_concat from the NativeTemplate, except in the
     special case of a single argument that is a quoted string and returns a
@@ -116,6 +123,8 @@ def quoted_native_concat(nodes):
 
     if len(head) == 1:
         raw = head[0]
+        if isinstance(raw, TextMarker):
+            return str(raw)
     else:
         raw = "".join([str(v) for v in chain(head, nodes)])
 
@@ -124,10 +133,7 @@ def quoted_native_concat(nodes):
     except (ValueError, SyntaxError, MemoryError):
         return raw
 
-    if len(head) == 1 and len(raw) > 2 and isinstance(result, str):
-        return _requote_result(raw, result)
-    else:
-        return result
+    return result
 
 
 class NativeSandboxTemplate(jinja2.nativetypes.NativeTemplate):  # mypy: ignore
@@ -423,12 +429,18 @@ def get_environment(
     args['extensions'].append(DocumentationExtension)
 
     env_cls: Type[jinja2.Environment]
+    text_filter: Type
     if native:
         env_cls = NativeSandboxEnvironment
+        text_filter = TextMarker
     else:
         env_cls = MacroFuzzEnvironment
+        text_filter = str
+
+    env = env_cls(**args)
+    env.filters['as_text'] = text_filter
 
-    return env_cls(**args)
+    return env
 
 
 @contextmanager
@@ -541,9 +553,15 @@ def add_rendered_test_kwargs(
     """
     looks_like_func = r'^\s*(env_var|ref|var|source|doc)\s*\(.+\)\s*$'
 
-    # we never care about the keypath
-    def _convert_function(value: Any, _: Any) -> Any:
+    def _convert_function(
+        value: Any, keypath: Tuple[Union[str, int], ...]
+    ) -> Any:
         if isinstance(value, str):
+            if keypath == ('column_name',):
+                # special case: Don't render column names as native, make them
+                # be strings
+                return value
+
             if re.match(looks_like_func, value) is not None:
                 # curly braces to make rendering happy
                 value = f'{{{{ {value} }}}}'

test/integration/042_sources_test/models/schema.yml

@@ -22,7 +22,7 @@ sources:
     tables:
       - name: test_table
         identifier: source
-        loaded_at_field: "{{ var('test_loaded_at') }}"
+        loaded_at_field: "{{ var('test_loaded_at') | as_text }}"
         freshness:
           error_after: {count: 18, period: hour}
         tags:
@@ -63,7 +63,7 @@ sources:
               - id_column
       - name: disabled_test_table
         freshness: null
-        loaded_at_field: "{{ var('test_loaded_at') }}"
+        loaded_at_field: "{{ var('test_loaded_at') | as_text }}"
   - name: other_source
     schema: "{{ var('test_run_schema') }}"
     quoting:

test/unit/test_jinja.py

@@ -1,5 +1,6 @@
 import unittest
 
+from dbt.clients.jinja import get_rendered
 from dbt.clients.jinja import get_template
 from dbt.clients.jinja import extract_toplevel_blocks
 from dbt.exceptions import CompilationException
@@ -13,6 +14,36 @@ def test_do(self):
         mod = template.make_module()
         self.assertEqual(mod.my_dict, {'a': 1})
 
+    def test_regular_render(self):
+        s = '{{ "some_value" }}'
+        value = get_rendered(s, {}, native=False)
+        assert value == 'some_value'
+        s = '{{ 1991 }}'
+        value = get_rendered(s, {}, native=False)
+        assert value == '1991'
+
+        s = '{{ "some_value" | as_text }}'
+        value = get_rendered(s, {}, native=True)
+        assert value == 'some_value'
+        s = '{{ 1991 | as_text }}'
+        value = get_rendered(s, {}, native=True)
+        assert value == '1991'
+
+    def test_native_render(self):
+        s = '{{ "some_value" }}'
+        value = get_rendered(s, {}, native=True)
+        assert value == 'some_value'
+        s = '{{ 1991 }}'
+        value = get_rendered(s, {}, native=True)
+        assert value == 1991
+
+        s = '{{ "some_value" | as_text }}'
+        value = get_rendered(s, {}, native=True)
+        assert value == 'some_value'
+        s = '{{ 1991 | as_text }}'
+        value = get_rendered(s, {}, native=True)
+        assert value == '1991'
+
 
 class TestBlockLexer(unittest.TestCase):
     def test_basic(self):
@@ -380,3 +411,5 @@ def test_if_endfor_newlines(self):
 hi
 {% endmaterialization %}
 '''
+
+