[BACKPORT 1.6.latest] Preserve decimal places for dbt show (#8561)

.changes/unreleased/Fixes-20230803-093502.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Add explicit support for integers for the show command
+time: 2023-08-03T09:35:02.163968-05:00
+custom:
+  Author: dave-connors-3
+  Issue: "8153"

core/dbt/clients/agate_helper.py

@@ -12,6 +12,20 @@
 BOM = BOM_UTF8.decode("utf-8")  # '\ufeff'
 
 
+class Integer(agate.data_types.DataType):
+    def cast(self, d):
+        # by default agate will cast none as a Number
+        # but we need to cast it as an Integer to preserve
+        # the type when merging and unioning tables
+        if type(d) == int or d is None:
+            return d
+        else:
+            raise agate.exceptions.CastError('Can not parse value "%s" as Integer.' % d)
+
+    def jsonify(self, d):
+        return d
+
+
 class Number(agate.data_types.Number):
     # undo the change in https://github.com/wireservice/agate/pull/733
     # i.e. do not cast True and False to numeric 1 and 0
@@ -47,6 +61,7 @@ def build_type_tester(
 ) -> agate.TypeTester:
 
     types = [
+        Integer(null_values=("null", "")),
         Number(null_values=("null", "")),
         agate.data_types.Date(null_values=("null", ""), date_format="%Y-%m-%d"),
         agate.data_types.DateTime(null_values=("null", ""), datetime_format="%Y-%m-%d %H:%M:%S"),
@@ -165,6 +180,13 @@ def __setitem__(self, key, value):
         elif isinstance(value, _NullMarker):
             # use the existing value
             return
+        # when one table column is Number while another is Integer, force the column to Number on merge
+        elif isinstance(value, Integer) and isinstance(existing_type, agate.data_types.Number):
+            # use the existing value
+            return
+        elif isinstance(existing_type, Integer) and isinstance(value, agate.data_types.Number):
+            # overwrite
+            super().__setitem__(key, value)
         elif not isinstance(value, type(existing_type)):
             # actual type mismatch!
             raise DbtRuntimeError(
@@ -176,8 +198,9 @@ def finalize(self) -> Dict[str, agate.data_types.DataType]:
         result: Dict[str, agate.data_types.DataType] = {}
         for key, value in self.items():
             if isinstance(value, _NullMarker):
-                # this is what agate would do.
-                result[key] = agate.data_types.Number()
+                # agate would make it a Number but we'll make it Integer so that if this column
+                # gets merged with another Integer column, it won't get forced to a Number
+                result[key] = Integer()
             else:
                 result[key] = value
         return result

tests/functional/show/fixtures.py

@@ -2,6 +2,31 @@
 select * from {{ ref('sample_seed') }}
 """
 
+models__sample_number_model = """
+select
+  cast(1.0 as int) as float_to_int_field,
+  3.0 as float_field,
+  4.3 as float_with_dec_field,
+  5 as int_field
+"""
+
+models__sample_number_model_with_nulls = """
+select
+  cast(1.0 as int) as float_to_int_field,
+  3.0 as float_field,
+  4.3 as float_with_dec_field,
+  5 as int_field
+
+union all
+
+select
+  cast(null as int) as float_to_int_field,
+  cast(null as float) as float_field,
+  cast(null as float) as float_with_dec_field,
+  cast(null as int) as int_field
+
+"""
+
 models__second_model = """
 select
     sample_num as col_one,

tests/functional/show/test_show.py

@@ -6,6 +6,8 @@
     models__second_ephemeral_model,
     seeds__sample_seed,
     models__sample_model,
+    models__sample_number_model,
+    models__sample_number_model_with_nulls,
     models__second_model,
     models__ephemeral_model,
     schema_yml,
@@ -14,11 +16,13 @@
 )
 
 
-class BaseTestShow:
+class TestShow:
     @pytest.fixture(scope="class")
     def models(self):
         return {
             "sample_model.sql": models__sample_model,
+            "sample_number_model.sql": models__sample_number_model,
+            "sample_number_model_with_nulls.sql": models__sample_number_model_with_nulls,
             "second_model.sql": models__second_model,
             "ephemeral_model.sql": models__ephemeral_model,
             "sql_header.sql": models__sql_header,
@@ -28,17 +32,13 @@ def models(self):
     def seeds(self):
         return {"sample_seed.csv": seeds__sample_seed}
 
-
-class TestNone(BaseTestShow):
     def test_none(self, project):
         with pytest.raises(
             DbtRuntimeError, match="Either --select or --inline must be passed to show"
         ):
             run_dbt(["seed"])
             run_dbt(["show"])
 
-
-class TestSelectModelText(BaseTestShow):
     def test_select_model_text(self, project):
         run_dbt(["build"])
         (results, log_output) = run_dbt_and_capture(["show", "--select", "second_model"])
@@ -48,8 +48,6 @@ def test_select_model_text(self, project):
         assert "col_two" in log_output
         assert "answer" in log_output
 
-
-class TestSelectMultModelText(BaseTestShow):
     def test_select_multiple_model_text(self, project):
         run_dbt(["build"])
         (results, log_output) = run_dbt_and_capture(
@@ -59,8 +57,6 @@ def test_select_multiple_model_text(self, project):
         assert "sample_num" in log_output
         assert "sample_bool" in log_output
 
-
-class TestSelectSingleMultModelJson(BaseTestShow):
     def test_select_single_model_json(self, project):
         run_dbt(["build"])
         (results, log_output) = run_dbt_and_capture(
@@ -70,8 +66,32 @@ def test_select_single_model_json(self, project):
         assert "sample_num" in log_output
         assert "sample_bool" in log_output
 
+    def test_numeric_values(self, project):
+        run_dbt(["build"])
+        (results, log_output) = run_dbt_and_capture(
+            ["show", "--select", "sample_number_model", "--output", "json"]
+        )
+        assert "Previewing node 'sample_number_model'" not in log_output
+        assert "1.0" not in log_output
+        assert "1" in log_output
+        assert "3.0" in log_output
+        assert "4.3" in log_output
+        assert "5" in log_output
+        assert "5.0" not in log_output
+
+    def test_numeric_values_with_nulls(self, project):
+        run_dbt(["build"])
+        (results, log_output) = run_dbt_and_capture(
+            ["show", "--select", "sample_number_model_with_nulls", "--output", "json"]
+        )
+        assert "Previewing node 'sample_number_model_with_nulls'" not in log_output
+        assert "1.0" not in log_output
+        assert "1" in log_output
+        assert "3.0" in log_output
+        assert "4.3" in log_output
+        assert "5" in log_output
+        assert "5.0" not in log_output
 
-class TestInlinePass(BaseTestShow):
     def test_inline_pass(self, project):
         run_dbt(["build"])
         (results, log_output) = run_dbt_and_capture(
@@ -81,8 +101,6 @@ def test_inline_pass(self, project):
         assert "sample_num" in log_output
         assert "sample_bool" in log_output
 
-
-class TestShowExceptions(BaseTestShow):
     def test_inline_fail(self, project):
         with pytest.raises(DbtException, match="Error parsing inline query"):
             run_dbt(["show", "--inline", "select * from {{ ref('third_model') }}"])
@@ -91,8 +109,6 @@ def test_inline_fail_database_error(self, project):
         with pytest.raises(DbtRuntimeError, match="Database Error"):
             run_dbt(["show", "--inline", "slect asdlkjfsld;j"])
 
-
-class TestEphemeralModels(BaseTestShow):
     def test_ephemeral_model(self, project):
         run_dbt(["build"])
         (results, log_output) = run_dbt_and_capture(["show", "--select", "ephemeral_model"])
@@ -105,8 +121,6 @@ def test_second_ephemeral_model(self, project):
         )
         assert "col_hundo" in log_output
 
-
-class TestLimit(BaseTestShow):
     @pytest.mark.parametrize(
         "args,expected",
         [
@@ -121,14 +135,10 @@ def test_limit(self, project, args, expected):
         results, log_output = run_dbt_and_capture(dbt_args)
         assert len(results.results[0].agate_table) == expected
 
-
-class TestSeed(BaseTestShow):
     def test_seed(self, project):
         (results, log_output) = run_dbt_and_capture(["show", "--select", "sample_seed"])
         assert "Previewing node 'sample_seed'" in log_output
 
-
-class TestSqlHeader(BaseTestShow):
     def test_sql_header(self, project):
         run_dbt(["build"])
         (results, log_output) = run_dbt_and_capture(["show", "--select", "sql_header"])

tests/unit/test_agate_helper.py

@@ -121,39 +121,64 @@ def test_datetime_formats(self):
             self.assertEqual(tbl[0][0], expected)
 
     def test_merge_allnull(self):
-        t1 = agate.Table([(1, "a", None), (2, "b", None)], ("a", "b", "c"))
-        t2 = agate.Table([(3, "c", None), (4, "d", None)], ("a", "b", "c"))
+        t1 = agate_helper.table_from_rows([(1, "a", None), (2, "b", None)], ("a", "b", "c"))
+        t2 = agate_helper.table_from_rows([(3, "c", None), (4, "d", None)], ("a", "b", "c"))
         result = agate_helper.merge_tables([t1, t2])
         self.assertEqual(result.column_names, ("a", "b", "c"))
-        assert isinstance(result.column_types[0], agate.data_types.Number)
+        assert isinstance(result.column_types[0], agate_helper.Integer)
         assert isinstance(result.column_types[1], agate.data_types.Text)
-        assert isinstance(result.column_types[2], agate.data_types.Number)
+        assert isinstance(result.column_types[2], agate_helper.Integer)
         self.assertEqual(len(result), 4)
 
     def test_merge_mixed(self):
-        t1 = agate.Table([(1, "a", None), (2, "b", None)], ("a", "b", "c"))
-        t2 = agate.Table([(3, "c", "dog"), (4, "d", "cat")], ("a", "b", "c"))
-        t3 = agate.Table([(3, "c", None), (4, "d", None)], ("a", "b", "c"))
+        t1 = agate_helper.table_from_rows(
+            [(1, "a", None, None), (2, "b", None, None)], ("a", "b", "c", "d")
+        )
+        t2 = agate_helper.table_from_rows(
+            [(3, "c", "dog", 1), (4, "d", "cat", 5)], ("a", "b", "c", "d")
+        )
+        t3 = agate_helper.table_from_rows(
+            [(3, "c", None, 1.5), (4, "d", None, 3.5)], ("a", "b", "c", "d")
+        )
 
         result = agate_helper.merge_tables([t1, t2])
-        self.assertEqual(result.column_names, ("a", "b", "c"))
-        assert isinstance(result.column_types[0], agate.data_types.Number)
+        self.assertEqual(result.column_names, ("a", "b", "c", "d"))
+        assert isinstance(result.column_types[0], agate_helper.Integer)
         assert isinstance(result.column_types[1], agate.data_types.Text)
         assert isinstance(result.column_types[2], agate.data_types.Text)
+        assert isinstance(result.column_types[3], agate_helper.Integer)
+        self.assertEqual(len(result), 4)
+
+        result = agate_helper.merge_tables([t1, t3])
+        self.assertEqual(result.column_names, ("a", "b", "c", "d"))
+        assert isinstance(result.column_types[0], agate_helper.Integer)
+        assert isinstance(result.column_types[1], agate.data_types.Text)
+        assert isinstance(result.column_types[2], agate_helper.Integer)
+        assert isinstance(result.column_types[3], agate.data_types.Number)
         self.assertEqual(len(result), 4)
 
         result = agate_helper.merge_tables([t2, t3])
-        self.assertEqual(result.column_names, ("a", "b", "c"))
-        assert isinstance(result.column_types[0], agate.data_types.Number)
+        self.assertEqual(result.column_names, ("a", "b", "c", "d"))
+        assert isinstance(result.column_types[0], agate_helper.Integer)
         assert isinstance(result.column_types[1], agate.data_types.Text)
         assert isinstance(result.column_types[2], agate.data_types.Text)
+        assert isinstance(result.column_types[3], agate.data_types.Number)
+        self.assertEqual(len(result), 4)
+
+        result = agate_helper.merge_tables([t3, t2])
+        self.assertEqual(result.column_names, ("a", "b", "c", "d"))
+        assert isinstance(result.column_types[0], agate_helper.Integer)
+        assert isinstance(result.column_types[1], agate.data_types.Text)
+        assert isinstance(result.column_types[2], agate.data_types.Text)
+        assert isinstance(result.column_types[3], agate.data_types.Number)
         self.assertEqual(len(result), 4)
 
         result = agate_helper.merge_tables([t1, t2, t3])
-        self.assertEqual(result.column_names, ("a", "b", "c"))
-        assert isinstance(result.column_types[0], agate.data_types.Number)
+        self.assertEqual(result.column_names, ("a", "b", "c", "d"))
+        assert isinstance(result.column_types[0], agate_helper.Integer)
         assert isinstance(result.column_types[1], agate.data_types.Text)
         assert isinstance(result.column_types[2], agate.data_types.Text)
+        assert isinstance(result.column_types[3], agate.data_types.Number)
         self.assertEqual(len(result), 6)
 
     def test_nocast_string_types(self):
@@ -191,7 +216,7 @@ def test_nocast_bool_01(self):
         self.assertEqual(len(tbl), len(result_set))
 
         assert isinstance(tbl.column_types[0], agate.data_types.Boolean)
-        assert isinstance(tbl.column_types[1], agate.data_types.Number)
+        assert isinstance(tbl.column_types[1], agate_helper.Integer)
 
         expected = [
             [True, Decimal(1)],