Make ambiguousprojection a default sqlmesh linter rule in init

Author: georgesittas

sqlmesh/cli/project_init.py

@@ -114,6 +114,7 @@ def _gen_config(
   rules:
     - ambiguousorinvalidcolumn
     - invalidselectstarexpansion
+    - noambiguousprojections
 """,
         ProjectTemplate.DBT: f"""# --- Virtual Data Environment Mode ---
 # Enable Virtual Data Environments (VDE) for *development* environments.

sqlmesh/core/linter/definition.py

@@ -1,15 +1,15 @@
 from __future__ import annotations
-import typing as t
-from sqlmesh.core.config.linter import LinterConfig
-from sqlmesh.core.model import Model
-from sqlmesh.utils.errors import raise_config_error
-from sqlmesh.core.console import LinterConsole, get_console
+
 import operator as op
+import typing as t
 from collections.abc import Iterator, Iterable, Set, Mapping, Callable
 from functools import reduce
-from sqlmesh.core.model import Model
-from sqlmesh.core.linter.rule import Rule, RuleViolation, Range, Fix
+
+from sqlmesh.core.config.linter import LinterConfig
 from sqlmesh.core.console import LinterConsole, get_console
+from sqlmesh.core.linter.rule import Rule, RuleViolation, Range, Fix
+from sqlmesh.core.model import Model
+from sqlmesh.utils.errors import raise_config_error
 
 if t.TYPE_CHECKING:
     from sqlmesh.core.context import GenericContext
@@ -38,6 +38,12 @@ def __init__(
         self.rules = rules
         self.warn_rules = warn_rules
 
+        if overlapping := rules.intersection(warn_rules):
+            overlapping_rules = ", ".join(rule for rule in overlapping)
+            raise_config_error(
+                f"Rules cannot simultaneously warn and raise an error: [{overlapping_rules}]"
+            )
+
     @classmethod
     def from_rules(cls, all_rules: RuleSet, config: LinterConfig) -> Linter:
         ignored_rules = select_rules(all_rules, config.ignored_rules)
@@ -46,12 +52,6 @@ def from_rules(cls, all_rules: RuleSet, config: LinterConfig) -> Linter:
         rules = select_rules(included_rules, config.rules)
         warn_rules = select_rules(included_rules, config.warn_rules)
 
-        if overlapping := rules.intersection(warn_rules):
-            overlapping_rules = ", ".join(rule for rule in overlapping)
-            raise_config_error(
-                f"Rules cannot simultaneously warn and raise an error: [{overlapping_rules}]"
-            )
-
         return Linter(config.enabled, all_rules, rules, warn_rules)
 
     def lint_model(

sqlmesh/core/linter/rules/builtin.py

@@ -275,7 +275,7 @@ def create_fix(self, model_name: str) -> t.Optional[Fix]:
 
 
 class NoAmbiguousProjections(Rule):
-    """All projections in a model must have unique, inferrable names or explicit aliases."""
+    """All projections in a model must have unique & inferrable names or explicit aliases."""
 
     def check_model(self, model: Model) -> t.Optional[RuleViolation]:
         query = model.render_query()

tests/cli/test_cli.py

@@ -982,6 +982,7 @@ def test_dlt_filesystem_pipeline(tmp_path):
         "  rules:\n"
         "    - ambiguousorinvalidcolumn\n"
         "    - invalidselectstarexpansion\n"
+        "    - noambiguousprojections\n"
     )
 
     with open(config_path) as file:
@@ -1048,6 +1049,7 @@ def test_dlt_pipeline(runner, tmp_path):
   rules:
     - ambiguousorinvalidcolumn
     - invalidselectstarexpansion
+    - noambiguousprojections
 """
 
     with open(tmp_path / "config.yaml") as file:
@@ -1990,6 +1992,7 @@ def test_init_project_engine_configs(tmp_path):
   rules:
     - ambiguousorinvalidcolumn
     - invalidselectstarexpansion
+    - noambiguousprojections
 """
 
         with open(tmp_path / "config.yaml") as file:

tests/core/test_context.py

@@ -3117,3 +3117,20 @@ def test_plan_no_start_configured():
         match=r"Model '.*xvg.*': Start date / time .* can't be greater than end date / time .*\.\nSet the `start` attribute in your project config model defaults to avoid this issue",
     ):
         context.plan("dev", execution_time="1999-01-05")
+
+
+def test_lint_model_projections(tmp_path: Path):
+    init_example_project(tmp_path, engine_type="duckdb", dialect="duckdb")
+
+    context = Context(paths=tmp_path)
+    context.upsert_model(
+        load_sql_based_model(
+            parse("""MODEL(name sqlmesh_example.m); SELECT 1 AS x, 2 AS x"""),
+            default_catalog="db",
+        )
+    )
+
+    config_err = "Linter detected errors in the code. Please fix them before proceeding."
+
+    with pytest.raises(LinterError, match=config_err):
+        prod_plan = context.plan(no_prompts=True, auto_apply=True)