feat: allow linter to return multiple violations

- also printed the line numbers

Author: benfdking

sqlmesh/core/console.py

@@ -2685,7 +2685,25 @@ def show_linter_violations(
         self, violations: t.List[RuleViolation], model: Model, is_error: bool = False
     ) -> None:
         severity = "errors" if is_error else "warnings"
-        violations_msg = "\n".join(f" - {violation}" for violation in violations)
+
+        # Sort violations by line, then alphabetically the name of the violation
+        # Violations with no range go first
+        sorted_violations = sorted(
+            violations,
+            key=lambda v: (
+                v.violation_range.start.line if v.violation_range else -1,
+                v.rule.name.lower(),
+            ),
+        )
+        violations_text = [
+            (
+                f" - Line {v.violation_range.start.line + 1}: {v.rule.name} - {v.violation_msg}"
+                if v.violation_range
+                else f" - {v.rule.name}: {v.violation_msg}"
+            )
+            for v in sorted_violations
+        ]
+        violations_msg = "\n".join(violations_text)
         msg = f"Linter {severity} for {model._path}:\n{violations_msg}"
 
         if is_error:

sqlmesh/core/linter/definition.py

@@ -108,9 +108,10 @@ def check_model(self, model: Model, context: GenericContext) -> t.List[RuleViola
 
         for rule in self._underlying.values():
             violation = rule(context).check_model(model)
-
+            if isinstance(violation, RuleViolation):
+                violation = [violation]
             if violation:
-                violations.append(violation)
+                violations.extend(violation)
 
         return violations
 

sqlmesh/core/linter/rule.py

@@ -70,7 +70,9 @@ def __init__(self, context: GenericContext):
         self.context = context
 
     @abc.abstractmethod
-    def check_model(self, model: Model) -> t.Optional[RuleViolation]:
+    def check_model(
+        self, model: Model
+    ) -> t.Optional[t.Union[RuleViolation, t.List[RuleViolation]]]:
         """The evaluation function that'll check for a violation of this rule."""
 
     @property