Remove cohort extractor support in v4

pipeline/models.py

@@ -15,6 +15,7 @@
     validate_databuilder_outputs,
     validate_glob_pattern,
     validate_no_kwargs,
+    validate_not_cohort_extractor_action,
     validate_type,
 )
 
@@ -238,7 +239,7 @@ def is_database_action(self) -> bool:
 class Pipeline:
     version: float
     actions: dict[str, Action]
-    expectations: Expectations
+    expectations: Expectations | None
 
     @classmethod
     def build(
@@ -262,13 +263,18 @@ def build(
             raise ValidationError(
                 f"`version` must be a number between 1 and {LATEST_VERSION}"
             )
+        feat = get_feature_flags_for_version(version)
 
         validate_type(actions, dict, "Project `actions` section")
         actions = {
             action_id: Action.build(action_id, **action_config)
             for action_id, action_config in actions.items()
         }
 
+        if feat.REMOVE_SUPPORT_FOR_COHORT_EXTRACTOR:
+            for config in actions.values():
+                validate_not_cohort_extractor_action(config)
+
         seen: dict[Command, list[str]] = defaultdict(list)
         for name, config in actions.items():
             run = config.run
@@ -278,7 +284,7 @@ def build(
                 )
             seen[run].append(name)
 
-        if get_feature_flags_for_version(version).UNIQUE_OUTPUT_PATH:
+        if feat.UNIQUE_OUTPUT_PATH:
             # find duplicate paths defined in the outputs section
             seen_files = []
             for config in actions.values():
@@ -298,19 +304,24 @@ def build(
                         f"Action `{a.action_id}` references an unknown action in its `needs` list: {n}"
                     )
 
-        feat = get_feature_flags_for_version(version)
-        if feat.EXPECTATIONS_POPULATION:
+        if feat.REMOVE_SUPPORT_FOR_COHORT_EXTRACTOR:
+            if expectations is not None:
+                raise ValidationError(
+                    "Project includes `expectations` section, which is not supported in this version"
+                )
+        elif feat.EXPECTATIONS_POPULATION:
             if expectations is None:
                 raise ValidationError("Project must include `expectations` section")
         else:
             expectations = {"population_size": 1000}
 
-        validate_type(expectations, dict, "Project `expectations` section")
-        if "population_size" not in expectations:
-            raise ValidationError(
-                "Project `expectations` section must include `population_size` section",
-            )
-        expectations = Expectations.build(**expectations)
+        if expectations is not None:
+            validate_type(expectations, dict, "Project `expectations` section")
+            if "population_size" not in expectations:
+                raise ValidationError(
+                    "Project `expectations` section must include `population_size` section",
+                )
+            expectations = Expectations.build(**expectations)
 
         return cls(version, actions, expectations)
 

pipeline/validation.py

@@ -79,6 +79,13 @@ def validate_glob_pattern(pattern: str, privacy_level: str) -> None:
         raise InvalidPatternError("is an absolute path")
 
 
+def validate_not_cohort_extractor_action(action: Action) -> None:
+    if action.run.parts[0].startswith("cohortextractor"):
+        raise ValidationError(
+            f"Action {action.action_id} uses cohortextractor actions, which are not supported in this version."
+        )
+
+
 def validate_cohortextractor_outputs(action_id: str, action: Action) -> None:
     """
     Check cohortextractor's output config is valid for this command

tests/test_models.py

@@ -129,6 +129,23 @@ def test_action_extraction_command_with_one_outputs():
     assert len(outputs.values()) == 1
 
 
+def test_cohortextractor_actions_not_used_after_v3():
+    data = {
+        "version": "4",
+        "actions": {
+            "generate_cohort": {
+                "run": "cohortextractor:latest generate_cohort",
+                "outputs": {
+                    "highly_sensitive": {"cohort": "output/input.csv"},
+                },
+            },
+        },
+    }
+    msg = "uses cohortextractor actions, which are not supported in this version."
+    with pytest.raises(ValidationError, match=msg):
+        Pipeline.build(**data)
+
+
 def test_command_properties():
     data = {
         "version": 1,
@@ -168,6 +185,22 @@ def test_expectations_before_v3_has_a_default_set():
     assert config.expectations.population_size == 1000
 
 
+def test_expectations_does_not_exist_after_v3():
+    data = {
+        "version": 4,
+        "expectations": {},
+        "actions": {
+            "generate_dataset": {
+                "run": "ehrql:v1 generate-dataset args --output output/dataset.csv.gz",
+                "outputs": {"highly_sensitive": {"dataset": "output/dataset.csv.gz"}},
+            }
+        },
+    }
+    msg = "Project includes `expectations` section"
+    with pytest.raises(ValidationError, match=msg):
+        Pipeline.build(**data)
+
+
 def test_expectations_exists_for_v3():
     # our logic for this is custom so ensure it works as expected
     data = {