SCP30 removed setting (#41)

Author: Gallaecio

docs/rules/scp30.rst

@@ -0,0 +1,24 @@
+.. _scp30:
+
+======================
+SCP30: Removed setting
+======================
+
+What it does
+============
+
+Reports setting names that have been removed from package versions frozen in
+your project requirements but do exist in lower versions of those packages.
+
+It also reports the package that defined the setting, the version in which the
+setting was deprecated, and the version in which it was removed, so that you
+can check the corresponging release notes for sunset guidance.
+
+Sometimes sunset guidance is also provided in the error message.
+
+Why is this bad?
+================
+
+Removed settings have stopped working the way they used to, and instead are
+silently ignored.
+

flake8_scrapy/finders/settings.py

@@ -125,8 +125,9 @@ def check_known_name(
         if name not in SETTINGS:
             return
         setting = SETTINGS[name]
-        deprecated_in = setting.deprecated_in
         added_in = setting.added_in
+        deprecated_in = setting.deprecated_in
+        removed_in = setting.removed_in
         if not deprecated_in and not added_in:
             return
         package = setting.package
@@ -154,11 +155,16 @@ def check_known_name(
             if version < deprecated_in:
                 return
             detail = f"deprecated in {package} {deprecated_in}"
+        if removed_in and version >= removed_in:
+            detail += f", removed in {removed_in}"
+            code, message = 30, "removed setting"
+        else:
+            code, message = 28, "deprecated setting"
         if setting.sunset_guidance:
             detail += f"; {setting.sunset_guidance}"
         yield Issue(
-            28,
-            "deprecated setting",
+            code,
+            message,
             detail=detail,
             node=resolved_node,
             column=column,

tests/test_settings.py

@@ -1133,6 +1133,23 @@ def default_issues(
                     ),
                 ),
             ),
+            # SCP30 removed setting
+            (
+                ("scrapy==2.1.0",),
+                "LOG_UNSERIALIZABLE_REQUESTS",
+                (
+                    Issue(
+                        "SCP15 insecure requirement: scrapy 2.11.2 implements security fixes",
+                        path="requirements.txt",
+                    ),
+                    Issue(
+                        "SCP30 removed setting: deprecated in scrapy 2.0.1 or "
+                        "lower, removed in 2.1.0; use SCHEDULER_DEBUG instead",
+                        path=path,
+                        column=column,
+                    ),
+                ),
+            ),
         )
     ),
     # scrapy_known_settings silences SCP27