Eliminate intermediate _parse_sql() method

By using a settings_changed signal receiver to clear the query caching,
the parse_sql() and _parse_sql() functions can be merged and the check
for the "PRETTIFY_SQL" setting can be moved back inside the
get_filter_stack() function.

Author: living180

debug_toolbar/panels/sql/utils.py

@@ -2,6 +2,8 @@
 from html import escape
 
 import sqlparse
+from django.dispatch import receiver
+from django.test.signals import setting_changed
 from sqlparse import tokens as T
 
 from debug_toolbar import settings as dt_settings
@@ -94,27 +96,19 @@ def reformat_sql(sql, with_toggle=False):
     return collapsed + uncollapsed
 
 
-def parse_sql(sql, *, simplify=False):
-    return _parse_sql(
-        sql,
-        prettify=dt_settings.get_config()["PRETTIFY_SQL"],
-        simplify=simplify,
-    )
-
-
 @lru_cache(maxsize=128)
-def _parse_sql(sql, *, prettify, simplify):
-    stack = get_filter_stack(prettify=prettify, simplify=simplify)
+def parse_sql(sql, *, simplify=False):
+    stack = get_filter_stack(simplify=simplify)
     return "".join(stack.run(sql))
 
 
 @lru_cache(maxsize=None)
-def get_filter_stack(*, prettify, simplify):
+def get_filter_stack(*, simplify):
     stack = sqlparse.engine.FilterStack()
     if simplify:
         stack.preprocess.append(ElideSelectListsFilter())
     else:
-        if prettify:
+        if dt_settings.get_config()["PRETTIFY_SQL"]:
             stack.enable_grouping()
         stack.stmtprocess.append(
             sqlparse.filters.AlignedIndentFilter(char="&nbsp;", n="<br/>")
@@ -124,6 +118,13 @@ def get_filter_stack(*, prettify, simplify):
     return stack
 
 
+@receiver(setting_changed)
+def clear_caches(*, setting, **kwargs):
+    if setting == "DEBUG_TOOLBAR_CONFIG":
+        parse_sql.cache_clear()
+        get_filter_stack.cache_clear()
+
+
 def contrasting_color_generator():
     """
     Generate contrasting colors by varying most significant bit of RGB first,

tests/panels/test_sql.py

@@ -14,7 +14,6 @@
 from django.test.utils import override_settings
 
 import debug_toolbar.panels.sql.tracking as sql_tracking
-from debug_toolbar import settings as dt_settings
 
 try:
     import psycopg
@@ -458,42 +457,39 @@ def test_regression_infinite_recursion(self):
         # ensure the stacktrace is populated
         self.assertTrue(len(query["stacktrace"]) > 0)
 
-    @override_settings(
-        DEBUG_TOOLBAR_CONFIG={"PRETTIFY_SQL": True},
-    )
     def test_prettify_sql(self):
         """
         Test case to validate that the PRETTIFY_SQL setting changes the output
         of the sql when it's toggled. It does not validate what it does
         though.
         """
-        list(User.objects.filter(username__istartswith="spam"))
-
-        response = self.panel.process_request(self.request)
-        self.panel.generate_stats(self.request, response)
-        pretty_sql = self.panel._queries[-1]["sql"]
-        self.assertEqual(len(self.panel._queries), 1)
+        with override_settings(DEBUG_TOOLBAR_CONFIG={"PRETTIFY_SQL": True}):
+            list(User.objects.filter(username__istartswith="spam"))
+            response = self.panel.process_request(self.request)
+            self.panel.generate_stats(self.request, response)
+            pretty_sql = self.panel._queries[-1]["sql"]
+            self.assertEqual(len(self.panel._queries), 1)
 
         # Reset the queries
         self.panel._queries = []
         # Run it again, but with prettify off. Verify that it's different.
-        dt_settings.get_config()["PRETTIFY_SQL"] = False
-        list(User.objects.filter(username__istartswith="spam"))
-        response = self.panel.process_request(self.request)
-        self.panel.generate_stats(self.request, response)
-        self.assertEqual(len(self.panel._queries), 1)
-        self.assertNotEqual(pretty_sql, self.panel._queries[-1]["sql"])
+        with override_settings(DEBUG_TOOLBAR_CONFIG={"PRETTIFY_SQL": False}):
+            list(User.objects.filter(username__istartswith="spam"))
+            response = self.panel.process_request(self.request)
+            self.panel.generate_stats(self.request, response)
+            self.assertEqual(len(self.panel._queries), 1)
+            self.assertNotEqual(pretty_sql, self.panel._queries[-1]["sql"])
 
         self.panel._queries = []
         # Run it again, but with prettify back on.
         # This is so we don't have to check what PRETTIFY_SQL does exactly,
         # but we know it's doing something.
-        dt_settings.get_config()["PRETTIFY_SQL"] = True
-        list(User.objects.filter(username__istartswith="spam"))
-        response = self.panel.process_request(self.request)
-        self.panel.generate_stats(self.request, response)
-        self.assertEqual(len(self.panel._queries), 1)
-        self.assertEqual(pretty_sql, self.panel._queries[-1]["sql"])
+        with override_settings(DEBUG_TOOLBAR_CONFIG={"PRETTIFY_SQL": True}):
+            list(User.objects.filter(username__istartswith="spam"))
+            response = self.panel.process_request(self.request)
+            self.panel.generate_stats(self.request, response)
+            self.assertEqual(len(self.panel._queries), 1)
+            self.assertEqual(pretty_sql, self.panel._queries[-1]["sql"])
 
     def test_simplification(self):
         """