fix view comparison

The previous function would ignore changes in numbers and quoted
whitespace. We can use sqlparse to normalize the given SQL for easy
comparison.

django_db_views/autodetector.py

@@ -1,9 +1,8 @@
-import re
-from itertools import zip_longest
 from typing import Type
 
 import django
 import six
+import sqlparse
 from django.apps import apps
 from django.conf import settings
 from django.db import connection, ProgrammingError
@@ -178,21 +177,19 @@ def get_current_view_models():
                     view_models[key] = model_class
         return view_models
 
-    def is_same_views(self, current: str, new: str) -> bool:
-        if not current:
-            return False
-        s1_words = filter(
-            lambda x: len(x) != 0, re.split(pattern="[^a-zA-Z]*", string=current)
-        )
-        s2_words = filter(
-            lambda x: len(x) != 0, re.split(pattern="[^a-zA-Z]*", string=new)
-        )
-        for w1, w2 in zip_longest(s1_words, s2_words):
-            if not w1 or not w2:
-                return False
-            if w1.lower() != w2.lower():
-                return False
-        return True
+    @staticmethod
+    def is_same_views(current: str, new: str) -> bool:
+        def sql_normalize(s: str) -> str:
+            return sqlparse.format(
+                s,
+                compact=True,
+                keyword_case="upper",
+                identifier_case="lower",
+                reindent=True,
+                strip_comments=True,
+            )
+
+        return sql_normalize(current) == sql_normalize(new)
 
     def generate_views_operations(self, graph: MigrationGraph) -> None:
         view_models = self.get_current_view_models()

tests/test_autodetector.py

@@ -0,0 +1,16 @@
+from django_db_views.autodetector import ViewMigrationAutoDetector
+
+
+def test_is_same_views():
+    is_same = ViewMigrationAutoDetector.is_same_views
+
+    assert is_same("A B C", "A B   C")
+    assert is_same("select * from xyz", "SELECT *   FROM xyz")
+    assert not is_same("select 1 from test", "select 2 from test")
+    assert is_same("select *\nfrom test\n", "select * from test")
+    assert is_same(
+        "SELECT\n\t   * \n FROM something where a = ' ' and B = \"  \"",
+        "select * from something where a = ' ' and b = \"  \"",
+    )
+    assert not is_same('SELECT " "', 'SELECT ""')
+    assert not is_same('SELECT "TEST "', 'SELECT "TEST    "')