Fixed #30754 -- Prevented inclusion of aliases in partial index conditions.

SQLite doesn't repoint table aliases in partial index conditions on table
rename which breaks the documented table alteration procedure.

Thanks Pēteris Caune for the report.

3 files changed, 11 insertions, 13 deletions

diff --git a/django/db/models/indexes.py b/django/db/models/indexes.py
index 5154de056e..b156366764 100644
--- a/django/db/models/indexes.py
+++ b/django/db/models/indexes.py
@@ -41,13 +41,10 @@ class Index:
         if self.condition is None:
             return None
         query = Query(model=model)
-        query.add_q(self.condition)
+        where = query.build_where(self.condition)
         compiler = query.get_compiler(connection=schema_editor.connection)
-        # Only the WhereNode is of interest for the partial index.
-        sql, params = query.where.as_sql(compiler=compiler, connection=schema_editor.connection)
-        # BaseDatabaseSchemaEditor does the same map on the params, but since
-        # it's handled outside of that class, the work is done here.
-        return sql % tuple(map(schema_editor.quote_value, params))
+        sql, params = where.as_sql(compiler, schema_editor.connection)
+        return sql % tuple(schema_editor.quote_value(p) for p in params)
 
     def create_sql(self, model, schema_editor, using='', **kwargs):
         fields = [model._meta.get_field(field_name) for field_name, _ in self.fields_orders]
diff --git a/docs/releases/2.2.6.txt b/docs/releases/2.2.6.txt
index e75160f8f3..59c29ef0a6 100644
--- a/docs/releases/2.2.6.txt
+++ b/docs/releases/2.2.6.txt
@@ -9,4 +9,5 @@ Django 2.2.6 fixes several bugs in 2.2.5.
 Bugfixes
 ========
 
-* ...
+* Fixed migrations crash on SQLite when altering a model containing partial
+  indexes (:ticket:`30754`).
diff --git a/tests/indexes/tests.py b/tests/indexes/tests.py
index ecc449ed4a..2272cadc4f 100644
--- a/tests/indexes/tests.py
+++ b/tests/indexes/tests.py
@@ -108,7 +108,7 @@ class PartialIndexConditionIgnoredTests(TransactionTestCase):
             editor.add_index(Article, index)
 
         self.assertNotIn(
-            'WHERE %s.%s' % (editor.quote_name(Article._meta.db_table), 'published'),
+            'WHERE %s' % editor.quote_name('published'),
             str(index.create_sql(Article, editor))
         )
 
@@ -258,7 +258,7 @@ class PartialIndexTests(TransactionTestCase):
                 )
             )
             self.assertIn(
-                'WHERE %s.%s' % (editor.quote_name(Article._meta.db_table), editor.quote_name("pub_date")),
+                'WHERE %s' % editor.quote_name('pub_date'),
                 str(index.create_sql(Article, schema_editor=editor))
             )
             editor.add_index(index=index, model=Article)
@@ -275,7 +275,7 @@ class PartialIndexTests(TransactionTestCase):
                 condition=Q(pk__gt=1),
             )
             self.assertIn(
-                'WHERE %s.%s' % (editor.quote_name(Article._meta.db_table), editor.quote_name('id')),
+                'WHERE %s' % editor.quote_name('id'),
                 str(index.create_sql(Article, schema_editor=editor))
             )
             editor.add_index(index=index, model=Article)
@@ -292,7 +292,7 @@ class PartialIndexTests(TransactionTestCase):
                 condition=Q(published=True),
             )
             self.assertIn(
-                'WHERE %s.%s' % (editor.quote_name(Article._meta.db_table), editor.quote_name('published')),
+                'WHERE %s' % editor.quote_name('published'),
                 str(index.create_sql(Article, schema_editor=editor))
             )
             editor.add_index(index=index, model=Article)
@@ -319,7 +319,7 @@ class PartialIndexTests(TransactionTestCase):
             sql = str(index.create_sql(Article, schema_editor=editor))
             where = sql.find('WHERE')
             self.assertIn(
-                'WHERE (%s.%s' % (editor.quote_name(Article._meta.db_table), editor.quote_name("pub_date")),
+                'WHERE (%s' % editor.quote_name('pub_date'),
                 sql
             )
             # Because each backend has different syntax for the operators,
@@ -339,7 +339,7 @@ class PartialIndexTests(TransactionTestCase):
                 condition=Q(pub_date__isnull=False),
             )
             self.assertIn(
-                'WHERE %s.%s IS NOT NULL' % (editor.quote_name(Article._meta.db_table), editor.quote_name("pub_date")),
+                'WHERE %s IS NOT NULL' % editor.quote_name('pub_date'),
                 str(index.create_sql(Article, schema_editor=editor))
             )
             editor.add_index(index=index, model=Article)