Fixed #28646 -- Prevented duplicate index when unique is set to True on PostgreSQL.

2 files changed, 225 insertions, 0 deletions

diff --git a/tests/schema/models.py b/tests/schema/models.py
index 75e32a0eab..2fc9095b61 100644
--- a/tests/schema/models.py
+++ b/tests/schema/models.py
@@ -147,6 +147,20 @@ class IntegerPK(models.Model):
         db_table = "INTEGERPK"  # uppercase to ensure proper quoting
 
 
+class CharFieldPK(models.Model):
+    field1 = models.CharField(max_length=10, primary_key=True)
+
+    class Meta:
+        apps = new_apps
+
+
+class CharFieldPKUnique(models.Model):
+    field1 = models.CharField(max_length=10, primary_key=True, unique=True)
+
+    class Meta:
+        apps = new_apps
+
+
 class Note(models.Model):
     info = models.TextField()
     address = models.TextField(null=True)
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 3a2947cf43..88e346e923 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -86,6 +86,8 @@ from .models import (
     BookWithO2O,
     BookWithoutAuthor,
     BookWithSlug,
+    CharFieldPK,
+    CharFieldPKUnique,
     IntegerPK,
     Node,
     Note,
@@ -121,6 +123,8 @@ class SchemaTests(TransactionTestCase):
         BookWithLongName,
         BookWithO2O,
         BookWithSlug,
+        CharFieldPK,
+        CharFieldPKUnique,
         IntegerPK,
         Node,
         Note,
@@ -5210,6 +5214,213 @@ class SchemaTests(TransactionTestCase):
             ["schema_tag_slug_2c418ba3_like", "schema_tag_slug_key"],
         )
 
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_charfield_primary_key_to_db_index(self):
+        # Create the table and verify initial indexes.
+        with connection.schema_editor() as editor:
+            editor.create_model(CharFieldPK)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPK, "field1"),
+            ["schema_charfieldpk_field1_0eb93b91_like", "schema_charfieldpk_pkey"],
+        )
+        # Alter to remove primary_key and set db_index=True.
+        old_field1 = CharFieldPK._meta.get_field("field1")
+        new_field1 = CharField(db_index=True, primary_key=False)
+        new_field1.set_attributes_from_name("field1")
+        with connection.schema_editor() as editor:
+            editor.alter_field(CharFieldPK, old_field1, new_field1, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPK, "field1"),
+            [
+                "schema_charfieldpk_field1_0eb93b91",
+                "schema_charfieldpk_field1_0eb93b91_like",
+            ],
+        )
+
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_charfield_primary_key_to_unique(self):
+        # Create the table and verify initial indexes.
+        with connection.schema_editor() as editor:
+            editor.create_model(CharFieldPK)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPK, "field1"),
+            ["schema_charfieldpk_field1_0eb93b91_like", "schema_charfieldpk_pkey"],
+        )
+        # Alter to remove primary_key and set unique=True.
+        old_field1 = CharFieldPK._meta.get_field("field1")
+        new_field1 = CharField(unique=True, primary_key=False)
+        new_field1.set_attributes_from_name("field1")
+        new_field1.model = CharFieldPK
+        with connection.schema_editor() as editor:
+            editor.alter_field(CharFieldPK, old_field1, new_field1, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPK, "field1"),
+            [
+                "schema_charfieldpk_field1_0eb93b91_like",
+                "schema_charfieldpk_field1_0eb93b91_uniq",
+            ],
+        )
+
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_charfield_primary_key_to_db_index_and_unique(self):
+        # Create the table and verify initial indexes.
+        with connection.schema_editor() as editor:
+            editor.create_model(CharFieldPK)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPK, "field1"),
+            ["schema_charfieldpk_field1_0eb93b91_like", "schema_charfieldpk_pkey"],
+        )
+        # Alter to remove primary_key and set db_index=True and unique=True.
+        old_field1 = CharFieldPK._meta.get_field("field1")
+        new_field1 = CharField(unique=True, db_index=True, primary_key=False)
+        new_field1.set_attributes_from_name("field1")
+        new_field1.model = CharFieldPK
+        with connection.schema_editor() as editor:
+            editor.alter_field(CharFieldPK, old_field1, new_field1, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPK, "field1"),
+            [
+                "schema_charfieldpk_field1_0eb93b91_like",
+                "schema_charfieldpk_field1_0eb93b91_uniq",
+            ],
+        )
+
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_charfield_primary_key_unique_to_just_unique(self):
+        # Create the table and verify initial indexes.
+        with connection.schema_editor() as editor:
+            editor.create_model(CharFieldPKUnique)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPKUnique, "field1"),
+            [
+                "schema_charfieldpkunique_field1_ffc9a22c_like",
+                "schema_charfieldpkunique_pkey",
+            ],
+        )
+        # Alter to remove primary_key (but still unique).
+        old_field1 = CharFieldPKUnique._meta.get_field("field1")
+        new_field1 = CharField(unique=True, primary_key=False)
+        new_field1.set_attributes_from_name("field1")
+        new_field1.model = CharFieldPKUnique
+        with connection.schema_editor() as editor:
+            editor.alter_field(CharFieldPKUnique, old_field1, new_field1, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(CharFieldPKUnique, "field1"),
+            [
+                "schema_charfieldpkunique_field1_ffc9a22c_like",
+                "schema_charfieldpkunique_field1_ffc9a22c_uniq",
+            ],
+        )
+
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_charfield_db_index_to_textfield_db_index(self):
+        with connection.schema_editor() as editor:
+            editor.create_model(AuthorCharFieldWithIndex)
+        self.assertEqual(
+            self.get_constraints_for_column(AuthorCharFieldWithIndex, "char_field"),
+            [
+                "schema_authorcharfieldwithindex_char_field_06a11776",
+                "schema_authorcharfieldwithindex_char_field_06a11776_like",
+            ],
+        )
+        old_field = AuthorCharFieldWithIndex._meta.get_field("char_field")
+        new_field = TextField(db_index=True)
+        new_field.set_attributes_from_name("char_field")
+        new_field.model = AuthorCharFieldWithIndex
+        with connection.schema_editor() as editor:
+            editor.alter_field(
+                AuthorCharFieldWithIndex, old_field, new_field, strict=True
+            )
+        self.assertEqual(
+            self.get_constraints_for_column(AuthorCharFieldWithIndex, "char_field"),
+            [
+                "schema_authorcharfieldwithindex_char_field_06a11776",
+                "schema_authorcharfieldwithindex_char_field_06a11776_like",
+            ],
+        )
+
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_charfield_change_max_length_no_index_created(self):
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+        self.assertEqual(
+            self.get_constraints_for_column(Author, "name"),
+            [],
+        )
+        old_name = Author._meta.get_field("name")
+        new_name = CharField(max_length=20)
+        new_name.set_attributes_from_name("name")
+        with connection.schema_editor() as editor:
+            editor.alter_field(Author, old_name, new_name, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(Author, "name"),
+            [],
+        )
+
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_remove_db_index(self):
+        with connection.schema_editor() as editor:
+            editor.create_model(AuthorCharFieldWithIndex)
+        self.assertEqual(
+            self.get_constraints_for_column(AuthorCharFieldWithIndex, "char_field"),
+            [
+                "schema_authorcharfieldwithindex_char_field_06a11776",
+                "schema_authorcharfieldwithindex_char_field_06a11776_like",
+            ],
+        )
+        old_char_field = AuthorCharFieldWithIndex._meta.get_field("char_field")
+        new_char_field = CharField(max_length=31, db_index=False)
+        new_char_field.set_attributes_from_name("char_field")
+        with connection.schema_editor() as editor:
+            editor.alter_field(
+                AuthorCharFieldWithIndex, old_char_field, new_char_field, strict=True
+            )
+        self.assertEqual(
+            self.get_constraints_for_column(AuthorCharFieldWithIndex, "char_field"),
+            [],
+        )
+
+    @isolate_apps("schema")
+    @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
+    def test_slugfields_change_primary_key(self):
+        class SimpleModel(Model):
+            field1 = SlugField(max_length=20, primary_key=True)
+            field2 = SlugField(max_length=20)
+
+            class Meta:
+                app_label = "schema"
+
+        with connection.schema_editor() as editor:
+            editor.create_model(SimpleModel)
+        self.assertEqual(
+            self.get_constraints_for_column(SimpleModel, "field1"),
+            [
+                "schema_simplemodel_field1_f07a3d6a_like",
+                "schema_simplemodel_pkey",
+            ],
+        )
+        # Remove primary_key from field1.
+        old_field1 = SimpleModel._meta.get_field("field1")
+        new_field1 = CharField(max_length=20, primary_key=False)
+        new_field1.set_attributes_from_name("field1")
+        with connection.schema_editor() as editor:
+            editor.alter_field(SimpleModel, old_field1, new_field1, strict=True)
+        self.assertEqual(self.get_constraints_for_column(SimpleModel, "field1"), [])
+        # Add primary_key to field2.
+        old_field2 = SimpleModel._meta.get_field("field2")
+        new_field2 = CharField(max_length=20, primary_key=True)
+        new_field2.set_attributes_from_name("field2")
+        new_field2.model = SimpleModel
+        with connection.schema_editor() as editor:
+            editor.alter_field(SimpleModel, old_field2, new_field2, strict=True)
+        self.assertEqual(
+            self.get_constraints_for_column(SimpleModel, "field2"),
+            [
+                "schema_simplemodel_field2_08772539_like",
+                "schema_simplemodel_field2_08772539_pk",
+            ],
+        )
+
     def test_alter_field_add_index_to_integerfield(self):
         # Create the table and verify no initial indexes.
         with connection.schema_editor() as editor: