Fixed #30183 -- Added introspection of inline SQLite constraints.

tests/backends/sqlite/test_introspection.py

 import unittest
 
+import sqlparse
+
 from django.db import connection
 from django.test import TestCase
 
@@ -25,3 +27,116 @@ class IntrospectionTests(TestCase):
                         self.assertEqual(field, expected_string)
                     finally:
                         cursor.execute('DROP TABLE test_primary')
+
+
+@unittest.skipUnless(connection.vendor == 'sqlite', 'SQLite tests')
+class ParsingTests(TestCase):
+    def parse_definition(self, sql, columns):
+        """Parse a column or constraint definition."""
+        statement = sqlparse.parse(sql)[0]
+        tokens = (token for token in statement.flatten() if not token.is_whitespace)
+        with connection.cursor():
+            return connection.introspection._parse_column_or_constraint_definition(tokens, set(columns))
+
+    def assertConstraint(self, constraint_details, cols, unique=False, check=False):
+        self.assertEqual(constraint_details, {
+            'unique': unique,
+            'columns': cols,
+            'primary_key': False,
+            'foreign_key': None,
+            'check': check,
+            'index': False,
+        })
+
+    def test_unique_column(self):
+        tests = (
+            ('"ref" integer UNIQUE,', ['ref']),
+            ('ref integer UNIQUE,', ['ref']),
+            ('"customname" integer UNIQUE,', ['customname']),
+            ('customname integer UNIQUE,', ['customname']),
+        )
+        for sql, columns in tests:
+            with self.subTest(sql=sql):
+                constraint, details, check, _ = self.parse_definition(sql, columns)
+                self.assertIsNone(constraint)
+                self.assertConstraint(details, columns, unique=True)
+                self.assertIsNone(check)
+
+    def test_unique_constraint(self):
+        tests = (
+            ('CONSTRAINT "ref" UNIQUE ("ref"),', 'ref', ['ref']),
+            ('CONSTRAINT ref UNIQUE (ref),', 'ref', ['ref']),
+            ('CONSTRAINT "customname1" UNIQUE ("customname2"),', 'customname1', ['customname2']),
+            ('CONSTRAINT customname1 UNIQUE (customname2),', 'customname1', ['customname2']),
+        )
+        for sql, constraint_name, columns in tests:
+            with self.subTest(sql=sql):
+                constraint, details, check, _ = self.parse_definition(sql, columns)
+                self.assertEqual(constraint, constraint_name)
+                self.assertConstraint(details, columns, unique=True)
+                self.assertIsNone(check)
+
+    def test_unique_constraint_multicolumn(self):
+        tests = (
+            ('CONSTRAINT "ref" UNIQUE ("ref", "customname"),', 'ref', ['ref', 'customname']),
+            ('CONSTRAINT ref UNIQUE (ref, customname),', 'ref', ['ref', 'customname']),
+        )
+        for sql, constraint_name, columns in tests:
+            with self.subTest(sql=sql):
+                constraint, details, check, _ = self.parse_definition(sql, columns)
+                self.assertEqual(constraint, constraint_name)
+                self.assertConstraint(details, columns, unique=True)
+                self.assertIsNone(check)
+
+    def test_check_column(self):
+        tests = (
+            ('"ref" varchar(255) CHECK ("ref" != \'test\'),', ['ref']),
+            ('ref varchar(255) CHECK (ref != \'test\'),', ['ref']),
+            ('"customname1" varchar(255) CHECK ("customname2" != \'test\'),', ['customname2']),
+            ('customname1 varchar(255) CHECK (customname2 != \'test\'),', ['customname2']),
+        )
+        for sql, columns in tests:
+            with self.subTest(sql=sql):
+                constraint, details, check, _ = self.parse_definition(sql, columns)
+                self.assertIsNone(constraint)
+                self.assertIsNone(details)
+                self.assertConstraint(check, columns, check=True)
+
+    def test_check_constraint(self):
+        tests = (
+            ('CONSTRAINT "ref" CHECK ("ref" != \'test\'),', 'ref', ['ref']),
+            ('CONSTRAINT ref CHECK (ref != \'test\'),', 'ref', ['ref']),
+            ('CONSTRAINT "customname1" CHECK ("customname2" != \'test\'),', 'customname1', ['customname2']),
+            ('CONSTRAINT customname1 CHECK (customname2 != \'test\'),', 'customname1', ['customname2']),
+        )
+        for sql, constraint_name, columns in tests:
+            with self.subTest(sql=sql):
+                constraint, details, check, _ = self.parse_definition(sql, columns)
+                self.assertEqual(constraint, constraint_name)
+                self.assertIsNone(details)
+                self.assertConstraint(check, columns, check=True)
+
+    def test_check_column_with_operators_and_functions(self):
+        tests = (
+            ('"ref" integer CHECK ("ref" BETWEEN 1 AND 10),', ['ref']),
+            ('"ref" varchar(255) CHECK ("ref" LIKE \'test%\'),', ['ref']),
+            ('"ref" varchar(255) CHECK (LENGTH(ref) > "max_length"),', ['ref', 'max_length']),
+        )
+        for sql, columns in tests:
+            with self.subTest(sql=sql):
+                constraint, details, check, _ = self.parse_definition(sql, columns)
+                self.assertIsNone(constraint)
+                self.assertIsNone(details)
+                self.assertConstraint(check, columns, check=True)
+
+    def test_check_and_unique_column(self):
+        tests = (
+            ('"ref" varchar(255) CHECK ("ref" != \'test\') UNIQUE,', ['ref']),
+            ('ref varchar(255) UNIQUE CHECK (ref != \'test\'),', ['ref']),
+        )
+        for sql, columns in tests:
+            with self.subTest(sql=sql):
+                constraint, details, check, _ = self.parse_definition(sql, columns)
+                self.assertIsNone(constraint)
+                self.assertConstraint(details, columns, unique=True)
+                self.assertConstraint(check, columns, check=True)

tests/introspection/models.py

@@ -58,3 +58,21 @@ class ArticleReporter(models.Model):
 
     class Meta:
         managed = False
+
+
+class Comment(models.Model):
+    ref = models.UUIDField(unique=True)
+    article = models.ForeignKey(Article, models.CASCADE, db_index=True)
+    email = models.EmailField()
+    pub_date = models.DateTimeField()
+    up_votes = models.PositiveIntegerField()
+    body = models.TextField()
+
+    class Meta:
+        constraints = [
+            models.CheckConstraint(name='up_votes_gte_0_check', check=models.Q(up_votes__gte=0)),
+            models.UniqueConstraint(fields=['article', 'email', 'pub_date'], name='article_email_pub_date_uniq'),
+        ]
+        indexes = [
+            models.Index(fields=['email', 'pub_date'], name='email_pub_date_idx'),
+        ]

tests/introspection/tests.py

@@ -5,7 +5,7 @@ from django.db.models import Index
 from django.db.utils import DatabaseError
 from django.test import TransactionTestCase, skipUnlessDBFeature
 
-from .models import Article, ArticleReporter, City, District, Reporter
+from .models import Article, ArticleReporter, City, Comment, District, Reporter
 
 
 class IntrospectionTests(TransactionTestCase):
@@ -211,3 +211,60 @@ class IntrospectionTests(TransactionTestCase):
                 self.assertEqual(val['orders'], ['ASC'] * len(val['columns']))
                 indexes_verified += 1
         self.assertEqual(indexes_verified, 4)
+
+    def test_get_constraints(self):
+        def assertDetails(details, cols, primary_key=False, unique=False, index=False, check=False, foreign_key=None):
+            # Different backends have different values for same constraints:
+            #               PRIMARY KEY     UNIQUE CONSTRAINT    UNIQUE INDEX
+            # MySQL      pk=1 uniq=1 idx=1  pk=0 uniq=1 idx=1  pk=0 uniq=1 idx=1
+            # PostgreSQL pk=1 uniq=1 idx=0  pk=0 uniq=1 idx=0  pk=0 uniq=1 idx=1
+            # SQLite     pk=1 uniq=0 idx=0  pk=0 uniq=1 idx=0  pk=0 uniq=1 idx=1
+            if details['primary_key']:
+                details['unique'] = True
+            if details['unique']:
+                details['index'] = False
+            self.assertEqual(details['columns'], cols)
+            self.assertEqual(details['primary_key'], primary_key)
+            self.assertEqual(details['unique'], unique)
+            self.assertEqual(details['index'], index)
+            self.assertEqual(details['check'], check)
+            self.assertEqual(details['foreign_key'], foreign_key)
+
+        with connection.cursor() as cursor:
+            constraints = connection.introspection.get_constraints(cursor, Comment._meta.db_table)
+        # Test custom constraints
+        custom_constraints = {
+            'article_email_pub_date_uniq',
+            'email_pub_date_idx',
+        }
+        if connection.features.supports_column_check_constraints:
+            custom_constraints.add('up_votes_gte_0_check')
+            assertDetails(constraints['up_votes_gte_0_check'], ['up_votes'], check=True)
+        assertDetails(constraints['article_email_pub_date_uniq'], ['article_id', 'email', 'pub_date'], unique=True)
+        assertDetails(constraints['email_pub_date_idx'], ['email', 'pub_date'], index=True)
+        # Test field constraints
+        field_constraints = set()
+        for name, details in constraints.items():
+            if name in custom_constraints:
+                continue
+            elif details['columns'] == ['up_votes'] and details['check']:
+                assertDetails(details, ['up_votes'], check=True)
+                field_constraints.add(name)
+            elif details['columns'] == ['ref'] and details['unique']:
+                assertDetails(details, ['ref'], unique=True)
+                field_constraints.add(name)
+            elif details['columns'] == ['article_id'] and details['index']:
+                assertDetails(details, ['article_id'], index=True)
+                field_constraints.add(name)
+            elif details['columns'] == ['id'] and details['primary_key']:
+                assertDetails(details, ['id'], primary_key=True, unique=True)
+                field_constraints.add(name)
+            elif details['columns'] == ['article_id'] and details['foreign_key']:
+                assertDetails(details, ['article_id'], foreign_key=('introspection_article', 'id'))
+                field_constraints.add(name)
+            elif details['check']:
+                # Some databases (e.g. Oracle) include additional check
+                # constraints.
+                field_constraints.add(name)
+        # All constraints are accounted for.
+        self.assertEqual(constraints.keys() ^ (custom_constraints | field_constraints), set())

tests/schema/tests.py

@@ -129,6 +129,14 @@ class SchemaTests(TransactionTestCase):
                 if c['index'] and len(c['columns']) == 1
             ]
 
+    def get_uniques(self, table):
+        with connection.cursor() as cursor:
+            return [
+                c['columns'][0]
+                for c in connection.introspection.get_constraints(cursor, table).values()
+                if c['unique'] and len(c['columns']) == 1
+            ]
+
     def get_constraints(self, table):
         """
         Get the constraints on a table using a new cursor.
@@ -1971,7 +1979,7 @@ class SchemaTests(TransactionTestCase):
             editor.add_field(Book, new_field3)
         self.assertIn(
             "slug",
-            self.get_indexes(Book._meta.db_table),
+            self.get_uniques(Book._meta.db_table),
         )
         # Remove the unique, check the index goes with it
         new_field4 = CharField(max_length=20, unique=False)
@@ -1980,7 +1988,7 @@ class SchemaTests(TransactionTestCase):
             editor.alter_field(BookWithSlug, new_field3, new_field4, strict=True)
         self.assertNotIn(
             "slug",
-            self.get_indexes(Book._meta.db_table),
+            self.get_uniques(Book._meta.db_table),
         )
 
     def test_text_field_with_db_index(self):