Add NotNull and NotEmpty constraint to Users.email column (#2248)

Fixes #2237

migration/migration.go

@@ -446,6 +446,9 @@ func GetMigrations() Migrations {
 	// Version 102
 	m = append(m, steps{ExecuteSQLFile("102-add-forward-and-reverse-link-type-descriptions.sql")})
 
+	// Version 103
+	m = append(m, steps{ExecuteSQLFile("103-user-email-notnull-notempty.sql")})
+
 	// Version N
 	//
 	// In order to add an upgrade, simply append an array of MigrationFunc to the

migration/migration_blackbox_test.go

@@ -152,6 +152,7 @@ func TestMigrations(t *testing.T) {
 	t.Run("TestMigration100", testDropUserspacedataTable)
 	t.Run("TestMigration101", testTypeGroupHasDescriptionField)
 	t.Run("TestMigration102", testLinkTypeDescriptionFields)
+	t.Run("TestMigration103", testMigration103NotNullNotEmptyonEmail)
 
 	// Perform the migration
 	err = migration.Migrate(sqlDB, databaseName)
@@ -1181,6 +1182,21 @@ func testMigration99CodebaseCVEScanDefaultFalse(t *testing.T) {
 	require.Nil(t, runSQLscript(sqlDB, "099-codebase-cve-scan-default-false-cleanup.sql"))
 }
 
+func testMigration103NotNullNotEmptyonEmail(t *testing.T) {
+	migrateToVersion(t, sqlDB, migrations[:103], 103)
+
+	// setup
+	require.Nil(t, runSQLscript(sqlDB, "103-user-email-notnull-notempty.sql"))
+
+	// migrate to the current version
+	migrateToVersion(t, sqlDB, migrations[:104], 104)
+
+	// check we do not have any empty/null emails
+	rows, err := sqlDB.Query("SELECT email FROM users where email IS NULL or email = '';")
+	require.Nil(t, err)
+	require.False(t, rows.Next(), "row found with email = '' or NULL when all should have a valid email")
+}
+
 // runSQLscript loads the given filename from the packaged SQL test files and
 // executes it on the given database. Golang text/template module is used
 // to handle all the optional arguments passed to the sql test files

migration/sql-files/103-user-email-notnull-notempty.sql

@@ -0,0 +1,6 @@
+-- Set email = id@example.com for users whose email is '' (empty) or ' ' (any
+-- length of only white spaces) or NULL in database
+UPDATE users SET email=concat(id::TEXT, '@example.com') WHERE COALESCE(trim(email), '') = '';
+
+ALTER TABLE users ALTER COLUMN email SET NOT NULL;
+ALTER TABLE users ADD CONSTRAINT email_notempty_check CHECK (trim(email) <> '');

migration/sql-test-files/103-user-email-notnull-notempty.sql

@@ -0,0 +1,6 @@
+-- Create users with null/empty email value
+
+INSERT INTO users (full_name, email) VALUES ('Lorem1', '');
+INSERT INTO users (full_name, email) VALUES ('Lorem2', '  ');
+INSERT INTO users (full_name, email) VALUES ('Lorem3', '    ');
+INSERT INTO users (full_name, email) VALUES ('Lorem4', NULL);