[TML-1610] adjust behavior for default namespace to avoid differences during migrate diff (#5699)

This PR addresses prisma/prisma#28240. 

When creating the db schema for a schema file we do NOT include the
`CREATE SCHEMA public ...`  statement. But when creating it from the
migrations (aka shadow db) it is included.

Due to this when creating a diff between the two as in migrate diff an
actual diff in the db schema is observed.

This bug only shows up when using `migrate diff` with the `--exit-only`
or `--script` options because of a missing implementation for schemas in
the drift summary.

This PR fixes the issue by changing the way how we determine the
`explicit_namespace` for rendering SQL statements (see
#5614) and ensuring that
the default namespace is always part of the namespace list - no matter
how the db schema is derived.

Author: FGoessler

schema-engine/connectors/sql-schema-connector/src/sql_migration.rs

@@ -46,6 +46,7 @@ impl SqlMigration {
             AlteredExtension,
             DroppedExtension,
             CreatedExtension,
+            AddedSchema,
             AddedEnum,
             AddedTable,
             RemovedEnum,
@@ -64,7 +65,9 @@ impl SqlMigration {
             let idx = idx as u32;
             match step {
                 SqlMigrationStep::AlterSequence(_, _) => (),
-                SqlMigrationStep::CreateSchema(_) => (), // todo
+                SqlMigrationStep::CreateSchema(_) => {
+                    drift_items.insert((DriftType::AddedSchema, "", idx));
+                }
                 SqlMigrationStep::DropView(drop_view) => {
                     drift_items.insert((
                         DriftType::RemovedView,
@@ -185,6 +188,9 @@ impl SqlMigration {
         for (line_idx, (new_state, item_name, step_idx)) in drift_items.iter().enumerate() {
             if render_state != (*new_state, item_name) || line_idx == 0 {
                 match new_state {
+                    DriftType::AddedSchema => {
+                        out.push_str("\n[+] Added Schemas\n");
+                    }
                     DriftType::AddedEnum => {
                         out.push_str("\n[+] Added enums\n");
                     }
@@ -235,7 +241,11 @@ impl SqlMigration {
                     out.push_str(self.schemas().next.walk(*enum_id).name());
                     out.push('\n');
                 }
-                SqlMigrationStep::CreateSchema(_) => {} // todo
+                SqlMigrationStep::CreateSchema(namespace) => {
+                    out.push_str("  - ");
+                    out.push_str(self.schemas().next.walk(*namespace).name());
+                    out.push('\n');
+                }
                 SqlMigrationStep::AlterEnum(alter_enum) => {
                     for added in &alter_enum.created_variants {
                         out.push_str("  [+] Added variant `");

schema-engine/connectors/sql-schema-connector/src/sql_schema_calculator.rs

@@ -61,6 +61,15 @@ fn push_namespaces<'a>(ctx: &mut Context<'a>, default_namespace: Option<&'a str>
     }
 
     if let Some(default_namespace) = default_namespace {
+        if ctx.schemas.is_empty() {
+            ctx.schemas.insert(
+                default_namespace,
+                ctx.schema
+                    .describer_schema
+                    .push_namespace(default_namespace.to_string()),
+            );
+        }
+
         ctx.schema
             .describer_schema
             .set_default_namespace(default_namespace.to_owned());

schema-engine/sql-migration-tests/tests/migrations/drift_summary.rs

@@ -62,6 +62,46 @@ fn empty_schemas() {
     )
 }
 
+#[test]
+fn additions_schemas() {
+    check(
+        "postgres",
+        r#"
+        datasource db {
+            provider = "postgres"
+        }
+        "#,
+        r#"
+        datasource db {
+            provider = "postgres"
+            schemas = ["one", "two"]
+        }
+
+        model Cat {
+            id Int @id
+
+            @@schema("one")
+        }
+
+        model Dog {
+            id Int @id
+
+            @@schema("two")
+        }
+        "#,
+        expect![[r#"
+
+            [+] Added Schemas
+              - one
+              - two
+
+            [+] Added tables
+              - Cat
+              - Dog
+        "#]],
+    );
+}
+
 #[test]
 fn additions_table() {
     check(

schema-engine/sql-migration-tests/tests/migrations/enums.rs

@@ -597,6 +597,9 @@ fn mapped_enum_defaults_must_work(api: TestApi) {
     "#;
 
     let expect = expect![[r#"
+        -- CreateSchema
+        CREATE SCHEMA IF NOT EXISTS "public";
+
         -- CreateEnum
         CREATE TYPE "Color" AS ENUM ('0', 'Grün', 'Blu', 'pfuh 🙄...');
 

schema-engine/sql-migration-tests/tests/migrations/mssql.rs

@@ -316,6 +316,9 @@ fn bigint_defaults_work(api: TestApi) {
 
         BEGIN TRAN;
 
+        -- CreateSchema
+        IF NOT EXISTS (SELECT * FROM sys.schemas WHERE name = N'dbo') EXEC sp_executesql N'CREATE SCHEMA [dbo];';
+
         -- CreateTable
         CREATE TABLE [dbo].[foo] (
             [id] NVARCHAR(1000) NOT NULL,
@@ -362,6 +365,9 @@ fn float_columns(api: TestApi) {
 
         BEGIN TRAN;
 
+        -- CreateSchema
+        IF NOT EXISTS (SELECT * FROM sys.schemas WHERE name = N'dbo') EXEC sp_executesql N'CREATE SCHEMA [dbo];';
+
         -- CreateTable
         CREATE TABLE [dbo].[foo] (
             [id] NVARCHAR(1000) NOT NULL,

schema-engine/sql-migration-tests/tests/migrations/postgres.rs

@@ -537,6 +537,9 @@ fn scalar_list_defaults_work(api: TestApi) {
     api.schema_push(schema).send().assert_green().assert_no_steps();
 
     let expected_sql = expect![[r#"
+        -- CreateSchema
+        CREATE SCHEMA IF NOT EXISTS "public";
+
         -- CreateEnum
         CREATE TYPE "Color" AS ENUM ('RED', 'GREEN', 'BLUE');
 
@@ -677,6 +680,9 @@ fn json_defaults_with_escaped_quotes_work(api: TestApi) {
     api.schema_push(schema).send().assert_green().assert_no_steps();
 
     let sql = expect![[r#"
+        -- CreateSchema
+        CREATE SCHEMA IF NOT EXISTS "public";
+
         -- CreateTable
         CREATE TABLE "Foo" (
             "id" INTEGER NOT NULL,
@@ -703,6 +709,9 @@ fn bigint_defaults_work(api: TestApi) {
         }
     "#;
     let sql = expect![[r#"
+        -- CreateSchema
+        CREATE SCHEMA IF NOT EXISTS "public";
+
         -- CreateTable
         CREATE TABLE "foo" (
             "id" TEXT NOT NULL,

schema-engine/sql-migration-tests/tests/single_migration_tests/postgres/empty_dbgenerated.prisma

@@ -12,6 +12,9 @@ model table {
 }
 
 // Expected Migration:
+// -- CreateSchema
+// CREATE SCHEMA IF NOT EXISTS "public";
+// 
 // -- CreateTable
 // CREATE TABLE "table" (
 //     "id" TEXT NOT NULL,

schema-engine/sql-migration-tests/tests/single_migration_tests/postgres/empty_unsupported_dbgenerated.prisma

@@ -12,6 +12,9 @@ model table {
 }
 
 // Expected Migration:
+// -- CreateSchema
+// CREATE SCHEMA IF NOT EXISTS "public";
+// 
 // -- CreateTable
 // CREATE TABLE "table" (
 //     "id" TEXT NOT NULL,

schema-engine/sql-migration-tests/tests/single_migration_tests/postgres/enums/enum_basic.prisma

@@ -17,6 +17,9 @@ enum MyEnum {
 }
 
 // Expected Migration:
+// -- CreateSchema
+// CREATE SCHEMA IF NOT EXISTS "public";
+// 
 // -- CreateEnum
 // CREATE TYPE "MyEnum" AS ENUM ('A', 'B');
 // 

schema-engine/sql-migration-tests/tests/single_migration_tests/postgres/enums/enum_fields.prisma

@@ -31,6 +31,9 @@ enum Kind {
 }
 
 // Expected Migration:
+// -- CreateSchema
+// CREATE SCHEMA IF NOT EXISTS "public";
+// 
 // -- CreateEnum
 // CREATE TYPE "Result" AS ENUM ('succeeded', 'failed');
 //