ci: fix mysql migration and diesel schema overwrite in integration tests

Two bugs exposed by the integration test workflow:

  1. MySQL migration 2022-07-27: groups_users and collections_groups used
     UNIQUE instead of PRIMARY KEY. Diesel requires primary keys on all
     tables for schema introspection (print-schema). PostgreSQL and SQLite
     migrations already used PRIMARY KEY correctly.

  2. diesel.toml has [print_schema] configured, so \`diesel migration run\`
     rewrites src/db/schema.rs with backend-specific types after running.
     This corrupted the checked-in schema before cargo test could compile,
     causing E0277 CompatibleType errors for every query. Fix by restoring
     the file immediately after each migration run.

.github/workflows/integration-test.yml

@@ -87,8 +87,13 @@ jobs:
 
       # Verify that all PostgreSQL migrations apply cleanly to a fresh database.
       # This catches broken SQL before it reaches a production deployment.
+      # Restore src/db/schema.rs after running: diesel.toml has [print_schema]
+      # configured, so diesel rewrites the file with backend-specific types after
+      # migration. The checked-in schema.rs must be restored before compiling.
       - name: Run PostgreSQL migrations
-        run: diesel migration run --migration-dir migrations/postgresql
+        run: |
+          diesel migration run --migration-dir migrations/postgresql
+          git checkout -- src/db/schema.rs
 
       # Run the test suite with a live PostgreSQL instance available.
       # Existing tests are unit tests (no DB access), but DATABASE_URL is set
@@ -152,8 +157,11 @@ jobs:
         run: cargo install diesel_cli --no-default-features --features mysql
 
       # Verify that all MySQL migrations apply cleanly to a fresh database.
+      # Restore src/db/schema.rs for the same reason as the PostgreSQL job above.
       - name: Run MySQL migrations
-        run: diesel migration run --migration-dir migrations/mysql
+        run: |
+          diesel migration run --migration-dir migrations/mysql
+          git checkout -- src/db/schema.rs
 
       # Run the test suite with a live MySQL instance available.
       - name: Run tests (mysql)

migrations/mysql/2022-07-27-110000_add_group_support/up.sql

@@ -11,7 +11,7 @@ CREATE TABLE `groups` (
 CREATE TABLE groups_users (
   groups_uuid                       CHAR(36) NOT NULL REFERENCES `groups` (uuid),
   users_organizations_uuid          VARCHAR(36) NOT NULL REFERENCES users_organizations (uuid),
-  UNIQUE (groups_uuid, users_organizations_uuid)
+  PRIMARY KEY (groups_uuid, users_organizations_uuid)
 );
 
 CREATE TABLE collections_groups (
@@ -19,5 +19,5 @@ CREATE TABLE collections_groups (
   groups_uuid                       CHAR(36) NOT NULL REFERENCES `groups` (uuid),
   read_only                         BOOLEAN NOT NULL,
   hide_passwords                    BOOLEAN NOT NULL,
-  UNIQUE (collections_uuid, groups_uuid)
-);
+  PRIMARY KEY (collections_uuid, groups_uuid)
+);