Docs fix in MigrateUpgradeForm

Postponed on #2687843: Add back incremental migrations through the UI

Problem/Motivation

A review of the patch in #2687843: Add back incremental migrations through the UI comment #98 included some points that were outside the scope of the issue and need to be addressed.

The relevant is in comment#99

This is a copy of the points to be addressed in this issue

Now in IncrementalForm.
2.    +++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
    @@ -236,6 +244,51 @@ public function submitOverviewForm(array &$form, FormStateInterface $form_state)
    +    $database_state_key = $this->state->get('migrate.fallback_state_key', '');
    +    if ($database_state_key) {

    Why would we use the fallback state key here? The user has entered explicit database credentials here, so I don't understand why we wouldn't just use those.

Now in OverviewForm.
3.    +++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
    @@ -236,6 +244,51 @@ public function submitOverviewForm(array &$form, FormStateInterface $form_state)
    +      $form_state->setValue('step', 'credentials');
    +      $form_state->setRebuild();

    Nit: setValue() is chainable, so we could do ->setValue()->setRebuild().

Now in MigrateUPgradeFormBase.
4.    +++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
    @@ -848,6 +877,44 @@ protected function getDatabaseTypes() {
    +   * Setup migrations.
    +   *
    +   * @param array $database
    +   *   Database array representing the source Drupal database.
    +   * @param \Drupal\Core\Form\FormStateInterface $form_state
    +   *   The current state of the form.
    +   */
    +  protected function setupMigrations(array $database, FormStateInterface $form_state) {

    Can this doc comment be expanded a bit? "Setup migrations" tells me nothing more than the method name already does.

Now in  CredentialForm.
5.    +++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
    @@ -848,6 +877,44 @@ protected function getDatabaseTypes() {
    +    $form_state->set('version', $version);
    +    $form_state->set('migrations', $migration_array);

    Nit: ->set() is chainable.

10.     +++ b/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
    @@ -315,4 +281,110 @@ protected function translatePostValues(array $values) {
    +   * @param $session
    +   *   The currenct session.

    $session needs a type hint (also in the method signature), and there's a typo in 'current'.

11.    +++ b/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
    @@ -315,4 +281,110 @@ protected function translatePostValues(array $values) {
    +   * @param $session
    +   *   The currenct session.
    +   */
    +  protected function assertIdConflict($session) {

    $session needs to be type hinted, and 'current' is misspelled. :)

12.    +++ b/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
    @@ -315,4 +281,110 @@ protected function translatePostValues(array $values) {
    +    // Have to reset all the statics after migration to ensure entities are

    'statics' should be 'static caches'.

Proposed resolution

2. The section of code is being removed in #2679835: Improve exception handling in Migrate UI

3. It is no longer relevant, the form step is stored in temp private store.

4. Already fixed in another issue.

5. These lines are no longer in the code and the form uses the temp private store for form information.

10. Already fixed in another issue.

11. Already fixed in another issue.

Remaining tasks

12. Fixed in this issue.