Add option to change the PostGreSQL Schema during installation

I am postponing this issue until #1060476: Multiple issues when PostgreSQL is used with non-public schema has landed.

All code changes look good to me.
The option has been added to the installer.
Testing has been added.
The default.settings.php have been updated.
The CR and Is are in order.
For me it is RTBC.

I was confused about where this is actually used, and why we were adding this to the documentation here, but #1060476: Multiple issues when PostgreSQL is used with non-public schema added this feature without documenting it.

1. +++ b/core/modules/pgsql/src/Driver/Database/pgsql/Install/Tasks.php
   @@ -313,6 +313,15 @@ public function getFormOptions(array $database) {
   +      // PostgreSQL's Max Identifier Length Is 63 Bytes.
   

   Title case is not appropriate here:

   // PostgreSQL's maximum identifier length is 63 characters.
   

2. +++ b/core/modules/pgsql/tests/src/Functional/InstallerNonDefaultSchemaTest.php
   @@ -0,0 +1,63 @@
   +    if ($connection_info['default']['driver'] !== 'pgsql') {
   +      // The schema option is only available for PostgreSQL.
   +      $this->markTestSkipped("This test does not support the {$connection_info['default']['driver']} database driver.");
   +    }
   

   Is this necessary now we have per-driver tests? Why would the Postgres tests run at all if we are in a MySQL CI environment?

Tried to address pointer 1.
Please review.

Thanks for working on this.

In addition to points from @longwave, there is at least one additional issue with the patch.

The new schema input field is not required. Therefore it could be left blank. In case you left that input blank, Drupal will not install, but throws an error:

Failed to CREATE a test table on your database server with the command CREATE TABLE {drupal_install_test} (id int NOT NULL PRIMARY KEY). The server reports the following message: SQLSTATE[42601]: Syntax error: 7 ERROR: zero-length delimited identifier at or near """" LINE 1: CREATE TABLE ""."drupal_install_test" (id int NOT NULL PRIMA... ^: CREATE TABLE ""."drupal_install_test" (id int NOT NULL PRIMARY KEY); Array ( ) .

When we compare it with the port input field, which is not required as well, Drupal will install in case you leave the port field empty. Therefore we need to either mark the schema field as required, or fix the additional handling of the value in case it is left empty (and use public instead).

I have not tested this further with empty schema in settings.php (whether the default public is used in this case as well), but will do it after the installation process will be working.

Not sure about the "Needs backport to D7" tag - I think, that the D7 is not working 100% correctly on schema different from public (it was not fixed unlike the D10), so probably there is no point in addressing this in D7 unless the schema usage has been fixed.

Does someone faced with next issue during re-installation drupal using drush command?
So, I have Drupal 10 site core, PostGreSQL database and use non-public schema. I have applied patches from the corresponding article. And It gives me result - I can make clean install site when my schema doesnot have any tables. But if I trying to re-install site by run 'drush si' command I faced with an error "To start over you ust empty your existing database".
When drupal ask:

You are about to:
 * DROP all tables in your 'db_name' database.

I choose yes and I got the error.

But if I do the same steps using 'public' schema I can successfully re-install the site and before installation all tables will be dropped.

@vadim.jin: Support for Drupal on PostgreSQL in another schema then public is something that is at the moment not supported. Would be great if we can make it work. You could work on this this by creating a PR and I will review it.