fix(db): skip orphaned sequences in resynchronizeDatabaseSequences

[boris324]

Fixes #58715

Orphaned PostgreSQL sequences (left behind after dropAutoincrementColumn in migrations like Version33000Date20251023110529) crash occ db:convert-type with:

SQLSTATE[42601]: Syntax error: ... SELECT setval('oc_preview_locations_id_seq', (SELECT MAX() FROM ))

The information_schema.columns lookup returns no row for these sequences, and the code accessed fields on the false result.

Changes:

• Skip sequences where no column references them
• Handle empty tables where MAX() returns NULL
• Use schema-qualified table names for the MAX query
• Added unit tests

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[findlayfeng]

Is this PR finished?

[slashrsm]

I can confirm that this fixed the problem for me and allowed me to complete the MariaDB to Postrgres coversion.

[gusdleon]

I can confirm this patch solves issues with:

In ExceptionConverter.php line 62:
  An exception occurred while executing a query: SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near ")"  
  LINE 1: SELECT setval('oc_jobs_id_seq', (SELECT MAX() FROM ))                                                        
                                                             ^                                                         
In Exception.php line 24:
  SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near ")"  
  LINE 1: SELECT setval('oc_jobs_id_seq', (SELECT MAX() FROM ))         
                                                             ^          
In Connection.php line 71:
  SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near ")"  
  LINE 1: SELECT setval('oc_jobs_id_seq', (SELECT MAX() FROM ))         
                                                             ^          
db:convert-type [--port PORT] [--password PASSWORD] [--clear-schema] [--all-apps] [--chunk-size CHUNK-SIZE] [--] <type> <username> <hostname> <database>

In a DB conversion from MariaDB to Postrgres

Commands used:

apk add --no-cache patch curl

then

curl -L https://github.com/nextcloud/server/pull/58762.patch | patch -p1 -d /app/www/public/

on a custom install of docker linuxserver/nextcloud

[kale1d0code]

Thanks for the fix!