Backup fails with PostgreSQL service connection (pg_service.conf) – NoneType has no attribute 'startswith'

[IncidGeo]

Hi everyone,
Here is what i think is a bug :

Summary

pgAdmin fails when performing Backup on a PostgreSQL connection defined exclusively via pg_service.conf.
The connection itself works correctly, but the Backup action crashes with the following error:

'NoneType' object has no attribute 'startswith'

This issue is reproducible on multiple operating systems and pgAdmin versions, which strongly suggests a pgAdmin-side bug in the Backup code path when using service-based connections.

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Steps to reproduce

1. Define a PostgreSQL service in pg_service.conf, for example:

   [Ubuntu]
   host=192.168.10.61
   port=5432
   dbname=db
   user=postgres
   

2. Ensure authentication is handled via .pgpass.

3. In pgAdmin:

   • Register a new server
   • Set Service = Ubuntu
   • Leave host, port, database name and user fields empty
   • Save the connection

4. Verify that the connection works (schemas can be expanded, queries run successfully).

5. Right-click the database → Backup…

6. Use default backup options and start the backup.

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Expected result

The backup should execute successfully using pg_dump with the service-based connection.

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Actual result

The backup fails immediately with the following error:

'NoneType' object has no attribute 'startswith'

No backup file is generated.

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Environments where the issue occurs

Environment 1

• OS: macOS Tahoe 26.2
• pgAdmin: 9.11
• PostgreSQL client: Postgres.app 17.2
• PostgreSQL server OS: Ubuntu 24.04.2

Environment 2

• OS: Ubuntu 24.04.2
• pgAdmin: 9.4
• PostgreSQL server: 17.x

The same behavior is observed on both environments.

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Additional information

• The connection works correctly when defined via pg_service.conf.

• The issue does not occur when the connection is defined using explicit host/user/password fields.

• The configured paths to PostgreSQL binaries in pgAdmin are correct.

• Running pg_dump directly from the command line with the same service works perfectly, for example:

  pg_dump "service=Ubuntu" -Fc -f backup.dump

This confirms that PostgreSQL, libpq, and pg_service.conf are functioning correctly and that the failure is specific to pgAdmin’s Backup/Restore implementation when using service-only connections.

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Conclusion

pgAdmin appears to incorrectly handle service-based connections in the Backup/Restore code path, likely passing None values internally when constructing the pg_dump command.