initdb: Reject empty string for -U/--username option

[yjhjstz]

performing post-bootstrap initialization ... 2025-07-01 19:48:42.006 PDT [14888] FATAL:  role """ does not exist at character 72

2025-07-01 19:48:42.006 PDT [14888] STATEMENT:  

	UPDATE pg_class   SET relacl = (SELECT array_agg(a.acl) FROM  (SELECT E'=r/""' as acl   UNION SELECT unnest(pg_catalog.acldefault(    CASE WHEN relkind = 'S' THEN 's'          ELSE 'r' END::"char",10::oid)) ) as a)   WHERE relkind IN ('r', 'v', 'm', 'S')  AND relacl IS NULL;

Previously, passing an empty string to the -U or --username option (e.g., initdb -U '') would cause confusing errors during bootstrap, as initdb attempted to create a role with an empty name.

This patch adds an explicit check for empty usernames and exits immediately with a clear error message.

A test case is added to verify that initdb fails when -U is given an empty string.

Fixes #ISSUE_Number

What does this PR do?

Type of Change

• Bug fix (non-breaking change)
• New feature (non-breaking change)
• Breaking change (fix or feature with breaking changes)
• Documentation update

Breaking Changes

Test Plan

• Unit tests added/updated
• Integration tests added/updated
• Passed make installcheck
• Passed make -C src/test installcheck-cbdb-parallel

Impact

Performance:

User-facing changes:

Dependencies:

Checklist

• Followed contribution guide
• Added/updated documentation
• Reviewed code for security implications
• Requested review from cloudberry committers

Additional Context

CI Skip Instructions

---

[my-ship-it]

LGTM

[reshke]

The only question here is how this works in PostgreSQL and why this is not an issue for pg (or is it?)

[yjhjstz]

The only question here is how this works in PostgreSQL and why this is not an issue for pg (or is it?)

yes , I also submit a patch. https://www.postgresql.org/message-id/CAAZLFmRK+XFp=mqCeruyNVkqGq5mH45CP+e-8oNttPRtLuB5eQ@mail.gmail.com