sysdb: consolidate ldb writes in sysdb_add_basic_group()

[alexey-tikhonov]

sysdb_add_basic_group() now accepts optional extra_attrs that are merged into the ldb_add message. This lets sysdb_add_incomplete_group() and sysdb_add_group() include all attributes in a single ldb_add instead of doing ldb_add followed by ldb_modify via sysdb_set_group_attr().

Per group this eliminates an ldb_modify on the main cache, the preceding ldb_search diff-check, and an ldb_modify on the timestamp cache.

[gemini-code-assist]

Code Review

This pull request refactors group creation in the sysdb layer by allowing sysdb_add_basic_group to accept extra attributes, streamlining operations in sysdb_add_group and sysdb_add_incomplete_group. Feedback suggests replacing the hardcoded SYSDB_POSIX check with a dynamic check for existing attributes in the ldb_message to prevent failures caused by duplicate single-valued attributes.

[gemini-code-assist]

Instead of hardcoding a check for SYSDB_POSIX, it is safer and more robust to check if the attribute already exists in the ldb_message. This prevents duplicate elements for all attributes added earlier in the function (such as name, objectCategory, gidNumber, and createTimestamp), which would otherwise cause ldb_add to fail for single-valued attributes.

            if (ldb_msg_find_element(msg, extra_attrs->a[i].name) != NULL) {
                continue; /* already added */
            }

[alexey-tikhonov]

This is intentional.
There should be no other duplicates.
Checking everything will consume CPU cycles and might hide logic errors / bugs introduced later.

[alexey-tikhonov]

Note: Covscan is clean.