Contacts with suffixes fail to merge with WhatsApp entries

[der8en]

Checklist

• I can reproduce the bug with the latest version given here.
• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one bug.
• I have read and understood the contribution guidelines.

Affected app version

1.5.0

Affected Android/Custom ROM version

Android 16

Affected device model

Pixel 9 Pro

How did you install the app?

F-Droid / IzzyOnDroid

Steps to reproduce the bug

1. Create a new contact with the following details:

• First Name: John (or leave blank and use Last Name)
• Last Name: (leave blank or use Smith)
• Suffix: "Great" (one or more words)
• Phone Number: [A number linked to a WhatsApp account]
  OR:
• First Name: John
• Last Name: Smith
• Suffix: "the Great" (multiple words with space)
• Phone Number: [A number linked to a WhatsApp account]

2. Wait for the contact to sync with WhatsApp.
3. Open the Fossify Contacts app.

Expected behavior

The local (or google/dav) contact and the WhatsApp contact should be merged into a single entry.

Actual behavior

The contact is displayed twice:

1. The local (or google/dav) entry, displayed as saved with comma (e.g., "John, the Great").

2. The WhatsApp entry, displayed without the comma

• "Great John" (suffix before Name, if only first or last Name)
• "John Smith the Great" (if first and last Name)

Screenshots/Screen recordings

No response

Additional information

No response

[antodc]

More or less the same issue here. I think the problem is that when there is a prefix/suffix the "WhatsApp version" of the contact misinterprets it and considers the prefix/suffix as part of the last/first name.
In @der8en's example above, most likely "Great John" is considered as "First Name = Great" and "Last Name = John", or viceversa, by WhatsApp. He/she could check by opening the contact details.
And, by the way, there seems to be the same issue with Signal contacts.