Able to edit someone to the same phone number

[jrchoo]

It is strange to allow two different people to have the same phone number. Duplicates could either be achieved through the add or edit command.

Steps:

1. edit 8 p/98765432

[nus-se-bot]

Team's Response

The issue of having the same phone number exists which is irrespective to the command and hence, we label this as a duplicate issue of the previously mentioned one.

The 'Original' Bug

[The team marked this bug as a duplicate of the following bug]

Can add 2 different people with the same mobile number

A phone number should be something unique to the individual, so it may be best that duplicates for different people should not be allowed.

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_{[original: nus-cs2103-AY2324S1/pe-interim#2151] [original labels: severity.Low type.FeatureFlaw]}

Their Response to the 'Original' Bug

[This is the team's response to the above 'original' bug]

Thank you for raising this issue. Indeed, phone numbers is unique but have you heard of instances where phone number can be recycled? Thus, when you add the user, that user actually has in possession of the phone number which logically, we should not be disallowing the user to add. Perhaps, in the future implementation, we can warn the user that there exist such a phone number in CampusConnect which will prompt them to rectify if the phone number is indeed inputted correctly. Furthermore, if you have carefully read our planned enhancements, we have clearly indicated that in the future iteration, we will be working towards making a person unique in CampusConnect.

Items for the Tester to Verify

:question: Issue duplicate status

Team chose to mark this issue as a duplicate of another issue (as explained in the Team's response above)

• [ ] I disagree

Reason for disagreement: [replace this with your explanation]

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## :question: Issue response Team chose [`response.NotInScope`] - [x] I disagree **Reason for disagreement:** I believe that checking for duplicates should have been implemented earlier instead of leaving it to iterations past v1.4. The linked article on recycled phone numbers merely shows that somebody has owned that phone number prior to the current owner. There is a line in the article that says: “You have a recycled number, these are common in Singapore and until it is under your name we cannot use this number to progress with the application”. The line "until it is under your name" suggests that the phone number has not yet been registered under the current user's name, and for the current user to obtain this phone number, the previous owner had to give it up. Thus, the previous owner would have changed numbers, meaning that 2 people cannot have the same phone number concurrently, reinforcing the idea that duplicate phone numbers should not be allowed. The app should either disallow this or provide a warning message to the user.

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## :question: Issue severity Team chose [`severity.Medium`] Originally [`severity.Low`] - [ ] I disagree **Reason for disagreement:** [replace this with your explanation]

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