Prevent panic in update_servers for Domain Name System Socket

[dunef-io]

I wanted to connect my microcontroller with the wifi, but this library caused panics, because it found more than just one DNS Server. So I needed to change one line in the src/socket/dns.rs file with the update_servers method.

Instead of causing panic if the length of the servers argument exceeds DNS_MAX_SERVER_COUNT, it should take a slice of servers for the first DNS_MAX_SERVER_COUNT elements.

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (d185a37) 79.82% compared to head (1f99b60) 79.91%.

Files	Patch %	Lines
src/socket/dns.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #892      +/-   ##
==========================================
+ Coverage   79.82%   79.91%   +0.08%     
==========================================
  Files          80       80              
  Lines       28053    28233     +180     
==========================================
+ Hits        22394    22561     +167     
- Misses       5659     5672      +13     

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[thvdveld]

Indeed, the documentation states that if the list of servers bigger than DNS_MAX_SERVER_COUNT, it will panic.

There are two options:

1. We prevent the panic and add logic for this.
2. We don't prevent the panic since it is written in the documentation that the list of servers cannot exceed DNS_MAX_SERVER_COUNT.

I'll leave the decision to @Dirbaio.

---

Your code might still panic. For example, it will panic when the length of the slice is smaller than DNS_MAX_SERVER_COUNT.

The update should be something like:

self.servers = Vec::from_slice(&servers[..servers.len().min(DNS_MAX_SERVER_COUNT)]).unwrap();

[dunef-io]

Ahh yes thanks for the correction!

[thvdveld]

I think it's better that the there is an actual panic when the provided list of servers is bigger than DNS_MAX_SERVER_COUNT. With your change, the user of the API would never know if all servers where added to the list of DNS servers. The function is also clearly documented that a panic might occur.