Cellular: Remove API's empty default implemetations

[mirelachirica]

Summary of changes

Cleanup the Cellular API by removing empty default implementations and making them pure virtual.

Targeted for release-version 6.0.0.

Impact of changes

• Classes inheriting CellularDevice will have to have implementation for the new pure virtual methods:

  • clear()
  • get_context_list()
    
    

• Classes inheriting CellularContext do not have to have implementation for:

  • get_netmask()
  • get_gateway()
  
  if they do not differ from the NetworkInterface's default implemetations:

  nsapi_error_t NetworkInterface::get_netmask(SocketAddress *)
  {
      return NSAPI_ERROR_UNSUPPORTED;
  }
  
  nsapi_error_t NetworkInterface::get_gateway(SocketAddress *)
  {
      return NSAPI_ERROR_UNSUPPORTED;
  }
  

Migration actions required

See Impact of changes section.

Documentation

None

---

Pull request type

[] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[x] Major update (Breaking change E.g. Return code change / API behaviour change)

---

Test results

[] No Tests required for this change (E.g docs only update)
[x] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

---

Reviewers

---

[ciarmcom]

@mirelachirica, thank you for your changes.
@ARMmbed/mbed-os-ipcore @ARMmbed/mbed-os-wan @ARMmbed/mbed-os-maintainers please review.

[bulislaw]

This is a breaking change, release notes are missing.

[adbridge]

@mirelachirica looks like you removed the impact of changes and migration sections from the template. Please re-add them and fill them in as per the requirements for a breaking change - the PR type should also be changed as this is not a patch. Thanks.

[adbridge]

@mirelachirica Shouldn't this be a feature type PR as you are changing APIs ?

[adbridge]

This is a breaking change, release notes are missing.

Actually as a breaking change it should go as Major

[mirelachirica]

This is a breaking change, release notes are missing.

Actually as a breaking change it should go as Major

Yes. Done.

[mirelachirica]

Can this proceed? Does it need more reviews?

[mirelachirica]

@AnttiKauppila could you review this?

[0xc0170]

CI started

[0xc0170]

@mirelachirica Can you add details about this breaking change to the commit itself ? it's important commit by itself. While we have release notes, commit message is also crucial to contain at least reasoning for this change and what it means to a user when they update.

Release notes added

[mbed-ci]

Test run: SUCCESS

Summary: 11 of 11 test jobs passed
Build number : 1
Build artifacts