Add newline after mbed error so greentea shows it

[c1728p9]

Description

When the function error is called without ending in a newline greentea will not display the error. This is because greentea is performing line buffering.

This patch ensures that all calls to error end with a newline. This is done by adding an additional newline to end end of the string.

Example code exhibiting this problem:

error("This function is not supported.");

Greentea output before this change:

++ MbedOS Error Info ++​
Error Status: 0x80FF0100 Code: 256 Module: 255​
Error Message: Fatal Run-time error​
Location: 0x1001766D​
Error Value: 0x0​
Current Thread: main  Id: 0x8003FD8 Entry: 0x1000E64F StackSize: 0x1000 StackMem: 0x8004AE8 SP: 0x8005898​
For more info, visit: https://mbed.com/s/error?error=0x80FF0100&tgt=target​
-- MbedOS Error Info --​
test suite run finished after 240.50 sec...

Greentea output after this change:

++ MbedOS Error Info ++​
Error Status: 0x80FF0100 Code: 256 Module: 255​
Error Message: Fatal Run-time error​
Location: 0x1001766D​
Error Value: 0x0​
Current Thread: main  Id: 0x8003FD8 Entry: 0x1000E64F StackSize: 0x1000 StackMem: 0x8004AE8 SP: 0x8005898​
For more info, visit: https://mbed.com/s/error?error=0x80FF0100&tgt=target​
-- MbedOS Error Info --​
This function is not supported.
test suite run finished after 240.50 sec...

Pull request type

[x] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Docs update
[ ] Test update
[ ] Breaking change

[ciarmcom]

@c1728p9, thank you for your changes.
@ARMmbed/mbed-os-core @ARMmbed/mbed-os-maintainers please review.

[0xc0170]

@kjbracey-arm We had discussions around newlines. I recall some patches adding newline in strings by themselves. This patch is important to have for the next week.

[kjbracey]

Thought we'd ensured a newline somewhere else recently for the same reason, but I guess it wasn't on this path.

[jeromecoutant]

Is this fixing #10626 ?

[0xc0170]

CI started (expected cloud client test to fail, we are investigating this)

[kjbracey]

I recall some patches adding newline in strings by themselves.

Ew, no. ROM space! Some APIs are inherently "single-line per call" (for potential packetisation purposes) like tr_info, and MBED_ERROR, so the newline/message boundary is implied.

error is potentially free-form like printf, so could be multiple-line or single line, but as it's fatal, sticking a final newline on just in case is fine, and can't cause any formatting grief.

Callers should only have to put their own newlines in when it's a free-form API that can actually print part of a line at a time, like printf. (You're not printing part of a line at a time with error!)

Is this fixing #10626 ?

So it is. That's what I was recalling. So we just talked about it, didn't do it...

[mbed-ci]

Test run: SUCCESS

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

[c1728p9]

Hi @jeromecoutant this fixes #10626. Thanks for pointing this out. I didn't realize there was an open issue when I created the PR.