Re: [PATCH RFCv3 3/3] lib/test_printf: add test cases for '%pD'

[Rasmus Villemoes]

On 11/06/2021 17.59, Jia He wrote:
> After the behaviour of specifier '%pD' is changed to print full path
> of struct file, the related test cases are also updated.
> 
> Given the string is prepended from the end of the buffer, the check
> of "wrote beyond the nul-terminator" should be skipped.

Sorry, that is far from enough justification.

I should probably have split the "wrote beyond nul-terminator" check in two:

One that checks whether any memory beyond the buffer given to
vsnprintf() was touched (including all the padding, but possibly more
for the cases where we pass a known-too-short buffer), symmetric to the
"wrote before buffer" check.

And then another that checks the area between the '\0' and the end of
the given buffer - I suppose that it's fair game for vsnprintf to use
all of that as scratch space, and for that it could be ok to add that
boolean knob.

Rasmus