[SystemSafety] MC/DC handling of conditional operators

[Derek M Jones]

All,

I have not seen an analysis of MC/DC that involves
conditional operators in if-statement conditions.

Why would anybody use conditional operators (also known as
a ternary operator) in this context you ask?
I thought the same until some recent analysis of
if-statement conditions.

As its name suggests, the conditional operator involves a
condition, and as such looks like it needs to be addressed
by MC/DC (I have added parenthesis to the following examples
to make things clear):

In: 1+(c!=0 ? x : y)
if c is not equal to zero, the result is 1+x,
otherwise the result is 1+y.

Now in C, C++ and other languages we can write:

if (1+(c!=0 ? x : y) == z)
    foo=bar;

or we can write the longer equivalent code

if (c != 0)
    {
    if (1+x == z)
       foo=bar;
    }
else
    {
    if (1+y == z)
       foo=bar;
    }

All the analysis of MC/DC that I have seen only involves
logical AND and logical OR.

Is the behavior of conditional operator something that gets
ignored?
Is there an unwritten MC/DC rule that conditional operators
not be used in if-statement conditions?

Shouldn't the conditional operator be part of the MC/DC
analysis, i.e., required to be tested along both arms?

SQLite says they achieve 100% MC/DC
https://www.sqlite.org/testing.html#mcdc

The SQLite source contains instances of the conditional
operator if if-statement conditions
https://shape-of-code.com/2024/10/13/if-statement-conditions-some-basic-measurements/

Does anybody know how SQLite+MC/DC deals with the
conditional operator?

-- 
Derek M. Jones           Evidence-based software engineering
blog:https://shape-of-code.com