Re: Git Test Coverage Report (Thursday, May 30th)

[Michael Platings <michael@platin.gs>]

Thanks very much for this Derrick. I looked into it and it turns out
that the missing coverage in blame.c for "certainties[i] =
CERTAINTY_NOT_CALCULATED" was due to earlier code overwriting the same
value in most cases, thereby defeating an optimization. I've deleted
that earlier code and now coverage is as expected. I posted the patch
here: https://public-inbox.org/git/20190601210925.15339-1-michael@platin.gs/T/#u
I also deleted the other uncovered code that appeared in the same
patch as it was unreachable.

> On 5/30/2019 8:52 AM, Derrick Stolee wrote:
> > blame.c
> > 170072f9 846)     (result[i] >= most_certain_line_a ||
> > 170072f9 847)      second_best_result[i] >= most_certain_line_a)) {
> > 170072f9 848) certainties[i] = CERTAINTY_NOT_CALCULATED;
>
> This section appears in the following block:
>
>         /* More invalidating of results that may be affected by the choice of
>          * most certain line.
>          * Discard the matches for lines in B that are currently matched with a
>          * line in A such that their ordering contradicts the ordering imposed
>          * by the choice of most certain line.
>          */
>         for (i = most_certain_local_line_b - 1; i >= invalidate_min; --i) {
>                 /* In this loop we discard results for lines in B that are
>                  * before most-certain-line-B but are matched with a line in A
>                  * that is after most-certain-line-A.
>                  */
>                 if (certainties[i] >= 0 &&
>                     (result[i] >= most_certain_line_a ||
>                      second_best_result[i] >= most_certain_line_a)) {
>                         certainties[i] = CERTAINTY_NOT_CALCULATED;
>                 }
>         }
>         for (i = most_certain_local_line_b + 1; i < invalidate_max; ++i) {
>                 /* In this loop we discard results for lines in B that are
>                  * after most-certain-line-B but are matched with a line in A
>                  * that is before most-certain-line-A.
>                  */
>                 if (certainties[i] >= 0 &&
>                     (result[i] <= most_certain_line_a ||
>                      second_best_result[i] <= most_certain_line_a)) {
>                         certainties[i] = CERTAINTY_NOT_CALCULATED;
>                 }
>         }
>
> Note that the first for loop includes the uncovered lines. The logical operands
> are backwards of the conditions in the second for loop, which are covered. This
> seems non-trivial enough to merit a test.