Re: [PATCH 17/19] t4000-t4999: detect and signal failure within loop

>Failures within `for` and `while` loops can go unnoticed if not detected
>and signaled manually since the loop itself does not abort when a
>contained command fails, nor will a failure necessarily be detected when
>the loop finishes since the loop returns the exit code of the last
>command it ran on the final iteration, which may not be the command
>which failed. Therefore, detect and signal failures manually within
>loops using the idiom `|| return 1` (or `|| exit 1` within subshells).
>
>Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
>---
>diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
>index 2c13b62d3c..ca5adabe14 100755
>--- a/t/t4015-diff-whitespace.sh
>+++ b/t/t4015-diff-whitespace.sh
>@@ -843,7 +843,7 @@ test_expect_success 'whitespace changes with modification reported (diffstat)' '
>
> test_expect_success 'whitespace-only changes reported across renames (diffstat)' '
> 	git reset --hard &&
>-	for i in 1 2 3 4 5 6 7 8 9; do echo "$i$i$i$i$i$i"; done >x &&
>+	for i in 1 2 3 4 5 6 7 8 9; do echo "$i$i$i$i$i$i" || return 1; done >x &&
> 	git add x &&
> 	git commit -m "base" &&
> 	sed -e "5s/^/ /" x >z &&
>@@ -859,7 +859,7 @@ test_expect_success 'whitespace-only changes reported across renames (diffstat)'
>
> test_expect_success 'whitespace-only changes reported across renames' '
> 	git reset --hard HEAD~1 &&
>-	for i in 1 2 3 4 5 6 7 8 9; do echo "$i$i$i$i$i$i"; done >x &&
>+	for i in 1 2 3 4 5 6 7 8 9; do echo "$i$i$i$i$i$i" || return 1; done >x &&
> 	git add x &&
> 	hash_x=$(git hash-object x) &&
> 	before=$(git rev-parse --short "$hash_x") &&