t: avoid incorrect negated commands #5282
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When `set -e` is enabled, not all commands trigger an error exit if they
return false. For example, it's clear that commands in an `if` or
`while` statement don't cause an error if they are false.
What is less obvious, however, is that negated commands and negated
pipelines also have no effect on `set -e`. From POSIX 1003.1-2017 (on
`sh -e`):
When this option is on, if a simple command fails for any of the
reasons listed in Consequences of Shell Errors or returns an exit
status value >0, and is not part of the compound list following a
while, until, or if keyword, and is not a part of an AND or OR list,
and is not a pipeline preceded by the ! reserved word, then the
shell shall immediately exit.
As such, writing something like `! grep` will never fail. Fortunately,
we can append `&& exit 1` instead of the `!` and that will work
correctly.
To make this work, run the following command to make the code properly
check the exit status of our commands:
git grep -l '! [a-z]' t | \
xargs ruby -pi -e '$_.gsub!(/^(\s+)! ([a-z].*)$/, "\\1\\2 && exit 1")'
Because such a command will still have a non-zero exit status, even if
it doesn't trigger `set -e`, add a `true` if this is the last statement
in a block, so that the test exits successfully and therefore passes.
chrisd8088
approved these changes
Feb 23, 2023
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When
set -eis enabled, not all commands trigger an error exit if they return false. For example, it's clear that commands in aniforwhilestatement don't cause an error if they are false.What is less obvious, however, is that negated commands and negated pipelines also have no effect on
set -e. From POSIX 1003.1-2017 (onsh -e):As such, writing something like
! grepwill never fail. Fortunately, we can append&& exit 1instead of the!and that will work correctly.To make this work, run the following command to make the code properly check the exit status of our commands:
Fixes #5183