bash: improve prior_trap processing #5142
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
We use `trap` to bootstrap our installation function (__bp_install). We
remove our code upon first execution but need to restore any preexisting
trap calls. We previously used `sed` to process the trap string, but
that had two downsides:
1. `sed` is an external command dependency. It needs to exist on the
system, and we need to invoke it in a subshell (which has some
runtime cost).
2. The regular expression pattern was imperfect and didn't handle
trickier cases like `'` characters in the trap string:
$ (trap "echo 'hello'" DEBUG; trap -p DEBUG)
hello
trap -- 'echo '\''hello'\''' DEBUG
This change removes the dependency on `sed` by locally evaluating the
trap string and extracting any prior trap. This works reliably because
we control the format our trap string, which looks like this (with
newlines expanded):
__bp_trap_string="$(trap -p DEBUG)"
trap - DEBUG
__bp_install
Closed
# for free
to join this conversation on GitHub.
Already have an account?
# to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
We use
trapto bootstrap our installation function (__bp_install). We remove our code upon first execution but need to restore any preexisting trap calls. We previously usedsedto process the trap string, but that had two downsides:sedis an external command dependency. It needs to exist on the system, and we need to invoke it in a subshell (which has some runtime cost).The regular expression pattern was imperfect and didn't handle trickier cases like
'characters in the trap string:This change removes the dependency on
sedby locally evaluating the trap string and extracting any prior trap. This works reliably because we control the format our trap string, which looks like this (with newlines expanded):Upstream: rcaloras/bash-preexec#170