Improve prior_trap processing #170
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This was referenced Jan 13, 2025
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
jparise
commented
Jan 14, 2025
| foo() { (( trap_invoked_count += 1 )); } | ||
|
|
||
| # note setting this causes BATS to mis-report the failure line when this test fails | ||
| trap "foo && echo 'hello' >/dev/null" debug |
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The previous sed-based pattern would fail with more complex cases like this.
akinomyoga
approved these changes
Jan 14, 2025
mitchellh
added a commit
to ghostty-org/ghostty
that referenced
this pull request
Jan 16, 2025
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
Upstream: rcaloras/bash-preexec#170
|
As a proof point, Ghostty 1.1.0 shipped with this change to its bundled bash-preexec, and we haven't heard of any issues through the pre- or post-release period yet. |
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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):