From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: zsh-workers@zsh.org
Subject: [PATCH 1/1] exec: run final pipeline command in a subshell in sh mode
Date: Sun, 24 Nov 2019 23:41:19 +0000 [thread overview]
Message-ID: <20191124234119.2403456-2-sandals@crustytoothpaste.net> (raw)
In-Reply-To: <20191124234119.2403456-1-sandals@crustytoothpaste.net>
zsh typically runs the final command in a pipeline in the main shell
instead of a subshell. However, POSIX requires that all commands in a
pipeline run in a subshell, but permits zsh's behavior as an extension.
Since zsh may be used as /bin/sh in some cases (such as macOS Catalina),
it makes sense to have the POSIX behavior when emulating sh, so do that
by checking for being the final item of a multi-item pipeline and
creating a subshell in that case.
---
Src/exec.c | 10 ++++++----
Test/B07emulate.ztst | 22 ++++++++++++++++++++++
2 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/Src/exec.c b/Src/exec.c
index 6014ec9a5..66dc8db2d 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -2861,11 +2861,13 @@ execcmd_exec(Estate state, Execcmd_params eparams,
pushnode(args, dupstring("fg"));
}
- if ((how & Z_ASYNC) || output) {
+ if ((how & Z_ASYNC) || output ||
+ (last1 == 2 && input && EMULATION(EMULATE_SH))) {
/*
- * If running in the background, or not the last command in a
- * pipeline, we don't need any of the rest of this function to
- * affect the state in the main shell, so fork immediately.
+ * If running in the background, not the last command in a
+ * pipeline, or the last command in a multi-stage pipeline
+ * in sh mode, we don't need any of the rest of this function
+ * to affect the state in the main shell, so fork immediately.
*
* In other cases we may need to process the command line
* a bit further before we make the decision.
diff --git a/Test/B07emulate.ztst b/Test/B07emulate.ztst
index 7b1592fa9..45c39b51d 100644
--- a/Test/B07emulate.ztst
+++ b/Test/B07emulate.ztst
@@ -276,3 +276,25 @@ F:Some reserved tokens are handled in alias expansion
0:--emulate followed by other options
>yes
>no
+
+ emulate sh -c '
+ foo () {
+ VAR=foo &&
+ echo $VAR | bar &&
+ echo "$VAR"
+ }
+ bar () {
+ tr f b &&
+ VAR="$(echo bar | tr r z)" &&
+ echo "$VAR"
+ }
+ foo
+ '
+ emulate sh -c 'func() { echo | local def="abc"; echo $def;}; func'
+ emulate sh -c 'abc="def"; echo | abc="ghi"; echo $abc'
+0:emulate sh uses subshell for last pipe entry
+>boo
+>baz
+>foo
+>
+>def
next prev parent reply other threads:[~2019-11-24 23:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-24 23:41 [PATCH 0/1] Run " brian m. carlson
2019-11-24 23:41 ` brian m. carlson [this message]
2019-12-07 19:23 ` brian m. carlson
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