zsh typically runs the final command in a pipeline in the main shell
instead of a subshell. However, POSIX specifies that all commands in a
pipeline run in a subshell, but permits zsh's behavior as an extension.
The default /bin/sh implementations on various Linux distros and the
BSDs always use a subshell for all components of a pipeline.
Since zsh may be used as /bin/sh in some cases (such as macOS Catalina),
it makes sense to have the common sh 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.
From the comment above execpline(), we know the following:
last1 is a flag that this command is the last command in a shell that
is about to exit, so we can exec instead of forking. It gets passed
all the way down to execcmd() which actually makes the decision. A 0
is always passed if the command is not the last in the pipeline. […]
If last1 is zero but the command is at the end of a pipeline, we pass
2 down to execcmd().
So there are three cases to consider in this code:
• last1 is 0, which means we are not at the end of a pipeline, in which
case we should not change behavior.
• last1 is 1, which means we are effectively running in a subshell,
because nothing that happens due to the exec is going to affect the
actual shell, since it will have been replaced. So there is nothing
to do here.
• last1 is 2, which means our command is at the end of the pipeline, so
in sh mode we should create a subshell by forking.
input is nonzero if the input to this process is a pipe that we've
opened. At the end of a multi-stage pipeline, it will necessarily be
nonzero.
Note that several of the tests may appear bizarre, since most developers
do not place useless variable assignments directly at the end of a
pipeline. However, as the function tests demonstrate, there are cases
where assignments may occur when a shell function is used at the end of
a command. The remaining assignment tests simply test additional cases,
such as the use of local, that would otherwise be untested.
This is useful when multiple plugins add region_highlight entries and
subsequently want to remove only their own entries. Without this
functionality, recognizing one's region_highlight entries is not trivial
because the 'start' and 'end' offsets are modified by editing of $BUFFER
and the highlight specification may not be unique or distinctive.
The tweaks are as follows:
- Change zfree() to zsfree() per workers/46070.
- Remove the mem.c hunk, as it changed the signature of only one out of
two alternative definitions of zsfree(). (The definition that hunk
touched is the one that's not used by default.)
The change in question was (deliberately) not merged to master before the 5.8
release. Therefore, it is a "post 5.8" change, even though it was written
when 5.7.1 was the latest release.
* Test/D02glob.ztst:
On the "unreadable directories can be globbed (users/24619, users/24626)"
test, resolve conflicts by removing the Cygwin-only skip that has been added
in master, since the test is passing on this branch. This effectively reverts
workers/45492. See discussion starting in workers/45504.
* origin/master:
unposted: Remove 'sgi', as that OpenBSD port has been discontinued.
45509: fix typos in B01cd.ztst
45490 (+45495 and a test): refactor rlimits.c
github #49: Fix typo: longson should be loongson
users/24710: Fix job control problem with sudo.
45492: skip test added by users/24633 on Cygwin
45488: COMP_WORDS for bash need "$@"-style quoting
45487: Missing mod_export declarations for AIX
45447: Complete vcs_info_hookadd and vcs_info_hookdel. Expose _vcs_info_hooks as a top-level helper function.
45463: test: kill: Document why we use SIGURG
45453: builtins: kill: Do not signal current process group when pid is empty
45452: builtins: kill: Add `kill ''` regression test with explicit sigspec
45451: builtins: kill: Add basic test suite
github #48/0002: vcs_info git: properly detect bare repositories
github #48/0001: vcs_info git: avoid warnings in bare repositories
unposted: Post-release version bump
unposted: Release 5.8
CVE-2019-20044: Update change log for preceding commits
Update NEWS/README
Add unsetopt/PRIVILEGED tests
Clean up error-message white space
Improve PRIVILEGED fixes (again)
Improve PRIVILEGED fixes
Drop privileges securely
unposted: V01zmodload: Fix failing test from workers/45385
45423: _su: Improve arg handling, shell look-ups
unposted: _zip: Recognise '--'
45385: Add a test for 'zmodload -Fa' preemptively disabling ("blacklisting"?) features.
unposted: Test release: 5.7.1-test-3
zsh/system: Fix infinite loop in sysread
_diff_options: Restore -w completion lost in workers/43351
unposted: Fix ChangeLog typo.
45368: Add tests for workers/45367's issue about double slashes in 'cd -P' and /home/daniel/in/zsh.
45373: Fix ERR_EXIT bug in else branch of if.
45372: Record a symlink loop bug involving :P
45365: _git: Fix __git_recent_branches for the case when a commit has an empty message
45343: Queue signals around arithmetic evaluations
45344: Document where third-party completion functions should be installed.
45345: internal: ztst.vim: Fix highlighting of zsh comments in test payload
unposted: internal: Add some comments and fix indentation. No functional change.
45340: internal: Document the difference between paramtab and realparamtab.
45332: _git: add completion for git-version
_brace_parameter: add missing \
Conflicts:
ChangeLog
Test/D02glob.ztst
Test/V01zmodload.ztst
Pick number of leading or trailing path components to substitute.
Active in history, brace parameters, glob qualifiers.
Add tests for all three environments.
Move detection of key/value pairs down into prefork().
Detect normal array assignment and [key]=val array assignemnt
separately. Mark key / value pairs with Marker and pass up flag. Deal
with marked triads specially later on.
path.
-d defaults to normal fpath
-r remembers the path without actually loading. May be combined with -d.
-R does the same but it's an error if not found
-X can now take a directory path: this is used to output not yet loaded
functions that have an associated path.
dana
Daniel Shahaf
brian m. carlson
Lawrence Velázquez
Bart Schaefer
Daniel Shahaf
Martijn Dekker
Peter Stephenson
Peter Stephenson
Anthony Sottile
Peter Stephenson
Stephane Chazelas
Barton E. Schaefer