On Tue, May 31, 2016 at 11:49:10PM -0700, Junio C Hamano wrote:
> Jeff King <peff@xxxxxxxx> writes:
>
> > OK, last email tonight, I promise.
> >
> > Here's the subshell version. I'm a little embarrassed not to have
> > thought of it sooner (though the other one was a fun exercise).
> >
> > test_env () {
> > (
> > while test $# -gt 0
> > do
> > case "$1" in
> > *=*)
> > eval "${1%%=*}=\${1#*=}"
>
> Is this an elaborate way to say 'eval "$1"', or is there anything
> more subtle going on?
Notice that the value half isn't expanded until we get inside the eval.
So:
$ good() { eval "${1%%=*}=\${1#*=}"; }
$ bad() { eval "$1"; }
$ good foo="funny variable"; echo $foo
funny variable
$ bad foo="funny variable"
bash: variable: command not found
> > *)
> > "$@"
> > exit
>
> ... or 'exec "$@"'
You can't exec a function, AFAIK (and that was the point of this
exercise).
> > )
> > }
>
> You can dedent the whole thing and remove the outermost {} pair.
True. I didn't know about that until recently. Is it portable
everywhere?
Here's the patch I wrote up earlier (but was too timid to send out after
my barrage of emails :) ).
It doesn't have the dedent, but I don't mind if you want to tweak it.
-- >8 --
Subject: test-lib: add in-shell "env" replacement
The one-shot environment variable syntax:
FOO=BAR some-program
is unportable when some-program is actually a shell
function, like test_must_fail (on some shells FOO remains
set after the function returns, and on others it does not).
We sometimes get around this by using env, like:
test_must_fail env FOO=BAR some-program
But that only works because test_must_fail's arguments are
themselves a command which can be run. You can't run:
env FOO=BAR test_must_fail some-program
because env does not know about our shell functions. So
there is no equivalent for test_commit, for example, and one
must resort to:
(
FOO=BAR
export FOO
test_commit
)
which is a bit verbose. Let's add a version of "env" that
works _inside_ the shell, by creating a subshell, exporting
variables from its argument list, and running the command.
Its use is demonstrated on a currently-unportable case in
t4014.
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
t/t4014-format-patch.sh | 2 +-
t/test-lib-functions.sh | 22 ++++++++++++++++++++++
2 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 8049cad..805dc90 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1072,7 +1072,7 @@ test_expect_success '--from omits redundant in-body header' '
'
test_expect_success 'in-body headers trigger content encoding' '
- GIT_AUTHOR_NAME="éxötìc" test_commit exotic &&
+ test_env GIT_AUTHOR_NAME="éxötìc" test_commit exotic &&
test_when_finished "git reset --hard HEAD^" &&
git format-patch -1 --stdout --from >patch &&
cat >expect <<-\EOF &&
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 3978fc0..48884d5 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -939,3 +939,25 @@ mingw_read_file_strip_cr_ () {
eval "$1=\$$1\$line"
done
}
+
+# Like "env FOO=BAR some-program", but run inside a subshell, which means
+# it also works for shell functions (though those functions cannot impact
+# the environment outside of the test_env invocation).
+test_env () {
+ (
+ while test $# -gt 0
+ do
+ case "$1" in
+ *=*)
+ eval "${1%%=*}=\${1#*=}"
+ eval "export ${1%%=*}"
+ shift
+ ;;
+ *)
+ "$@"
+ exit
+ ;;
+ esac
+ done
+ )
+}
--
2.9.0.rc0.174.g479a78d
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