ash: eval: Do not cache value of eflag in evaltree

Upsteam commit:

    Date: Mon, 17 May 2021 15:19:23 +0800
    eval: Do not cache value of eflag in evaltree

    Patrick Brünn <P.Bruenn@beckhoff.com> wrote:
    > Since we are migrating to Debian bullseye, we discovered a new behavior
    > with our scripts, which look like this:
    >>cleanup() {
    >>        set +e
    >>        rmdir ""
    >>}
    >>set -eu
    >>trap 'cleanup' EXIT INT TERM
    >>echo 'Hello world!'
    >
    > With old dash v0.5.10.2 this script would return 0 as we expected it.
    > But since commit 62cf6955f8abe875752d7163f6f3adbc7e49ebae it returns
    > the last exit code of our cleanup function.
    ...
    Thanks for the report.  This is actually a fairly old bug with
    set -e that's just been exposed by the exit status change.  What's
    really happening is that cleanup itself is triggering a set -e
    exit incorrectly because evaltree cached the value of eflag prior
    to the function call.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/shell/ash_test/ash-misc/exitcode_trap7.tests b/shell/ash_test/ash-misc/exitcode_trap7.tests
new file mode 100755
index 0000000..9772a7b
--- /dev/null
+++ b/shell/ash_test/ash-misc/exitcode_trap7.tests
@@ -0,0 +1,7 @@
+$THIS_SH -c '
+cleanup() { set +e; false; }
+set -eu
+trap cleanup EXIT
+echo Start
+'
+echo Ok:$?