tests: ensure failure to write warnings is handled gracefully

* tests/misc/warning-errors.sh: Add a new test to ensure
failure to write warnings is diagnosed in the exit status.
* tests/local.mk: Reference the new test.

diff --git a/tests/local.mk b/tests/local.mk
index 792636d329de42c41f60dc885bcb995dfe135fc8..f2ed9889fa8498b96265a59b9b05e1527ea5989a 100644 (file)
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -184,6 +184,7 @@ all_tests =                                 \
   tests/tty/tty-eof.pl                         \
   tests/misc/io-errors.sh                      \
   tests/misc/read-errors.sh                    \
+  tests/misc/warning-errors.sh                 \
   tests/misc/write-errors.sh                   \
   tests/tail/basic-seek.sh                     \
   tests/tail/inotify-hash-abuse.sh             \

diff --git a/tests/misc/warning-errors.sh b/tests/misc/warning-errors.sh
new file mode 100755 (executable)
index 0000000..5a1f254
--- /dev/null
+++ b/tests/misc/warning-errors.sh
@@ -0,0 +1,63 @@
+#!/bin/sh
+# Make sure failure to write warnings is handled gracefully
+
+# Copyright (C) 2026 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+
+if ! test -w /dev/full || ! test -c /dev/full; then
+  skip_ '/dev/full is required'
+fi
+
+touch foo || framework_failure_
+
+# Commands that write to stderr but don't exit immediately
+# Escapes must be double escaped.
+printf '%s' "\
+cksum --debug /dev/null
+date --debug -d 'now'
+du --max-depth=0 --summarize /dev/null
+env --debug true
+ginstall --strip-program=foo foo bar
+numfmt --debug 1
+od -w1 /dev/null
+printf 'foo' 'bar'
+sort --debug /dev/null
+stat --printf '\\\\' .
+tail -n0 --retry foo
+tr . '\\\\' < /dev/null
+wc -l --debug /dev/null
+" |
+sort -k 1b,1 > all_writers || framework_failure_
+
+printf '%s\n' $built_programs |
+sort -k 1b,1 > built_programs || framework_failure_
+
+join all_writers built_programs > built_writers || framework_failure_
+
+
+expected_failure_status_sort=2
+expected_failure_status_env=0  # env's exec resets default exit handlers
+
+while read writer; do
+  cmd=$(printf '%s\n' "$writer" | cut -d ' ' -f1) || framework_failure_
+  eval "expected=\$expected_failure_status_$cmd"
+  test x$expected = x && expected=1
+  returns_ $expected \
+   $SHELL -c "env $writer" 2>/dev/full || fail=1
+done < built_writers
+
+Exit $fail