[PATCH] tail: always fail when followed files become inaccessible

[Pádraig Brady]

* src/tail.c (tail forever): Exit with failure status
like we do for the inotify case.  This is also consistent
with the failure exit if no file was accessible at tail startup.
* tests/tail/follow-stdin.sh: Tweak due to earlier exit.
* tests/tail/follow-name.sh: Test with and without inotify.
* NEWS: Mention the bug fix.
---
 NEWS                       |  4 ++++
 src/tail.c                 |  2 +-
 tests/tail/follow-name.sh  | 21 +++++++++++++--------
 tests/tail/follow-stdin.sh |  1 -
 4 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/NEWS b/NEWS
index 332e862d6..aabf83bf4 100644
--- a/NEWS
+++ b/NEWS
@@ -32,6 +32,10 @@ GNU coreutils NEWS                                    -*- 
outline -*-
   file names that are moved elsewhere within the same file system.
   [bug introduced in coreutils-8.24]
 
+  `tail --follow` will consistently exit with failure status where
+  inotify is not used, when all followed files become inaccessible.
+  [inconsistency introduced in coreutils-8.12]
+
   'tail -c 4096 /dev/zero' no longer loops forever.
   [This bug was present in "the beginning".]
 
diff --git a/src/tail.c b/src/tail.c
index 8cefb9c07..19f572556 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -1305,7 +1305,7 @@ tail_forever (struct File_spec *f, size_t n_files, double 
sleep_interval)
 
       if (! any_live_files (f, n_files))
         {
-          error (0, 0, _("no files remaining"));
+          error (EXIT_FAILURE, 0, _("no files remaining"));
           break;
         }
 
diff --git a/tests/tail/follow-name.sh b/tests/tail/follow-name.sh
index f92839c9e..8ce029c54 100755
--- a/tests/tail/follow-name.sh
+++ b/tests/tail/follow-name.sh
@@ -29,14 +29,19 @@ returns_ 1 timeout 10 tail --follow=name no-such > out 2> 
err || fail=1
 sed '/inotify cannot be used/d' err > k && mv k err
 compare exp err || fail=1
 
-# Between coreutils 8.34 and 9.5 inclusive, tail would have
-# waited indefinitely when a file was moved to the same file system
+# Between coreutils 8.34 and 9.5 inclusive, with inotify, tail would
+# have waited indefinitely when a file was moved to the same file system.
+# Also without inotify tail would have exited with success.
 cleanup_() { kill $pid 2>/dev/null && wait $pid; }
-touch file || framework_failure_
-timeout 10 tail --follow=name file & pid=$!
-sleep .1 # Usually in inotify loop here
-mv file file.unfollow || framework_failure_
-wait $pid
-test $? = 1 || fail=1
+fastpoll='-s.1 --max-unchanged-stats=1'  # speedup non inotify systems
+for inotify in '' '---disable-inotify'; do
+  touch file || framework_failure_
+  timeout 10 tail --follow=name $fastpoll file & pid=$!
+  sleep .1 # Usually in tail_{,inotify}_forever() here
+  mv file file.unfollow || framework_failure_
+  wait $pid
+  test $? = 1 || fail=1
+  rm -f file file.unfollow || framework_failure_
+done
 
 Exit $fail
diff --git a/tests/tail/follow-stdin.sh b/tests/tail/follow-stdin.sh
index 799353a0e..ecc8d8a79 100755
--- a/tests/tail/follow-stdin.sh
+++ b/tests/tail/follow-stdin.sh
@@ -61,7 +61,6 @@ cat <<\EOF >exp || framework_failure_
 tail: cannot fstat 'standard input'
 tail: error reading 'standard input'
 tail: no files remaining
-tail: -
 EOF
 sed 's/\(tail:.*\):.*/\1/' errt > err || framework_failure_
 compare exp err || fail=1
-- 
2.47.1