From aee982627874e9719bc151007b7e0144edd3963e Mon Sep 17 00:00:00 2001
From: =?utf8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Tue, 9 Jun 2015 11:33:44 +0100
Subject: [PATCH] tail: display consistent diagnostics upon file replacement

* src/tail.c (recheck): Display diagnostices for replaced files
even with reused inodes which is a common case.
* tests/tail-2/F-vs-missing.sh: Use correct diagnostic in comment.
* tests/tail-2/F-vs-rename.sh: Likewise.
---
 src/tail.c                   | 55 ++++++++++++++++--------------------
 tests/tail-2/F-vs-missing.sh |  2 +-
 tests/tail-2/F-vs-rename.sh  |  2 +-
 3 files changed, 27 insertions(+), 32 deletions(-)

diff --git a/src/tail.c b/src/tail.c
index 4d6b28a195..c062d403ff 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -1019,42 +1019,37 @@ recheck (struct File_spec *f, bool blocking)
       assert (f->fd == -1);
       error (0, 0, _("%s has become accessible"), quote (pretty_name (f)));
     }
+  else if (f->fd == -1)
+    {
+      /* A new file even when inodes haven't changed as <dev,inode>
+         pairs can be reused, and we know the file was missing
+         on the previous iteration.  Note this also means the file
+         is redisplayed in --follow=name mode if renamed away from
+         and back to a monitored name.  */
+      new_file = true;
+
+      error (0, 0,
+             _("%s has appeared;  following new file"),
+             quote (pretty_name (f)));
+    }
   else if (f->ino != new_stats.st_ino || f->dev != new_stats.st_dev)
     {
+      /* File has been replaced (e.g., via log rotation) --
+        tail the new one.  */
       new_file = true;
-      if (f->fd == -1)
-        {
-          error (0, 0,
-                 _("%s has appeared;  following new file"),
-                 quote (pretty_name (f)));
-        }
-      else
-        {
-          /* Close the old one.  */
-          close_fd (f->fd, pretty_name (f));
-
-          /* File has been replaced (e.g., via log rotation) --
-             tail the new one.  */
-          error (0, 0,
-                 _("%s has been replaced;  following new file"),
-                 quote (pretty_name (f)));
-        }
+
+      error (0, 0,
+             _("%s has been replaced;  following new file"),
+             quote (pretty_name (f)));
+
+      /* Close the old one.  */
+      close_fd (f->fd, pretty_name (f));
+
     }
   else
     {
-      if (f->fd == -1)
-        {
-          /* This happens when one iteration finds the file missing,
-             then the preceding <dev,inode> pair is reused as the
-             file is recreated.  Note this also means the file is redisplayed
-             in --follow=name mode if renamed away from and back to
-             a monitored name.  */
-          new_file = true;
-        }
-      else
-        {
-          close_fd (fd, pretty_name (f));
-        }
+      /* No changes detected, so close new fd.  */
+      close_fd (fd, pretty_name (f));
     }
 
   /* FIXME: When a log is rotated, daemons tend to log to the
diff --git a/tests/tail-2/F-vs-missing.sh b/tests/tail-2/F-vs-missing.sh
index be20ee3b88..54fe30a884 100755
--- a/tests/tail-2/F-vs-missing.sh
+++ b/tests/tail-2/F-vs-missing.sh
@@ -48,7 +48,7 @@ for mode in '' '---disable-inotify'; do
   (cd missing && echo x > file) || framework_failure_
 
   # Wait up to 12.7s for this to appear in the output:
-  # "tail: '...' has appeared;  following end of new file"
+  # "tail: '...' has appeared;  following new file"
   tail_re='has appeared' retry_delay_ check_tail_output .1 7 ||
     { echo "$0: file: unexpected delay?"; cat out; fail=1; }
 
diff --git a/tests/tail-2/F-vs-rename.sh b/tests/tail-2/F-vs-rename.sh
index ee61a548b6..06733fb410 100755
--- a/tests/tail-2/F-vs-rename.sh
+++ b/tests/tail-2/F-vs-rename.sh
@@ -53,7 +53,7 @@ for mode in '' '---disable-inotify'; do
 
   echo x > a
   # Wait up to 12.7s for this to appear in the output:
-  # "tail: '...' has appeared;  following end of new file"
+  # "tail: '...' has appeared;  following new file"
   tail_re='has appeared' retry_delay_ check_tail_output .1 7 ||
     { echo "$0: a: unexpected delay?"; cat out; fail=1; }
 
-- 
2.47.2