avoid spurious failures from MacOS readdir bug

[Eric Blake]

As reported by various people, most recently by Bruce Dugan, the autoconf 
testsuite has spurious failures on MacOS 10.5, where readdir intermittently 
lists a file more than once in the face of a rapidly changing directory.  I'm 
applying this, under the assumption that 'sort -u' is portable (at any rate, it 
is already in use in mktests.sh, so the testsuite isn't even built properly if 
it is not portable).  I didn't spend the time researching the list archives for 
the first instance of a similar report; if someone feels that would be 
important, we can commit a followup with additional attribution.

From: Eric Blake <address@hidden>
Date: Tue, 2 Dec 2008 11:15:55 -0700
Subject: [PATCH] Avoid MacOS readdir bug in testsuite.

* tests/local.at (AC_STATE_SAVE): Avoid spurious failures due to
duplicated ls entries.
* THANKS: Update.
Reported by Bruce Dugan and others.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog      |    8 ++++++++
 THANKS         |    1 +
 tests/local.at |    4 +++-
 3 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 2db458d..7ca53e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2008-12-02  Eric Blake  <address@hidden>
+
+       Avoid MacOS readdir bug in testsuite.
+       * tests/local.at (AC_STATE_SAVE): Avoid spurious failures due to
+       duplicated ls entries.
+       * THANKS: Update.
+       Reported by Bruce Dugan and others.
+
 2008-11-29  Ralf Wildenhues  <address@hidden>
 
        * lib/autotest/general.m4 (AT_JOB_FIFO_FD): Hide zsh 4.3.4
diff --git a/THANKS b/THANKS
index bd394e1..a3ae8c2 100644
--- a/THANKS
+++ b/THANKS
diff --git a/tests/local.at b/tests/local.at
index 041d103..2ec7bc5 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -197,9 +197,11 @@ m4_define([AT_CONFIGURE_AC],
 # confirm that no test modifies variables outside the Autoconf namespace or
 # leaves temporary files.  AT_CONFIG_CMP uses the variable dumps to confirm 
that
 # tests have the same side effects regardless of caching.
+# The sort -u is necessary, since MacOS 10.5 has a bug where readdir can
+# list a file multiple times in a rapidly changing directory.
 m4_defun([AC_STATE_SAVE],
 [(set) 2>&1 | sort >state-env.$][1
-ls -1 | sed '/^at-/d;/^state-/d;/^config\./d' | sort >state-ls.$][1
+ls -1 | sed '/^at-/d;/^state-/d;/^config\./d' | sort -u >state-ls.$][1
 ])# AC_STATE_SAVE
 ]])
 
-- 
1.6.0.4