From 0c393e38c41b56bfb65f0fcc3efb343aae51911c Mon Sep 17 00:00:00 2001
From: "Gustavo J. A. M. Carneiro" <gjc@inescporto.pt>
Date: Sun, 6 Apr 2008 19:22:39 +0100
Subject: [PATCH] Fix case of 'diff xxx | head' appearing to succeed even if
 the diff command returned non-zero exit statux.

---
 wscript | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/wscript b/wscript
index 885ccd1a7..dbcf5a9ba 100644
--- a/wscript
+++ b/wscript
@@ -677,12 +677,16 @@ class Regression(object):
             run_program(testName, command_template=get_command_template())
 
             if verbose:
-                diffCmd = "diff traces " + refTestDirName + " | head"
+                #diffCmd = "diff traces " + refTestDirName + " | head"
+                diffCmd = subprocess.Popen(args=["diff", "traces", refTestDirName], stdout=subprocess.PIPE)
+                headCmd = subprocess.Popen(args=["diff", "traces", refTestDirName], stdin=diffCmd.stdout)
+                rc1 = diffCmd.wait()
+                rc2 = headCmd.wait()
+                rc = rc1 or rc2
             else:
                 diffCmd = "diff traces " + refTestDirName + \
                     " > /dev/null 2>&1"
-
-            rc = os.system(diffCmd)
+                rc = os.system(diffCmd)
             if rc:
                 print "----------"
                 print "Traces differ in test: test-" + testName