Bug 50960 - read on System.in hangs for forked java task
read on System.in hangs for forked java task
Product: Ant
Classification: Unclassified
Component: Core tasks
Macintosh All
: P2 regression (vote)
: 1.8.3
Assigned To: Ant Notifications List
: 50529 (view as bug list)
Depends on:
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Reported: 2011-03-23 17:30 UTC by Ron Goldman
Modified: 2012-01-19 15:02 UTC (History)
1 user (show)

build file to demonstrate the problem (1.73 KB, text/plain)
2011-03-23 17:31 UTC, Ron Goldman

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Description Ron Goldman 2011-03-23 17:30:04 UTC
I just started using Ant 1.8.2 as it was installed along with the latest Java Update for the Mac (JavaForMacOSX10.6Update4). Projects that worked fine with Ant 1.8.1 no longer work in 1.8.2. The problem seems to be that a Java task that forks a jvm hangs when it tries to read from System.in. Has anyone else seen this problem? 

Attached is a simple build.xml file that demonstrates the problem. It creates a simple Java file that just calls readLine() and echos the input, compiles the file, and runs it twice: once in a non-forked JVM, which works fine, and again in a forked JVM, which hangs.

-- Ron --

Here is a sample output:

> ant 
Buildfile: /Users/Ron/Development/Spots/tmp/ant-test/build.xml 

   [echo] ant.version      = Apache Ant(TM) version 1.8.2 compiled on December 20 2010 
   [echo] ant.home         = /usr/share/ant 
   [echo] ant.library.dir  = /usr/share/ant/lib 
   [echo] ant.java.version = 1.6 
  [javac] Compiling 1 source file to /Users/Ron/Development/Spots/tmp/ant-test 

   [echo] This will work: calling Java with fork=false 
   [java] Please enter some text and hit return: 
   [java] Text entered = asdf 

   [echo] This will hang: calling Java with fork=true 
   [java] Please enter some text and hit return: 
C-c C-c


On Mar 23, 2011, at 1:57 PM, Nicolas Lalevée wrote:

I can reproduce it locally. Could you please fill a bugzilla bug report [1], I'll look deeper into it.

Comment 1 Ron Goldman 2011-03-23 17:31:27 UTC
Created attachment 26795 [details]
build file to demonstrate the problem
Comment 2 Nicolas Lalevée 2011-03-29 17:02:00 UTC
Some stream was not flushed. Now fixed in trunk. Thanks for the report.
Comment 3 Antoine Levy-Lambert 2011-04-21 12:28:16 UTC
The edit done to fix this was svn 1086741
Comment 4 Antoine Levy-Lambert 2011-04-21 12:30:11 UTC
Link in viewvc is http://svn.apache.org/viewvc?view=revision&revision=1086741
Comment 5 Jesse Glick 2012-01-19 15:02:47 UTC
*** Bug 50529 has been marked as a duplicate of this bug. ***