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https://issues.apache.org/jira/browse/GROOVY-7414?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14530394#comment-14530394
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Paul King commented on GROOVY-7414:
-----------------------------------
This is "as designed" behavior. The consumeProcessOutput and waitFor methods
are low-level primitives if you like which have known limitations but have been
left around for people wanting that low-level and for legacy reasons. The
higher-level waitForProcessOutput method is the correct abstraction for most
users and is the recommended one to use. Perhaps we need to stress that further
in the documentation.
> Process output not always consumed before waitFor() returns
> -----------------------------------------------------------
>
> Key: GROOVY-7414
> URL: https://issues.apache.org/jira/browse/GROOVY-7414
> Project: Groovy
> Issue Type: Bug
> Components: groovy-jdk
> Affects Versions: 2.4.3
> Environment: Linux junk 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt9-2
> (2015-04-13) x86_64 GNU/Linux running in a VirtualBox VM
> Reporter: Sergey Gromov
> Assignee: Guillaume Laforge
>
> Sometimes the {{Process.consumeProcessOutput(Appendable, Appendable)}} and
> {{Process.waitFor()}} combination does not work as expected. More
> specifically, sometimes {{waitFor()}} returns before all input is actually
> written into {{Appendable}}.
> The following script reproduces the problem:
> {code:title=bug.gy}
> 100.times {
> def out = new StringBuilder()
> def err = new StringBuilder()
> def p = 'echo stuff'.execute()
> p.consumeProcessOutput(out, err)
> p.waitFor()
> def s = out.toString()
> if (s != 'stuff\n') {
> println 'Bug!'
> println 'OUT: ' + s.inspect()
> }
> }
> {code}
> The ability to reproduce this issue seems to depend on the system
> performance. E.g. I can easily reproduce it in my virtual Linux box. The
> above script fails 2 or 3 times on every launch. OTOH it's quite problematic
> to reproduce on my host Windows machine even though I increased the number of
> tries to 1000. Nevertheless I have reproduced it on Windows, too, a couple of
> times.
> I think this is major because I'm not aware of any viable workaround. The
> only thing that works is to sleep a bit after waitFor() which is often
> unacceptable, and it's impossible to guess for how long to sleep.
> Note that {{Process.consumeProcessOutput(OutputStream, OutputStream)}}
> exhibits the same broken behavior.
> Also note that {{Process.waitForProcessOutput(arg, arg)}} methods work
> flawlessly.
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