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From Kristian Waagan <Kristian.Waa...@Sun.COM>
Subject Re: Change the behavior of PropertySetter?
Date Tue, 04 May 2010 08:34:11 GMT
On 04.05.10 04:15, Bryan Pendleton wrote:
>> Derby build to fail. The typical pattern is that (1) detects a valid
>> Java SE 6 installation, and then (2) picks up an invalid installation of
>> Java SE 5.0 or J2SE 1.4.
> What is an "invalid installation" in this description?
> In general, your proposal sounds fine to me, I'm just trying to 
> understand
> what sort of invalid installations the build tool is uncovering and why.

Hi Byran,

The two problematic installations I have stumbled across lately, where I 
tried to build Derby and it failed due to incorrect compilation 
classpaths, were:
  a) A JDK 1.4 was uninstalled, but because a custom jar had been placed 
into the jre/lib/ext directory, the directory structure wasn't removed. 
This caused an empty classpath.

  b) A gcj-installation on a Linux distro was picked up as the 1.5 JDK, 
but even though it contained a jre/lib (with rt.jar), it didn't have any 
executables (java or javac). As far as I can see, the directory was a 
valid part of an installed package (maybe even installed by default on a 
fresh install).

These were picked up because they met the following requirements:
  1) The base directory contained the target JDK version (i.e. 1.5).
  2) The base directory contained the directories jre/lib.

My point is that the new algorithm has a few more requirements, and it 
didn't pick up these installations for a reason. Therefore, if the new 
algorithm does the job by fulfilling the minimal JDK requirement, I 
suggest to skip the old algorithm.
However, if the new algorithm fails to locate a JDK, we can run the old 
one - it may manage to pick up one that can be used.

More along the lines of what Rick wrote in his reply, both of these 
algorithms will fail for some JDKs. This means that if we want almost 
all of our casual developers / hackers to be able to successfully run 
'ant all buildjars', we will have to extend PropertySetter.


> thanks,
> bryan

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