[OpenJDK 2D-Dev] [12] JDK-8212202: NPE in the print tests after JDK-8153732

Phil Race philip.race at oracle.com
Wed Nov 28 17:49:28 UTC 2018

I am not understanding you. I thought the problem to be we got an array 
of (say) 3 values
(ie printer names) returned from native where some or all of the 
*values* were NULL.
And I am saying we should in such a case in the native code, before 
remove from the returned array all values that are NULL.
That could result in an empty (zero length) array being returned from 
native but
no null names ..


On 11/26/18 10:23 PM, Shashidhara Veerabhadraiah wrote:
> The windows function EnumPrinters() returns a value that could be zero 
> or greater. If it is zero we have no other option but to return null 
> from the function. I do not think there is a way where we can always 
> make sure we get a non-zero value considering the various system 
> scenarios. So we should handle the null return values as well in the 
> caller of this function I think.
> Here is the updated Webrev for test fix:
> http://cr.openjdk.java.net/~sveerabhadra/8212202/webrev.01/
> Thanks and regards,
> Shashi
> *From:*Phil Race
> *Sent:* Tuesday, November 27, 2018 1:52 AM
> *To:* Prasanta Sadhukhan <prasanta.sadhukhan at oracle.com>; Shashidhara 
> Veerabhadraiah <shashidhara.veerabhadraiah at oracle.com>; 
> 2d-dev at openjdk.java.net
> *Subject:* Re: [OpenJDK 2D-Dev] [12] JDK-8212202: NPE in the print 
> tests after JDK-8153732
> [Removed swing-dev as this as nothing to do with swing].
> You mention in the bug eval that you don't need a new test because this
> is already covered by the test for 8153732. If that is the case then this
> bugid should be added to that test.
> Although it also looks like there are plenty of tests that provoke this ..
> if all you need is a system without any printers then this is a 
> serious regression.
> I am not sure I am following why doCompare() is the place to fix this.
> If getRemotePrinterNames() is returning NULL strings, then maybe it 
> should not !
> I suggest to fix it there.
> -phil.
> On 11/26/18 7:51 AM, Prasanta Sadhukhan wrote:
>     I am not against doCompare() changes. I am just saying run()
>     changes are not needed.
>     Regards
>     Prasanta
>     On 26-Nov-18 9:15 PM, Shashidhara Veerabhadraiah wrote:
>         There is a possible case and that is the reason for this fix.
>         The possible states for prevRemotePinters and
>         currentRemotePrinters are null and valid values and they can
>         reach those states at any time either because of network
>         disconnect or any other OS related changes. With that in mind,
>         this fix tries to eliminate the possible NPE cases.
>         Thanks and regards,
>         Shashi
>         *From:*Prasanta Sadhukhan
>         *Sent:* Monday, November 26, 2018 8:01 PM
>         *To:* Shashidhara Veerabhadraiah
>         <shashidhara.veerabhadraiah at oracle.com>
>         <mailto:shashidhara.veerabhadraiah at oracle.com>;
>         swing-dev at openjdk.java.net
>         <mailto:swing-dev at openjdk.java.net>; 2d-dev at openjdk.java.net
>         <mailto:2d-dev at openjdk.java.net>
>         *Subject:* Re: [OpenJDK 2D-Dev] [12] JDK-8212202: NPE in the
>         print tests after JDK-8153732
>         On 26-Nov-18 6:51 PM, shashidhara.veerabhadraiah at oracle.com
>         <mailto:shashidhara.veerabhadraiah at oracle.com> wrote:
>             Hi Prasanta, I think we should not create a behavior
>             across the functions. doCompare() does only the comparison
>             and it may be used for other purposes and is complete with
>             respect to the comparison functionality.
>             run() function has a different behavior as it needs to
>             populate the prevRemotePrinters and then the
>             currentRemotePrinters and then use the comparison
>             functionality. I think this is a good way to do.
>         Even without the if-else check, it does populates the
>         prevRemotePrinters, no?
>         if "prevRemotePrinters" is null and currentRemotePrinters is
>         null, then no need to update. If currentRemotePrinters is
>         null, then what is the point of using getRemotePrintersNames()
>         to update prevRemotePrinters as currentRemotePrinters is also
>         obtained from getRemotePrintersNames!!
>         If "prevRemotePrinters" is null and currentRemotePrinters is
>         not null, then doCompare() called from run() will be true and
>         prevRemotePrinters will be populated with currentRemotePrinters.
>         If "prevRemotePrinters" is not null and currentRemotePrinters
>         is null, then also prevRemotePrinters will be populated with
>         currentRemotePrinters.
>         Regards
>         Prasanta
>             Thanks and regards,
>             Shashi
>             On 26/11/18 6:03 PM, Prasanta Sadhukhan wrote:
>                 Hi Shashi,
>                 I think l437 check of if-else *if (prevRemotePrinters
>                 != null) {*
>                 is not required. prevRemotePrinters null check is
>                 addressed in str1==null case in doCompare().
>                 If prevRemotePrinters is null and
>                 currentRemotePrinters is not null, then you update
>                 prevRemotePrinters to currentRemotePrinters as per
>                 l415 where doCompare returns true.
>                 Also, If prevRemotePrinters is not null and
>                 currentRemotePrinters is null, then also you update
>                 prevRemotePrinters to currentRemotePrinters which is
>                 the output of getRemotePrintersNames().
>                 Regards
>                 Prasanta
>                 On 26-Nov-18 2:33 PM, Shashidhara Veerabhadraiah wrote:
>                     Hi All, Please review a NPE fix for the below bug.
>                     Bug: https://bugs.openjdk.java.net/browse/JDK-8212202
>                     Webrev:
>                     http://cr.openjdk.java.net/~sveerabhadra/8212202/webrev.00/
>                     <http://cr.openjdk.java.net/%7Esveerabhadra/8212202/webrev.00/>
>                     Function getRemotePrintersNames() may return null
>                     values and hence they need to be handled from the
>                     caller of that function which was missing earlier.
>                     This fix handles the null return values of the
>                     said function.
>                     Thanks and regards,
>                     Shashi

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