Hi Phil, I have updated with small code updates: http://cr.openjdk.java.net/~sveerabhadra/8212202/webrev.04/
Thanks and regards, Shashi From: Shashidhara Veerabhadraiah Sent: Monday, December 10, 2018 3:19 PM To: Philip Race <philip.r...@oracle.com> Cc: Prasanta Sadhukhan <prasanta.sadhuk...@oracle.com>; 2d-dev@openjdk.java.net Subject: RE: [OpenJDK 2D-Dev] [12] JDK-8212202: NPE in the print tests after JDK-8153732 Hi Phil, Please find the updated Webrev. http://cr.openjdk.java.net/~sveerabhadra/8212202/webrev.03/ Thanks and regards, Shashi From: Philip Race Sent: Friday, December 7, 2018 8:54 PM To: Shashidhara Veerabhadraiah <HYPERLINK "mailto:shashidhara.veerabhadra...@oracle.com"shashidhara.veerabhadra...@oracle.com> Cc: Prasanta Sadhukhan <HYPERLINK "mailto:prasanta.sadhuk...@oracle.com"prasanta.sadhuk...@oracle.com>; HYPERLINK "mailto:2d-dev@openjdk.java.net"2d-dev@openjdk.java.net Subject: Re: [OpenJDK 2D-Dev] [12] JDK-8212202: NPE in the print tests after JDK-8153732 First off, I think the high order bit is that if a non-null array reference is returned there are NO null String entries in it. Whether a zero length or null array is returned when there are no printers is the less important issue. However an empty array also tells you there are no printers, and you are less likely to get an NPE from that. It is arguably easier for the caller, if they don't need the extra null check first. FWIW the javax.print public APIs return zero length arrays instead of null and applications seem to survive :-) I don't know what you mean by : > (And anyway we need to handle the first null string reference)? If you are referring to a small matter of coding in the native layer, then that is not an insurmountable problem. Basically if there are problems getting names or whatever in the native layer, handle it THERE, don't make everyone else have to deal with it. One caveat: JNI calls can theoretically fail due to OOME .. in such a case we are doomed and the main goal is to not crash in native and to obey all JNI rules. What is returned in that case can be a null array reference and an NPE in a Java-level user of that reference in such a case is not a big deal. -phil On 12/6/18, 8:10 PM, Shashidhara Veerabhadraiah wrote: Hi Phil, Is it advisable to return zero length array from native? The null return from native is telling the caller that there are no printers connected to the system. To tell this should we allocate a zero length array containing null back to the caller(And anyway we need to handle the first null string reference)? Handling the null on the caller isn't an easier option? Thanks and regards, Shashi From: Phil Race Sent: Thursday, December 6, 2018 2:35 AM To: Shashidhara Veerabhadraiah HYPERLINK "mailto:shashidhara.veerabhadra...@oracle.com";<shashidhara.veerabhadra...@oracle.com>; Prasanta Sadhukhan HYPERLINK "mailto:prasanta.sadhuk...@oracle.com";<prasanta.sadhuk...@oracle.com>; HYPERLINK "mailto:2d-dev@openjdk.java.net"2d-dev@openjdk.java.net Subject: Re: [OpenJDK 2D-Dev] [12] JDK-8212202: NPE in the print tests after JDK-8153732 But what I am saying is we should not return a NULL string reference from native. You are still allowing that and then having to handle it in Java code. And FWIW you can return a zero length array as well so there isn't a NULL array reference to deal with either. -phil. On 12/3/18 8:29 AM, Shashidhara Veerabhadraiah wrote: Hi Phil, There were 2 problems earlier. One is that, from the native it is possible to have no printers being associated with the system(causing to return null reference) and other problem in the implementation was that there may be no network printers and still return a valid array reference containing a null string. The first problem is fixed by handling null references returned from this function and other problem was that earlier there were different base conditions, for updating the reference and use it to create the printer name array which could produce a valid reference pointing to null string. Here is the updated Webrev which fixes these problems: HYPERLINK "http://cr.openjdk.java.net/%7Esveerabhadra/8212202/webrev.02/"http://cr.openjdk.java.net/~sveerabhadra/8212202/webrev.02/ The big problem was that I was not able to reproduce this problem neither at my end nor at the systems used for PIT testing. Only Sergey had produced this NPE till now. Thanks and regards, Shashi From: Phil Race Sent: Wednesday, November 28, 2018 11:19 PM To: Shashidhara Veerabhadraiah HYPERLINK "mailto:shashidhara.veerabhadra...@oracle.com";<shashidhara.veerabhadra...@oracle.com>; Prasanta Sadhukhan HYPERLINK "mailto:prasanta.sadhuk...@oracle.com";<prasanta.sadhuk...@oracle.com>; HYPERLINK "mailto:2d-dev@openjdk.java.net"2d-dev@openjdk.java.net Subject: Re: [OpenJDK 2D-Dev] [12] JDK-8212202: NPE in the print tests after JDK-8153732 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 returning, 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 .. -phil. 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: HYPERLINK "http://cr.openjdk.java.net/%7Esveerabhadra/8212202/webrev.01/"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 HYPERLINK "mailto:prasanta.sadhuk...@oracle.com";<prasanta.sadhuk...@oracle.com>; Shashidhara Veerabhadraiah HYPERLINK "mailto:shashidhara.veerabhadra...@oracle.com";<shashidhara.veerabhadra...@oracle.com>; HYPERLINK "mailto:2d-dev@openjdk.java.net"2d-dev@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 HYPERLINK "mailto:shashidhara.veerabhadra...@oracle.com";<shashidhara.veerabhadra...@oracle.com>; HYPERLINK "mailto:swing-...@openjdk.java.net"swing-...@openjdk.java.net; HYPERLINK "mailto:2d-dev@openjdk.java.net"2d-dev@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, HYPERLINK "mailto:shashidhara.veerabhadra...@oracle.com"shashidhara.veerabhadra...@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: HYPERLINK "http://cr.openjdk.java.net/%7Esveerabhadra/8212202/webrev.00/"http://cr.openjdk.java.net/~sveerabhadra/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
