Bug 5740

Summary: break m<TAB> causes an NPE
Product: frysk Reporter: Phil Muldoon <pmuldoon>
Component: generalAssignee: Unassigned <frysk-bugzilla>
Status: NEW ---    
Severity: normal    
Priority: P2    
Version: unspecified   
Target Milestone: ---   
Host: Target:
Build: Last reconfirmed:
Bug Depends on:    
Bug Blocks: 2246    

Description Phil Muldoon 2008-02-06 13:12:39 UTC 
break <TAB> causes same:

[pmuldoon@localhost frysk-core]$ ./frysk/bindir/fhpd 
(fhpd) load /bin/sleep 
Loaded executable file: /bin/sleep

(fhpd) start
Attached to process 17018
starting/running with this command: /bin/sleep 

(fhpd) break mjava.lang.NullPointerException
   at frysk.debuginfo.ObjectDeclarationSearchEngine.complete(fhpd)
   at frysk.expr.IncompleteIdentifierException.complete(fhpd)
   at frysk.expr.ExpressionFactory.complete(fhpd)
   at frysk.hpd.CompletionFactory.completeExpression(fhpd)
   at frysk.hpd.BreakpointCommand.completer(fhpd)
   at frysk.hpd.ParameterizedCommand.complete(fhpd)
   at frysk.hpd.MultiLevelCom
mand.complete(fhpd)
   at frysk.hpd.CLI.complete(fhpd)
   at frysk.bindir.fhpd$FhpdCompletor.complete(fhpd)
   at jline.ConsoleReader.complete(fhpd)
   at jline.ConsoleReader.readLine(fhpd)
   at jline.ConsoleReader.readLine(fhpd)
   at frysk.bindir.fhpd.main(fhpd)
breakpoint 0 deferred
Comment 1 Mark Wielaard 2008-02-06 13:23:54 UTC 
This comes from not checking whether the compilation unit for the current
address actually exists.

Quick and dirty patch that seems to work around the issue.
The XXX in the comments suggest this is code isn't finished though.

diff --git a/frysk-core/frysk/debuginfo/ObjectDeclarationSearchEngine.java b/fry
index 94aee90..86e8e1b 100644
--- a/frysk-core/frysk/debuginfo/ObjectDeclarationSearchEngine.java
+++ b/frysk-core/frysk/debuginfo/ObjectDeclarationSearchEngine.java
@@ -139,16 +139,18 @@ public class ObjectDeclarationSearchEngine implements Expr
     /**
      * XXX: Who knows if this works; it is certainly not implemented
      * correctly as it should use the ObjectDeclaration.
      */
     public void complete(String incomplete, List candidates) {
        long pc = frame.getAdjustedAddress();
        Dwfl dwfl = DwflCache.getDwfl(frame.getTask());
        DwflDieBias bias = dwfl.getCompilationUnit(pc);
+       if (bias == null)
+         return;
        DwarfDie die = bias.die;
        DwarfDie[] allDies = die.getScopes(pc - bias.bias);
        List candidates_p = die.getScopeVarNames(allDies, incomplete);
        for (Iterator i = candidates_p.iterator(); i.hasNext();) {
             String sNext = (String) i.next();
             candidates.add(sNext);
         }
     }