[NETBEANS-4259] NPE in code completion when in incorrect cast syntax

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 11.3
• Component/s: java - Source

Environment

NetBeans 11.3 on Windows (OS shouldn't matter)

• Assignee: Unassigned
• Reporter: Eirik Bakke
• Created: 27/Apr/20 16:03
• Updated: 18/May/20 15:08

Description

In the following class, put the cursor after "dat" and invoke code completion (Ctrl+Space). This situation often happens from muscle memory while typing a cast. A NPE will result:

public class TestFoo {
  private String someMethod(Object someArg) {
    if (someArg instanceof String)
      return (String dat); // To see parser error, open code completion with cursor after "dat
    return null;
  }
}

The desired behavior is to just ignore the incorrect syntax, and perform no completion. Instead, the following exception is shown:

java.lang.NullPointerException
	at org.netbeans.modules.java.completion.BaseTask.getEnvImpl(BaseTask.java:389)
	at org.netbeans.modules.java.completion.BaseTask.getCompletionEnvironment(BaseTask.java:270)
	at org.netbeans.modules.java.completion.JavaCompletionTask.resolve(JavaCompletionTask.java:297)
	at org.netbeans.modules.java.completion.BaseTask.run(BaseTask.java:94)
	at org.netbeans.modules.java.completion.JavaCompletionTask.run(JavaCompletionTask.java:60)
	at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:586)
	at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:130)
	at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:114)
	at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:181)
	at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:178)
	at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:153)
	at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:335)
	at org.netbeans.modules.parsing.nb.DataObjectEnvFactory.runPriorityIO(DataObjectEnvFactory.java:118)
	at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:67)
	at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:178)
Caused: org.netbeans.modules.parsing.spi.ParseException
	at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:186)
	at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:81)
[catch] at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.query(JavaCompletionProvider.java:193)
	at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:198)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1418)
	at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:45)
	at org.openide.util.lookup.Lookups.executeWith(Lookups.java:278)
	at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)

Reporting this bug in case a pattern emerges where various kinds of errors like this pop up instead of being silently ignored.