8373094: javac may fail because of unattributed break in a loop

[lahodaj]

Consider a case like this:

package test;
public class Intermediate<T> extends Base<T> {}

package test;
public class Base<T> {
    public void t(Missing<T> m) {}
}
package test;
public class Missing<T> {}

this is compiled, and then Missing is deleted. Then a test file is compiled with the above classes on the classpath:

$ cat src/test/Test.java 
package test;
public class Test extends Intermediate<String> {
    private void test() {
        while (true) { break; }
    }
}
$ javac -XDdev -XDshould-stop.at=FLOW -d classes -classpath classes src/test/Test.java
src/test/Test.java:2: error: cannot access Missing
public class Test extends Intermediate<String> {
       ^
  class file for test.Missing not found
1 error
An exception has occurred in the compiler (25.0.1). Please file a bug against the Java compiler via the Java bug reporting page (https://bugreport.java.com) after checking the Bug Database (https://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
java.lang.AssertionError
        at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:155)
        at jdk.compiler/com.sun.tools.javac.util.Assert.check(Assert.java:46)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.clearPendingExits(Flow.java:631)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.visitMethodDef(Flow.java:619)
...

The reason is that the CompletionFailure will be thrown from chk.checkCompatibleSupertypes(tree.pos(), c.type);, and since that's before attributing the method bodies, the method bodies will remain blank. And hence the break will have no target set, and Flow will fail on it.

I spent some time trying to figure out if we could improve handling on CompletionFailures more generally, so that we would not need to catch them on more-or-less arbitrary places. But everything I was able to do so far didn't really improve the situation. So the proposal herein is to catch and handle the CompletionFailure on some place.

---

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Warning

 ⚠️ Found leading lowercase letter in issue title for 8373094: javac may fail because of unattributed break in a loop

Issue

• JDK-8373094: javac may fail because of unattributed break in a loop (Bug - P3)

Reviewers

• Vicente Romero (@vicente-romero-oracle - Reviewer)

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[openjdk]

@lahodaj This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8373094: javac may fail because of unattributed break in a loop

Reviewed-by: vromero

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At the time when this comment was updated there had been 22 new commits pushed to the master branch:

• 2596608: 8370846: Support execution of mlvm testing with test thread factory
• be8cbfa: 8362083: JDI VirtualMachine/dispose/dispose001 failed with FATAL ERROR in native method: JDWP cannot set thread local storage, jvmtiError=JVMTI_ERROR_WRONG_PHASE(112)
• f3dd8da: 8371748: Remove the (empty) ThreadPoolExecutor.finalize() method
• ... and 19 more: https://git.openjdk.org/jdk/compare/2735140147b159d3a3238804f221db4f835ef744...master

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[mlbridge]

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• 00: Full (fd60a0f4)

[vicente-romero-oracle]

lgtm