Bug 317212

Summary:

[compiler] Illegal permission to invoke the constructor of a member class of an inaccessible type.

Product:

[Eclipse Project] JDT

Reporter:

Christian Zoller <eclipse>

Component:

Core

Assignee:

Srikanth Sankaran <srikanth_sankaran>

Status:

VERIFIED FIXED

QA Contact:

Severity:

normal

Priority:

CC:

amj87.iitr, jarthana, Olivier_Thomann

Version:

3.6

Flags:

jarthana: review+

Target Milestone:

3.7 M1

Hardware:

OS:

Linux

Whiteboard:

Attachments:

Description	Flags
Example code	none
example with obvious corrections	none
Patch under test	none
Revised patch	none

Description Christian Zoller

2010-06-17 12:26:47 EDT

Build Identifier: 20100218-1602

There is no compiler error, when you call the constructor of a member class of an inaccessible enclosing class. This violates JLS § 6.6.1, which says that "A member (class, interface, field, or method) of a reference (class, interface, or array) type or a constructor of a class type is accessible only if the type is accessible [...]"

Reproducible: Always

Steps to Reproduce:
1. Write a package-private class A with a public member class M.
2. Write public class B in the same package, that has a public method m() with return type A.
3. Write a class C in another package that calls the constructor of M at the return value of B.m()

Comment 1 Christian Zoller

2010-06-17 12:33:24 EDT

Created attachment 172139 [details]
Example code

Comment 2 Olivier Thomann

2010-06-17 12:36:32 EDT

Potential 3.6.1 candidate depending on the risk of the fix.

Comment 3 Christian Zoller

2010-06-17 12:37:00 EDT

Comment on attachment 172139 [details]
Example code

> B.m().new M();

This line should produce a compiler error according to JLS § 6.6.1, but does nut.

=> http://java.sun.com/docs/books/jls/third_edition/html/names.html#6.6.1

Comment 4 Stephan Herrmann

2010-06-18 08:17:44 EDT

Created attachment 172209 [details]
example with obvious corrections

The same example code with two tiny obvious corrections:
- return type of m() must be A, not B
- added missing import in C

Interestingly, javac (1.6.0_18) gives a pretty strange error:

p1/C.java:6: package p0.A does not exist
        B.m().new M();
                  ^
1 error

I'm sure the JDT can do better :)

Comment 5 Christian Zoller

2010-06-18 08:23:43 EDT

> The same example code with two tiny obvious corrections:
> - return type of m() must be A, not B
> - added missing import in C

Thank you. I was a bit in a hurry when I wrote that. Sorry.

Comment 6 Srikanth Sankaran

2010-06-22 00:25:22 EDT

Reproduced on HEAD. See that for method invocations and
field references under similar conditions, we do issue the
correct error. The problem seems to be specific to 
constructors.

Comment 7 Srikanth Sankaran

2010-06-22 01:50:41 EDT

Also broken is:

public class B {
    public static A m() {
        return new A();
    }
    private static class A {
        public class M {
            public M() {}
        }
}
}

class C {
    public static void main(String[] args) {
        B.m().new M();  // no error here 
    }
}

Comment 8 Srikanth Sankaran

2010-06-22 02:33:21 EDT

Created attachment 172386 [details]
Patch under test

Comment 9 Srikanth Sankaran

2010-06-22 04:44:05 EDT

Created attachment 172392 [details]
Revised patch

Earlier patch had a problem, like this one better.

Comment 10 Jay Arthanareeswaran

2010-06-23 02:46:53 EDT

Patch looks good to me.

Comment 11 Srikanth Sankaran

2010-06-23 02:58:30 EDT

Fixed an unneeded set of parenthesis pointed out by
Jay and released patch in HEAD for 3.7 M1

Comment 12 Ayushman Jain

2010-08-03 08:09:06 EDT

Verified for 3.7M1 using build I20100802-1800.

Note that the quick fix given here is "change visibility of m() to public", which is not correct. It should instead offer changing visibility of A to public. Raised bug 321582 for that.