Redundant check in java.security.BasicPermission.implies()

[Tom Hawtin]

On 29/11/2013 15:46, Alex Yursha wrote:

> // make sure ap.path is longer so a.b.* doesn't imply a.b
                                                            ^.
Somebody has removed the full stop from the sentence fragment. I'll give 
you that this class API docs should be better.

>                 return (that.path.length() > this.path.length()) &&
>                     that.path.startsWith(this.path);

> As the highlighted comment states, the length comparison check is
> performed in order to prevent such cases where "a.b.*" would imply
> "a.b". But the contract for java.lang.String.startsWith() is such that
> if the prefix length is greater than the string length than that test
> will fail. So it seems like java.security.BasicPermission.implies()
> tries to duplicate the check that is performed by
> java.lang.String.startswith() out of the box.

So, suppose we had permissions with names "a.b.*" and "a.b.". These have 
paths "a.b." and "a.b." (respectively, or not). startsWith will return 
true, but the length comparison false.

So

  - the check is not redundant
  - a.b. is not implied by a.b.*
  - BasicPermission does not correctly specify behaviour of wildcards
      (should probably have a CR)

Tom