Require optional linking error

[Paul Sandoz]

Hi,

If i have the following modules:

module x at 1.0 {
  requires y at 2.0;
}
module y at 2.0 {
}
module z at 1.0 {
  requires optional y at 1.0;
  requires x;
}

and javac processes module z first, then the resolver passes and module z at 1.0 will get linked to y at 2.0:

     [exec]   context +y
     [exec]     module y at 2.0
     [exec]       view y at 2.0
     [exec]     local  [y at 2.0]
     [exec]     remote [+jdk.auth+jdk.base+jdk.desktop+jdk.jndi+jdk.prefs+jdk.tls+sun.charsets+sun.localedata+sun.resources]
...
     [exec]   context +z
     [exec]     module z at 1.0
     [exec]       view z at 1.0
     [exec]     local  [z at 1.0]
     [exec]     remote [+jdk.auth+jdk.base+jdk.desktop+jdk.jndi+jdk.prefs+jdk.tls+sun.charsets+sun.localedata+sun.resources, +y, +x]
...
     [exec]   context +x
     [exec]     module x at 1.0
     [exec]       view x at 1.0
     [exec]     local  [x at 1.0]
     [exec]     remote [+jdk.auth+jdk.base+jdk.desktop+jdk.jndi+jdk.prefs+jdk.tls+sun.charsets+sun.localedata+sun.resources, +y]

This is similar to the permits issues that i previously highlighted.

It's easy to catch this error (and the one for permits) if optional dependency resolution is augmented on to result of the mandatory dependency resolution.

Paul.