Short: bug with virtual variables
Type: Bug
State: Done: Fixed.
From: Christian Mudra <c_mudra@informatik.uni-kl.de>
See also: b-981208-4, p-990217

Hiho,

I want to point out to a bug in the virtual inheritance, which lead to
some nasty bugs. Because I found that bug still remaining in the
3.2.5.dev25-release, I report it ...

Although I discovered the bug (in TubMud), Alfe@Tubmud worked it out to make
a minimal version, which is now following:

We have four files, [a-d].c:

a.c:
inherit "players/alfe/2virtual/b";
inherit "players/alfe/2virtual/c";

b.c:
private mixed one = "this is b::one";

c.c:
virtual inherit "players/alfe/2virtual/d";
void bar() { "players/alfe/2virtual/d"::foo(); }

d.c:
private mixed two;
void foo() { printf("output of d::two: %O\n",two); }

Now we call a->bar() and receive:
output of d::two: "this is b::one"

Something is wrong with the access to variables with virtual inheritance.
Up to now there is only a workaround possible; to make private query-functions
for all variables. In that example, the workaround would be a
  private mixed query_two() { return two; }
in d.c, and of course usage of query_two() instead of direct access of 'two'.
I'm not a C-wizard (nor C++), so I can only send an LPC-example.

I'm glad too to here, that you (and some other) are going to cleanup
and debugging Amylaar's driver. Good decision :-)

Many greetings,

  Christian alias Coogan@TubMud.

----------------------------------------------------------------------------
Christian Mudra                         Just remember what your mother
c_mudra@informatik.uni-kl.de                   always told you:
Universitaet Kaiserslautern        "When you open windows you let in bugs".