[aur-dev] [PATCH] Fix: FS#13189, infinite variable replacement cycle

[Loui Chang]

> > 2009/2/14 Gergely Imreh <imrehg at gmail.com>:
> >>  Bug report FS#13189 brought to light a situation when certain lines
> >> in the PKGBUILD would cause the pkgbuild.php end up in an infinite
> >> cycle.
> >>  Example is a line such as:
> >>  foo=$foo
> >>  or as in the bug report:
> >>  CXXFLAGS=$CXXFLAGS' -fpic'
> >>
> >>  In the first case, e.g. $foo would be recognized as a call for
> >> replacement for "foo", and then replaced with "$foo", then checked
> >> again for values to replace.... you can guess how well it goes...
> >>
> >>  This patch removes this situation by setting the variable value to
> >> empty (to ""), if it recognizes that there would be such a cycle. This
> >> behaviour is not exactly what bash would do, since e.g. if there are
> >> two lines in the PKGBUILD such as:
> >>  foo=something
> >>  foo=$foo
> >>  then in bash in the end foo would have a proper value ("something"),
> >> while in our case it would be empty. In my opinion this is not a
> >> problem, since generally these kind of PKGBUILDs could be considered
> >> malformed.....
> >>
> >>  The eval type parameter substitution is not changed at the moment,
> >> since even if does not give the same value as bash, it does not cause
> >> such cycle as the normal substitution.

Many thanks for the fix. This is pushed.