Ken Takata wrote:
> 2016/8/1 Mon 0:29:26 UTC+9 Bram Moolenaar wrote:
> > Ken Takata wrote:
> >
> > > 2016/7/31 Sun 4:17:46 UTC+9 Bram Moolenaar wrote:
> > > > Ken Takata wrote:
> > > >
> > > > > 2016/7/30 Sat 5:38:42 UTC+9 Bram Moolenaar wrote:
> > > > > > Patch 7.4.2120
> > > > > > Problem: User defined functions can't be a closure.
> > > > > > Solution: Add the "closure" argument. Allow using :unlet on a
> > > > > > bound
> > > > > > variable. (Yasuhiro Matsumoto, Ken Takata)
> > > > > > Files: runtime/doc/eval.txt, src/testdir/test_lambda.vim,
> > > > > > src/userfunc.c,
> > > > > > src/eval.c src/proto/userfunc.pro
> > > > >
> > > > > I had a report that this patch doesn't work as expected:
> > > > >
> > > > > function! Foo()
> > > > > let x = 0
> > > > > function! Bar() closure
> > > > > let x += 1
> > > > > return x
> > > > > endfunction
> > > > > return function('Bar')
> > > > > endfunction
> > > > >
> > > > > let Count = Foo()
> > > > > echo Count() " => 1
> > > > > echo Count() " => 2
> > > > > echo Count() " => 3
> > > > >
> > > > > let Count2 = Foo()
> > > > > echo Count() " => 1 (Should be 4)
> > >
> > > I found another problem. The following causes an error:
> > >
> > > function! Foo()
> > > let x = 0
> > > function! Bar() closure
> > > let x += 1
> > > return x
> > > endfunction
> > > return function('Bar')
> > > endfunction
> > >
> > > let Count = Foo()
> > > call test_garbagecollect_now()
> > > echo Count() " Cannot access x
> > >
> > > Reference counting was wrong. The following patch fixes the problem:
> > > https://bitbucket.org/k_takata/vim-ktakata-mq/src/7685fd93bf6a1ea0079d7c7da537dc062a67bc9f/fix-closure-refcount.patch?at=default
> >
> > I had trouble reproducing this problem. Looks like Foo() needs to be
> > called twice. But then your patch doesn't fix it...
>
> Thank you for fixing this. BTW, refcount seems wrong when using dict function
> with closure. E.g.:
>
> let d = {}
> function! d.Bar() closure
> ...
>
> The refcount becomes 2 instead of 1. I think this should fix the problem:
>
> --- a/src/userfunc.c
> +++ b/src/userfunc.c
> @@ -2326,7 +2326,8 @@ ex_function(exarg_T *eap)
> fp->uf_lines = newlines;
> if ((flags & FC_CLOSURE) != 0)
> {
> - ++fp->uf_refcount;
> + if (fudi.fd_dict == NULL)
> + ++fp->uf_refcount;
> if (register_closure(fp) == FAIL)
> goto erret;
> }
>
>
> > While trying to write a test I also noticed memory access errors when
> > using :delfunction.
>
> I will look at this.
> Maybe uf_calls should be incremented in register_closure()?
I have started looking into this and found several related problems.
Not resetting uf_scoped was the main thing, fixed in 7.4.2136.
I can't really make a patch that fixes part of the problem, because the
tests would break or memory leaks appear.
I also found several existing problems with function reference counts.
They went unnoticed because until now it only mattered for numbered
functions and lambdas.
I'll try to get my change in a working state, perhaps with some
remaining leaks to fix.
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/// Bram Moolenaar -- [email protected] -- http://www.Moolenaar.net \\\
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