bug#20093: master: setting merge-generics duplicate-binding-handler @ expand time raises an error

[Andy Wingo <wingo@pobox.com>]

Hi,

This was interesting -- turned out that GOOPS imports `map' from (srfi
srfi-1), and it's also there from (guile-user).  SRFI-1 specified it via
#:replace so all is well, no warnings.  However merge-generics is itself
a generic which needs `map' to dispatch over its types (at first) and
then that recurses, leading to badness.

But, you say, I only specified the duplicates handler after loading
goops!  Well indeed, but if a module didn't specify #:duplicates, its
duplicates handling was implicitly dynamically scoped to whatever the
current default-duplicates-handlers were.  That seems bogus to me: the
module declares its imports and exports and a lack of a declaration of
#:duplicates indicates that the module is implicitly specifying the
duplicate handlers that are described in the manual.

In master I have changed the `default-duplicate-binding-handler' to
simply access the handlers for the current module, as that seems to be
the correct thing.  Let me know how it goes!  Closing as done but let's
follow up :)

Andy

On Thu 12 Mar 2015 04:17, David Pirotte <david@altosw.be> writes:

> Hello guilers,
> Hi Andy,
>
> Following our brief chat on irc, yesterday, here is he bug I was referring to:
>
> 	GNU Guile 2.1.0.322-eb3d6
>
> 	setting merge-generics duplicate-binding-handler @ expand time raises an
> 	error.
>
> a) here is a short test case:
>
> #! /bin/sh
> # -*- mode: scheme; coding: utf-8 -*-
> exec guile -e main -s $0 "$@"
> !#
>
> (eval-when (expand load eval)
>   (use-modules (oop goops))
>   (default-duplicate-binding-handler
>     '(merge-generics replace warn-override-core warn last)))
>
> (define (main args)
>   (display "hello\n"))
>
> =>
>
> david@capac:~/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler 76 $ ./hello 
> ;;; note: source file /usr/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler/./hello
> ;;;       newer than compiled /home/david/.cache/guile/ccache/2.2-LE-8-3.6/usr/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler/hello.go
> ;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
> ;;;       or pass the --no-auto-compile argument to disable.
> ;;; compiling /usr/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler/./hello
> ;;; WARNING: compilation of /usr/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler/./hello failed:
> ;;; ERROR: No applicable method for #<<generic> merge-generics (3)> in call Error while printing exception.
> hello!
>
>
> b) here is how it propagates, 'just' trying to import 2 gnome modules:
>
> #! /bin/sh
> # -*- mode: scheme; coding: utf-8 -*-
> exec guile -e main -s $0 "$@"
> !#
>
> (eval-when (expand load eval)
>   (use-modules (oop goops))
>   (default-duplicate-binding-handler
>     '(merge-generics replace warn-override-core warn last)))
>
> (use-modules (gnome-2)
>              (gnome gobject)
>              (gnome glib))
>
> (define (main args)
>   (display "hello!\n"))
>
> =>
>
> david@capac:~/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler 40 $ ./hello
> ;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
> ;;;       or pass the --no-auto-compile argument to disable.
> ;;; compiling /usr/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler/./hello
> ;;; WARNING: compilation of /usr/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler/./hello failed:
> ;;; ERROR: No applicable method for #<<generic> merge-generics (3)> in call Error while printing exception.
> Backtrace:
> In ice-9/boot-9.scm:
> 3275: 19 [try-module-autoload _ _]
> 2611: 18 [save-module-excursion #<program b6fe10 7f8a1b537984>]
> 3295: 17 [#<program b6fe10 7f8a1b537984>]
> In unknown file:
>    ?: 16 [primitive-load-path "gnome/gw/glib" #<program cb7120 7f8a1b537acc>]
> In gnome/gw/glib.scm:
>   15: 15 [#<unspecified>]
> In unknown file:
>    ?: 14 [load-extension "libgw-guile-gnome-glib" "gw_init_wrapset_gnome_glib"]
> In ice-9/boot-9.scm:
> 2999: 13 [#<variable ac1fd0 value: #<program 7f8a1b57ae68 7f8a1b539380>> # _ _ ...]
> 3275: 12 [try-module-autoload _ _]
> 2611: 11 [save-module-excursion #<program b6fc90 7f8a1b537984>]
> 3295: 10 [#<program b6fc90 7f8a1b537984>]
> In unknown file:
>    ?: 9 [primitive-load-path "gnome/gw/generics" #<program d01a60 7f8a1b537acc>]
> In gnome/gw/generics.scm:
>   35: 8 [#f]
> In ice-9/boot-9.scm:
> 3136: 7 [define-module* _ #:filename _ #:pure _ #:version _ #:duplicates ...]
> 3074: 6 [resolve-interface (gnome gobject generics) #:select ...]
> 2999: 5 [#<variable ac1fd0 value: #<program 7f8a1b57ae68 7f8a1b539380>> # _ _ ...]
> 3275: 4 [try-module-autoload _ _]
> 2611: 3 [save-module-excursion #<program b6fc30 7f8a1b537984>]
> 3295: 2 [#<program b6fc30 7f8a1b537984>]
> In unknown file:
>    ?: 1 [primitive-load-path "gnome/gobject/generics" ...]
> In gnome/gobject/generics.scm:
>  130: 0 [()]
>
> gnome/gobject/generics.scm:130:0: In procedure ():
> gnome/gobject/generics.scm:130:0: In procedure module-lookup: Unbound variable: <gobject>
> david@capac:~/alto/projects/guile-tests/2.2/goops/duplicate-binding-handler 41 $ 
>
>
> Cheers,
> David