[Sugar-devel] [PATCH] Avoid popping an empty list in the

[Michael Stone]

> On Sun, May 23, 2010 at 02:50:16PM -0400, Michael Stone wrote:
> > When you run Sugar with no activities installed,
> > UpdateModel._bundles_to_check is empty. Attempting to unconditionally
> > pop this list results in an IndexError.  Instead, the updater should
> > stop trying to update bundles when it determines that it has no more
> > bundles to check.
> > 
> > Signed-off-by: Michael Stone <michael at laptop.org>
> 
> It will work where it is, but the check could go another two lines
> higher up, or even in check_updates.
> 
> It's also odd that you're returning False and the function otherwise
> returns None.  gobject.idle_add is specified as removing the function
> from the main loop when False is returned, but I've tested and it is
> doing so with a None return as well.
> 
> The patch below (on top of your two patches) implements what I mean:
> 
> diff --git a/main/extensions/cpsection/updater/model.py b/main/extensions/cpsection/updater/model.py
> index 5bb8cf4..9bf0330 100755
> --- a/main/extensions/cpsection/updater/model.py
> +++ b/main/extensions/cpsection/updater/model.py
> @@ -64,14 +64,13 @@ class UpdateModel(gobject.GObject):
>      def check_updates(self):
>          self.updates = []
>          self._bundles_to_check = list(bundleregistry.get_registry())
> -        self._check_next_update()
> +        if len(self._bundles_to_check) > 0:
> +            self._check_next_update()
>  
>      def _check_next_update(self):
>          total = len(bundleregistry.get_registry())
>          current = total - len(self._bundles_to_check)
>  
> -        if len(self._bundles_to_check) == 0:
> -            return False
>          bundle = self._bundles_to_check.pop()
>          self.emit('progress', UpdateModel.ACTION_CHECKING, bundle.get_name(),
>                    current, total)

Good suggestion.

Michael