[PATCH 3 of 4] largefiles: use a context manager to control the progress bar lifetime

[Matt Harbison]

On Sat, 01 Sep 2018 02:05:32 -0400, Matt Harbison <mharbison72 at gmail.com>  
wrote:

> # HG changeset patch
> # User Matt Harbison <matt_harbison at yahoo.com>
> # Date 1535216964 14400
> #      Sat Aug 25 13:09:24 2018 -0400
> # Node ID 9a5c52a1933072c6d88ba33d64ccc14f24472115
> # Parent  f01ec535806db02e65db9845d80914de7663a1bd
> largefiles: use a context manager to control the progress bar lifetime
>
> diff --git a/hgext/largefiles/basestore.py  
> b/hgext/largefiles/basestore.py
> --- a/hgext/largefiles/basestore.py
> +++ b/hgext/largefiles/basestore.py
> @@ -62,25 +62,24 @@ class basestore(object):
>         at = 0
>          available = self.exists(set(hash for (_filename, hash) in  
> files))
> -        progress = ui.makeprogress(_('getting largefiles'),  
> unit=_('files'),
> -                                   total=len(files))
> -        for filename, hash in files:
> -            progress.update(at)
> -            at += 1
> -            ui.note(_('getting %s:%s\n') % (filename, hash))
> +        with ui.makeprogress(_('getting largefiles'), unit=_('files'),
> +                             total=len(files)) as progress:
> +            for filename, hash in files:
> +                progress.update(at)
> +                at += 1
> +                ui.note(_('getting %s:%s\n') % (filename, hash))

I see this sort of manual tracking of the progress in several places  
(instead of just calling increment()).  The best I could surmise is that  
this is trying to show the progressbar immediately, but only if there's  
something to iterate over (so it doesn't show 0/0).  Does it seem  
reasonable for update(0) to be called when entering the context manager if  
a total is set and it's not 0?  That way, most of these loops could just  
increment at the bottom.

This probably dovetails with Martin's question a few weeks ago about  
starting at 0/X vs 1/X, but I couldn't find that again to see how it was  
decided.