Re: Crash on empty HOME var in Windows registry

[Vincent Liard]

> I'm not sure whether is the right thing to do, though: first,
> because a null HOME or SHELL in the registry is likely an
> error; and second, because I'm not sure it makes sense for
> other environment variables to have null values on the
> registry.

As for me, I have switched to the solution of using a HOME 
environment var, anyway. And I agree on you view for the content 
of the registry entry.

> > having an empty HOME string value at this place causes emacs to
> > crash at start.
>
> In fact Emacs is not crashing, but aborting because it doesn't have a
> valid HOME value in its environment. It's a check.

At first, I get an emacs notification error "A fatal error has 
occurred! Select Abort to exit, Retry to debug, Ignore to 
continue". But when deciding to ignore, I get a Windows error 
indicating that GNU Emacs encountered a problem and ought to stop 
(approximately translated from the French error message).

The error signature given is :
AppName: emacs.exe
AppVer: 21.2.0.0
ModName: msvcrt.dll
ModVer: 7.0.2600.2180
Offset: 000360cb

> It could be fixed with the simple patch below, which forces
> environment variables coming from the registry to have non-null values
> (else they get the default value).

Apart from the opening curly brace which is on the + but not on 
the - in the changelog, I guess it would be ok for emacs and thus 
prevent the error from Windows.

Vincent

> Index: src/w32.c
> ===================================================================
> RCS file: /cvsroot/emacs/emacs/src/w32.c,v
> retrieving revision 1.113
> diff -u -2 -r1.113 w32.c
> --- src/w32.c    14 Jun 2007 15:58:13 -0000    1.113
> +++ src/w32.c    18 Jun 2007 12:07:47 -0000
> @@ -1156,5 +1156,6 @@
>         int dont_free = 0;
>
> -        if ((lpval = w32_get_resource (env_vars[i].name, &dwType)) == 
> NULL)
> +        if ((lpval = w32_get_resource (env_vars[i].name, &dwType)) == NULL
> +        || *lpval == 0)
>           {
>         lpval = env_vars[i].def_value;