Re: [PATCH v4 5/8] status: print per-file porcelain v2 status data

On Fri, Aug 05, 2016 at 02:09:48PM -0700, Junio C Hamano wrote:

On Fri, Aug 5, 2016 at 2:02 PM, Jeff King [off-list ref] wrote:

quoted

On Tue, Aug 02, 2016 at 10:12:14AM -0400, Jeff Hostetler wrote:

quoted

+     switch (d->stagemask) {
+     case 1: key = "DD"; break; /* both deleted */
+ ...
+     case 7: key = "UU"; break; /* both modified */
+     }
[...]
+     fprintf(s->fp, "%c %s %s %06o %06o %06o %06o %s %s %s %s%c",
+                     unmerged_prefix, key, submodule_token,

Coverity complains that "key" can be uninitialized here. I think it's
wrong, and just doesn't know that d->stagemask is constrained to 1-7.

But perhaps it is worth adding a:

  default:
        die("BUG: unhandled unmerged status %x", d->stagemask);

to the end of the switch. That would shut up Coverity, and give us a
better indication if our constraint is violated.

This is pure curiosity but I wonder if Coverity shuts up if we
instead switched on (d->stagemask & 07). Your "default: BUG"
suggestion is what we should use as a real fix, of course.

I suspect yes. It's pretty clever about analyzing the flow and placing
constraints on values (though in this case "& 07" includes "0", which is
not handled in the switch).

Unfortunately it is hard for me to test a one-off, as running it locally
is a complete pain. Stefan set it up long ago to pull "pu" and email out
the results from their central servers, so I just scan those emails for
things that look like real issues.

-Peff