From: Jeff King Date: Thu, 21 Mar 2013 11:05:28 +0000 (-0400) Subject: wt-status: fix possible use of uninitialized variable X-Git-Tag: v1.8.2.1~50 X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/b8527d5fa61f4401c38e5992b154d7a323aacbf0 wt-status: fix possible use of uninitialized variable In wt_status_print_change_data, we accept a change_type flag that is meant to be either WT_STATUS_UPDATED or WT_STATUS_CHANGED. We then switch() on this value to set the local variable "status" for each case, but do not provide a fallback "default" label to the switch statement. As a result, the compiler realizes that "status" might be unset, and complains with a warning. To silence this warning, we use the "int status = status" trick. This is correct with the current code, as all callers provide one of the two expected change_type flags. However, it's also a maintenance trap, as there is nothing to prevent future callers from passing another flag, nor to document this assumption. Instead of using the "x = x" hack, let's handle the default case in the switch() statement with a die("BUG"). That tells the compiler and any readers of the code exactly what the function's input assumptions are. We could also convert the flag to an enum, which would provide a compile-time check on the function input. However, since these flags are part of a larger enum, that would make the code unnecessarily complex (we would have to make a new enum with just the two flags, and then convert it to the old enum for passing to sub-functions). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- diff --git a/wt-status.c b/wt-status.c index ef405d03d9..7555817786 100644 --- a/wt-status.c +++ b/wt-status.c @@ -264,7 +264,7 @@ static void wt_status_print_change_data(struct wt_status *s, { struct wt_status_change_data *d = it->util; const char *c = color(change_type, s); - int status = status; + int status; char *one_name; char *two_name; const char *one, *two; @@ -292,6 +292,9 @@ static void wt_status_print_change_data(struct wt_status *s, } status = d->worktree_status; break; + default: + die("BUG: unhandled change_type %d in wt_status_print_change_data", + change_type); } one = quote_path(one_name, -1, &onebuf, s->prefix);