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

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 <>
 wt-status.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/wt-status.c b/wt-status.c
index ef405d0..7555817 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;
+       default:
+               die("BUG: unhandled change_type %d in 
+                   change_type);
        one = quote_path(one_name, -1, &onebuf, s->prefix);

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