Re: [PATCH 3/3] wt-status: use "format" function attribute for status_printf

[Jeff King <peff@peff.net>]

On Tue, Jul 09, 2013 at 10:35:25PM -0700, Junio C Hamano wrote:

> > You can "fix" it with -Wno-zero-format-length, so the hassle is not
> > huge. 
> 
> Yes, or just do func(..., "%s", "") perhaps?  That also sound iffy.

I imagine that is the method intended by upstream (though who
knows...the whole warning seems kind of stupid to me; it is clear that
printf("") is a no-op, but it is obviously not clear that arbitrary
functions using __attribute__(format) are).

The patch to do it is below, but I actually think an explicit blank-line
function like:

  status_print_empty_line(s, color);

would be more obvious to a reader.

---
diff --git a/builtin/commit.c b/builtin/commit.c
index 6b693c1..1fe81bc 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -768,7 +768,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 				committer_ident.buf);
 
 		if (ident_shown)
-			status_printf_ln(s, GIT_COLOR_NORMAL, "");
+			status_printf_ln(s, GIT_COLOR_NORMAL, "%s", "");
 
 		saved_color_setting = s->use_color;
 		s->use_color = 0;
diff --git a/wt-status.c b/wt-status.c
index b191c65..5876032 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -178,7 +178,7 @@ static void wt_status_print_unmerged_header(struct wt_status *s)
 	} else {
 		status_printf_ln(s, c, _("  (use \"git add/rm <file>...\" as appropriate to mark resolution)"));
 	}
-	status_printf_ln(s, c, "");
+	status_printf_ln(s, c, "%s", "");
 }
 
 static void wt_status_print_cached_header(struct wt_status *s)
@@ -194,7 +194,7 @@ static void wt_status_print_cached_header(struct wt_status *s)
 		status_printf_ln(s, c, _("  (use \"git reset %s <file>...\" to unstage)"), s->reference);
 	else
 		status_printf_ln(s, c, _("  (use \"git rm --cached <file>...\" to unstage)"));
-	status_printf_ln(s, c, "");
+	status_printf_ln(s, c, "%s", "");
 }
 
 static void wt_status_print_dirty_header(struct wt_status *s,
@@ -213,7 +213,7 @@ static void wt_status_print_dirty_header(struct wt_status *s,
 	status_printf_ln(s, c, _("  (use \"git checkout -- <file>...\" to discard changes in working directory)"));
 	if (has_dirty_submodules)
 		status_printf_ln(s, c, _("  (commit or discard the untracked or modified content in submodules)"));
-	status_printf_ln(s, c, "");
+	status_printf_ln(s, c, "%s", "");
 }
 
 static void wt_status_print_other_header(struct wt_status *s,
@@ -225,12 +225,12 @@ static void wt_status_print_trailer(struct wt_status *s)
 	if (!advice_status_hints)
 		return;
 	status_printf_ln(s, c, _("  (use \"git %s <file>...\" to include in what will be committed)"), how);
-	status_printf_ln(s, c, "");
+	status_printf_ln(s, c, "%s", "");
 }
 
 static void wt_status_print_trailer(struct wt_status *s)
 {
-	status_printf_ln(s, color(WT_STATUS_HEADER, s), "");
+	status_printf_ln(s, color(WT_STATUS_HEADER, s), "%s", "");
 }
 
 #define quote_path quote_path_relative
@@ -1191,7 +1191,7 @@ void wt_status_print(struct wt_status *s)
 				on_what = _("Not currently on any branch.");
 			}
 		}
-		status_printf(s, color(WT_STATUS_HEADER, s), "");
+		status_printf(s, color(WT_STATUS_HEADER, s), "%s", "");
 		status_printf_more(s, branch_status_color, "%s", on_what);
 		status_printf_more(s, branch_color, "%s\n", branch_name);
 		if (!s->is_initial)
@@ -1204,9 +1204,9 @@ void wt_status_print(struct wt_status *s)
 	free(state.detached_from);
 
 	if (s->is_initial) {
-		status_printf_ln(s, color(WT_STATUS_HEADER, s), "");
+		status_printf_ln(s, color(WT_STATUS_HEADER, s), "%s", "");
 		status_printf_ln(s, color(WT_STATUS_HEADER, s), _("Initial commit"));
-		status_printf_ln(s, color(WT_STATUS_HEADER, s), "");
+		status_printf_ln(s, color(WT_STATUS_HEADER, s), "%s", "");
 	}
 
 	wt_status_print_updated(s);
@@ -1223,7 +1223,7 @@ void wt_status_print(struct wt_status *s)
 		if (s->show_ignored_files)
 			wt_status_print_other(s, &s->ignored, _("Ignored files"), "add -f");
 		if (advice_status_u_option && 2000 < s->untracked_in_ms) {
-			status_printf_ln(s, GIT_COLOR_NORMAL, "");
+			status_printf_ln(s, GIT_COLOR_NORMAL, "%s", "");
 			status_printf_ln(s, GIT_COLOR_NORMAL,
 					 _("It took %.2f seconds to enumerate untracked files. 'status -uno'\n"
 					   "may speed it up, but you have to be careful not to forget to add\n"