difftool: hack around -Wzero-length-format warning

Building with "gcc -Wall" will complain that the format in:

warning("")

is empty. Which is true, but the warning is over-eager. We
are calling the function for its side effect of printing
"warning:", even with an empty string.

Our DEVELOPER Makefile knob disables the warning, but not
everybody uses it. Let's silence the warning in the code so
that nobody reports it or tries to "fix" it.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 42ad9e804aa65ee6397a58ea853bb6510fd71918..b5e85ab0794fc08941cfdb87c4a8c2e62447e199 100644 (file)
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -567,7 +567,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
                                warning(_("both files modified: '%s' and '%s'."),
                                        wtdir.buf, rdir.buf);
                                warning(_("working tree file has been left."));
-                               warning("");
+                               warning("%s", "");
                                err = 1;
                        } else if (unlink(wtdir.buf) ||
                                   copy_file(wtdir.buf, rdir.buf, st.st_mode))