merge-options.txt: clarify meaning of various ff-related options

diff --git a/range-diff.c b/range-diff.c
index 767af8c5bb5617016ba2c341334c05696fdcbcc1..48b0e1b4ce0ff69b9c7a430174db25b1ca6494f8 100644 (file)
--- a/range-diff.c
+++ b/range-diff.c
@@ -460,7 +460,11 @@ int show_range_diff(const char *range1, const char *range2,
                struct diff_options opts;
                struct strbuf indent = STRBUF_INIT;
 
-               memcpy(&opts, diffopt, sizeof(opts));
+               if (diffopt)
+                       memcpy(&opts, diffopt, sizeof(opts));
+               else
+                       diff_setup(&opts);
+
                if (!opts.output_format)
                        opts.output_format = DIFF_FORMAT_PATCH;
                opts.flags.suppress_diff_headers = 1;