describe: when failing, tell the user about options that work

diff --git a/builtin-diff.c b/builtin-diff.c
index dddcf697d7447b11d618ac5983516fd1789b0d39..ffcdd055ca0b9b30bec2ce1f22e348ec15d58c81 100644 (file)
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -70,7 +70,7 @@ static int builtin_diff_b_f(struct rev_info *revs,
                usage(builtin_diff_usage);
 
        if (lstat(path, &st))
-               die("'%s': %s", path, strerror(errno));
+               die_errno("failed to stat '%s'", path);
        if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
                die("'%s': not a regular file or symlink", path);
 
@@ -218,6 +218,8 @@ static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv
                        revs->max_count = 3;
                else if (!strcmp(argv[1], "-q"))
                        options |= DIFF_SILENT_ON_REMOVED;
+               else if (!strcmp(argv[1], "-h"))
+                       usage(builtin_diff_usage);
                else
                        return error("invalid option: %s", argv[1]);
                argv++; argc--;
@@ -290,8 +292,9 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
        /* Otherwise, we are doing the usual "git" diff */
        rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 
-       /* Default to let external be used */
+       /* Default to let external and textconv be used */
        DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
+       DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
 
        if (nongit)
                die("Not a git repository");
@@ -303,7 +306,6 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
        }
 
        DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
-       DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
 
        /*
         * If the user asked for our exit code then don't start a