t/README: justify why "! grep foo" is sufficient

diff --git a/parse-options.c b/parse-options.c
index c2cbca25cc6bb010996063c88c9af3e7b38aad5a..62e9b1cc6831768315dd74eac30348668de22da3 100644 (file)
--- a/parse-options.c
+++ b/parse-options.c
@@ -43,8 +43,42 @@ static void fix_filename(const char *prefix, const char **file)
        *file = xstrdup(prefix_filename(prefix, strlen(prefix), *file));
 }
 
+static int opt_command_mode_error(const struct option *opt,
+                                 const struct option *all_opts,
+                                 int flags)
+{
+       const struct option *that;
+       struct strbuf message = STRBUF_INIT;
+       struct strbuf that_name = STRBUF_INIT;
+
+       /*
+        * Find the other option that was used to set the variable
+        * already, and report that this is not compatible with it.
+        */
+       for (that = all_opts; that->type != OPTION_END; that++) {
+               if (that == opt ||
+                   that->type != OPTION_CMDMODE ||
+                   that->value != opt->value ||
+                   that->defval != *(int *)opt->value)
+                       continue;
+
+               if (that->long_name)
+                       strbuf_addf(&that_name, "--%s", that->long_name);
+               else
+                       strbuf_addf(&that_name, "-%c", that->short_name);
+               strbuf_addf(&message, ": incompatible with %s", that_name.buf);
+               strbuf_release(&that_name);
+               opterror(opt, message.buf, flags);
+               strbuf_release(&message);
+               return -1;
+       }
+       return opterror(opt, ": incompatible with something else", flags);
+}
+
 static int get_value(struct parse_opt_ctx_t *p,
-                    const struct option *opt, int flags)
+                    const struct option *opt,
+                    const struct option *all_opts,
+                    int flags)
 {
        const char *s, *arg;
        const int unset = flags & OPT_UNSET;
@@ -83,6 +117,16 @@ static int get_value(struct parse_opt_ctx_t *p,
                *(int *)opt->value = unset ? 0 : opt->defval;
                return 0;
 
+       case OPTION_CMDMODE:
+               /*
+                * Giving the same mode option twice, although is unnecessary,
+                * is not a grave error, so let it pass.
+                */
+               if (*(int *)opt->value && *(int *)opt->value != opt->defval)
+                       return opt_command_mode_error(opt, all_opts, flags);
+               *(int *)opt->value = opt->defval;
+               return 0;
+
        case OPTION_SET_PTR:
                *(void **)opt->value = unset ? NULL : (void *)opt->defval;
                return 0;
@@ -143,12 +187,13 @@ static int get_value(struct parse_opt_ctx_t *p,
 
 static int parse_short_opt(struct parse_opt_ctx_t *p, const struct option *options)
 {
+       const struct option *all_opts = options;
        const struct option *numopt = NULL;
 
        for (; options->type != OPTION_END; options++) {
                if (options->short_name == *p->opt) {
                        p->opt = p->opt[1] ? p->opt + 1 : NULL;
-                       return get_value(p, options, OPT_SHORT);
+                       return get_value(p, options, all_opts, OPT_SHORT);
                }
 
                /*
@@ -177,6 +222,7 @@ static int parse_short_opt(struct parse_opt_ctx_t *p, const struct option *optio
 static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
                           const struct option *options)
 {
+       const struct option *all_opts = options;
        const char *arg_end = strchr(arg, '=');
        const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
        int abbrev_flags = 0, ambiguous_flags = 0;
@@ -253,7 +299,7 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
                                continue;
                        p->opt = rest + 1;
                }
-               return get_value(p, options, flags ^ opt_flags);
+               return get_value(p, options, all_opts, flags ^ opt_flags);
        }
 
        if (ambiguous_option)
@@ -265,18 +311,20 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
                        (abbrev_flags & OPT_UNSET) ?  "no-" : "",
                        abbrev_option->long_name);
        if (abbrev_option)
-               return get_value(p, abbrev_option, abbrev_flags);
+               return get_value(p, abbrev_option, all_opts, abbrev_flags);
        return -2;
 }
 
 static int parse_nodash_opt(struct parse_opt_ctx_t *p, const char *arg,
                            const struct option *options)
 {
+       const struct option *all_opts = options;
+
        for (; options->type != OPTION_END; options++) {
                if (!(options->flags & PARSE_OPT_NODASH))
                        continue;
                if (options->short_name == arg[0] && arg[1] == '\0')
-                       return get_value(p, options, OPT_SHORT);
+                       return get_value(p, options, all_opts, OPT_SHORT);
        }
        return -2;
 }