config: Improve "Unknown setting" error with more details and suggestions

List the autoprefixed setting names that were attempted. Also try to give
suggestions for corrected setting names with named list filters.

diff --git a/src/config/config-parser.c b/src/config/config-parser.c
index b12fd1a94b8ba796d3ffa120e2e7855fc5c5a490..b2883538aedcd500b2cd31b11f22f5968318f7e6 100644 (file)
--- a/src/config/config-parser.c
+++ b/src/config/config-parser.c
@@ -871,6 +871,69 @@ config_key_can_autoprefix(struct config_parser_context *ctx, const char *key)
        return def->type != SET_FILTER_NAME;
 }
 
+static void
+config_set_unknown_key_error(struct config_parser_context *ctx, const char *key)
+{
+       string_t *errstr = t_str_new(128);
+       str_printfa(errstr, "Unknown setting: %s", key);
+
+       const char *filter_name =
+               ctx->cur_section->filter_parser->filter.filter_name;
+       if (filter_name == NULL) {
+               ctx->error = p_strdup(ctx->pool, str_c(errstr));
+               return;
+       }
+       const char *filter_name_key = t_strcut(filter_name, '/');
+       str_printfa(errstr, " (%s_%s", filter_name_key, key);
+       if (ctx->cur_section->filter_parser->filter.filter_name_array) {
+               str_printfa(errstr, " or %s_%s",
+                           t_str_replace(filter_name, '/', '_'), key);
+       }
+       str_append(errstr, " not found either.");
+       if (!ctx->cur_section->filter_parser->filter.filter_name_array) {
+               str_append_c(errstr, ')');
+               ctx->error = p_strdup(ctx->pool, str_c(errstr));
+               return;
+       }
+
+       /* Perhaps autoprefixing didn't work as expected with a named list
+          filter. For example passdb static2 { password } - try to find
+          passdb_*_password and suggest using that. */
+       string_t *alt_keys = t_str_new(128);
+       const char *prefix = t_strconcat(filter_name_key, "_", NULL);
+       struct hash_iterate_context *iter =
+               hash_table_iterate_init(ctx->all_keys);
+       const char *hash_key, *suffix;
+       struct config_parser_key *config_key;
+       unsigned int found_count = 0;
+       while (hash_table_iterate(iter, ctx->all_keys, &hash_key, &config_key)) {
+               if (!str_begins(hash_key, prefix, &suffix))
+                       continue;
+               /* Skip over the next element. Don't skip over multiple '_'
+                  since there are no settings where that would match. */
+               while (*suffix != '_' && *suffix != '\0')
+                       suffix++;
+               /* the rest should match the key */
+               if (suffix[0] == '_' && strcmp(suffix + 1, key) == 0) {
+                       if (str_len(alt_keys) > 0)
+                               str_append(alt_keys, ", ");
+                       str_append(alt_keys, hash_key);
+                       found_count++;
+               }
+
+       }
+       hash_table_iterate_deinit(&iter);
+       if (found_count == 0)
+               str_append_c(errstr, ')');
+       else if (found_count == 1)
+               str_printfa(errstr, " Did you mean %s?)", str_c(alt_keys));
+       else {
+               str_printfa(errstr, " Did you mean one of: %s?)",
+                           str_c(alt_keys));
+       }
+       ctx->error = p_strdup(ctx->pool, str_c(errstr));
+}
+
 static int
 config_apply_line_full(struct config_parser_context *ctx,
                       const struct config_line *line,
@@ -1011,8 +1074,7 @@ again:
        if (ret == 0) {
                if (ctx->ignore_unknown)
                        return 0;
-               ctx->error = p_strconcat(ctx->pool, "Unknown setting: ",
-                                        key, NULL);
+               config_set_unknown_key_error(ctx, key);
                return -1;
        }
        return ret < 0 ? -1 : 0;