Merge pull request #255136 from Ma27/synapse-url-blacklist-type

            };

            url_preview_url_blacklist = mkOption {

              type = types.listOf types.str;

              # FIXME revert to just `listOf (attrsOf str)` after some time(tm).

              type = types.listOf (

                types.coercedTo

                  types.str

                  (const (throw ''

                    Setting `config.services.matrix-synapse.settings.url_preview_url_blacklist`

                    to a list of strings has never worked. Due to a bug, this was the type accepted

                    by the module, but in practice it broke on runtime and as a result, no URL

                    preview worked anywhere if this was set.

                    See https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#url_preview_url_blacklist

                    on how to configure it properly.

                  ''))

                  (types.attrsOf types.str));

              default = [];

              example = literalExpression ''

                [

                  { scheme = "http"; } # no http previews

                  { netloc = "www.acme.com"; path = "/foo"; } # block http(s)://www.acme.com/foo

                ]

              '';

              description = lib.mdDoc ''

                Optional list of URL matches that the URL preview spider is

                denied from accessing.