cli: Teach param.reset -j to output param.show

bin/varnishd/mgt/mgt_param.c

@@ -713,7 +713,7 @@ mcf_wash_param(struct cli *cli, struct parspec *pp, enum mcf_which_e which,
 static struct cli_proto cli_params[] = {
 	{ CLICMD_PARAM_SHOW,	"", mcf_param_show, mcf_param_show_json },
 	{ CLICMD_PARAM_SET,	"", mcf_param_set, mcf_param_set_json },
-	{ CLICMD_PARAM_RESET,	"", mcf_param_reset },
+	{ CLICMD_PARAM_RESET,	"", mcf_param_reset, mcf_param_set_json },
 	{ NULL }
 };
 

bin/varnishtest/tests/c00054.vtc

@@ -10,6 +10,7 @@ varnish v1 -cliok "param.show vsl_mask"
 
 varnish v1 -cliexpect {"value": "none"} "param.set -j feature none"
 varnish v1 -cliexpect {"value": "all"} "param.set -j vsl_mask all"
+varnish v1 -cliexpect {"value": "all(,-\w+)+"} "param.reset -j vsl_mask"
 
 varnish v1 -clierr 106 "param.set vsl_mask FooBar"
 varnish v1 -clierr 106 "param.set vsl_mask -FooBar"

include/tbl/cli_cmds.h

@@ -172,9 +172,11 @@ CLI_CMD(VCL_LABEL,
 
 CLI_CMD(PARAM_RESET,
 	"param.reset",
-	"param.reset <param>",
+	"param.reset [-j] <param>",
 	"Reset parameter to default value.",
-	"",
+	"  The JSON output is the same as ``param.show -j <param>`` and"
+	" contains the updated value as it would be represented by a"
+	" subsequent execution of ``param.show``.\n\n",
 	1,1
 )