fix(limit-count): conf with group and disable can't be configured

[soulbird]

Description

Fixes #7375

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)

[spacewander]

apisix/apisix/plugins/limit-count.lua

Lines 153 to 168 in 2f7833e

	local fields = {}
	for k in pairs(schema.properties) do
	tab_insert(fields, k)
	end
	local extra = policy_to_additional_properties[conf.policy]
	if extra then
	for k in pairs(extra.properties) do
	tab_insert(fields, k)
	end
	end
	local prev_conf = group_conf_lru(conf.group, "", group_conf, conf)
	for _, field in ipairs(fields) do
	if not core.table.deep_eq(prev_conf[field], conf[field]) then
	core.log.error("previous limit-conn group ", prev_conf.group,

We use a whitelist for the fields which need to be compared, and disable is expected not in the list?

[soulbird]

apisix/apisix/plugins/limit-count.lua

Lines 153 to 168 in 2f7833e

	local fields = {}
	for k in pairs(schema.properties) do
	tab_insert(fields, k)
	end
	local extra = policy_to_additional_properties[conf.policy]
	if extra then
	for k in pairs(extra.properties) do
	tab_insert(fields, k)
	end
	end
	local prev_conf = group_conf_lru(conf.group, "", group_conf, conf)
	for _, field in ipairs(fields) do
	if not core.table.deep_eq(prev_conf[field], conf[field]) then
	core.log.error("previous limit-conn group ", prev_conf.group,

We use a whitelist for the fields which need to be compared, and disable is expected not in the list?

Yes, it's injected in: https://github.com/apache/apisix/blob/master/apisix/plugin.lua#L139-L162

[soulbird]

The whitelist for the fields does not work as it should, because the schema may be injected into other fields, currently there are disable _meta $comment. A better approach is to move all injected fields into _meta and manually filter out this field in the whitelist. But this would introduce a break change, not sure if it's worth it. cc @spacewander