From 3756e3c8350e942e5765df06dc24be712d2e3d7a Mon Sep 17 00:00:00 2001
From: Kim Alvefur <zash@zash.se>
Date: Wed, 21 Jul 2021 21:22:17 +0200
Subject: util.pubsub: Handle absence of node data interface

This is in preparation for fixing the behavior of 'persist_items', which
was misunderstood at some point. In mod_pep it toggles between
persistent storage and in-memory storage, while the correct behavior
would be to toggle whether published items are stored at all or
forgotten after being broadcast.
---
 util/pubsub.lua | 49 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/util/pubsub.lua b/util/pubsub.lua
index 98399dae..54b3ec4a 100644
--- a/util/pubsub.lua
+++ b/util/pubsub.lua
@@ -565,15 +565,13 @@ function service:publish(node, actor, id, item, requested_config) --> ok, err
 		return nil, "invalid-item";
 	end
 	local node_data = self.data[node];
-	if not node_data then
-		-- FIXME how is this possible?  #1657
-		return nil, "internal-server-error";
-	end
-	local ok = node_data:set(id, item);
-	if not ok then
-		return nil, "internal-server-error";
+	if node_data then
+		local ok = node_data:set(id, item);
+		if not ok then
+			return nil, "internal-server-error";
+		end
+		if type(ok) == "string" then id = ok; end
 	end
-	if type(ok) == "string" then id = ok; end
 	local event_data = { service = self, node = node, actor = actor, id = id, item = item };
 	self.events.fire_event("item-published/"..node, event_data);
 	self.events.fire_event("item-published", event_data);
@@ -593,12 +591,17 @@ function service:retract(node, actor, id, retract) --> ok, err
 	end
 	--
 	local node_obj = self.nodes[node];
-	if (not node_obj) or (not self.data[node]:get(id)) then
+	if not node_obj then
 		return false, "item-not-found";
 	end
-	local ok = self.data[node]:set(id, nil);
-	if not ok then
-		return nil, "internal-server-error";
+	if self.data[node] then
+		if not self.data[node]:get(id) then
+			return false, "item-not-found";
+		end
+		local ok = self.data[node]:set(id, nil);
+		if not ok then
+			return nil, "internal-server-error";
+		end
 	end
 	self.events.fire_event("item-retracted", { service = self, node = node, actor = actor, id = id });
 	if retract then
@@ -617,10 +620,12 @@ function service:purge(node, actor, notify) --> ok, err
 	if not node_obj then
 		return false, "item-not-found";
 	end
-	if self.data[node] and self.data[node].clear then
-		self.data[node]:clear()
-	else
-		self.data[node] = self.config.itemstore(self.nodes[node].config, node);
+	if self.data[node] then
+		if self.data[node].clear then
+			self.data[node]:clear()
+		else
+			self.data[node] = self.config.itemstore(self.nodes[node].config, node);
+		end
 	end
 	self.events.fire_event("node-purged", { service = self, node = node, actor = actor });
 	if notify then
@@ -643,6 +648,9 @@ function service:get_items(node, actor, ids) --> (true, { id, [id] = node }) or
 		ids = { ids };
 	end
 	local data = {};
+	if not self.data[node] then
+		return true, data;
+	end
 	if ids then
 		for _, key in ipairs(ids) do
 			local value = self.data[node]:get(key);
@@ -672,6 +680,11 @@ function service:get_last_item(node, actor) --> (true, id, node) or (false, err)
 		return false, "item-not-found";
 	end
 
+	if not self.data[node] then
+		-- FIXME Should this be a success or failure?
+		return true, nil;
+	end
+
 	-- Returns success, id, item
 	return true, self.data[node]:head();
 end
@@ -805,7 +818,9 @@ function service:set_node_config(node, actor, new_config) --> ok, err
 	if old_config["persist_items"] ~= node_obj.config["persist_items"] then
 		self.data[node] = self.config.itemstore(self.nodes[node].config, node);
 	elseif old_config["max_items"] ~= node_obj.config["max_items"] then
-		self.data[node]:resize(self.nodes[node].config["max_items"]);
+		if self.data[node] then
+			self.data[node]:resize(self.nodes[node].config["max_items"]);
+		end
 	end
 
 	return true;
-- 
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