# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1688155309 -7200
# Node ID 8ec7b7d6556f72adca1427557190b6feb4605766
# Parent  4906d4990ffec6c9a494e769a34b08ec53547e97
util.cache: Keep eviction candidate if callback resized to make room

Previously either the old or the new values would be rejected, even if
the cache was resized to allow more items.

diff -r 4906d4990ffe -r 8ec7b7d6556f spec/util_cache_spec.lua
--- a/spec/util_cache_spec.lua	Fri Jun 30 18:51:03 2023 +0200
+++ b/spec/util_cache_spec.lua	Fri Jun 30 22:01:49 2023 +0200
@@ -388,5 +388,26 @@
 			c:resize(3);
 			assert.same({"v5", "v4", "v3"}, vs(c));
 		end);
+
+		it("eviction stuff", function ()
+			local c;
+			c = cache.new(4, function(_k,_v)
+				if c.size < 10 then
+					c:resize(c.size*2);
+				end
+			end)
+			for i = 1,20 do
+				c:set(i,i)
+			end
+			assert.equal(16, c.size);
+			assert.is_nil(c:get(1))
+			assert.is_nil(c:get(4))
+			assert.equal(5, c:get(5))
+			assert.equal(20, c:get(20))
+			c:resize(4)
+			assert.equal(20, c:get(20))
+			assert.equal(17, c:get(17))
+			assert.is_nil(c:get(10))
+		end)
 	end);
 end);
diff -r 4906d4990ffe -r 8ec7b7d6556f util/cache.lua
--- a/util/cache.lua	Fri Jun 30 18:51:03 2023 +0200
+++ b/util/cache.lua	Fri Jun 30 22:01:49 2023 +0200
@@ -54,12 +54,17 @@
 	if self._count == self.size then
 		local tail = self._tail;
 		local on_evict, evicted_key, evicted_value = self._on_evict, tail.key, tail.value;
-		if on_evict ~= nil and (on_evict == false or on_evict(evicted_key, evicted_value) == false) then
+
+		local do_evict = on_evict and on_evict(evicted_key, evicted_value);
+
+		if do_evict == false then
 			-- Cache is full, and we're not allowed to evict
 			return false;
+		elseif self._count == self.size then
+			-- Cache wasn't grown
+			_remove(self, tail);
+			self._data[evicted_key] = nil;
 		end
-		_remove(self, tail);
-		self._data[evicted_key] = nil;
 	end
 
 	m = { key = k, value = v, prev = nil, next = nil };