#29: Check cache staleness whenever a tree is requested.

apis/github

@@ -198,20 +198,26 @@ Release.tree = function(self)
 end
 
 -- A class for a repository
-local __repoPriv = setmetatable({}, {mode='k'})
 local Repository = {}
 Repository.__index = Repository
 Repository.new = function(user, name, auth)
-	local r = setmetatable({user=user, name=name, auth=auth}, Repository)
-	__repoPriv[r] = {trees={}}
-	return r
+	return setmetatable({
+		user = user,
+		name = name,
+		auth = auth,
+		_treeCache = {}
+	}, Repository)
 end
 Repository.tree = function(self, sha)
 	sha = sha or "master"
-	if not __repoPriv[self].trees[sha] then
-		__repoPriv[self].trees[sha] = Tree.new(self, sha)
+	local cachedTree = _treeCache[sha]
+	local newTree = Tree.new(self, sha)
+	newTree:getContents() -- Force resolution of commit-ish
+	if cachedTree and newTree.sha == cachedTree.sha then
+		return cachedTree
 	end
-	return __repoPriv[self].trees[sha]
+	_treeCache[sha] = newTree
+	return newTree
 end
 local function releaseFromURL(url, repo)
 	local status, data = getAPI(url, repo.auth)