Fix context.mergeFilters

src/base/context.lua

@@ -137,8 +137,14 @@
 --
 
 	function context.mergeFilters(ctx, src)
-		for k,v in pairs(src.terms) do
-			ctx.terms[k] = v
+		if src.terms ~= nil then
+			for k, v in pairs(src.terms) do
+				ctx.terms[k] = table.joinunique(ctx.terms[k] or {}, src.terms[k])
+
+				if #ctx.terms[k] == 1 then
+					ctx.terms[k] = ctx.terms[k][1]
+				end
+			end
 		end
 	end
 

src/base/table.lua

@@ -581,3 +581,33 @@
 		end
 		return result
 	end
+
+--
+-- Adds the values from one array to the end of another without duplicates and
+-- returns the result.
+--
+	function table.joinunique(...)
+
+		local arg = {...}
+		local elems = { }
+		local result = { }
+
+		local function insertunique(elem)
+			if not elems[elem] then
+				table.insert(result, elem)
+				elems[elem] = true
+			end
+		end
+
+		for _,t in ipairs(arg) do
+
+			if type(t) == "table" then
+				table.foreachi(t, insertunique)
+			else
+				insertunique(t)
+			end
+
+		end
+
+		return result
+	end

tests/base/test_context.lua

@@ -73,3 +73,41 @@
 		-- detoken in extended context should result in value set in that environ.
 		test.isequal("text", ext.targetname)
 	end
+
+--
+-- mergeFilters should behave as expected for tags
+--
+
+	function suite.mergeFilters()
+
+		ctx = { terms = { tags = { "ctxtags" } } }
+		src = { terms = { tags = { "srctags" } } }
+
+		context.mergeFilters(ctx, src)
+
+		result = { terms = { tags = { "ctxtags", "srctags" } } }
+
+		test.isequal(result, ctx)
+	end
+
+	function suite.mergeFilters_keeptype()
+
+		ctx = { terms = { kind = "ConsoleApp" } }
+		src = { terms = { kind = "ConsoleApp" } }
+
+		context.mergeFilters(ctx, src)
+
+		test.isequal("string", type(ctx.terms.kind))
+	end
+
+	function suite.mergeFilters_createtable()
+
+		ctx = { terms = { tags = "ctxtags" } }
+		src = { terms = { tags = "srctags" } }
+
+		context.mergeFilters(ctx, src)
+
+		result = { terms = { tags = { "ctxtags", "srctags" } } }
+
+		test.isequal(result, ctx)
+	end