Fixed multi-nested recipe serving amount calculation (fixes #1806)

changelog/67_UNRELEASED_xxxx-xx-xx.md

@@ -19,6 +19,7 @@
 - Fixed that consuming recipes was possible when not all ingredients were in-stock (and this potentially consumed some of the in-stock ingredients; not matching the message "nothing removed")
 - Fixed that the price of the "Produces product"-product, which is added to stock on consuming a recipe, was wrong (was the recipe total costs multiplied by the serving amount instead of only the recipe total costs)
 - Fixed that calories of recipe ingredients were displayed with an indefinite number of decimal places
+- Fixed that ingredient amounts were wrong for multi-nested (> 2 levels) recipes, when the included recipe used an serving amount other than 1
 
 ### Meal plan
 

migrations/0174.sql

@@ -0,0 +1,26 @@
+DROP VIEW recipes_nestings_resolved;
+CREATE VIEW recipes_nestings_resolved
+AS
+WITH RECURSIVE r1(recipe_id, includes_recipe_id, includes_servings, level)
+AS (
+	SELECT
+		id AS recipe_id,
+		id AS includes_recipe_id,
+		1 AS includes_servings,
+		0 AS level
+	FROM recipes
+
+	UNION ALL
+
+	SELECT
+		rn.recipe_id,
+		r1.includes_recipe_id,
+		CASE WHEN r1.level = 0 THEN rn.servings ELSE (SELECT servings FROM recipes_nestings WHERE recipe_id = r1.recipe_id AND includes_recipe_id = r1.includes_recipe_id) END AS includes_servings,
+		r1.level + 1 AS level
+	FROM recipes_nestings rn, r1 r1
+	WHERE rn.includes_recipe_id = r1.recipe_id
+)
+SELECT
+	*,
+	1 AS id -- Dummy, LessQL needs an id column
+FROM r1;