Fix an issue where null values were causing an error in automation loops (#14083)

* fixes an issue where nulls weren't being handled correctly in loops

* remove log

* update recursive gate to be more specific

* use lodash for object check

packages/server/src/automations/loopUtils.ts

@@ -1,4 +1,5 @@
 import * as automationUtils from "./automationUtils"
+import { isPlainObject } from "lodash"
 
 type ObjValue = {
   [key: string]: string | ObjValue
@@ -18,6 +19,10 @@ function replaceBindingsRecursive(
   value: string | ObjValue,
   loopStepNumber: number
 ) {
+  if (value === null || value === undefined) {
+    return value
+  }
+
   if (typeof value === "object") {
     for (const [innerKey, innerValue] of Object.entries(value)) {
       if (typeof innerValue === "string") {
@@ -25,7 +30,11 @@ function replaceBindingsRecursive(
           innerValue,
           `steps.${loopStepNumber}`
         )
-      } else if (typeof innerValue === "object") {
+      } else if (
+        innerValue &&
+        isPlainObject(innerValue) &&
+        Object.keys(innerValue).length > 0
+      ) {
         value[innerKey] = replaceBindingsRecursive(innerValue, loopStepNumber)
       }
     }

packages/server/src/automations/tests/loop.spec.ts

@@ -4,6 +4,7 @@ import { loopAutomation } from "../../tests/utilities/structures"
 import { context } from "@budibase/backend-core"
 import * as setup from "./utilities"
 import { Table } from "@budibase/types"
+import * as loopUtils from "../loopUtils"
 import { LoopInput, LoopStepType } from "../../definitions/automations"
 
 describe("Attempt to run a basic loop automation", () => {
@@ -51,4 +52,98 @@ describe("Attempt to run a basic loop automation", () => {
     })
     expect(resp.steps[2].outputs.iterations).toBe(1)
   })
+
+  describe("replaceFakeBindings", () => {
+    it("should replace loop bindings in nested objects", () => {
+      const originalStepInput = {
+        schema: {
+          name: {
+            type: "string",
+            constraints: {
+              type: "string",
+              length: { maximum: null },
+              presence: false,
+            },
+            name: "name",
+            display: { type: "Text" },
+          },
+        },
+        row: {
+          tableId: "ta_aaad4296e9f74b12b1b90ef7a84afcad",
+          name: "{{ loop.currentItem.pokemon }}",
+        },
+      }
+
+      const loopStepNumber = 3
+
+      const result = loopUtils.replaceFakeBindings(
+        originalStepInput,
+        loopStepNumber
+      )
+
+      expect(result).toEqual({
+        schema: {
+          name: {
+            type: "string",
+            constraints: {
+              type: "string",
+              length: { maximum: null },
+              presence: false,
+            },
+            name: "name",
+            display: { type: "Text" },
+          },
+        },
+        row: {
+          tableId: "ta_aaad4296e9f74b12b1b90ef7a84afcad",
+          name: "{{ steps.3.currentItem.pokemon }}",
+        },
+      })
+    })
+
+    it("should handle null values in nested objects", () => {
+      const originalStepInput = {
+        nullValue: null,
+        nestedNull: {
+          someKey: null,
+        },
+        validValue: "{{ loop.someValue }}",
+      }
+
+      const loopStepNumber = 2
+
+      const result = loopUtils.replaceFakeBindings(
+        originalStepInput,
+        loopStepNumber
+      )
+
+      expect(result).toEqual({
+        nullValue: null,
+        nestedNull: {
+          someKey: null,
+        },
+        validValue: "{{ steps.2.someValue }}",
+      })
+    })
+
+    it("should handle empty objects and arrays", () => {
+      const originalStepInput = {
+        emptyObject: {},
+        emptyArray: [],
+        nestedEmpty: {
+          emptyObj: {},
+          emptyArr: [],
+        },
+      }
+
+      const loopStepNumber = 1
+
+      const result = loopUtils.replaceFakeBindings(
+        originalStepInput,
+        loopStepNumber
+      )
+
+      expect(result).toEqual(originalStepInput)
+    })
+  })
 })