Merge pull request #653 from reduxjs/warning-stack

package.json

@@ -29,6 +29,7 @@
     "prepack": "yarn build",
     "bench": "vitest --run bench --mode production",
     "test": "node --expose-gc ./node_modules/vitest/dist/cli-wrapper.js run",
+    "test:watch": "node --expose-gc ./node_modules/vitest/dist/cli-wrapper.js watch",
     "test:cov": "vitest run --coverage",
     "type-check": "vitest --run typecheck",
     "type-check:trace": "vitest --run typecheck && tsc --noEmit -p typescript_test/tsconfig.json --generateTrace trace && npx @typescript/analyze-trace trace && rimraf trace",

src/devModeChecks/identityFunctionCheck.ts

@@ -19,11 +19,19 @@ export const runIdentityFunctionCheck = (resultFunc: AnyFunction) => {
     // Do nothing
   }
   if (isInputSameAsOutput) {
+    let stack: string | undefined = undefined
+    try {
+      throw new Error()
+    } catch (e) {
+      // eslint-disable-next-line @typescript-eslint/no-extra-semi, no-extra-semi
+      ;({ stack } = e as Error)
+    }
     console.warn(
       'The result function returned its own inputs without modification. e.g' +
         '\n`createSelector([state => state.todos], todos => todos)`' +
         '\nThis could lead to inefficient memoization and unnecessary re-renders.' +
-        '\nEnsure transformation logic is in the result function, and extraction logic is in the input selectors.'
+        '\nEnsure transformation logic is in the result function, and extraction logic is in the input selectors.',
+      { stack }
     )
   }
 }

src/devModeChecks/inputStabilityCheck.ts

@@ -31,7 +31,13 @@ export const runInputStabilityCheck = (
     createAnEmptyObject.apply(null, inputSelectorResults) ===
     createAnEmptyObject.apply(null, inputSelectorResultsCopy)
   if (!areInputSelectorResultsEqual) {
-    // do we want to log more information about the selector?
+    let stack: string | undefined = undefined
+    try {
+      throw new Error()
+    } catch (e) {
+      // eslint-disable-next-line @typescript-eslint/no-extra-semi, no-extra-semi
+      ;({ stack } = e as Error)
+    }
     console.warn(
       'An input selector returned a different result when passed same arguments.' +
         '\nThis means your output selector will likely run more frequently than intended.' +
@@ -40,7 +46,8 @@ export const runInputStabilityCheck = (
       {
         arguments: inputSelectorArgs,
         firstInputs: inputSelectorResults,
-        secondInputs: inputSelectorResultsCopy
+        secondInputs: inputSelectorResultsCopy,
+        stack
       }
     )
   }

test/identityFunctionCheck.test.ts

@@ -2,19 +2,21 @@ import { createSelector, setGlobalDevModeChecks } from 'reselect'
 import type { LocalTestContext, RootState } from './testUtils'
 import { localTest } from './testUtils'
 
-describe<LocalTestContext>('identityFunctionCheck', () => {
+describe('identityFunctionCheck', () => {
   const consoleSpy = vi.spyOn(console, 'warn').mockImplementation(() => {})
   const identityFunction = vi.fn(<T>(state: T) => state)
-  const badSelector = createSelector(
+  let badSelector = createSelector(
     [(state: RootState) => state],
     identityFunction
   )
 
   afterEach(() => {
     consoleSpy.mockClear()
     identityFunction.mockClear()
-    badSelector.clearCache()
-    badSelector.memoizedResultFunc.clearCache()
+    badSelector = createSelector(
+      [(state: RootState) => state],
+      identityFunction
+    )
   })
   afterAll(() => {
     consoleSpy.mockRestore()
@@ -39,6 +41,21 @@ describe<LocalTestContext>('identityFunctionCheck', () => {
     }
   )
 
+  localTest('includes stack with warning', ({ state }) => {
+    expect(badSelector(state)).toBe(state)
+
+    expect(identityFunction).toHaveBeenCalledTimes(2)
+
+    expect(consoleSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        'The result function returned its own inputs without modification'
+      ),
+      {
+        stack: expect.any(String)
+      }
+    )
+  })
+
   localTest('disables check if global setting is set to never', ({ state }) => {
     setGlobalDevModeChecks({ identityFunctionCheck: 'never' })
 

test/inputStabilityCheck.spec.ts

@@ -45,7 +45,8 @@ describe('inputStabilityCheck', () => {
         ]),
         secondInputs: expect.arrayContaining([
           expect.objectContaining({ a: 1, b: 2 })
-        ])
+        ]),
+        stack: expect.any(String)
       })
     )
   })