fix(gatsby): invalidate queries if page context changes between runs

packages/gatsby/src/query/__tests__/data-tracking.js

@@ -186,9 +186,10 @@ const setup = async ({ restart = isFirstRun, clearCache = false } = {}) => {
 
   if (restart) {
     await require(`../../schema`).build({})
-    await apiRunner(`createPages`)
   }
 
+  await apiRunner(`createPages`)
+
   Object.entries(pageQueries).forEach(([componentPath, query]) => {
     store.dispatch({
       type: `QUERY_EXTRACTED`,
@@ -806,7 +807,7 @@ describe(`query caching between builds`, () => {
     }, 99999)
   })
 
-  describe.skip(`Changing page context invalidates page queries`, () => {
+  describe(`Changing page context invalidates page queries`, () => {
     beforeAll(() => {
       let pageChangeCounter = 1
       let nodeChangeCounter = 1

packages/gatsby/src/redux/__tests__/__snapshots__/index.js.snap

@@ -48,6 +48,9 @@ Object {
       },
     },
   },
+  "pageContextHashes": Map {
+    "/my-sweet-new-page/" => "4cf9cfa61c013b4697445e9bb48dd436",
+  },
   "pageData": Map {},
   "pageDataStats": Map {},
   "pendingPageDataWrites": Object {

packages/gatsby/src/redux/__tests__/__snapshots__/pages.ts.snap

@@ -77,6 +77,7 @@ Map {
 exports[`Add pages allows you to add pages 1`] = `
 Object {
   "contextModified": false,
+  "pageContextHash": "99914b932bd37a50b983c5e7c90ae93b",
   "payload": Object {
     "component": "/whatever/index.js",
     "componentChunkName": "component---whatever-index-js",
@@ -117,6 +118,7 @@ Map {
 exports[`Add pages allows you to add pages with context 1`] = `
 Object {
   "contextModified": false,
+  "pageContextHash": "426ef2719c86cbc77ce9d399793dd8d4",
   "payload": Object {
     "component": "/whatever/index.js",
     "componentChunkName": "component---whatever-index-js",
@@ -161,6 +163,7 @@ Map {
 exports[`Add pages allows you to add pages with matchPath 1`] = `
 Object {
   "contextModified": false,
+  "pageContextHash": "99914b932bd37a50b983c5e7c90ae93b",
   "payload": Object {
     "component": "/whatever/index.js",
     "componentChunkName": "component---whatever-index-js",

packages/gatsby/src/redux/actions/public.js

@@ -23,6 +23,7 @@ const {
 const apiRunnerNode = require(`../../utils/api-runner-node`)
 const { trackCli } = require(`gatsby-telemetry`)
 const { getNonGatsbyCodeFrame } = require(`../../utils/stack-trace-utils`)
+import { createContentDigest } from "gatsby-core-utils"
 
 /**
  * Memoize function used to pick shadowed page components to avoid expensive I/O.
@@ -378,6 +379,10 @@ ${reservedFields.map(f => `  * "${f}"`).join(`\n`)}
     page.path = truncatedPath
   }
 
+  if (!page.context) {
+    page.context = {}
+  }
+
   const internalPage: Page = {
     internalComponentName,
     path: page.path,
@@ -387,7 +392,7 @@ ${reservedFields.map(f => `  * "${f}"`).join(`\n`)}
     isCreatedByStatefulCreatePages:
       actionOptions?.traceId === `initial-createPagesStatefully`,
     // Ensure the page has a context object
-    context: page.context || {},
+    context: page.context,
     updatedAt: Date.now(),
   }
 
@@ -396,9 +401,12 @@ ${reservedFields.map(f => `  * "${f}"`).join(`\n`)}
     internalPage.path = `/${internalPage.path}`
   }
 
-  const oldPage: Page = store.getState().pages.get(internalPage.path)
+  const oldPageContextHash = store
+    .getState()
+    .pageContextHashes.get(internalPage.path)
+  const pageContextHash = createContentDigest(page.context)
   const contextModified =
-    !!oldPage && !_.isEqual(oldPage.context, internalPage.context)
+    !!oldPageContextHash && oldPageContextHash !== pageContextHash
 
   const alternateSlashPath = page.path.endsWith(`/`)
     ? page.path.slice(0, -1)
@@ -418,6 +426,7 @@ ${reservedFields.map(f => `  * "${f}"`).join(`\n`)}
     ...actionOptions,
     type: `CREATE_PAGE`,
     contextModified,
+    pageContextHash,
     plugin,
     payload: internalPage,
   }

packages/gatsby/src/redux/index.ts

@@ -100,6 +100,7 @@ export const saveState = (): void => {
     pendingPageDataWrites: state.pendingPageDataWrites,
     staticQueriesByTemplate: state.staticQueriesByTemplate,
     queries: state.queries,
+    pageContextHashes: state.pageContextHashes,
   })
 }
 

packages/gatsby/src/redux/reducers/index.ts

@@ -28,6 +28,7 @@ import { inferenceMetadataReducer } from "./inference-metadata"
 import { staticQueriesByTemplateReducer } from "./static-queries-by-template"
 import { queriesReducer } from "./queries"
 import { visitedPagesReducer } from "./visited-page"
+import { pageContextHashesReducer } from "./page-context-hashes"
 
 /**
  * @property exports.nodesTouched Set<string>
@@ -63,4 +64,5 @@ export {
   pendingPageDataWritesReducer as pendingPageDataWrites,
   staticQueriesByTemplateReducer as staticQueriesByTemplate,
   queriesReducer as queries,
+  pageContextHashesReducer as pageContextHashes,
 }

packages/gatsby/src/redux/reducers/page-context-hashes.ts

@@ -0,0 +1,31 @@
+import {
+  IGatsbyState,
+  IDeleteCacheAction,
+  ICreatePageAction,
+  IDeletePageAction,
+} from "../types"
+
+export const pageContextHashesReducer = (
+  state: IGatsbyState["pageContextHashes"] = new Map<string, string>(),
+  action: IDeleteCacheAction | ICreatePageAction | IDeletePageAction
+): IGatsbyState["pageContextHashes"] => {
+  switch (action.type) {
+    case `DELETE_CACHE`:
+      return new Map()
+
+    case `CREATE_PAGE`: {
+      // Add page to the state with the path as key
+      state.set(action.payload.path, action.pageContextHash)
+      return state
+    }
+
+    case `DELETE_PAGE`: {
+      state.delete(action.payload.path)
+
+      return state
+    }
+
+    default:
+      return state
+  }
+}

packages/gatsby/src/redux/types.ts

@@ -277,6 +277,7 @@ export interface IGatsbyState {
   pageDataStats: Map<SystemPath, number>
   pageData: Map<Identifier, string>
   visitedPages: Map<string, Set<string>>
+  pageContextHashes: Map<string, string>
 }
 
 export interface ICachedReduxState {
@@ -291,6 +292,7 @@ export interface ICachedReduxState {
   staticQueriesByTemplate: IGatsbyState["staticQueriesByTemplate"]
   pendingPageDataWrites: IGatsbyState["pendingPageDataWrites"]
   queries: IGatsbyState["queries"]
+  pageContextHashes: IGatsbyState["pageContextHashes"]
 }
 
 export type ActionsUnion =
@@ -608,6 +610,7 @@ export interface ICreatePageAction {
   payload: IGatsbyPage
   plugin?: IGatsbyPlugin
   contextModified?: boolean
+  pageContextHash: string
 }
 
 export interface ICreateRedirectAction {