fix(gatsby): fix race condition in cache lock

packages/gatsby/src/cache/cache-fs.ts

@@ -228,11 +228,7 @@ DiskStore.prototype.reset = wrapCallback(async function (): Promise<void> {
  * @private
  */
 DiskStore.prototype._lock = function _lock(filePath): Promise<void> {
-  return new Promise((resolve, reject) =>
-    innerLock(resolve, reject, filePath)
-  ).then(() => {
-    globalGatsbyCacheLock.set(filePath, Date.now())
-  })
+  return new Promise((resolve, reject) => innerLock(resolve, reject, filePath))
 }
 
 function innerLock(resolve, reject, filePath): void {
@@ -251,6 +247,8 @@ function innerLock(resolve, reject, filePath): void {
         innerLock(resolve, reject, filePath)
       }, 50)
     } else {
+      // set sync
+      globalGatsbyCacheLock.set(filePath, Date.now())
       resolve()
     }
   } catch (e) {

packages/gatsby/src/cache/json-file-store.ts

@@ -104,32 +104,40 @@ exports.read = async function (path, options): Promise<string> {
   }
 
   const externalBuffers = []
-  const data = JSON.parse(dataString, function bufferReceiver(k, value) {
-    if (value && value.type === `Buffer` && value.data) {
-      return Buffer.from(value.data)
-    } else if (
-      value &&
-      value.type === `ExternalBuffer` &&
-      typeof value.index === `number` &&
-      typeof value.size === `number`
-    ) {
-      //JSON.parse is sync so we need to return a buffer sync, we will fill the buffer later
-      const buffer = Buffer.alloc(value.size)
-      externalBuffers.push({
-        index: +value.index,
-        buffer: buffer,
-      })
-      return buffer
-    } else if (
-      value &&
-      value.type === `Infinity` &&
-      typeof value.sign === `number`
-    ) {
-      return Infinity * value.sign
-    } else {
-      return value
-    }
-  })
+  let data
+  try {
+    data = JSON.parse(dataString, function bufferReceiver(k, value) {
+      if (value && value.type === `Buffer` && value.data) {
+        return Buffer.from(value.data)
+      } else if (
+        value &&
+        value.type === `ExternalBuffer` &&
+        typeof value.index === `number` &&
+        typeof value.size === `number`
+      ) {
+        //JSON.parse is sync so we need to return a buffer sync, we will fill the buffer later
+        const buffer = Buffer.alloc(value.size)
+        externalBuffers.push({
+          index: +value.index,
+          buffer: buffer,
+        })
+        return buffer
+      } else if (
+        value &&
+        value.type === `Infinity` &&
+        typeof value.sign === `number`
+      ) {
+        return Infinity * value.sign
+      } else {
+        return value
+      }
+    })
+  } catch (e) {
+    throw new Error(
+      "json-file-store failed to JSON.parse this string: `" +
+        dataString.replace(/\n/g, `⏎`)
+    )
+  }
 
   //read external buffers
   await Promise.all(