From 1dc2e495bebad68d9a5ff2b210ec29ae32bbe229 Mon Sep 17 00:00:00 2001
From: develar <develar@gmail.com>
Date: Wed, 11 Oct 2017 09:18:24 +0200
Subject: [PATCH] =?UTF-8?q?feat:=20differential=20update=20=E2=80=94=20use?=
 =?UTF-8?q?=20content=20defined=20chunking?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .idea/dictionaries/develar.xml                |   4 +
 .../Debug_differential_update_buider.xml      |   8 +
 .../Debug_differential_update_builder.xml     |   8 +
 package.json                                  |   7 +-
 packages/app-package-builder/package.json     |   3 +-
 .../src/ContentDefinedChunker.ts              |  86 +++++++++
 packages/app-package-builder/src/blockMap.ts  |  80 +++++---
 packages/app-package-builder/src/main.ts      |   3 +-
 .../builder-util-runtime/src/blockMapApi.ts   |  16 +-
 packages/electron-builder/package.json        |   2 +-
 .../electron-builder/src/targets/nsis/nsis.ts |   9 +
 packages/electron-publisher-s3/package.json   |   2 +-
 packages/electron-updater/CHANGELOG.md        |   6 +
 packages/electron-updater/package.json        |   5 +-
 .../src/differentialPackage.ts                |  75 ++++----
 yarn.lock                                     | 177 ++++++++++++------
 16 files changed, 355 insertions(+), 136 deletions(-)
 create mode 100644 .idea/runConfigurations/Debug_differential_update_buider.xml
 create mode 100644 .idea/runConfigurations/Debug_differential_update_builder.xml
 create mode 100644 packages/app-package-builder/src/ContentDefinedChunker.ts

diff --git a/.idea/dictionaries/develar.xml b/.idea/dictionaries/develar.xml
index 457c173b9af..e534df15401 100644
--- a/.idea/dictionaries/develar.xml
+++ b/.idea/dictionaries/develar.xml
@@ -44,11 +44,14 @@
       <w>checksums</w>
       <w>chipset</w>
       <w>chown</w>
+      <w>chunker</w>
+      <w>chunking</w>
       <w>circleci</w>
       <w>clcerts</w>
       <w>cleanuped</w>
       <w>cleanuper</w>
       <w>codesigning</w>
+      <w>confirmative</w>
       <w>controlfields</w>
       <w>coroutine</w>
       <w>cpus</w>
@@ -349,6 +352,7 @@
       <w>zenity</w>
       <w>zisofs</w>
       <w>zlib</w>
+      <w>zsync</w>
     </words>
   </dictionary>
 </component>
\ No newline at end of file
diff --git a/.idea/runConfigurations/Debug_differential_update_buider.xml b/.idea/runConfigurations/Debug_differential_update_buider.xml
new file mode 100644
index 00000000000..91832dfd17e
--- /dev/null
+++ b/.idea/runConfigurations/Debug_differential_update_buider.xml
@@ -0,0 +1,8 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Debug differential update buider" type="NodeJSConfigurationType" factoryName="Node.js" path-to-js-file="main.js" working-dir="$PROJECT_DIR$/packages/app-package-builder/out">
+    <envs>
+      <env name="NODE_PATH" value="$PROJECT_DIR$/packages" />
+    </envs>
+    <method />
+  </configuration>
+</component>
\ No newline at end of file
diff --git a/.idea/runConfigurations/Debug_differential_update_builder.xml b/.idea/runConfigurations/Debug_differential_update_builder.xml
new file mode 100644
index 00000000000..c4bc7763942
--- /dev/null
+++ b/.idea/runConfigurations/Debug_differential_update_builder.xml
@@ -0,0 +1,8 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Debug differential update builder" type="NodeJSConfigurationType" factoryName="Node.js" path-to-js-file="main.js" working-dir="$PROJECT_DIR$/packages/app-package-builder/out">
+    <envs>
+      <env name="NODE_PATH" value="$PROJECT_DIR$/packages" />
+    </envs>
+    <method />
+  </configuration>
+</component>
\ No newline at end of file
diff --git a/package.json b/package.json
index 5e96af0dd88..6b701c617a6 100644
--- a/package.json
+++ b/package.json
@@ -31,7 +31,7 @@
     "7zip-bin": "^2.2.4",
     "archiver": "^2.0.3",
     "async-exit-hook": "^2.0.1",
-    "aws-sdk": "^2.130.0",
+    "aws-sdk": "^2.131.0",
     "bluebird-lst": "^1.0.4",
     "chalk": "^2.1.0",
     "chromium-pickle-js": "^0.2.0",
@@ -60,6 +60,7 @@
     "normalize-package-data": "^2.4.0",
     "parse-color": "^1.0.0",
     "plist": "^2.1.0",
+    "rabin-bindings": "~1.7.3",
     "read-config-file": "1.1.1",
     "sanitize-filename": "^1.6.1",
     "semver": "^5.4.1",
@@ -67,7 +68,7 @@
     "stat-mode": "^0.2.2",
     "temp-file": "^2.0.3",
     "tunnel-agent": "^0.6.0",
-    "update-notifier": "^2.2.0",
+    "update-notifier": "^2.3.0",
     "xelement": "^1.0.16",
     "yargs": "^9.0.1"
   },
@@ -92,7 +93,7 @@
     "babel-preset-ts-node4-bluebird": "^0.1.1",
     "convert-source-map": "^1.5.0",
     "decompress-zip": "^0.3.0",
-    "depcheck": "^0.6.7",
+    "depcheck": "^0.6.8",
     "develar-typescript-json-schema": "0.17.0",
     "electron-builder-tslint-config": "^1.0.4",
     "env-paths": "^1.0.0",
diff --git a/packages/app-package-builder/package.json b/packages/app-package-builder/package.json
index c339ff86a62..193b7768707 100644
--- a/packages/app-package-builder/package.json
+++ b/packages/app-package-builder/package.json
@@ -16,7 +16,8 @@
     "int64-buffer": "^0.1.9",
     "builder-util-runtime": "^0.0.0-semantic-release",
     "builder-util": "^0.0.0-semantic-release",
-    "js-yaml": "^3.10.0"
+    "js-yaml": "^3.10.0",
+    "rabin-bindings": "~1.7.3"
   },
   "types": "./out/main.d.ts"
 }
diff --git a/packages/app-package-builder/src/ContentDefinedChunker.ts b/packages/app-package-builder/src/ContentDefinedChunker.ts
new file mode 100644
index 00000000000..1355f892d99
--- /dev/null
+++ b/packages/app-package-builder/src/ContentDefinedChunker.ts
@@ -0,0 +1,86 @@
+import { createHash } from "crypto"
+import { read } from "fs-extra-p"
+import { FileChunks } from "builder-util-runtime/out/blockMapApi"
+import { Rabin } from "rabin-bindings"
+
+export class ContentDefinedChunker {
+  async computeChunks(fd: number, start: number, end: number, name: string): Promise<FileChunks> {
+    console.log(name)
+
+    const fileSize = end - start
+    const buffer = Buffer.allocUnsafe(Math.min(4 * 1024 * 1024, fileSize))
+
+    const rabin = Rabin()
+    const avgBits = 12
+    const min = 8 * 1024
+    // see note in the nsis.ts about archive dict size
+    const max = 32 * 1024
+    rabin.configure(avgBits, min, max)
+
+    const checksums: Array<string> = []
+    const allSizes: Array<number> = []
+
+    let tailBufferData: Buffer | null = null
+    let readOffset = start
+    while (true) {
+      const actualBufferSize = Math.min(end - readOffset, buffer.length)
+      await read(fd, buffer, 0, actualBufferSize, readOffset)
+
+      const dataBuffer: Buffer = buffer.length === actualBufferSize ? buffer : buffer.slice(0, actualBufferSize)
+      const sizes: Array<number> = []
+      rabin.fingerprint([dataBuffer], sizes)
+
+      let chunkStart = 0
+      for (const size of sizes) {
+        allSizes.push(size)
+        let chunkEnd = chunkStart + size
+
+        const hash = createHash("sha256")
+        if (tailBufferData !== null) {
+          hash.update(tailBufferData)
+          // if there is the tail data (already processed by rabin data), first size includes it
+          chunkEnd -= tailBufferData.length
+          tailBufferData = null
+        }
+        hash.update(dataBuffer.slice(chunkStart, chunkEnd))
+        checksums.push(hash.digest("base64"))
+        chunkStart = chunkEnd
+      }
+
+      const tailSize = actualBufferSize - chunkStart
+      if (tailSize !== 0) {
+        if (tailBufferData !== null) {
+          throw new Error(`Internal error (${name}): tailBufferData must be null`)
+        }
+        tailBufferData = dataBuffer.slice(chunkStart, chunkStart + tailSize)
+      }
+
+      readOffset += actualBufferSize
+      if (readOffset >= end) {
+        if (tailBufferData !== null) {
+          allSizes.push(tailSize)
+          checksums.push(computeChecksum(tailBufferData))
+        }
+        break
+      }
+      else if (tailBufferData !== null) {
+        // copy data
+        tailBufferData = Buffer.from(tailBufferData)
+      }
+    }
+
+    const totalSize = allSizes.reduce((accumulator, currentValue) => accumulator + currentValue)
+    if (totalSize !== fileSize) {
+      throw new Error(`Internal error (${name}): size mismatch: expected: ${fileSize}, got: ${totalSize}`)
+    }
+
+    return {checksums, sizes: allSizes}
+  }
+}
+
+function computeChecksum(chunk: Buffer) {
+  // node-base91 doesn't make a lot of sense - 29KB vs 30KB Because for base64 string value in the yml never escaped, but node-base91 often escaped (single quotes) and it adds extra 2 symbols.
+  return createHash("sha256")
+    .update(chunk)
+    .digest("base64")
+}
diff --git a/packages/app-package-builder/src/blockMap.ts b/packages/app-package-builder/src/blockMap.ts
index 729fcf641ef..c296b65a2fd 100644
--- a/packages/app-package-builder/src/blockMap.ts
+++ b/packages/app-package-builder/src/blockMap.ts
@@ -2,12 +2,12 @@ import BluebirdPromise from "bluebird-lst"
 import { hashFile } from "builder-util"
 import { PackageFileInfo } from "builder-util-runtime"
 import { BlockMap, SIGNATURE_HEADER_SIZE } from "builder-util-runtime/out/blockMapApi"
-import { createHash } from "crypto"
-import { appendFile, read, stat } from "fs-extra-p"
+import { appendFile, stat, writeFile } from "fs-extra-p"
 import { safeDump } from "js-yaml"
 import { Archive } from "./Archive"
 import { SevenZArchiveEntry } from "./SevenZArchiveEntry"
 import { SevenZFile } from "./SevenZFile"
+import { ContentDefinedChunker } from "./ContentDefinedChunker"
 
 const deflateRaw: any = BluebirdPromise.promisify(require("zlib").deflateRaw)
 
@@ -27,6 +27,9 @@ export async function createDifferentialPackage(archiveFile: string): Promise<Pa
     sevenZFile.close()
 
     const blockMapDataString = safeDump(blockMap)
+    if (process.env.DEBUG_BLOCKMAP) {
+      await writeFile(archiveFile + ".blockMap.yml", blockMapDataString)
+    }
     const blockMapFileData = await deflateRaw(blockMapDataString, {level: 9})
     await appendFile(archiveFile, blockMapFileData)
     const packageFileInfo = await createPackageFileInfo(archiveFile)
@@ -49,25 +52,6 @@ export async function createPackageFileInfo(file: string): Promise<PackageFileIn
   }
 }
 
-async function computeBlocks(fd: number, start: number, end: number): Promise<Array<string>> {
-  const chunkSize = 64 * 1024
-  const buffer = Buffer.allocUnsafe(chunkSize)
-  const blocks = []
-
-  for (let offset = start; offset < end; offset += chunkSize) {
-    const actualChunkSize = Math.min(end - offset, chunkSize)
-    await read(fd, buffer, 0, actualChunkSize, offset)
-
-    const hash = createHash("md5")
-    hash.update(actualChunkSize === chunkSize ? buffer : buffer.slice(0, actualChunkSize))
-    // node-base91 doesn't make a lot of sense - 29KB vs 30KB Because for base64 string value in the yml never escaped, but node-base91 often escaped (single quotes) and it adds extra 2 symbols.
-    // And in any case data stored as deflated in the package.
-    blocks.push(hash.digest("base64"))
-  }
-
-  return blocks
-}
-
 class BlockMapBuilder {
   private currentFolderIndex = -1
 
@@ -129,19 +113,61 @@ export async function computeBlockMap(sevenZFile: SevenZFile): Promise<BlockMap>
     }
   }
 
+  const stats: Array<string> = []
   const blocks = await BluebirdPromise.map(files, async entry => {
-    const blocks = await computeBlocks(sevenZFile.fd, entry.dataStart, entry.dataEnd)
+    const chunker = new ContentDefinedChunker()
+    const blocks = await chunker.computeChunks(sevenZFile.fd, entry.dataStart, entry.dataEnd, entry.name)
+
+    if (process.env.DEBUG_BLOCKMAP) {
+      stats.push(getStat(blocks.sizes, entry.name))
+    }
+
     return {
       name: entry.name.replace(/\\/g, "/"),
       offset: entry.dataStart,
       size: entry.dataEnd - entry.dataStart,
-      blocks,
+      ...blocks,
+    }
+  }, {concurrency: 2})
+
+  if (process.env.DEBUG_BLOCKMAP) {
+    let duplicate = 0
+    let savedSize = 0
+    // noinspection JSMismatchedCollectionQueryUpdate
+    const checksums: Array<string> = []
+    // noinspection JSMismatchedCollectionQueryUpdate
+    const sizes: Array<number> = []
+    const index = new Map<string, number>()
+    for (const file of blocks) {
+      for (let i = 0; i < file.checksums.length; i++) {
+        const checksum = file.checksums[i]
+        const size = file.sizes[i]
+        if (index.has(checksum)) {
+          duplicate++
+          savedSize += size
+        }
+        else {
+          index.set(checksum, checksums.length)
+          checksums.push(checksum)
+          sizes.push(size)
+        }
+      }
     }
-  }, {concurrency: 4})
+
+    console.log(stats.join("\n"))
+    console.log(`duplicates: ${duplicate}, saved: ${savedSize}`)
+  }
+
   return {
-    blockSize: 64,
-    hashMethod: "md5",
-    compressionLevel: 9,
+    version: "2",
     files: blocks,
   }
+}
+
+function getStat(sizes: Array<number>, name: string) {
+  const sortedSizes = sizes.slice().sort((a, b) => a - b)
+  const middle = Math.floor(sortedSizes.length / 2)
+  const isEven = sortedSizes.length % 2 === 0
+  const median = isEven ? (sortedSizes[middle] + sortedSizes[middle - 1]) / 2 : sortedSizes[middle]
+  return `${sizes.length} chunks generated for ${name} (min: ${sortedSizes[0]}, max: ${sortedSizes[sortedSizes.length - 1]}, median: ${median})`
 }
\ No newline at end of file
diff --git a/packages/app-package-builder/src/main.ts b/packages/app-package-builder/src/main.ts
index daa9e6f4a9d..374a42ae494 100644
--- a/packages/app-package-builder/src/main.ts
+++ b/packages/app-package-builder/src/main.ts
@@ -7,8 +7,7 @@ if (process.mainModule === module) {
   require(a + "map-support").install()
 
   async function main() {
-    // const file = new SevenZFile("/Users/develar/Documents/onshape-desktop-shell/dist/Onshape-0.5.13-x64.nsis.7z")
-    const file = "/Users/develar/Documents/onshape-desktop-shell/dist/Onshape-0.5.13-x64.nsis.7z"
+    const file = "/Volumes/test/electron-builder-test/dist/nsis-web/TestApp-1.0.1-x64.nsis.7z"
     await createDifferentialPackage(file)
     // const archive = await file.read()
     // for (const entry of archive.files) {
diff --git a/packages/builder-util-runtime/src/blockMapApi.ts b/packages/builder-util-runtime/src/blockMapApi.ts
index 91a8c6438cb..91706005b43 100644
--- a/packages/builder-util-runtime/src/blockMapApi.ts
+++ b/packages/builder-util-runtime/src/blockMapApi.ts
@@ -1,20 +1,18 @@
 export const BLOCK_MAP_FILE_NAME = "_blockMap.yml"
 export const SIGNATURE_HEADER_SIZE = 12 /* signature + 2 bytes version + 4 bytes CRC */ + 20
 
-export interface BlockMap {
-  blockSize: number
-  hashMethod: "sha256" | "md5"
-
-  compressionLevel: 9 | 1
+export interface FileChunks {
+  checksums: Array<string>
+  sizes: Array<number>
+}
 
+export interface BlockMap {
+  version: "1" | "2"
   files: Array<BlockMapFile>
 }
 
-export interface BlockMapFile {
+export interface BlockMapFile extends FileChunks {
   name: string
   offset: number
   size: number
-
-  // size of block 64K, last block size `size % (64 * 1024)`
-  blocks: Array<string>
 }
\ No newline at end of file
diff --git a/packages/electron-builder/package.json b/packages/electron-builder/package.json
index 7fd91158cb4..e997906c91a 100644
--- a/packages/electron-builder/package.json
+++ b/packages/electron-builder/package.json
@@ -74,7 +74,7 @@
     "plist": "^2.1.0",
     "sanitize-filename": "^1.6.1",
     "semver": "^5.4.1",
-    "update-notifier": "^2.2.0",
+    "update-notifier": "^2.3.0",
     "yargs": "^9.0.1",
     "debug": "^3.1.0",
     "asar-integrity": "0.0.0-semantic-release",
diff --git a/packages/electron-builder/src/targets/nsis/nsis.ts b/packages/electron-builder/src/targets/nsis/nsis.ts
index 67dbea460c2..dda2e55f084 100644
--- a/packages/electron-builder/src/targets/nsis/nsis.ts
+++ b/packages/electron-builder/src/targets/nsis/nsis.ts
@@ -72,6 +72,15 @@ export class NsisTarget extends Target {
       archiveOptions.solid = false
       // our reader doesn't support compressed headers
       archiveOptions.isArchiveHeaderCompressed = false
+      /*
+       * dict size 64 MB: Full: 33,744.88 KB, To download: 17,630.3 KB (52%)
+       * dict size 16 MB: Full: 33,936.84 KB, To download: 16,175.9 KB (48%)
+       * dict size  8 MB: Full: 34,187.59 KB, To download:  8,229.9 KB (24%)
+       * dict size  4 MB: Full: 34,628.73 KB, To download: 3,782.97 KB (11%)
+
+       as we can see, if file changed in one place, all block is invalidated (and update size approximately equals to dict size)
+       */
+      archiveOptions.dictSize = 8
       // do not allow to change compression level to avoid different packages
       compression = "normal"
     }
diff --git a/packages/electron-publisher-s3/package.json b/packages/electron-publisher-s3/package.json
index 09ddbd90bd8..690547e59f8 100644
--- a/packages/electron-publisher-s3/package.json
+++ b/packages/electron-publisher-s3/package.json
@@ -12,7 +12,7 @@
   ],
   "dependencies": {
     "fs-extra-p": "^4.4.3",
-    "aws-sdk": "^2.130.0",
+    "aws-sdk": "^2.131.0",
     "mime": "^2.0.3",
     "electron-publish": "~0.0.0-semantic-release",
     "builder-util": "^0.0.0-semantic-release",
diff --git a/packages/electron-updater/CHANGELOG.md b/packages/electron-updater/CHANGELOG.md
index 0c44aa76b22..2cac44c5c60 100644
--- a/packages/electron-updater/CHANGELOG.md
+++ b/packages/electron-updater/CHANGELOG.md
@@ -1,3 +1,9 @@
+# 2.11.0
+
+### Features
+
+* Differential updater: use [content defined chunking](https://github.com/electron-userland/electron-builder/releases/tag/v19.36.0)
+
 # 2.10.2
 
 ### Bug Fixes
diff --git a/packages/electron-updater/package.json b/packages/electron-updater/package.json
index e0460b0ccef..04a5683e2dd 100644
--- a/packages/electron-updater/package.json
+++ b/packages/electron-updater/package.json
@@ -23,5 +23,8 @@
     "xelement": "^1.0.16",
     "lodash.isequal": "^4.5.0"
   },
-  "typings": "./out/main.d.ts"
+  "typings": "./out/main.d.ts",
+  "publishConfig": {
+    "tag": "next"
+  }
 }
diff --git a/packages/electron-updater/src/differentialPackage.ts b/packages/electron-updater/src/differentialPackage.ts
index d3b480ed3d9..192f1cb694c 100644
--- a/packages/electron-updater/src/differentialPackage.ts
+++ b/packages/electron-updater/src/differentialPackage.ts
@@ -17,6 +17,16 @@ export class DifferentialDownloaderOptions {
   readonly requestHeaders: OutgoingHttpHeaders | null
 }
 
+function buildChecksumToOffsetMap(file: BlockMapFile, fileOffset: number) {
+  const result = new Map<string, number>()
+  let offset = fileOffset
+  for (let i = 0; i < file.checksums.length; i++) {
+    result.set(file.checksums[i], offset)
+    offset += file.sizes[i]
+  }
+  return result
+}
+
 export class DifferentialDownloader {
   private readonly baseRequestOptions: RequestOptions
 
@@ -49,11 +59,8 @@ export class DifferentialDownloader {
     const newBlockMap = await readBlockMap(this.fileMetadataBuffer.slice(this.packageInfo.headerSize!!))
 
     // we don't check other metadata like compressionMethod - generic check that it is make sense to differentially update is suitable for it
-    if (oldBlockMap.hashMethod !== newBlockMap.hashMethod) {
-      throw new Error(`hashMethod is different (${oldBlockMap.hashMethod} - ${newBlockMap.hashMethod}), full download is required`)
-    }
-    if (oldBlockMap.blockSize !== newBlockMap.blockSize) {
-      throw new Error(`blockSize is different (${oldBlockMap.blockSize} - ${newBlockMap.blockSize}), full download is required`)
+    if (oldBlockMap.version !== newBlockMap.version) {
+      throw new Error(`version is different (${oldBlockMap.version} - ${newBlockMap.version}), full download is required`)
     }
 
     const operations = this.computeOperations(oldBlockMap, newBlockMap)
@@ -78,7 +85,7 @@ export class DifferentialDownloader {
       throw new Error(`Internal error, size mismatch: downloadSize: ${downloadSize}, copySize: ${copySize}, newPackageSize: ${newPackageSize}`)
     }
 
-    this.logger.info(`Full: ${formatBytes(newPackageSize)}, To download: ${formatBytes(downloadSize)} (${Math.round((((newPackageSize - downloadSize) / newPackageSize) * 100))}%)`)
+    this.logger.info(`Full: ${formatBytes(newPackageSize)}, To download: ${formatBytes(downloadSize)} (${Math.round(downloadSize / (newPackageSize / 100))}%)`)
 
     await this.downloadFile(operations)
   }
@@ -178,9 +185,6 @@ export class DifferentialDownloader {
     const nameToOldBlocks = buildBlockFileMap(oldBlockMap.files)
     const nameToNewBlocks = buildBlockFileMap(newBlockMap.files)
 
-    // convert kb to bytes
-    const blockSize = newBlockMap.blockSize * 1024
-
     const oldEntryMap = buildEntryMap(oldBlockMap.files)
 
     const operations: Array<Operation> = []
@@ -205,33 +209,22 @@ export class DifferentialDownloader {
 
       let changedBlockCount = 0
 
+      const checksumToOldOffset = buildChecksumToOffsetMap(oldFile, oldEntry.offset)
+
+      let newOffset = 0
       blockMapLoop:
-      for (let i = 0; i < newFile.blocks.length; i++) {
-        if (i >= oldFile.blocks.length) {
-          break
-        }
+      for (let i = 0; i < newFile.checksums.length; newOffset += newFile.sizes[i], i++) {
+        const currentBlockSize = newFile.sizes[i]
 
-        const isFirstBlock = i === 0
-        const isLastBlock = i === (newFile.blocks.length - 1)
-        const currentBlockSize = isLastBlock ? (newFile.size % blockSize) : blockSize
-
-        if (oldFile.blocks[i] === newFile.blocks[i]) {
-          if (lastOperation == null || lastOperation.kind !== OperationKind.COPY) {
-            const start = oldEntry.offset + (i * blockSize)
-            const end = start + currentBlockSize
-            if (isFirstBlock) {
-              if (operations.length > 0) {
-                const prevOperation = operations[operations.length - 1]
-                if (prevOperation.kind === OperationKind.COPY && prevOperation.end === start) {
-                  lastOperation = prevOperation
-                  prevOperation.end = end
-                  continue blockMapLoop
-                }
-              }
-            }
+        const oldOffset = checksumToOldOffset.get(newFile.checksums[i])
+        if (oldOffset == null) {
+          changedBlockCount++
 
+          const start = blockMapFile.offset + newOffset
+          const end = start + currentBlockSize
+          if (lastOperation == null || lastOperation.kind !== OperationKind.DOWNLOAD) {
             lastOperation = {
-              kind: OperationKind.COPY,
+              kind: OperationKind.DOWNLOAD,
               start,
               end,
             }
@@ -242,14 +235,20 @@ export class DifferentialDownloader {
           }
         }
         else {
-          changedBlockCount++
+          if (lastOperation == null || lastOperation.kind !== OperationKind.COPY || lastOperation.end !== oldOffset) {
+            const end: number = oldOffset + currentBlockSize
+            if (i === 0 && operations.length > 0) {
+              const prevOperation = operations[operations.length - 1]
+              if (prevOperation.kind === OperationKind.COPY && prevOperation.end === oldOffset) {
+                lastOperation = prevOperation
+                prevOperation.end = end
+                continue blockMapLoop
+              }
+            }
 
-          const start = blockMapFile.offset + (i * blockSize)
-          const end = start + currentBlockSize
-          if (lastOperation == null || lastOperation.kind !== OperationKind.DOWNLOAD) {
             lastOperation = {
-              kind: OperationKind.DOWNLOAD,
-              start,
+              kind: OperationKind.COPY,
+              start: oldOffset,
               end,
             }
             operations.push(lastOperation)
diff --git a/yarn.lock b/yarn.lock
index 322b9a53fbb..22be3f45f17 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -453,9 +453,9 @@ asynckit@^0.4.0:
   version "0.4.0"
   resolved "https://registry.yarnpkg.com/asynckit/-/asynckit-0.4.0.tgz#c79ed97f7f34cb8f2ba1bc9790bcc366474b4b79"
 
-aws-sdk@^2.130.0:
-  version "2.130.0"
-  resolved "https://registry.yarnpkg.com/aws-sdk/-/aws-sdk-2.130.0.tgz#f0c6da7dbda9a15cb0c2beb3030f6da2a4c03c36"
+aws-sdk@^2.131.0:
+  version "2.131.0"
+  resolved "https://registry.yarnpkg.com/aws-sdk/-/aws-sdk-2.131.0.tgz#5b213fa493ce36a88130b50bef0e9a0cb6cd9f72"
   dependencies:
     buffer "4.9.1"
     crypto-browserify "1.0.9"
@@ -765,6 +765,10 @@ binary@^0.3.0:
     buffers "~0.1.1"
     chainsaw "~0.1.0"
 
+bindings@^1.3.0:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/bindings/-/bindings-1.3.0.tgz#b346f6ecf6a95f5a815c5839fc7cdb22502f1ed7"
+
 bl@^1.0.0:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/bl/-/bl-1.2.1.tgz#cac328f7bee45730d404b692203fcb590e172d5e"
@@ -826,7 +830,7 @@ boom@2.x.x:
   dependencies:
     hoek "2.x.x"
 
-boxen@^1.0.0:
+boxen@^1.2.1:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/boxen/-/boxen-1.2.1.tgz#0f11e7fe344edb9397977fc13ede7f64d956481d"
   dependencies:
@@ -920,10 +924,6 @@ camelcase@^2.0.0, camelcase@^2.0.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-2.1.1.tgz#7c1d16d679a1bbe59ca02cacecfb011e201f5a1f"
 
-camelcase@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-3.0.0.tgz#32fc4b9fcdaf845fcdf7e73bb97cac2261f0ab0a"
-
 camelcase@^4.0.0, camelcase@^4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-4.1.0.tgz#d545635be1e33c542649c69173e5de6acfae34dd"
@@ -955,7 +955,7 @@ chainsaw@~0.1.0:
   dependencies:
     traverse ">=0.3.0 <0.4"
 
-chalk@^1.0.0, chalk@^1.1.3:
+chalk@^1.1.3:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/chalk/-/chalk-1.1.3.tgz#a8115c55e4a702fe4d150abd3872822a7e09fc98"
   dependencies:
@@ -1021,6 +1021,10 @@ chokidar@^1.6.0, chokidar@^1.7.0:
   optionalDependencies:
     fsevents "^1.0.0"
 
+chownr@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/chownr/-/chownr-1.0.1.tgz#e2a75042a9551908bebd25b8523d5f9769d79181"
+
 chromium-pickle-js@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/chromium-pickle-js/-/chromium-pickle-js-0.2.0.tgz#04a106672c18b085ab774d983dfa3ea138f22205"
@@ -1406,9 +1410,9 @@ delegates@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/delegates/-/delegates-1.0.0.tgz#84c6e159b81904fdca59a0ef44cd870d31250f9a"
 
-depcheck@^0.6.7:
-  version "0.6.7"
-  resolved "https://registry.yarnpkg.com/depcheck/-/depcheck-0.6.7.tgz#6b3d1e993931e09ee673d3507d3175db734823e6"
+depcheck@^0.6.8:
+  version "0.6.8"
+  resolved "https://registry.yarnpkg.com/depcheck/-/depcheck-0.6.8.tgz#822bd72efe900afd66b78b59dd269ba63b10020c"
   dependencies:
     babel-traverse "^6.7.3"
     babylon "^6.1.21"
@@ -1420,7 +1424,7 @@ depcheck@^0.6.7:
     minimatch "^3.0.2"
     require-package-name "^2.0.1"
     walkdir "0.0.11"
-    yargs "^6.0.0"
+    yargs "^8.0.2"
 
 depd@1.1.1, depd@~1.1.0, depd@~1.1.1:
   version "1.1.1"
@@ -1609,7 +1613,7 @@ encodeurl@~1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/encodeurl/-/encodeurl-1.0.1.tgz#79e3d58655346909fe6f0f45a5de68103b294d20"
 
-end-of-stream@^1.0.0:
+end-of-stream@^1.0.0, end-of-stream@^1.1.0:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/end-of-stream/-/end-of-stream-1.4.0.tgz#7a90d833efda6cfa6eac0f4949dbb0fad3a63206"
   dependencies:
@@ -1783,6 +1787,10 @@ expand-range@^1.8.1:
   dependencies:
     fill-range "^2.1.0"
 
+expand-template@^1.0.2:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/expand-template/-/expand-template-1.1.0.tgz#e09efba977bf98f9ee0ed25abd0c692e02aec3fc"
+
 expect@^21.2.1:
   version "21.2.1"
   resolved "https://registry.yarnpkg.com/expect/-/expect-21.2.1.tgz#003ac2ac7005c3c29e73b38a272d4afadd6d1d7b"
@@ -2117,6 +2125,10 @@ gitbook-plugin-theme-default@1.0.7:
   version "1.0.7"
   resolved "https://registry.yarnpkg.com/gitbook-plugin-theme-default/-/gitbook-plugin-theme-default-1.0.7.tgz#51f71fbca74a261054e9e9d141c42167afefce88"
 
+github-from-package@0.0.0:
+  version "0.0.0"
+  resolved "https://registry.yarnpkg.com/github-from-package/-/github-from-package-0.0.0.tgz#97fb5d96bfde8973313f20e8288ef9a167fa64ce"
+
 github-slugid@1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/github-slugid/-/github-slugid-1.0.1.tgz#bccdd0815bfad69d8a359fa4fd65947d606ec3c0"
@@ -2155,6 +2167,12 @@ glob@^7.0.0, glob@^7.0.3, glob@^7.0.5, glob@^7.1.0, glob@^7.1.1, glob@^7.1.2, gl
     once "^1.3.0"
     path-is-absolute "^1.0.0"
 
+global-dirs@^0.1.0:
+  version "0.1.0"
+  resolved "https://registry.yarnpkg.com/global-dirs/-/global-dirs-0.1.0.tgz#10d34039e0df04272e262cf24224f7209434df4f"
+  dependencies:
+    ini "^1.3.4"
+
 globals@^9.18.0:
   version "9.18.0"
   resolved "https://registry.yarnpkg.com/globals/-/globals-9.18.0.tgz#aa3896b3e69b487f17e31ed2143d69a8e30c2d8a"
@@ -2467,6 +2485,13 @@ is-glob@^2.0.0, is-glob@^2.0.1:
   dependencies:
     is-extglob "^1.0.0"
 
+is-installed-globally@^0.1.0:
+  version "0.1.0"
+  resolved "https://registry.yarnpkg.com/is-installed-globally/-/is-installed-globally-0.1.0.tgz#0dfd98f5a9111716dd535dda6492f67bf3d25a80"
+  dependencies:
+    global-dirs "^0.1.0"
+    is-path-inside "^1.0.0"
+
 is-npm@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/is-npm/-/is-npm-1.0.0.tgz#f2fb63a65e4905b406c86072765a1a4dc793b9f4"
@@ -2487,6 +2512,12 @@ is-obj@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/is-obj/-/is-obj-1.0.1.tgz#3e4729ac1f5fde025cd7d83a896dab9f4f67db0f"
 
+is-path-inside@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/is-path-inside/-/is-path-inside-1.0.0.tgz#fc06e5a1683fbda13de667aff717bbc10a48f37f"
+  dependencies:
+    path-is-inside "^1.0.1"
+
 is-posix-bracket@^0.1.0:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/is-posix-bracket/-/is-posix-bracket-0.1.1.tgz#3334dc79774368e92f016e6fbc0a88f5cd6e6bc4"
@@ -3424,7 +3455,7 @@ ms@2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.0.0.tgz#5608aeadfc00be6c2901df5f9861788de0d597c8"
 
-nan@^2.3.0:
+nan@^2.3.0, nan@^2.7.0:
   version "2.7.0"
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.7.0.tgz#d95bf721ec877e08db276ed3fc6eb78f9083ad46"
 
@@ -3440,6 +3471,10 @@ next-tick@~0.2.2:
   version "0.2.2"
   resolved "https://registry.yarnpkg.com/next-tick/-/next-tick-0.2.2.tgz#75da4a927ee5887e39065880065b7336413b310d"
 
+node-abi@^2.1.1:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/node-abi/-/node-abi-2.1.1.tgz#c9cda256ec8aa99bcab2f6446db38af143338b2a"
+
 node-emoji@^1.8.1:
   version "1.8.1"
   resolved "https://registry.yarnpkg.com/node-emoji/-/node-emoji-1.8.1.tgz#6eec6bfb07421e2148c75c6bba72421f8530a826"
@@ -3486,6 +3521,10 @@ node.flow@1.2.3:
   dependencies:
     node.extend "1.0.8"
 
+noop-logger@^0.1.1:
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/noop-logger/-/noop-logger-0.1.1.tgz#94a2b1633c4f1317553007d8966fd0e841b6a4c2"
+
 nopt@^3.0.1:
   version "3.0.6"
   resolved "https://registry.yarnpkg.com/nopt/-/nopt-3.0.6.tgz#c6465dbf08abcd4db359317f79ac68a646b28ff9"
@@ -3526,7 +3565,7 @@ npm-run-path@^2.0.0:
   dependencies:
     path-key "^2.0.0"
 
-npmlog@^4.0.2:
+npmlog@^4.0.1, npmlog@^4.0.2:
   version "4.1.2"
   resolved "https://registry.yarnpkg.com/npmlog/-/npmlog-4.1.2.tgz#08a7f2a8bf734604779a9efa4ad5cc717abb954b"
   dependencies:
@@ -3617,7 +3656,7 @@ on-finished@~2.3.0:
   dependencies:
     ee-first "1.1.1"
 
-once@^1.3.0, once@^1.3.3, once@^1.4.0:
+once@^1.3.0, once@^1.3.1, once@^1.3.3, once@^1.4.0:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/once/-/once-1.4.0.tgz#583b1aa775961d4b113ac17d9c50baef9dd76bd1"
   dependencies:
@@ -3655,7 +3694,7 @@ optionator@^0.8.1:
     type-check "~0.3.2"
     wordwrap "~1.0.0"
 
-os-homedir@^1.0.0:
+os-homedir@^1.0.0, os-homedir@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/os-homedir/-/os-homedir-1.0.2.tgz#ffbc4988336e0e833de0c168c7ef152121aa7fb3"
 
@@ -3758,6 +3797,10 @@ path-is-absolute@^1.0.0, path-is-absolute@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/path-is-absolute/-/path-is-absolute-1.0.1.tgz#174b9268735534ffbc7ace6bf53a5a9e1b5c5f5f"
 
+path-is-inside@^1.0.1:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/path-is-inside/-/path-is-inside-1.0.2.tgz#365417dede44430d1c11af61027facf074bdfc53"
+
 path-key@^2.0.0:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/path-key/-/path-key-2.0.1.tgz#411cadb574c5a140d3a4b1910d40d80cc9f40b40"
@@ -3814,6 +3857,25 @@ plist@^2.1.0:
     xmlbuilder "8.2.2"
     xmldom "0.1.x"
 
+prebuild-install@^2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/prebuild-install/-/prebuild-install-2.3.0.tgz#19481247df728b854ab57b187ce234211311b485"
+  dependencies:
+    expand-template "^1.0.2"
+    github-from-package "0.0.0"
+    minimist "^1.2.0"
+    mkdirp "^0.5.1"
+    node-abi "^2.1.1"
+    noop-logger "^0.1.1"
+    npmlog "^4.0.1"
+    os-homedir "^1.0.1"
+    pump "^1.0.1"
+    rc "^1.1.6"
+    simple-get "^1.4.2"
+    tar-fs "^1.13.0"
+    tunnel-agent "^0.6.0"
+    xtend "4.0.1"
+
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
@@ -3863,6 +3925,13 @@ pseudomap@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/pseudomap/-/pseudomap-1.0.2.tgz#f052a28da70e618917ef0a8ac34c1ae5a68286b3"
 
+pump@^1.0.0, pump@^1.0.1:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/pump/-/pump-1.0.2.tgz#3b3ee6512f94f0e575538c17995f9f16990a5d51"
+  dependencies:
+    end-of-stream "^1.1.0"
+    once "^1.3.1"
+
 punycode@1.3.2:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-1.3.2.tgz#9653a036fb7c1ee42342f2325cceefea3926c48d"
@@ -3891,6 +3960,14 @@ querystring@0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/querystring/-/querystring-0.2.0.tgz#b209849203bb25df820da756e747005878521620"
 
+rabin-bindings@~1.7.3:
+  version "1.7.3"
+  resolved "https://registry.yarnpkg.com/rabin-bindings/-/rabin-bindings-1.7.3.tgz#fb6ae9dbf897988bc2504ccf4832ee4f0546d32a"
+  dependencies:
+    bindings "^1.3.0"
+    nan "^2.7.0"
+    prebuild-install "^2.3.0"
+
 randomatic@^1.1.3:
   version "1.1.7"
   resolved "https://registry.yarnpkg.com/randomatic/-/randomatic-1.1.7.tgz#c7abe9cc8b87c0baa876b19fde83fd464797e38c"
@@ -4321,6 +4398,14 @@ signal-exit@^3.0.0, signal-exit@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
 
+simple-get@^1.4.2:
+  version "1.4.3"
+  resolved "https://registry.yarnpkg.com/simple-get/-/simple-get-1.4.3.tgz#e9755eda407e96da40c5e5158c9ea37b33becbeb"
+  dependencies:
+    once "^1.3.1"
+    unzip-response "^1.0.0"
+    xtend "^4.0.0"
+
 single-line-log@^1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/single-line-log/-/single-line-log-1.1.2.tgz#c2f83f273a3e1a16edb0995661da0ed5ef033364"
@@ -4586,6 +4671,15 @@ taffydb@2.6.2:
   version "2.6.2"
   resolved "https://registry.yarnpkg.com/taffydb/-/taffydb-2.6.2.tgz#7cbcb64b5a141b6a2efc2c5d2c67b4e150b2a268"
 
+tar-fs@^1.13.0:
+  version "1.16.0"
+  resolved "https://registry.yarnpkg.com/tar-fs/-/tar-fs-1.16.0.tgz#e877a25acbcc51d8c790da1c57c9cf439817b896"
+  dependencies:
+    chownr "^1.0.1"
+    mkdirp "^0.5.1"
+    pump "^1.0.0"
+    tar-stream "^1.1.2"
+
 tar-pack@^3.4.0:
   version "3.4.0"
   resolved "https://registry.yarnpkg.com/tar-pack/-/tar-pack-3.4.0.tgz#23be2d7f671a8339376cbdb0b8fe3fdebf317984"
@@ -4599,7 +4693,7 @@ tar-pack@^3.4.0:
     tar "^2.2.1"
     uid-number "^0.0.6"
 
-tar-stream@^1.5.0:
+tar-stream@^1.1.2, tar-stream@^1.5.0:
   version "1.5.4"
   resolved "https://registry.yarnpkg.com/tar-stream/-/tar-stream-1.5.4.tgz#36549cf04ed1aee9b2a30c0143252238daf94016"
   dependencies:
@@ -4888,18 +4982,23 @@ unpipe@1.0.0, unpipe@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/unpipe/-/unpipe-1.0.0.tgz#b2bf4ee8514aae6165b4817829d21b2ef49904ec"
 
+unzip-response@^1.0.0:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/unzip-response/-/unzip-response-1.0.2.tgz#b984f0877fc0a89c2c773cc1ef7b5b232b5b06fe"
+
 unzip-response@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/unzip-response/-/unzip-response-2.0.1.tgz#d2f0f737d16b0615e72a6935ed04214572d56f97"
 
-update-notifier@^2.2.0:
-  version "2.2.0"
-  resolved "https://registry.yarnpkg.com/update-notifier/-/update-notifier-2.2.0.tgz#1b5837cf90c0736d88627732b661c138f86de72f"
+update-notifier@^2.3.0:
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/update-notifier/-/update-notifier-2.3.0.tgz#4e8827a6bb915140ab093559d7014e3ebb837451"
   dependencies:
-    boxen "^1.0.0"
-    chalk "^1.0.0"
+    boxen "^1.2.1"
+    chalk "^2.0.1"
     configstore "^3.0.0"
     import-lazy "^2.1.0"
+    is-installed-globally "^0.1.0"
     is-npm "^1.0.0"
     latest-version "^3.0.0"
     semver-diff "^2.0.0"
@@ -5045,10 +5144,6 @@ whatwg-url@^4.3.0:
     tr46 "~0.0.3"
     webidl-conversions "^3.0.0"
 
-which-module@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/which-module/-/which-module-1.0.0.tgz#bba63ca861948994ff307736089e3b96026c2a4f"
-
 which-module@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/which-module/-/which-module-2.0.0.tgz#d9ef07dce77b9902b8a3a8fa4b31c3e3f7e6e87a"
@@ -5186,7 +5281,7 @@ xmlhttprequest@~1.7.0:
   version "1.7.0"
   resolved "https://registry.yarnpkg.com/xmlhttprequest/-/xmlhttprequest-1.7.0.tgz#dc697a8df0258afacad526c1c296b1bdd12c4ab3"
 
-"xtend@>=4.0.0 <4.1.0-0", xtend@^4.0.0, xtend@^4.0.1, xtend@~4.0.0:
+xtend@4.0.1, "xtend@>=4.0.0 <4.1.0-0", xtend@^4.0.0, xtend@^4.0.1, xtend@~4.0.0:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.1.tgz#a5c6d532be656e23db820efb943a1f04998d63af"
 
@@ -5204,12 +5299,6 @@ yallist@^2.1.2:
   version "2.1.2"
   resolved "https://registry.yarnpkg.com/yallist/-/yallist-2.1.2.tgz#1c11f9218f076089a47dd512f93c6699a6a81d52"
 
-yargs-parser@^4.2.0:
-  version "4.2.1"
-  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-4.2.1.tgz#29cceac0dc4f03c6c87b4a9f217dd18c9f74871c"
-  dependencies:
-    camelcase "^3.0.0"
-
 yargs-parser@^7.0.0:
   version "7.0.0"
   resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-7.0.0.tgz#8d0ac42f16ea55debd332caf4c4038b3e3f5dfd9"
@@ -5228,24 +5317,6 @@ yargs@^3.32.0:
     window-size "^0.1.4"
     y18n "^3.2.0"
 
-yargs@^6.0.0:
-  version "6.6.0"
-  resolved "https://registry.yarnpkg.com/yargs/-/yargs-6.6.0.tgz#782ec21ef403345f830a808ca3d513af56065208"
-  dependencies:
-    camelcase "^3.0.0"
-    cliui "^3.2.0"
-    decamelize "^1.1.1"
-    get-caller-file "^1.0.1"
-    os-locale "^1.4.0"
-    read-pkg-up "^1.0.1"
-    require-directory "^2.1.1"
-    require-main-filename "^1.0.1"
-    set-blocking "^2.0.0"
-    string-width "^1.0.2"
-    which-module "^1.0.0"
-    y18n "^3.2.1"
-    yargs-parser "^4.2.0"
-
 yargs@^8.0.2:
   version "8.0.2"
   resolved "https://registry.yarnpkg.com/yargs/-/yargs-8.0.2.tgz#6299a9055b1cefc969ff7e79c1d918dceb22c360"