fix: range end is zero-indexed (#3826) (#3827)

* fix: range end is zero-indexed

* tests: update tests for retry handler

(cherry picked from commit 2b81fbc)

Co-authored-by: D Trombett <[email protected]>

Author: github-actions[bot]

lib/handler/retry-handler.js

@@ -229,7 +229,7 @@ class RetryHandler {
         return false
       }
 
-      const { start, size, end = size } = contentRange
+      const { start, size, end = size - 1 } = contentRange
 
       assert(this.start === start, 'content-range mismatch')
       assert(this.end == null || this.end === end, 'content-range mismatch')
@@ -252,7 +252,7 @@ class RetryHandler {
           )
         }
 
-        const { start, size, end = size } = range
+        const { start, size, end = size - 1 } = range
         assert(
           start != null && Number.isFinite(start),
           'content-range mismatch'
@@ -266,7 +266,7 @@ class RetryHandler {
       // We make our best to checkpoint the body for further range headers
       if (this.end == null) {
         const contentLength = headers['content-length']
-        this.end = contentLength != null ? Number(contentLength) : null
+        this.end = contentLength != null ? Number(contentLength) - 1 : null
       }
 
       assert(Number.isFinite(this.start))

test/interceptors/retry.js

@@ -253,14 +253,15 @@ test('Should handle 206 partial content', async t => {
   const server = createServer((req, res) => {
     if (x === 0) {
       t.ok(true, 'pass')
+      res.setHeader('content-length', '6')
       res.setHeader('etag', 'asd')
       res.write('abc')
       setTimeout(() => {
         res.destroy()
       }, 1e2)
     } else if (x === 1) {
-      t.deepStrictEqual(req.headers.range, 'bytes=3-')
-      res.setHeader('content-range', 'bytes 3-6/6')
+      t.deepStrictEqual(req.headers.range, 'bytes=3-5')
+      res.setHeader('content-range', 'bytes 3-5/6')
       res.setHeader('etag', 'asd')
       res.statusCode = 206
       res.end('def')