Fixed race condition

index.js

@@ -181,7 +181,9 @@ WriteRequest.prototype.run = function (req) {
     if (err) return req.callback(err)
 
     this.req = req
-    if (!this.writer || this.writer.length !== file.size) return this.makeWriter()
+    if (!this.writer) {
+      return this.makeWriter()
+    }
 
     const end = req.offset + req.size
     if (end > file.size && !this.lock()) return

test.js

@@ -1,3 +1,4 @@
+const { promisify } = require('util')
 const test = require('tape')
 const randomAccessTest = require('random-access-test')
 const racf = require('./')
@@ -14,20 +15,8 @@ test('write/read concurrent requests', async t => {
   const st = storage('random')
 
   const rand = (min, max) => Math.floor(Math.random() * max) + min
-
-  const read = (...args) => new Promise((resolve, reject) => {
-    st.read(...args, (err) => {
-      if (err) return reject(err)
-      resolve()
-    })
-  })
-
-  const write = (...args) => new Promise((resolve, reject) => {
-    st.write(...args, (err) => {
-      if (err) return reject(err)
-      resolve()
-    })
-  })
+  const read = promisify(st.read.bind(st))
+  const write = promisify(st.write.bind(st))
 
   try {
     await new Promise(resolve => st.open(() => resolve()))
@@ -55,3 +44,24 @@ test('write/read concurrent requests', async t => {
     t.end(err)
   }
 })
+
+test('write concurrent requests over the same offset different size', async t => {
+  const st = storage('random')
+
+  const write = promisify(st.write.bind(st))
+
+  try {
+    await new Promise(resolve => st.open(() => resolve()))
+
+    await Promise.all([
+      write(0, Buffer.alloc(10)),
+      write(0, Buffer.alloc(1)),
+      write(0, Buffer.alloc(5))
+    ])
+
+    t.pass('should write multiple requests over the same offset different size')
+    t.end()
+  } catch (err) {
+    t.end(err)
+  }
+})