build: fix errors spotted by ineffassign linter

These were mostly caused by shadowing err and a good fraction of them
will have caused errors not to be propagated properly.

backend/b2/upload.go

@@ -357,7 +357,8 @@ outer:
 		buf := up.f.getUploadBlock()
 
 		// Read the chunk
-		n, err := io.ReadFull(up.in, buf)
+		var n int
+		n, err = io.ReadFull(up.in, buf)
 		if err == io.ErrUnexpectedEOF {
 			fs.Debugf(up.o, "Read less than a full chunk, making this the last one.")
 			buf = buf[:n]
@@ -366,7 +367,6 @@ outer:
 		} else if err == io.EOF {
 			fs.Debugf(up.o, "Could not read any more bytes, previous chunk was the last.")
 			up.f.putUploadBlock(buf)
-			hasMoreParts = false
 			err = nil
 			break outer
 		} else if err != nil {

backend/cache/cache.go

@@ -647,7 +647,6 @@ func (f *Fs) NewObject(remote string) (fs.Object, error) {
 
 	// search for entry in source or temp fs
 	var obj fs.Object
-	err = nil
 	if f.tempWritePath != "" {
 		obj, err = f.tempFs.NewObject(remote)
 		// not found in temp fs

backend/cache/cache_internal_test.go

@@ -988,8 +988,9 @@ func TestInternalUploadTempFileOperations(t *testing.T) {
 		require.Error(t, err)
 		_, err = os.Stat(path.Join(runInstance.tmpUploadDir, id, runInstance.encryptRemoteIfNeeded(t, "second/one")))
 		require.NoError(t, err)
-		started, err := boltDb.SearchPendingUpload(runInstance.encryptRemoteIfNeeded(t, path.Join(id, "test/one")))
+		_, err = boltDb.SearchPendingUpload(runInstance.encryptRemoteIfNeeded(t, path.Join(id, "test/one")))
 		require.Error(t, err)
+		var started bool
 		started, err = boltDb.SearchPendingUpload(runInstance.encryptRemoteIfNeeded(t, path.Join(id, "second/one")))
 		require.NoError(t, err)
 		require.False(t, started)

backend/cache/handle.go

@@ -446,7 +446,6 @@ func (w *worker) run() {
 					continue
 				}
 			}
-			err = nil
 		} else {
 			if w.r.storage().HasChunk(w.r.cachedObject, chunkStart) {
 				continue
@@ -493,7 +492,7 @@ func (w *worker) download(chunkStart, chunkEnd int64, retry int) {
 	}
 
 	data = make([]byte, chunkEnd-chunkStart)
-	sourceRead := 0
+	var sourceRead int
 	sourceRead, err = io.ReadFull(w.rc, data)
 	if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
 		fs.Errorf(w, "failed to read chunk %v: %v", chunkStart, err)

backend/http/http_internal_test.go

@@ -151,6 +151,7 @@ func TestOpen(t *testing.T) {
 	fd, err := o.Open()
 	require.NoError(t, err)
 	data, err := ioutil.ReadAll(fd)
+	require.NoError(t, err)
 	require.NoError(t, fd.Close())
 	assert.Equal(t, "beetroot\n", string(data))
 
@@ -158,6 +159,7 @@ func TestOpen(t *testing.T) {
 	fd, err = o.Open(&fs.RangeOption{Start: 1, End: 5})
 	require.NoError(t, err)
 	data, err = ioutil.ReadAll(fd)
+	require.NoError(t, err)
 	require.NoError(t, fd.Close())
 	assert.Equal(t, "eetro", string(data))
 }

backend/local/local.go

@@ -593,7 +593,6 @@ func (o *Object) Hash(r hash.Type) (string, error) {
 	o.fs.objectHashesMu.Unlock()
 
 	if !o.modTime.Equal(oldtime) || oldsize != o.size || hashes == nil {
-		hashes = make(map[hash.Type]string)
 		in, err := os.Open(o.path)
 		if err != nil {
 			return "", errors.Wrap(err, "hash: failed to open")

backend/local/local_internal_test.go

@@ -44,9 +44,11 @@ func TestUpdatingCheck(t *testing.T) {
 	}
 
 	fi, err := fd.Stat()
+	require.NoError(t, err)
 	o := &Object{size: fi.Size(), modTime: fi.ModTime()}
 	wrappedFd := readers.NewLimitedReadCloser(fd, -1)
 	hash, err := hash.NewMultiHasherTypes(hash.Supported)
+	require.NoError(t, err)
 	in := localOpenFile{
 		o:    o,
 		in:   wrappedFd,

backend/swift/swift.go

@@ -391,7 +391,8 @@ func (f *Fs) list(dir string, recurse bool, fn addEntryFn) error {
 			err = fn(d)
 		} else {
 			// newObjectWithInfo does a full metadata read on 0 size objects which might be dynamic large objects
-			o, err := f.newObjectWithInfo(remote, object)
+			var o fs.Object
+			o, err = f.newObjectWithInfo(remote, object)
 			if err != nil {
 				return err
 			}
@@ -847,7 +848,7 @@ func urlEncode(str string) string {
 // container.  It returns a string which prefixes current segments.
 func (o *Object) updateChunks(in0 io.Reader, headers swift.Headers, size int64, contentType string) (string, error) {
 	// Create the segmentsContainer if it doesn't exist
-	var err error = swift.ContainerNotFound
+	var err error
 	_, _, err = o.fs.c.Container(o.fs.segmentsContainer)
 	if err == swift.ContainerNotFound {
 		err = o.fs.c.ContainerCreate(o.fs.segmentsContainer, nil)

bin/get-github-release.go

@@ -149,6 +149,9 @@ func getAsset(project string, matchName *regexp.Regexp) (string, string) {
 	log.Printf("Fetching asset info for %q from %q", project, url)
 	user, pass := os.Getenv("GITHUB_USER"), os.Getenv("GITHUB_TOKEN")
 	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		log.Fatalf("Failed to make http request %q: %v", url, err)
+	}
 	if user != "" && pass != "" {
 		log.Printf("Fetching using GITHUB_USER and GITHUB_TOKEN")
 		req.SetBasicAuth(user, pass)

cmd/cachestats/cachestats.go

@@ -52,6 +52,9 @@ Print cache stats for a remote in JSON format
 				}
 			}
 			m, err := fsCache.Stats()
+			if err != nil {
+				return err
+			}
 
 			raw, err := json.MarshalIndent(m, "", "  ")
 			if err != nil {

cmd/cmount/fs.go

@@ -350,7 +350,6 @@ func (fsys *FS) Read(path string, buff []byte, ofst int64, fh uint64) (n int) {
 	}
 	n, err := handle.ReadAt(buff, ofst)
 	if err == io.EOF {
-		err = nil
 	} else if err != nil {
 		return translateError(err)
 	}

fs/object/object_test.go

@@ -76,7 +76,7 @@ func TestMemoryFs(t *testing.T) {
 	assert.Error(t, err)
 
 	err = f.Rmdir("dir")
-	assert.Error(t, fs.ErrorDirNotFound)
+	assert.Equal(t, fs.ErrorDirNotFound, err)
 }
 
 func TestMemoryObject(t *testing.T) {

fs/operations/dedupe.go

@@ -288,9 +288,9 @@ func Deduplicate(f fs.Fs, mode DeduplicateMode) error {
 			case DeduplicateRename:
 				dedupeRename(remote, objs)
 			case DeduplicateLargest:
-				size, largest, largestIndex := int64(0), int64(-1), -1
+				largest, largestIndex := int64(-1), -1
 				for i, obj := range objs {
-					size = obj.Size()
+					size := obj.Size()
 					if size > largest {
 						largest, largestIndex = size, i
 					}

vfs/make_open_tests.go

@@ -90,7 +90,7 @@ func test(fileName string, flags int, mode string) {
 		_, readExistingErr = f.Read(buf)
 
 		// write some bytes
-		n, writeExistingErr = f.Write([]byte("HEL"))
+		_, writeExistingErr = f.Write([]byte("HEL"))
 
 		// close
 		err = f.Close()

vfs/read_test.go

@@ -105,7 +105,7 @@ func TestReadFileHandleSeek(t *testing.T) {
 	assert.Equal(t, "d", readString(t, fh, 1))
 
 	// Seek off the end
-	n, err = fh.Seek(100, io.SeekStart)
+	_, err = fh.Seek(100, io.SeekStart)
 	assert.NoError(t, err)
 
 	// Get the error on read
@@ -168,7 +168,7 @@ func TestReadFileHandleReadAt(t *testing.T) {
 
 	// check noSeek gives an error
 	fh.noSeek = true
-	n, err = fh.ReadAt(buf, 100)
+	_, err = fh.ReadAt(buf, 100)
 	assert.Equal(t, ESPIPE, err)
 
 	// Properly close the file
@@ -176,7 +176,7 @@ func TestReadFileHandleReadAt(t *testing.T) {
 
 	// check reading on closed file
 	fh.noSeek = true
-	n, err = fh.ReadAt(buf, 100)
+	_, err = fh.ReadAt(buf, 100)
 	assert.Equal(t, ECLOSED, err)
 }
 

vfs/read_write.go

@@ -116,7 +116,7 @@ func (fh *RWFileHandle) openPending(truncate bool) (err error) {
 		if o != nil && fh.file.rwOpens() == 0 {
 			cacheObj, err := fh.d.vfs.cache.f.NewObject(fh.remote)
 			if err == nil && cacheObj != nil {
-				cacheObj, err = copyObj(fh.d.vfs.cache.f, cacheObj, fh.remote, o)
+				_, err = copyObj(fh.d.vfs.cache.f, cacheObj, fh.remote, o)
 				if err != nil {
 					return errors.Wrap(err, "open RW handle failed to update cached file")
 				}

vfs/read_write_test.go

@@ -155,7 +155,7 @@ func TestRWFileHandleSeek(t *testing.T) {
 	assert.Equal(t, "d", rwReadString(t, fh, 1))
 
 	// Seek off the end
-	n, err = fh.Seek(100, io.SeekStart)
+	_, err = fh.Seek(100, io.SeekStart)
 	assert.NoError(t, err)
 
 	// Get the error on read
@@ -215,7 +215,7 @@ func TestRWFileHandleReadAt(t *testing.T) {
 	assert.NoError(t, fh.Close())
 
 	// check reading on closed file
-	n, err = fh.ReadAt(buf, 100)
+	_, err = fh.ReadAt(buf, 100)
 	assert.Equal(t, ECLOSED, err)
 }
 
@@ -351,6 +351,7 @@ func TestRWFileHandleMethodsWrite(t *testing.T) {
 
 	// check vfs
 	root, err := vfs.Root()
+	require.NoError(t, err)
 	checkListing(t, root, []string{"file1,11,false"})
 
 	// check the underlying r.Fremote but not the modtime
@@ -399,6 +400,7 @@ func TestRWFileHandleWriteAt(t *testing.T) {
 
 	// check vfs
 	root, err := vfs.Root()
+	require.NoError(t, err)
 	checkListing(t, root, []string{"file1,11,false"})
 
 	// check the underlying r.Fremote but not the modtime
@@ -427,6 +429,7 @@ func TestRWFileHandleWriteNoWrite(t *testing.T) {
 
 	// check vfs
 	root, err := vfs.Root()
+	require.NoError(t, err)
 	checkListing(t, root, []string{"file1,0,false", "file2,0,false"})
 
 	// check the underlying r.Fremote but not the modtime

vfs/vfs_test.go

@@ -187,10 +187,10 @@ func TestVFSStatParent(t *testing.T) {
 	assert.Equal(t, "/", node.Name())
 	assert.Equal(t, "not found", leaf)
 
-	node, leaf, err = vfs.StatParent("not found dir/not found")
+	_, _, err = vfs.StatParent("not found dir/not found")
 	assert.Equal(t, os.ErrNotExist, err)
 
-	node, leaf, err = vfs.StatParent("file1/under a file")
+	_, _, err = vfs.StatParent("file1/under a file")
 	assert.Equal(t, os.ErrExist, err)
 }
 

vfs/write_test.go

@@ -85,6 +85,7 @@ func TestWriteFileHandleMethods(t *testing.T) {
 
 	// check vfs
 	root, err := vfs.Root()
+	require.NoError(t, err)
 	checkListing(t, root, []string{"file1,5,false"})
 
 	// check the underlying r.Fremote but not the modtime
@@ -101,6 +102,7 @@ func TestWriteFileHandleMethods(t *testing.T) {
 	// Check trying to open the file and writing it now it exists
 	// returns an error
 	h, err = vfs.OpenFile("file1", os.O_WRONLY|os.O_CREATE, 0777)
+	require.NoError(t, err)
 	_, err = h.Write([]byte("hello1"))
 	require.Equal(t, EPERM, err)
 	assert.NoError(t, h.Close())
@@ -115,6 +117,7 @@ func TestWriteFileHandleMethods(t *testing.T) {
 
 	// Check opening the file with O_TRUNC and writing does work
 	h, err = vfs.OpenFile("file1", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0777)
+	require.NoError(t, err)
 	_, err = h.WriteString("hello12")
 	require.NoError(t, err)
 	assert.NoError(t, h.Close())
@@ -159,6 +162,7 @@ func TestWriteFileHandleWriteAt(t *testing.T) {
 
 	// check vfs
 	root, err := vfs.Root()
+	require.NoError(t, err)
 	checkListing(t, root, []string{"file1,11,false"})
 
 	// check the underlying r.Fremote but not the modtime