all: Apply staticcheck recommendations

41 files changed, 98 insertions, 252 deletions

diff --git a/cache/filecache/filecache.go b/cache/filecache/filecache.go
index d4e3f5d6a..6ad417117 100644
--- a/cache/filecache/filecache.go
+++ b/cache/filecache/filecache.go
@@ -274,7 +274,7 @@ func (c *Cache) isExpired(modTime time.Time) bool {
 	if c.maxAge < 0 {
 		return false
 	}
-	return c.maxAge == 0 || time.Now().Sub(modTime) > c.maxAge
+	return c.maxAge == 0 || time.Since(modTime) > c.maxAge
 }
 
 // For testing
diff --git a/common/math/math.go b/common/math/math.go
index 3c5ef1f9d..cd06379aa 100644
--- a/common/math/math.go
+++ b/common/math/math.go
@@ -46,7 +46,7 @@ func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
 				bu = 0
 			}
 		default:
-			return nil, errors.New("Can't apply the operator to the values")
+			return nil, errors.New("can't apply the operator to the values")
 		}
 	case reflect.Float32, reflect.Float64:
 		af = av.Float()
@@ -58,7 +58,7 @@ func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
 		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
 			bf = float64(bv.Uint()) // may overflow
 		default:
-			return nil, errors.New("Can't apply the operator to the values")
+			return nil, errors.New("can't apply the operator to the values")
 		}
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
 		au = av.Uint()
@@ -79,7 +79,7 @@ func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
 		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
 			bu = bv.Uint()
 		default:
-			return nil, errors.New("Can't apply the operator to the values")
+			return nil, errors.New("can't apply the operator to the values")
 		}
 	case reflect.String:
 		as := av.String()
@@ -87,9 +87,9 @@ func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
 			bs := bv.String()
 			return as + bs, nil
 		}
-		return nil, errors.New("Can't apply the operator to the values")
+		return nil, errors.New("can't apply the operator to the values")
 	default:
-		return nil, errors.New("Can't apply the operator to the values")
+		return nil, errors.New("can't apply the operator to the values")
 	}
 
 	switch op {
@@ -128,8 +128,8 @@ func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
 		} else if bu != 0 {
 			return au / bu, nil
 		}
-		return nil, errors.New("Can't divide the value by 0")
+		return nil, errors.New("can't divide the value by 0")
 	default:
-		return nil, errors.New("There is no such an operation")
+		return nil, errors.New("there is no such an operation")
 	}
 }
diff --git a/create/content.go b/create/content.go
index 264a0f3ac..e48dfc078 100644
--- a/create/content.go
+++ b/create/content.go
@@ -142,6 +142,9 @@ func newContentFromDir(
 		}
 
 		out, err := targetFs.Create(targetFilename)
+		if err != nil {
+			return err
+		}
 
 		_, err = io.Copy(out, in)
 		if err != nil {
diff --git a/helpers/content.go b/helpers/content.go
index bc19f6559..be5090c21 100644
--- a/helpers/content.go
+++ b/helpers/content.go
@@ -147,10 +147,8 @@ func newBlackfriday(config map[string]interface{}) *BlackFriday {
 		siteConfig[k] = v
 	}
 
-	if config != nil {
-		for k, v := range config {
-			siteConfig[k] = v
-		}
+	for k, v := range config {
+		siteConfig[k] = v
 	}
 
 	combinedConfig := &BlackFriday{}
@@ -755,7 +753,7 @@ func externallyRenderContent(ctx *RenderingContext, path string, args []string)
 	err := cmd.Run()
 	// Most external helpers exit w/ non-zero exit code only if severe, i.e.
 	// halting errors occurred. -> log stderr output regardless of state of err
-	for _, item := range strings.Split(string(cmderr.Bytes()), "\n") {
+	for _, item := range strings.Split(cmderr.String(), "\n") {
 		item := strings.TrimSpace(item)
 		if item != "" {
 			jww.ERROR.Printf("%s: %s", ctx.DocumentName, item)
diff --git a/helpers/emoji_test.go b/helpers/emoji_test.go
index f9189eb43..89f9df5fa 100644
--- a/helpers/emoji_test.go
+++ b/helpers/emoji_test.go
@@ -80,7 +80,7 @@ func BenchmarkEmojiKyokomiFprint(b *testing.B) {
 		defer bufferpool.PutBuffer(buff)
 		emoji.Fprint(buff, string(in))
 
-		bc := make([]byte, buff.Len(), buff.Len())
+		bc := make([]byte, buff.Len())
 		copy(bc, buff.Bytes())
 		return bc
 	}
diff --git a/helpers/general.go b/helpers/general.go
index 962b35bc6..3cf7ba8af 100644
--- a/helpers/general.go
+++ b/helpers/general.go
@@ -57,7 +57,7 @@ func FindAvailablePort() (*net.TCPAddr, error) {
 		if a, ok := addr.(*net.TCPAddr); ok {
 			return a, nil
 		}
-		return nil, fmt.Errorf("Unable to obtain a valid tcp port. %v", addr)
+		return nil, fmt.Errorf("unable to obtain a valid tcp port: %v", addr)
 	}
 	return nil, err
 }
@@ -128,7 +128,7 @@ func ReaderToBytes(lines io.Reader) []byte {
 
 	b.ReadFrom(lines)
 
-	bc := make([]byte, b.Len(), b.Len())
+	bc := make([]byte, b.Len())
 	copy(bc, b.Bytes())
 	return bc
 }
@@ -417,10 +417,8 @@ func NormalizeHugoFlags(f *pflag.FlagSet, name string) pflag.NormalizedName {
 	switch name {
 	case "baseUrl":
 		name = "baseURL"
-		break
 	case "uglyUrls":
 		name = "uglyURLs"
-		break
 	}
 	return pflag.NormalizedName(name)
 }
diff --git a/helpers/path.go b/helpers/path.go
index de2c9b0a0..36bd3269b 100644
--- a/helpers/path.go
+++ b/helpers/path.go
@@ -29,6 +29,7 @@ import (
 	"github.com/gohugoio/hugo/common/hugio"
 	_errors "github.com/pkg/errors"
 	"github.com/spf13/afero"
+	"golang.org/x/text/runes"
 	"golang.org/x/text/transform"
 	"golang.org/x/text/unicode/norm"
 )
@@ -155,7 +156,7 @@ func (p *PathSpec) UnicodeSanitize(s string) string {
 
 	if p.RemovePathAccents {
 		// remove accents - see https://blog.golang.org/normalization
-		t := transform.Chain(norm.NFD, transform.RemoveFunc(isMn), norm.NFC)
+		t := transform.Chain(norm.NFD, runes.Remove(runes.In(unicode.Mn)), norm.NFC)
 		result, _, _ = transform.String(t, string(target))
 	} else {
 		result = string(target)
@@ -164,10 +165,6 @@ func (p *PathSpec) UnicodeSanitize(s string) string {
 	return result
 }
 
-func isMn(r rune) bool {
-	return unicode.Is(unicode.Mn, r) // Mn: nonspacing marks
-}
-
 // ReplaceExtension takes a path and an extension, strips the old extension
 // and returns the path with the new extension.
 func ReplaceExtension(path string, newExt string) string {
@@ -208,7 +205,7 @@ func makePathRelative(inPath string, possibleDirectories ...string) (string, err
 			return strings.TrimPrefix(inPath, currentPath), nil
 		}
 	}
-	return inPath, errors.New("Can't extract relative path, unknown prefix")
+	return inPath, errors.New("can't extract relative path, unknown prefix")
 }
 
 // Should be good enough for Hugo.
@@ -403,15 +400,13 @@ func ExtractRootPaths(paths []string) []string {
 
 }
 
-var numInPathRe = regexp.MustCompile("\\.(\\d+)\\.")
-
 // FindCWD returns the current working directory from where the Hugo
 // executable is run.
 func FindCWD() (string, error) {
 	serverFile, err := filepath.Abs(os.Args[0])
 
 	if err != nil {
-		return "", fmt.Errorf("Can't get absolute path for executable: %v", err)
+		return "", fmt.Errorf("can't get absolute path for executable: %v", err)
 	}
 
 	path := filepath.Dir(serverFile)
@@ -437,7 +432,7 @@ func SymbolicWalk(fs afero.Fs, root string, walker filepath.WalkFunc) error {
 
 	// Sanity check
 	if root != "" && len(root) < 4 {
-		return errors.New("Path is too short")
+		return errors.New("path is too short")
 	}
 
 	// Handle the root first
@@ -448,7 +443,7 @@ func SymbolicWalk(fs afero.Fs, root string, walker filepath.WalkFunc) error {
 	}
 
 	if !fileInfo.IsDir() {
-		return fmt.Errorf("Cannot walk regular file %s", root)
+		return fmt.Errorf("cannot walk regular file %s", root)
 	}
 
 	if err := walker(realPath, fileInfo, err); err != nil && err != filepath.SkipDir {
diff --git a/helpers/path_test.go b/helpers/path_test.go
index c249a519d..98291936c 100644
--- a/helpers/path_test.go
+++ b/helpers/path_test.go
@@ -171,7 +171,7 @@ func TestGetRealPath(t *testing.T) {
 		t.Skip("Skip TestGetRealPath as os.Symlink needs administrator rights on Windows")
 	}
 
-	d1, err := ioutil.TempDir("", "d1")
+	d1, _ := ioutil.TempDir("", "d1")
 	defer os.Remove(d1)
 	fs := afero.NewOsFs()
 
@@ -418,6 +418,7 @@ func createNonZeroSizedFileInTempDir() (*os.File, error) {
 	f, err := createZeroSizedFileInTempDir()
 	if err != nil {
 		// no file ??
+		return nil, err
 	}
 	byteString := []byte("byteString")
 	err = ioutil.WriteFile(f.Name(), byteString, 0644)
@@ -430,10 +431,7 @@ func createNonZeroSizedFileInTempDir() (*os.File, error) {
 }
 
 func deleteFileInTempDir(f *os.File) {
-	err := os.Remove(f.Name())
-	if err != nil {
-		// now what?
-	}
+	_ = os.Remove(f.Name())
 }
 
 func createEmptyTempDir() (string, error) {
@@ -449,7 +447,7 @@ func createEmptyTempDir() (string, error) {
 func createTempDirWithZeroLengthFiles() (string, error) {
 	d, dirErr := createEmptyTempDir()
 	if dirErr != nil {
-		//now what?
+		return "", dirErr
 	}
 	filePrefix := "_path_test_"
 	_, fileErr := ioutil.TempFile(d, filePrefix) // dir is os.TempDir()
@@ -467,7 +465,7 @@ func createTempDirWithZeroLengthFiles() (string, error) {
 func createTempDirWithNonZeroLengthFiles() (string, error) {
 	d, dirErr := createEmptyTempDir()
 	if dirErr != nil {
-		//now what?
+		return "", dirErr
 	}
 	filePrefix := "_path_test_"
 	f, fileErr := ioutil.TempFile(d, filePrefix) // dir is os.TempDir()
@@ -494,10 +492,7 @@ func createTempDirWithNonZeroLengthFiles() (string, error) {
 }
 
 func deleteTempDir(d string) {
-	err := os.RemoveAll(d)
-	if err != nil {
-		// now what?
-	}
+	_ = os.RemoveAll(d)
 }
 
 func TestExists(t *testing.T) {
diff --git a/helpers/pygments.go b/helpers/pygments.go
index 64c5b3ea8..0fe1e7592 100644
--- a/helpers/pygments.go
+++ b/helpers/pygments.go
@@ -153,7 +153,7 @@ func (h highlighters) pygmentsHighlight(code, lang, optsStr string) (string, err
 		return code, err
 	}
 
-	str := string(normalizeExternalHelperLineFeeds([]byte(out.String())))
+	str := string(normalizeExternalHelperLineFeeds(out.Bytes()))
 
 	str = h.injectCodeTag(str, lang)
 
@@ -235,10 +235,8 @@ func parseOptions(defaults map[string]string, in string) (map[string]string, err
 	in = strings.Trim(in, " ")
 	opts := make(map[string]string)
 
-	if defaults != nil {
-		for k, v := range defaults {
-			opts[k] = v
-		}
+	for k, v := range defaults {
+		opts[k] = v
 	}
 
 	if in == "" {
diff --git a/helpers/url.go b/helpers/url.go
index a24f05b12..6dbdea299 100644
--- a/helpers/url.go
+++ b/helpers/url.go
@@ -142,7 +142,7 @@ func MakePermalink(host, plink string) *url.URL {
 	}
 
 	if p.Host != "" {
-		panic(fmt.Errorf("Can't make permalink from absolute link %q", plink))
+		panic(fmt.Errorf("can't make permalink from absolute link %q", plink))
 	}
 
 	base.Path = path.Join(base.Path, p.Path)
diff --git a/hugofs/language_composite_fs_test.go b/hugofs/language_composite_fs_test.go
index bb4ddf701..ab4e25fc0 100644
--- a/hugofs/language_composite_fs_test.go
+++ b/hugofs/language_composite_fs_test.go
@@ -70,6 +70,7 @@ func TestCompositeLanguagFsTest(t *testing.T) {
 	assert.NoError(err)
 	defer f.Close()
 	files, err := f.Readdir(-1)
+	assert.NoError(err)
 	assert.Equal(4, len(files))
 	expected := map[string]bool{
 		filepath.FromSlash("/content/en/f1.txt"):    true,
diff --git a/hugolib/filesystems/basefs.go b/hugolib/filesystems/basefs.go
index ee1c870d9..d88141efd 100644
--- a/hugolib/filesystems/basefs.go
+++ b/hugolib/filesystems/basefs.go
@@ -17,7 +17,6 @@ package filesystems
 
 import (
 	"errors"
-	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -759,22 +758,3 @@ func removeDuplicatesKeepRight(in []string) []string {
 
 	return out
 }
-
-func printFs(fs afero.Fs, path string, w io.Writer) {
-	if fs == nil {
-		return
-	}
-	afero.Walk(fs, path, func(path string, info os.FileInfo, err error) error {
-		if info != nil && !info.IsDir() {
-			s := path
-			if lang, ok := info.(hugofs.LanguageAnnouncer); ok {
-				s = s + "\tLANG: " + lang.Lang()
-			}
-			if fp, ok := info.(hugofs.FilePather); ok {
-				s = s + "\tRF: " + fp.Filename() + "\tBP: " + fp.BaseDir()
-			}
-			fmt.Fprintln(w, "    ", s)
-		}
-		return nil
-	})
-}
diff --git a/hugolib/page.go b/hugolib/page.go
index 24d659fb1..576342cfa 100644
--- a/hugolib/page.go
+++ b/hugolib/page.go
@@ -20,12 +20,10 @@ import (
 	"os"
 	"path"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strings"
 
 	"github.com/bep/gitmap"
-	"github.com/spf13/cast"
 
 	"github.com/gohugoio/hugo/helpers"
 
@@ -831,19 +829,6 @@ func (ps pageStatePages) findPagePosByFilnamePrefix(prefix string) int {
 	return currPos
 }
 
-func content(c resource.ContentProvider) string {
-	cc, err := c.Content()
-	if err != nil {
-		panic(err)
-	}
-
-	ccs, err := cast.ToStringE(cc)
-	if err != nil {
-		panic(err)
-	}
-	return ccs
-}
-
 func (s *Site) sectionsFromFile(fi source.File) []string {
 	dirname := fi.Dir()
 	dirname = strings.Trim(dirname, helpers.FilePathSeparator)
@@ -861,9 +846,3 @@ func (s *Site) sectionsFromFile(fi source.File) []string {
 
 	return parts
 }
-
-func printStackTrace(length int) string {
-	trace := make([]byte, length)
-	runtime.Stack(trace, true)
-	return string(trace)
-}
diff --git a/hugolib/paths/baseURL.go b/hugolib/paths/baseURL.go
index de36c8636..a3c7e9d27 100644
--- a/hugolib/paths/baseURL.go
+++ b/hugolib/paths/baseURL.go
@@ -62,7 +62,7 @@ func (b BaseURL) WithProtocol(protocol string) (string, error) {
 	if isFullProtocol && u.Opaque != "" {
 		u.Opaque = "//" + u.Opaque
 	} else if isOpaqueProtocol && u.Opaque == "" {
-		return "", fmt.Errorf("Cannot determine BaseURL for protocol %q", protocol)
+		return "", fmt.Errorf("cannot determine BaseURL for protocol %q", protocol)
 	}
 
 	return u.String(), nil
diff --git a/hugolib/site.go b/hugolib/site.go
index be70db5ee..145ae2d49 100644
--- a/hugolib/site.go
+++ b/hugolib/site.go
@@ -67,9 +67,6 @@ import (
 	"github.com/spf13/viper"
 )
 
-// used to indicate if run as a test.
-var testMode bool
-
 // Site contains all the information relevant for constructing a static
 // site.  The basic flow of information is as follows:
 //
diff --git a/hugolib/site_test.go b/hugolib/site_test.go
index 98fe1ff4f..21575072d 100644
--- a/hugolib/site_test.go
+++ b/hugolib/site_test.go
@@ -35,10 +35,6 @@ const (
 	templateWithURLAbs  = "<a href=\"/foobar.jpg\">Going</a>"
 )
 
-func init() {
-	testMode = true
-}
-
 func TestRenderWithInvalidTemplate(t *testing.T) {
 	t.Parallel()
 	cfg, fs := newTestCfg()
diff --git a/hugolib/testhelpers_test.go b/hugolib/testhelpers_test.go
index 7de2280c7..0a8fbe7f5 100644
--- a/hugolib/testhelpers_test.go
+++ b/hugolib/testhelpers_test.go
@@ -20,6 +20,7 @@ import (
 	"github.com/gohugoio/hugo/resources/page"
 	"github.com/sanity-io/litter"
 	"github.com/spf13/afero"
+	"github.com/spf13/cast"
 
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/tpl"
@@ -27,6 +28,8 @@ import (
 
 	"os"
 
+	"github.com/gohugoio/hugo/resources/resource"
+
 	"github.com/gohugoio/hugo/common/loggers"
 	"github.com/gohugoio/hugo/hugofs"
 	"github.com/stretchr/testify/assert"
@@ -672,6 +675,19 @@ func getPage(in page.Page, ref string) page.Page {
 	return p
 }
 
+func content(c resource.ContentProvider) string {
+	cc, err := c.Content()
+	if err != nil {
+		panic(err)
+	}
+
+	ccs, err := cast.ToStringE(cc)
+	if err != nil {
+		panic(err)
+	}
+	return ccs
+}
+
 func dumpPages(pages ...page.Page) {
 	fmt.Println("---------")
 	for i, p := range pages {
@@ -726,11 +742,3 @@ func parallel(t *testing.T) {
 		t.Parallel()
 	}
 }
-
-// Useful to debug nilpointers/panics in templates.
-// Put "defer recoverStack()" in top of the failing function.
-func recoverStack() {
-	if r := recover(); r != nil {
-		fmt.Println(printStackTrace(1000))
-	}
-}
diff --git a/minifiers/minifiers.go b/minifiers/minifiers.go
index db2251b68..9533ebb69 100644
--- a/minifiers/minifiers.go
+++ b/minifiers/minifiers.go
@@ -80,7 +80,7 @@ func New(mediaTypes media.Types, outputFormats output.Formats) Client {
 	addMinifier(m, mediaTypes, "css", cssMin)
 	addMinifierFunc(m, mediaTypes, "js", js.Minify)
 	m.AddFuncRegexp(regexp.MustCompile("^(application|text)/(x-)?(java|ecma)script$"), js.Minify)
-	m.AddFuncRegexp(regexp.MustCompile("^(application|text)/(x-|ld\\+)?json$"), json.Minify)
+	m.AddFuncRegexp(regexp.MustCompile(`^(application|text)/(x-|ld\+)?json$`), json.Minify)
 	addMinifierFunc(m, mediaTypes, "json", json.Minify)
 	addMinifierFunc(m, mediaTypes, "svg", svg.Minify)
 	addMinifierFunc(m, mediaTypes, "xml", xml.Minify)
diff --git a/parser/frontmatter.go b/parser/frontmatter.go
index ab1bc4d55..4965d3fe8 100644
--- a/parser/frontmatter.go
+++ b/parser/frontmatter.go
@@ -22,7 +22,7 @@ import (
 
 	"github.com/BurntSushi/toml"
 
-	"gopkg.in/yaml.v2"
+	yaml "gopkg.in/yaml.v2"
 )
 
 const (
@@ -62,7 +62,7 @@ func InterfaceToConfig(in interface{}, format metadecoders.Format, w io.Writer)
 		return err
 
 	default:
-		return errors.New("Unsupported Format provided")
+		return errors.New("unsupported Format provided")
 	}
 }
 
diff --git a/parser/pageparser/pagelexer.go b/parser/pageparser/pagelexer.go
index 11723f279..d010c8152 100644
--- a/parser/pageparser/pagelexer.go
+++ b/parser/pageparser/pagelexer.go
@@ -442,13 +442,6 @@ func lexMainSection(l *pageLexer) stateFunc {
 
 }
 
-func (l *pageLexer) posFirstNonWhiteSpace() int {
-	f := func(c rune) bool {
-		return !unicode.IsSpace(c)
-	}
-	return bytes.IndexFunc(l.input[l.pos:], f)
-}
-
 func lexDone(l *pageLexer) stateFunc {
 
 	// Done!
@@ -477,14 +470,6 @@ func (l *pageLexer) hasPrefix(prefix []byte) bool {
 	return bytes.HasPrefix(l.input[l.pos:], prefix)
 }
 
-func (l *pageLexer) hasPrefixByte(prefix byte) bool {
-	b := l.input[l.pos:]
-	if len(b) == 0 {
-		return false
-	}
-	return b[0] == prefix
-}
-
 // helper functions
 
 // returns the min index >= 0
diff --git a/releaser/releaser.go b/releaser/releaser.go
index 0c0765a71..01c1d5219 100644
--- a/releaser/releaser.go
+++ b/releaser/releaser.go
@@ -102,7 +102,7 @@ func (r *ReleaseHandler) Run() error {
 	}
 
 	if exists {
-		return fmt.Errorf("Tag %q already exists", tag)
+		return fmt.Errorf("tag %q already exists", tag)
 	}
 
 	var changeLogFromTag string
diff --git a/resources/image_test.go b/resources/image_test.go
index ffa482296..fd1eb5410 100644
--- a/resources/image_test.go
+++ b/resources/image_test.go
@@ -171,21 +171,21 @@ func TestImageTransformConcurrent(t *testing.T) {
 				for k := 0; k < 2; k++ {
 					r1, err := img.Resize(fmt.Sprintf("%dx", id-k))
 					if err != nil {
-						t.Fatal(err)
+						t.Error(err)
 					}
 
 					if r1.Width() != id-k {
-						t.Fatalf("Width: %d:%d", r1.Width(), j)
+						t.Errorf("Width: %d:%d", r1.Width(), j)
 					}
 
 					r2, err := r1.Resize(fmt.Sprintf("%dx", id-k-1))
 					if err != nil {
-						t.Fatal(err)
+						t.Error(err)
 					}
 
 					_, err = r2.decodeSource()
 					if err != nil {
-						t.Fatal("Err decode:", err)
+						t.Error("Err decode:", err)
 					}
 
 					img = r1
diff --git a/source/fileInfo.go b/source/fileInfo.go
index 752f104e8..3f262fb5e 100644
--- a/source/fileInfo.go
+++ b/source/fileInfo.go
@@ -14,8 +14,6 @@
 package source
 
 import (
-	"fmt"
-	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -23,8 +21,6 @@ import (
 
 	"github.com/gohugoio/hugo/common/hugio"
 
-	"github.com/spf13/afero"
-
 	"github.com/gohugoio/hugo/hugofs"
 
 	"github.com/gohugoio/hugo/helpers"
@@ -286,24 +282,3 @@ func (sp *SourceSpec) NewFileInfo(baseDir, filename string, isLeafBundle bool, f
 	return f
 
 }
-
-func printFs(fs afero.Fs, path string, w io.Writer) {
-	if fs == nil {
-		return
-	}
-	afero.Walk(fs, path, func(path string, info os.FileInfo, err error) error {
-
-		if info != nil && !info.IsDir() {
-
-			s := path
-			if lang, ok := info.(hugofs.LanguageAnnouncer); ok {
-				s = s + "\t" + lang.Lang()
-			}
-			if fp, ok := info.(hugofs.FilePather); ok {
-				s = s + "\t" + fp.Filename()
-			}
-			fmt.Fprintln(w, "    ", s)
-		}
-		return nil
-	})
-}
diff --git a/source/filesystem_test.go b/source/filesystem_test.go
index 2c1eeb171..8c8e30413 100644
--- a/source/filesystem_test.go
+++ b/source/filesystem_test.go
@@ -32,14 +32,6 @@ func TestEmptySourceFilesystem(t *testing.T) {
 	}
 }
 
-type TestPath struct {
-	filename string
-	logical  string
-	content  string
-	section  string
-	dir      string
-}
-
 func TestUnicodeNorm(t *testing.T) {
 	if runtime.GOOS != "darwin" {
 		// Normalization code is only for Mac OS, since it is not necessary for other OSes.
diff --git a/source/filesystem_unix_test.go b/source/filesystem_unix_test.go
deleted file mode 100644
index 560d824ae..000000000
--- a/source/filesystem_unix_test.go
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright 2015 The Hugo Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build linux darwin !windows
-
-package source
-
-//
-// NOTE, any changes here need to be reflected in filesystem_windows_test.go
-//
-var platformBase = "/base/"
-var platformPaths = []TestPath{
-	{"foobar", "foobar", "aaa", "", ""},
-	{"b/1file", "1file", "aaa", "b", "b/"},
-	{"c/d/2file", "2file", "aaa", "c", "c/d/"},
-	{"/base/e/f/3file", "3file", "aaa", "e", "e/f/"},
-	{"section/foo.rss", "foo.rss", "aaa", "section", "section/"},
-}
diff --git a/source/filesystem_windows_test.go b/source/filesystem_windows_test.go
deleted file mode 100644
index 4662c5fd6..000000000
--- a/source/filesystem_windows_test.go
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright 2015 The Hugo Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package source
-
-//
-// NOTE, any changes here need to be reflected in filesystem_linux_test.go
-//
-
-// Note the case of the volume drive.  It must be the same in all examples.
-var platformBase = "C:\\foo\\"
-var platformPaths = []TestPath{
-	{"foobar", "foobar", "aaa", "", ""},
-	{"b\\1file", "1file", "aaa", "b", "b\\"},
-	{"c\\d\\2file", "2file", "aaa", "c", "c\\d\\"},
-	{"C:\\foo\\e\\f\\3file", "3file", "aaa", "e", "e\\f\\"}, // note volume case is equal to platformBase
-	{"section\\foo.rss", "foo.rss", "aaa", "section", "section\\"},
-}
diff --git a/source/sourceSpec.go b/source/sourceSpec.go
index 13aac4592..9731a8d8d 100644
--- a/source/sourceSpec.go
+++ b/source/sourceSpec.go
@@ -124,6 +124,10 @@ func (s *SourceSpec) IsRegularSourceFile(filename string) (bool, error) {
 
 	if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
 		link, err := filepath.EvalSymlinks(filename)
+		if err != nil {
+			return false, err
+		}
+
 		fi, err = helpers.LstatIfPossible(s.SourceFs, link)
 		if err != nil {
 			return false, err
diff --git a/tpl/collections/reflect_helpers.go b/tpl/collections/reflect_helpers.go
index fca65481f..69425fcb0 100644
--- a/tpl/collections/reflect_helpers.go
+++ b/tpl/collections/reflect_helpers.go
@@ -38,7 +38,7 @@ func numberToFloat(v reflect.Value) (float64, error) {
 	case kind == reflect.Interface:
 		return numberToFloat(v.Elem())
 	default:
-		return 0, fmt.Errorf("Invalid kind %s in numberToFloat", kind)
+		return 0, fmt.Errorf("invalid kind %s in numberToFloat", kind)
 	}
 }
 
diff --git a/tpl/data/data.go b/tpl/data/data.go
index 81fde9d70..15f039294 100644
--- a/tpl/data/data.go
+++ b/tpl/data/data.go
@@ -58,18 +58,18 @@ func (ns *Namespace) GetCSV(sep string, urlParts ...string) (d [][]string, err e
 	url := strings.Join(urlParts, "")
 	cache := ns.cacheGetCSV
 
-	unmarshal := func(b []byte) (error, bool) {
+	unmarshal := func(b []byte) (bool, error) {
 		if !bytes.Contains(b, []byte(sep)) {
-			return _errors.Errorf("cannot find separator %s in CSV for %s", sep, url), false
+			return false, _errors.Errorf("cannot find separator %s in CSV for %s", sep, url)
 		}
 
 		if d, err = parseCSV(b, sep); err != nil {
 			err = _errors.Wrapf(err, "failed to parse CSV file %s", url)
 
-			return err, true
+			return true, err
 		}
 
-		return nil, false
+		return false, nil
 	}
 
 	var req *http.Request
@@ -103,12 +103,12 @@ func (ns *Namespace) GetJSON(urlParts ...string) (interface{}, error) {
 		return nil, _errors.Wrapf(err, "Failed to create request for getJSON resource %s", url)
 	}
 
-	unmarshal := func(b []byte) (error, bool) {
+	unmarshal := func(b []byte) (bool, error) {
 		err := json.Unmarshal(b, &v)
 		if err != nil {
-			return err, true
+			return true, err
 		}
-		return nil, false
+		return false, nil
 	}
 
 	req.Header.Add("Accept", "application/json")
diff --git a/tpl/data/resources.go b/tpl/data/resources.go
index 8b246a662..7de440ca6 100644
--- a/tpl/data/resources.go
+++ b/tpl/data/resources.go
@@ -34,7 +34,7 @@ var (
 )
 
 // getRemote loads the content of a remote file. This method is thread safe.
-func (ns *Namespace) getRemote(cache *filecache.Cache, unmarshal func([]byte) (error, bool), req *http.Request) error {
+func (ns *Namespace) getRemote(cache *filecache.Cache, unmarshal func([]byte) (bool, error), req *http.Request) error {
 	url := req.URL.String()
 	id := helpers.MD5String(url)
 	var handled bool
@@ -63,7 +63,7 @@ func (ns *Namespace) getRemote(cache *filecache.Cache, unmarshal func([]byte) (e
 			}
 			res.Body.Close()
 
-			err, retry = unmarshal(b)
+			retry, err = unmarshal(b)
 
 			if err == nil {
 				// Return it so it can be cached.
@@ -85,7 +85,7 @@ func (ns *Namespace) getRemote(cache *filecache.Cache, unmarshal func([]byte) (e
 
 	if !handled {
 		// This is cached content and should be correct.
-		err, _ = unmarshal(b)
+		_, err = unmarshal(b)
 	}
 
 	return err
@@ -104,14 +104,14 @@ func getLocal(url string, fs afero.Fs, cfg config.Provider) ([]byte, error) {
 
 // getResource loads the content of a local or remote file and returns its content and the
 // cache ID used, if relevant.
-func (ns *Namespace) getResource(cache *filecache.Cache, unmarshal func(b []byte) (error, bool), req *http.Request) error {
+func (ns *Namespace) getResource(cache *filecache.Cache, unmarshal func(b []byte) (bool, error), req *http.Request) error {
 	switch req.URL.Scheme {
 	case "":
 		b, err := getLocal(req.URL.String(), ns.deps.Fs.Source, ns.deps.Cfg)
 		if err != nil {
 			return err
 		}
-		err, _ = unmarshal(b)
+		_, err = unmarshal(b)
 		return err
 	default:
 		return ns.getRemote(cache, unmarshal, req)
diff --git a/tpl/data/resources_test.go b/tpl/data/resources_test.go
index d1091b23f..a42232f94 100644
--- a/tpl/data/resources_test.go
+++ b/tpl/data/resources_test.go
@@ -114,9 +114,9 @@ func TestScpGetRemote(t *testing.T) {
 		ns.client = cl
 
 		var c []byte
-		f := func(b []byte) (error, bool) {
+		f := func(b []byte) (bool, error) {
 			c = b
-			return nil, false
+			return false, nil
 		}
 
 		err = ns.getRemote(cache, f, req)
@@ -158,15 +158,15 @@ func TestScpGetRemoteParallel(t *testing.T) {
 				defer wg.Done()
 				for j := 0; j < 10; j++ {
 					var c []byte
-					f := func(b []byte) (error, bool) {
+					f := func(b []byte) (bool, error) {
 						c = b
-						return nil, false
+						return false, nil
 					}
 					err := ns.getRemote(ns.cacheGetJSON, f, req)
 
 					assert.NoError(t, err)
 					if string(content) != string(c) {
-						t.Fatalf("expected\n%q\ngot\n%q", content, c)
+						t.Errorf("expected\n%q\ngot\n%q", content, c)
 					}
 
 					time.Sleep(23 * time.Millisecond)
diff --git a/tpl/math/math.go b/tpl/math/math.go
index 0bc813dce..08be42b47 100644
--- a/tpl/math/math.go
+++ b/tpl/math/math.go
@@ -78,11 +78,11 @@ func (ns *Namespace) Mod(a, b interface{}) (int64, error) {
 	bi, errb := cast.ToInt64E(b)
 
 	if erra != nil || errb != nil {
-		return 0, errors.New("Modulo operator can't be used with non integer value")
+		return 0, errors.New("modulo operator can't be used with non integer value")
 	}
 
 	if bi == 0 {
-		return 0, errors.New("The number can't be divided by zero at modulo operation")
+		return 0, errors.New("the number can't be divided by zero at modulo operation")
 	}
 
 	return ai % bi, nil
diff --git a/tpl/os/os.go b/tpl/os/os.go
index cc4a42d5d..2dab5c490 100644
--- a/tpl/os/os.go
+++ b/tpl/os/os.go
@@ -73,7 +73,7 @@ func readFile(fs afero.Fs, filename string) (string, error) {
 
 	if info, err := fs.Stat(filename); err == nil {
 		if info.Size() > 1000000 {
-			return "", fmt.Errorf("File %q is too big", filename)
+			return "", fmt.Errorf("file %q is too big", filename)
 		}
 	} else {
 		return "", err
@@ -108,7 +108,7 @@ func (ns *Namespace) ReadDir(i interface{}) ([]_os.FileInfo, error) {
 
 	list, err := afero.ReadDir(ns.deps.Fs.WorkingDir, path)
 	if err != nil {
-		return nil, fmt.Errorf("Failed to read Directory %s with error message %s", path, err)
+		return nil, fmt.Errorf("failed to read directory %q: %s", path, err)
 	}
 
 	return list, nil
diff --git a/tpl/partials/partials.go b/tpl/partials/partials.go
index ece16276d..1e8a84954 100644
--- a/tpl/partials/partials.go
+++ b/tpl/partials/partials.go
@@ -107,7 +107,7 @@ func (ns *Namespace) Include(name string, contextList ...interface{}) (interface
 
 	}
 
-	return "", fmt.Errorf("Partial %q not found", name)
+	return "", fmt.Errorf("partial %q not found", name)
 }
 
 // IncludeCached executes and caches partial templates.  An optional variant
diff --git a/tpl/template.go b/tpl/template.go
index 07152166a..01f79c407 100644
--- a/tpl/template.go
+++ b/tpl/template.go
@@ -152,7 +152,7 @@ func (t *TemplateAdapter) Execute(w io.Writer, data interface{}) (execErr error)
 		// Panics in templates are a little bit too common (nil pointers etc.)
 		// See https://github.com/gohugoio/hugo/issues/5327
 		if r := recover(); r != nil {
-			execErr = t.addFileContext(t.Name(), fmt.Errorf(`panic in Execute: %s. See "https://github.com/gohugoio/hugo/issues/5327" for the reason why we cannot provide a better error message for this.`, r))
+			execErr = t.addFileContext(t.Name(), fmt.Errorf(`panic in Execute: %s. See "https://github.com/gohugoio/hugo/issues/5327" for the reason why we cannot provide a better error message for this`, r))
 		}
 	}()
 
@@ -174,7 +174,7 @@ func (t *TemplateAdapter) TemplateInfo() Info {
 
 // The identifiers may be truncated in the log, e.g.
 // "executing "main" at <$scaled.SRelPermalin...>: can't evaluate field SRelPermalink in type *resource.Image"
-var identifiersRe = regexp.MustCompile("at \\<(.*?)(\\.{3})?\\>:")
+var identifiersRe = regexp.MustCompile(`at \<(.*?)(\.{3})?\>:`)
 
 func (t *TemplateAdapter) extractIdentifiers(line string) []string {
 	m := identifiersRe.FindAllStringSubmatch(line, -1)
diff --git a/tpl/tplimpl/embedded/generate/generate.go b/tpl/tplimpl/embedded/generate/generate.go
index a48e00756..df4de4799 100644
--- a/tpl/tplimpl/embedded/generate/generate.go
+++ b/tpl/tplimpl/embedded/generate/generate.go
@@ -39,6 +39,9 @@ func main() {
 	var nameValues []string
 
 	err = filepath.Walk(temlatePath, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
 
 		if info.IsDir() {
 			return nil
diff --git a/tpl/transform/remarshal.go b/tpl/transform/remarshal.go
index 62d826b43..182bd21d6 100644
--- a/tpl/transform/remarshal.go
+++ b/tpl/transform/remarshal.go
@@ -41,6 +41,9 @@ func (ns *Namespace) Remarshal(format string, data interface{}) (string, error)
 	}
 
 	meta, err := metadecoders.Default.UnmarshalToMap([]byte(from), fromFormat)
+	if err != nil {
+		return "", err
+	}
 
 	var result bytes.Buffer
 	if err := parser.InterfaceToConfig(meta, mark, &result); err != nil {
diff --git a/transform/chain_test.go b/transform/chain_test.go
index e34024296..a8d59f902 100644
--- a/transform/chain_test.go
+++ b/transform/chain_test.go
@@ -58,8 +58,8 @@ func TestChaingMultipleTransformers(t *testing.T) {
 
 	expected := "Test: f4r f3r f1r f2r f1r The End."
 
-	if string(out.Bytes()) != expected {
-		t.Errorf("Expected %s got %s", expected, string(out.Bytes()))
+	if out.String() != expected {
+		t.Errorf("Expected %s got %s", expected, out.String())
 	}
 }
 
diff --git a/transform/livereloadinject/livereloadinject_test.go b/transform/livereloadinject/livereloadinject_test.go
index 0e0f708d3..1058244b4 100644
--- a/transform/livereloadinject/livereloadinject_test.go
+++ b/transform/livereloadinject/livereloadinject_test.go
@@ -35,7 +35,7 @@ func doTestLiveReloadInject(t *testing.T, bodyEndTag string) {
 	tr.Apply(out, in)
 
 	expected := fmt.Sprintf(`<script data-no-instant>document.write('<script src="/livereload.js?port=1313&mindelay=10"></' + 'script>')</script>%s`, bodyEndTag)
-	if string(out.Bytes()) != expected {
-		t.Errorf("Expected %s got %s", expected, string(out.Bytes()))
+	if out.String() != expected {
+		t.Errorf("Expected %s got %s", expected, out.String())
 	}
 }
diff --git a/transform/urlreplacers/absurlreplacer.go b/transform/urlreplacers/absurlreplacer.go
index 02083d9f5..545df914a 100644
--- a/transform/urlreplacers/absurlreplacer.go
+++ b/transform/urlreplacers/absurlreplacer.go
@@ -37,8 +37,6 @@ type absurllexer struct {
 	quotes [][]byte
 }
 
-type stateFunc func(*absurllexer) stateFunc
-
 type prefix struct {
 	disabled bool
 	b        []byte
@@ -54,11 +52,6 @@ func newPrefixState() []*prefix {
 	}
 }
 
-type absURLMatcher struct {
-	match []byte
-	quote []byte
-}
-
 func (l *absurllexer) emit() {
 	l.w.Write(l.content[l.start:l.pos])
 	l.start = l.pos
diff --git a/transform/urlreplacers/absurlreplacer_test.go b/transform/urlreplacers/absurlreplacer_test.go
index f7a5b1656..3c2dbf777 100644
--- a/transform/urlreplacers/absurlreplacer_test.go
+++ b/transform/urlreplacers/absurlreplacer_test.go
@@ -41,7 +41,6 @@ const (
 	replace1 = "No replacements."
 	replace2 = "ᚠᛇᚻ ᛒᛦᚦ ᚠᚱᚩᚠᚢᚱ\nᚠᛁᚱᚪ ᚷᛖᚻᚹᛦᛚᚳᚢᛗ"
 	replace3 = `End of file: src="/`
-	replace4 = `End of file: srcset="/`
 	replace5 = `Srcsett with no closing quote: srcset="/img/small.jpg do be do be do.`
 
 	// Issue: 816, schemaless links combined with others