diff --git a/modules/analyze/generated.go b/modules/analyze/generated.go
new file mode 100644
index 00000000000..0f14d285452
--- /dev/null
+++ b/modules/analyze/generated.go
@@ -0,0 +1,28 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package analyze
+
+import (
+	"path/filepath"
+	"strings"
+
+	"github.com/go-enry/go-enry/v2/data"
+)
+
+// IsGenerated returns whether or not path is a generated path.
+func IsGenerated(path string) bool {
+	ext := strings.ToLower(filepath.Ext(path))
+	if _, ok := data.GeneratedCodeExtensions[ext]; ok {
+		return true
+	}
+
+	for _, m := range data.GeneratedCodeNameMatchers {
+		if m(path) {
+			return true
+		}
+	}
+
+	return false
+}
diff --git a/modules/git/repo_attribute.go b/modules/git/repo_attribute.go
index aa5e4c10e70..0bd7d7e49c9 100644
--- a/modules/git/repo_attribute.go
+++ b/modules/git/repo_attribute.go
@@ -6,7 +6,12 @@ package git
 
 import (
 	"bytes"
+	"context"
 	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
 )
 
 // CheckAttributeOpts represents the possible options to CheckAttribute
@@ -21,7 +26,7 @@ type CheckAttributeOpts struct {
 func (repo *Repository) CheckAttribute(opts CheckAttributeOpts) (map[string]map[string]string, error) {
 	err := LoadGitVersion()
 	if err != nil {
-		return nil, fmt.Errorf("Git version missing: %v", err)
+		return nil, fmt.Errorf("git version missing: %v", err)
 	}
 
 	stdOut := new(bytes.Buffer)
@@ -55,13 +60,14 @@ func (repo *Repository) CheckAttribute(opts CheckAttributeOpts) (map[string]map[
 	cmd := NewCommand(cmdArgs...)
 
 	if err := cmd.RunInDirPipeline(repo.Path, stdOut, stdErr); err != nil {
-		return nil, fmt.Errorf("Failed to run check-attr: %v\n%s\n%s", err, stdOut.String(), stdErr.String())
+		return nil, fmt.Errorf("failed to run check-attr: %v\n%s\n%s", err, stdOut.String(), stdErr.String())
 	}
 
+	// FIXME: This is incorrect on versions < 1.8.5
 	fields := bytes.Split(stdOut.Bytes(), []byte{'\000'})
 
 	if len(fields)%3 != 1 {
-		return nil, fmt.Errorf("Wrong number of fields in return from check-attr")
+		return nil, fmt.Errorf("wrong number of fields in return from check-attr")
 	}
 
 	var name2attribute2info = make(map[string]map[string]string)
@@ -80,3 +86,276 @@ func (repo *Repository) CheckAttribute(opts CheckAttributeOpts) (map[string]map[
 
 	return name2attribute2info, nil
 }
+
+// CheckAttributeReader provides a reader for check-attribute content that can be long running
+type CheckAttributeReader struct {
+	// params
+	Attributes []string
+	Repo       *Repository
+	IndexFile  string
+	WorkTree   string
+
+	stdinReader io.ReadCloser
+	stdinWriter *os.File
+	stdOut      attributeWriter
+	cmd         *Command
+	env         []string
+	ctx         context.Context
+	cancel      context.CancelFunc
+	running     chan struct{}
+}
+
+// Init initializes the cmd
+func (c *CheckAttributeReader) Init(ctx context.Context) error {
+	c.running = make(chan struct{})
+	cmdArgs := []string{"check-attr", "--stdin", "-z"}
+
+	if len(c.IndexFile) > 0 && CheckGitVersionAtLeast("1.7.8") == nil {
+		cmdArgs = append(cmdArgs, "--cached")
+		c.env = []string{"GIT_INDEX_FILE=" + c.IndexFile}
+	}
+
+	if len(c.WorkTree) > 0 && CheckGitVersionAtLeast("1.7.8") == nil {
+		c.env = []string{"GIT_WORK_TREE=" + c.WorkTree}
+	}
+
+	if len(c.Attributes) > 0 {
+		cmdArgs = append(cmdArgs, c.Attributes...)
+		cmdArgs = append(cmdArgs, "--")
+	} else {
+		lw := new(nulSeparatedAttributeWriter)
+		lw.attributes = make(chan attributeTriple)
+
+		c.stdOut = lw
+		c.stdOut.Close()
+		return fmt.Errorf("no provided Attributes to check")
+	}
+
+	c.ctx, c.cancel = context.WithCancel(ctx)
+	c.cmd = NewCommandContext(c.ctx, cmdArgs...)
+	var err error
+	c.stdinReader, c.stdinWriter, err = os.Pipe()
+	if err != nil {
+		return err
+	}
+
+	if CheckGitVersionAtLeast("1.8.5") == nil {
+		lw := new(nulSeparatedAttributeWriter)
+		lw.attributes = make(chan attributeTriple, 5)
+
+		c.stdOut = lw
+	} else {
+		lw := new(lineSeparatedAttributeWriter)
+		lw.attributes = make(chan attributeTriple, 5)
+
+		c.stdOut = lw
+	}
+	return nil
+}
+
+// Run run cmd
+func (c *CheckAttributeReader) Run() error {
+	stdErr := new(bytes.Buffer)
+	err := c.cmd.RunInDirTimeoutEnvFullPipelineFunc(c.env, -1, c.Repo.Path, c.stdOut, stdErr, c.stdinReader, func(_ context.Context, _ context.CancelFunc) error {
+		close(c.running)
+		return nil
+	})
+	defer c.cancel()
+	_ = c.stdOut.Close()
+	if err != nil && c.ctx.Err() != nil && err.Error() != "signal: killed" {
+		return fmt.Errorf("failed to run attr-check. Error: %w\nStderr: %s", err, stdErr.String())
+	}
+
+	return nil
+}
+
+// CheckPath check attr for given path
+func (c *CheckAttributeReader) CheckPath(path string) (map[string]string, error) {
+	select {
+	case <-c.ctx.Done():
+		return nil, c.ctx.Err()
+	case <-c.running:
+	}
+
+	if _, err := c.stdinWriter.Write([]byte(path + "\x00")); err != nil {
+		defer c.cancel()
+		return nil, err
+	}
+
+	if err := c.stdinWriter.Sync(); err != nil {
+		defer c.cancel()
+		return nil, err
+	}
+
+	rs := make(map[string]string)
+	for range c.Attributes {
+		select {
+		case attr := <-c.stdOut.ReadAttribute():
+			rs[attr.Attribute] = attr.Value
+		case <-c.ctx.Done():
+			return nil, c.ctx.Err()
+		}
+	}
+	return rs, nil
+}
+
+// Close close pip after use
+func (c *CheckAttributeReader) Close() error {
+	select {
+	case <-c.running:
+	default:
+		close(c.running)
+	}
+	defer c.cancel()
+	return c.stdinWriter.Close()
+}
+
+type attributeWriter interface {
+	io.WriteCloser
+	ReadAttribute() <-chan attributeTriple
+}
+
+type attributeTriple struct {
+	Filename  string
+	Attribute string
+	Value     string
+}
+
+type nulSeparatedAttributeWriter struct {
+	tmp        []byte
+	attributes chan attributeTriple
+	working    attributeTriple
+	pos        int
+}
+
+func (wr *nulSeparatedAttributeWriter) Write(p []byte) (n int, err error) {
+	l, read := len(p), 0
+
+	nulIdx := bytes.IndexByte(p, '\x00')
+	for nulIdx >= 0 {
+		wr.tmp = append(wr.tmp, p[:nulIdx]...)
+		switch wr.pos {
+		case 0:
+			wr.working = attributeTriple{
+				Filename: string(wr.tmp),
+			}
+		case 1:
+			wr.working.Attribute = string(wr.tmp)
+		case 2:
+			wr.working.Value = string(wr.tmp)
+		}
+		wr.tmp = wr.tmp[:0]
+		wr.pos++
+		if wr.pos > 2 {
+			wr.attributes <- wr.working
+			wr.pos = 0
+		}
+		read += nulIdx + 1
+		if l > read {
+			p = p[nulIdx+1:]
+			nulIdx = bytes.IndexByte(p, '\x00')
+		} else {
+			return l, nil
+		}
+	}
+	wr.tmp = append(wr.tmp, p...)
+	return len(p), nil
+}
+
+func (wr *nulSeparatedAttributeWriter) ReadAttribute() <-chan attributeTriple {
+	return wr.attributes
+}
+
+func (wr *nulSeparatedAttributeWriter) Close() error {
+	close(wr.attributes)
+	return nil
+}
+
+type lineSeparatedAttributeWriter struct {
+	tmp        []byte
+	attributes chan attributeTriple
+}
+
+func (wr *lineSeparatedAttributeWriter) Write(p []byte) (n int, err error) {
+	l := len(p)
+
+	nlIdx := bytes.IndexByte(p, '\n')
+	for nlIdx >= 0 {
+		wr.tmp = append(wr.tmp, p[:nlIdx]...)
+
+		if len(wr.tmp) == 0 {
+			// This should not happen
+			if len(p) > nlIdx+1 {
+				wr.tmp = wr.tmp[:0]
+				p = p[nlIdx+1:]
+				nlIdx = bytes.IndexByte(p, '\n')
+				continue
+			} else {
+				return l, nil
+			}
+		}
+
+		working := attributeTriple{}
+		if wr.tmp[0] == '"' {
+			sb := new(strings.Builder)
+			remaining := string(wr.tmp[1:])
+			for len(remaining) > 0 {
+				rn, _, tail, err := strconv.UnquoteChar(remaining, '"')
+				if err != nil {
+					if len(remaining) > 2 && remaining[0] == '"' && remaining[1] == ':' && remaining[2] == ' ' {
+						working.Filename = sb.String()
+						wr.tmp = []byte(remaining[3:])
+						break
+					}
+					return l, fmt.Errorf("unexpected tail %s", string(remaining))
+				}
+				_, _ = sb.WriteRune(rn)
+				remaining = tail
+			}
+		} else {
+			idx := bytes.IndexByte(wr.tmp, ':')
+			if idx < 0 {
+				return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
+			}
+			working.Filename = string(wr.tmp[:idx])
+			if len(wr.tmp) < idx+2 {
+				return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
+			}
+			wr.tmp = wr.tmp[idx+2:]
+		}
+
+		idx := bytes.IndexByte(wr.tmp, ':')
+		if idx < 0 {
+			return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
+		}
+
+		working.Attribute = string(wr.tmp[:idx])
+		if len(wr.tmp) < idx+2 {
+			return l, fmt.Errorf("unexpected input %s", string(wr.tmp))
+		}
+
+		working.Value = string(wr.tmp[idx+2:])
+
+		wr.attributes <- working
+		wr.tmp = wr.tmp[:0]
+		if len(p) > nlIdx+1 {
+			p = p[nlIdx+1:]
+			nlIdx = bytes.IndexByte(p, '\n')
+			continue
+		} else {
+			return l, nil
+		}
+	}
+
+	wr.tmp = append(wr.tmp, p...)
+	return l, nil
+}
+
+func (wr *lineSeparatedAttributeWriter) ReadAttribute() <-chan attributeTriple {
+	return wr.attributes
+}
+
+func (wr *lineSeparatedAttributeWriter) Close() error {
+	close(wr.attributes)
+	return nil
+}
diff --git a/modules/git/repo_attribute_test.go b/modules/git/repo_attribute_test.go
new file mode 100644
index 00000000000..92d1a78fa4d
--- /dev/null
+++ b/modules/git/repo_attribute_test.go
@@ -0,0 +1,159 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package git
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_nulSeparatedAttributeWriter_ReadAttribute(t *testing.T) {
+	wr := &nulSeparatedAttributeWriter{
+		attributes: make(chan attributeTriple, 5),
+	}
+
+	testStr := ".gitignore\"\n\x00linguist-vendored\x00unspecified\x00"
+
+	n, err := wr.Write([]byte(testStr))
+
+	assert.Equal(t, n, len(testStr))
+	assert.NoError(t, err)
+	select {
+	case attr := <-wr.ReadAttribute():
+		assert.Equal(t, ".gitignore\"\n", attr.Filename)
+		assert.Equal(t, "linguist-vendored", attr.Attribute)
+		assert.Equal(t, "unspecified", attr.Value)
+	case <-time.After(100 * time.Millisecond):
+		assert.Fail(t, "took too long to read an attribute from the list")
+	}
+	// Write a second attribute again
+	n, err = wr.Write([]byte(testStr))
+
+	assert.Equal(t, n, len(testStr))
+	assert.NoError(t, err)
+
+	select {
+	case attr := <-wr.ReadAttribute():
+		assert.Equal(t, ".gitignore\"\n", attr.Filename)
+		assert.Equal(t, "linguist-vendored", attr.Attribute)
+		assert.Equal(t, "unspecified", attr.Value)
+	case <-time.After(100 * time.Millisecond):
+		assert.Fail(t, "took too long to read an attribute from the list")
+	}
+
+	//Write a partial attribute
+	_, err = wr.Write([]byte("incomplete-file"))
+	assert.NoError(t, err)
+	_, err = wr.Write([]byte("name\x00"))
+	assert.NoError(t, err)
+
+	select {
+	case <-wr.ReadAttribute():
+		assert.Fail(t, "There should not be an attribute ready to read")
+	case <-time.After(100 * time.Millisecond):
+	}
+	_, err = wr.Write([]byte("attribute\x00"))
+	assert.NoError(t, err)
+	select {
+	case <-wr.ReadAttribute():
+		assert.Fail(t, "There should not be an attribute ready to read")
+	case <-time.After(100 * time.Millisecond):
+	}
+
+	_, err = wr.Write([]byte("value\x00"))
+	assert.NoError(t, err)
+
+	attr := <-wr.ReadAttribute()
+	assert.Equal(t, "incomplete-filename", attr.Filename)
+	assert.Equal(t, "attribute", attr.Attribute)
+	assert.Equal(t, "value", attr.Value)
+
+	_, err = wr.Write([]byte("shouldbe.vendor\x00linguist-vendored\x00set\x00shouldbe.vendor\x00linguist-generated\x00unspecified\x00shouldbe.vendor\x00linguist-language\x00unspecified\x00"))
+	assert.NoError(t, err)
+	attr = <-wr.ReadAttribute()
+	assert.NoError(t, err)
+	assert.EqualValues(t, attributeTriple{
+		Filename:  "shouldbe.vendor",
+		Attribute: "linguist-vendored",
+		Value:     "set",
+	}, attr)
+	attr = <-wr.ReadAttribute()
+	assert.NoError(t, err)
+	assert.EqualValues(t, attributeTriple{
+		Filename:  "shouldbe.vendor",
+		Attribute: "linguist-generated",
+		Value:     "unspecified",
+	}, attr)
+	attr = <-wr.ReadAttribute()
+	assert.NoError(t, err)
+	assert.EqualValues(t, attributeTriple{
+		Filename:  "shouldbe.vendor",
+		Attribute: "linguist-language",
+		Value:     "unspecified",
+	}, attr)
+}
+
+func Test_lineSeparatedAttributeWriter_ReadAttribute(t *testing.T) {
+	wr := &lineSeparatedAttributeWriter{
+		attributes: make(chan attributeTriple, 5),
+	}
+
+	testStr := `".gitignore\"\n": linguist-vendored: unspecified
+`
+	n, err := wr.Write([]byte(testStr))
+
+	assert.Equal(t, n, len(testStr))
+	assert.NoError(t, err)
+
+	select {
+	case attr := <-wr.ReadAttribute():
+		assert.Equal(t, ".gitignore\"\n", attr.Filename)
+		assert.Equal(t, "linguist-vendored", attr.Attribute)
+		assert.Equal(t, "unspecified", attr.Value)
+	case <-time.After(100 * time.Millisecond):
+		assert.Fail(t, "took too long to read an attribute from the list")
+	}
+
+	// Write a second attribute again
+	n, err = wr.Write([]byte(testStr))
+
+	assert.Equal(t, n, len(testStr))
+	assert.NoError(t, err)
+
+	select {
+	case attr := <-wr.ReadAttribute():
+		assert.Equal(t, ".gitignore\"\n", attr.Filename)
+		assert.Equal(t, "linguist-vendored", attr.Attribute)
+		assert.Equal(t, "unspecified", attr.Value)
+	case <-time.After(100 * time.Millisecond):
+		assert.Fail(t, "took too long to read an attribute from the list")
+	}
+
+	//Write a partial attribute
+	_, err = wr.Write([]byte("incomplete-file"))
+	assert.NoError(t, err)
+	_, err = wr.Write([]byte("name: "))
+	assert.NoError(t, err)
+	select {
+	case <-wr.ReadAttribute():
+		assert.Fail(t, "There should not be an attribute ready to read")
+	case <-time.After(100 * time.Millisecond):
+	}
+	_, err = wr.Write([]byte("attribute: "))
+	assert.NoError(t, err)
+	select {
+	case <-wr.ReadAttribute():
+		assert.Fail(t, "There should not be an attribute ready to read")
+	case <-time.After(100 * time.Millisecond):
+	}
+	_, err = wr.Write([]byte("value\n"))
+	assert.NoError(t, err)
+	attr := <-wr.ReadAttribute()
+	assert.Equal(t, "incomplete-filename", attr.Filename)
+	assert.Equal(t, "attribute", attr.Attribute)
+	assert.Equal(t, "value", attr.Value)
+}
diff --git a/modules/git/repo_index.go b/modules/git/repo_index.go
index 2c351e209fa..b301ff2437b 100644
--- a/modules/git/repo_index.go
+++ b/modules/git/repo_index.go
@@ -6,11 +6,17 @@ package git
 
 import (
 	"bytes"
+	"context"
+	"io/ioutil"
+	"os"
 	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
 )
 
 // ReadTreeToIndex reads a treeish to the index
-func (repo *Repository) ReadTreeToIndex(treeish string) error {
+func (repo *Repository) ReadTreeToIndex(treeish string, indexFilename ...string) error {
 	if len(treeish) != 40 {
 		res, err := NewCommand("rev-parse", "--verify", treeish).RunInDir(repo.Path)
 		if err != nil {
@@ -24,17 +30,42 @@ func (repo *Repository) ReadTreeToIndex(treeish string) error {
 	if err != nil {
 		return err
 	}
-	return repo.readTreeToIndex(id)
+	return repo.readTreeToIndex(id, indexFilename...)
 }
 
-func (repo *Repository) readTreeToIndex(id SHA1) error {
-	_, err := NewCommand("read-tree", id.String()).RunInDir(repo.Path)
+func (repo *Repository) readTreeToIndex(id SHA1, indexFilename ...string) error {
+	var env []string
+	if len(indexFilename) > 0 {
+		env = append(os.Environ(), "GIT_INDEX_FILE="+indexFilename[0])
+	}
+	_, err := NewCommand("read-tree", id.String()).RunInDirWithEnv(repo.Path, env)
 	if err != nil {
 		return err
 	}
 	return nil
 }
 
+// ReadTreeToTemporaryIndex reads a treeish to a temporary index file
+func (repo *Repository) ReadTreeToTemporaryIndex(treeish string) (filename string, cancel context.CancelFunc, err error) {
+	tmpIndex, err := ioutil.TempFile("", "index")
+	if err != nil {
+		return
+	}
+	filename = tmpIndex.Name()
+	cancel = func() {
+		err := util.Remove(filename)
+		if err != nil {
+			log.Error("failed to remove tmp index file: %v", err)
+		}
+	}
+	err = repo.ReadTreeToIndex(treeish, filename)
+	if err != nil {
+		defer cancel()
+		return "", func() {}, err
+	}
+	return
+}
+
 // EmptyIndex empties the index
 func (repo *Repository) EmptyIndex() error {
 	_, err := NewCommand("read-tree", "--empty").RunInDir(repo.Path)
diff --git a/modules/git/repo_language_stats_gogit.go b/modules/git/repo_language_stats_gogit.go
index 0a4cfbbc7bf..3abce1f0773 100644
--- a/modules/git/repo_language_stats_gogit.go
+++ b/modules/git/repo_language_stats_gogit.go
@@ -9,10 +9,12 @@ package git
 
 import (
 	"bytes"
+	"context"
 	"io"
 	"io/ioutil"
 
 	"code.gitea.io/gitea/modules/analyze"
+	"code.gitea.io/gitea/modules/log"
 
 	"github.com/go-enry/go-enry/v2"
 	"github.com/go-git/go-git/v5"
@@ -42,9 +44,73 @@ func (repo *Repository) GetLanguageStats(commitID string) (map[string]int64, err
 		return nil, err
 	}
 
+	var checker *CheckAttributeReader
+
+	if CheckGitVersionAtLeast("1.7.8") == nil {
+		indexFilename, deleteTemporaryFile, err := repo.ReadTreeToTemporaryIndex(commitID)
+		if err == nil {
+			defer deleteTemporaryFile()
+
+			checker = &CheckAttributeReader{
+				Attributes: []string{"linguist-vendored", "linguist-generated", "linguist-language"},
+				Repo:       repo,
+				IndexFile:  indexFilename,
+			}
+			ctx, cancel := context.WithCancel(DefaultContext)
+			if err := checker.Init(ctx); err != nil {
+				log.Error("Unable to open checker for %s. Error: %v", commitID, err)
+			} else {
+				go func() {
+					err = checker.Run()
+					if err != nil {
+						log.Error("Unable to open checker for %s. Error: %v", commitID, err)
+						cancel()
+					}
+				}()
+			}
+			defer cancel()
+		}
+	}
+
 	sizes := make(map[string]int64)
 	err = tree.Files().ForEach(func(f *object.File) error {
-		if f.Size == 0 || analyze.IsVendor(f.Name) || enry.IsDotFile(f.Name) ||
+		if f.Size == 0 {
+			return nil
+		}
+
+		notVendored := false
+		notGenerated := false
+
+		if checker != nil {
+			attrs, err := checker.CheckPath(f.Name)
+			if err == nil {
+				if vendored, has := attrs["linguist-vendored"]; has {
+					if vendored == "set" || vendored == "true" {
+						return nil
+					}
+					notVendored = vendored == "false"
+				}
+				if generated, has := attrs["linguist-generated"]; has {
+					if generated == "set" || generated == "true" {
+						return nil
+					}
+					notGenerated = generated == "false"
+				}
+				if language, has := attrs["linguist-language"]; has && language != "unspecified" && language != "" {
+					// group languages, such as Pug -> HTML; SCSS -> CSS
+					group := enry.GetLanguageGroup(language)
+					if len(group) == 0 {
+						language = group
+					}
+
+					sizes[language] += f.Size
+
+					return nil
+				}
+			}
+		}
+
+		if (!notVendored && analyze.IsVendor(f.Name)) || enry.IsDotFile(f.Name) ||
 			enry.IsDocumentation(f.Name) || enry.IsConfiguration(f.Name) {
 			return nil
 		}
@@ -54,7 +120,7 @@ func (repo *Repository) GetLanguageStats(commitID string) (map[string]int64, err
 		if f.Size <= bigFileSize {
 			content, _ = readFile(f, fileSizeLimit)
 		}
-		if enry.IsGenerated(f.Name, content) {
+		if !notGenerated && enry.IsGenerated(f.Name, content) {
 			return nil
 		}
 
diff --git a/modules/git/repo_language_stats_nogogit.go b/modules/git/repo_language_stats_nogogit.go
index 7425e2dbb1d..c3b96ea841e 100644
--- a/modules/git/repo_language_stats_nogogit.go
+++ b/modules/git/repo_language_stats_nogogit.go
@@ -10,6 +10,7 @@ package git
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"io"
 	"math"
 
@@ -62,13 +63,78 @@ func (repo *Repository) GetLanguageStats(commitID string) (map[string]int64, err
 		return nil, err
 	}
 
+	var checker *CheckAttributeReader
+
+	if CheckGitVersionAtLeast("1.7.8") == nil {
+		indexFilename, deleteTemporaryFile, err := repo.ReadTreeToTemporaryIndex(commitID)
+		if err == nil {
+			defer deleteTemporaryFile()
+
+			checker = &CheckAttributeReader{
+				Attributes: []string{"linguist-vendored", "linguist-generated", "linguist-language"},
+				Repo:       repo,
+				IndexFile:  indexFilename,
+			}
+			ctx, cancel := context.WithCancel(DefaultContext)
+			if err := checker.Init(ctx); err != nil {
+				log.Error("Unable to open checker for %s. Error: %v", commitID, err)
+			} else {
+				go func() {
+					err = checker.Run()
+					if err != nil {
+						log.Error("Unable to open checker for %s. Error: %v", commitID, err)
+						cancel()
+					}
+				}()
+			}
+			defer cancel()
+		}
+	}
+
 	contentBuf := bytes.Buffer{}
 	var content []byte
 	sizes := make(map[string]int64)
 	for _, f := range entries {
 		contentBuf.Reset()
 		content = contentBuf.Bytes()
-		if f.Size() == 0 || analyze.IsVendor(f.Name()) || enry.IsDotFile(f.Name()) ||
+
+		if f.Size() == 0 {
+			continue
+		}
+
+		notVendored := false
+		notGenerated := false
+
+		if checker != nil {
+			attrs, err := checker.CheckPath(f.Name())
+			if err == nil {
+				if vendored, has := attrs["linguist-vendored"]; has {
+					if vendored == "set" || vendored == "true" {
+						continue
+					}
+					notVendored = vendored == "false"
+				}
+				if generated, has := attrs["linguist-generated"]; has {
+					if generated == "set" || generated == "true" {
+						continue
+					}
+					notGenerated = generated == "false"
+				}
+				if language, has := attrs["linguist-language"]; has && language != "unspecified" && language != "" {
+					// group languages, such as Pug -> HTML; SCSS -> CSS
+					group := enry.GetLanguageGroup(language)
+					if len(group) == 0 {
+						language = group
+					}
+
+					sizes[language] += f.Size()
+
+					continue
+				}
+			}
+		}
+
+		if (!notVendored && analyze.IsVendor(f.Name())) || enry.IsDotFile(f.Name()) ||
 			enry.IsDocumentation(f.Name()) || enry.IsConfiguration(f.Name()) {
 			continue
 		}
@@ -102,11 +168,10 @@ func (repo *Repository) GetLanguageStats(commitID string) (map[string]int64, err
 				return nil, err
 			}
 		}
-		if enry.IsGenerated(f.Name(), content) {
+		if !notGenerated && enry.IsGenerated(f.Name(), content) {
 			continue
 		}
 
-		// TODO: Use .gitattributes file for linguist overrides
 		// FIXME: Why can't we split this and the IsGenerated tests to avoid reading the blob unless absolutely necessary?
 		// - eg. do the all the detection tests using filename first before reading content.
 		language := analyze.GetCodeLanguage(f.Name(), content)
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index 3462a15cca4..17701094d78 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -2011,6 +2011,8 @@ diff.file_byte_size = Size
 diff.file_suppressed = File diff suppressed because it is too large
 diff.file_suppressed_line_too_long = File diff suppressed because one or more lines are too long
 diff.too_many_files = Some files were not shown because too many files changed in this diff
+diff.generated = generated
+diff.vendored = vendored
 diff.comment.placeholder = Leave a comment
 diff.comment.markdown_info = Styling with markdown is supported.
 diff.comment.add_single_comment = Add single comment
diff --git a/services/gitdiff/gitdiff.go b/services/gitdiff/gitdiff.go
index 4be115f0301..65d0dab4caa 100644
--- a/services/gitdiff/gitdiff.go
+++ b/services/gitdiff/gitdiff.go
@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/analyze"
 	"code.gitea.io/gitea/modules/charset"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/highlight"
@@ -30,6 +31,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/process"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 
 	"github.com/sergi/go-diff/diffmatchpatch"
 	stdcharset "golang.org/x/net/html/charset"
@@ -593,6 +595,8 @@ type DiffFile struct {
 	IsIncomplete            bool
 	IsIncompleteLineTooLong bool
 	IsProtected             bool
+	IsGenerated             bool
+	IsVendored              bool
 }
 
 // GetType returns type of diff file.
@@ -1268,7 +1272,81 @@ func GetDiffRangeWithWhitespaceBehavior(gitRepo *git.Repository, beforeCommitID,
 	if err != nil {
 		return nil, fmt.Errorf("ParsePatch: %v", err)
 	}
+
+	var checker *git.CheckAttributeReader
+
+	if git.CheckGitVersionAtLeast("1.7.8") == nil {
+		indexFilename, deleteTemporaryFile, err := gitRepo.ReadTreeToTemporaryIndex(afterCommitID)
+		if err == nil {
+			defer deleteTemporaryFile()
+			workdir, err := ioutil.TempDir("", "empty-work-dir")
+			if err != nil {
+				log.Error("Unable to create temporary directory: %v", err)
+				return nil, err
+			}
+			defer func() {
+				_ = util.RemoveAll(workdir)
+			}()
+
+			checker = &git.CheckAttributeReader{
+				Attributes: []string{"linguist-vendored", "linguist-generated"},
+				Repo:       gitRepo,
+				IndexFile:  indexFilename,
+				WorkTree:   workdir,
+			}
+			ctx, cancel := context.WithCancel(git.DefaultContext)
+			if err := checker.Init(ctx); err != nil {
+				log.Error("Unable to open checker for %s. Error: %v", afterCommitID, err)
+			} else {
+				go func() {
+					err = checker.Run()
+					if err != nil && err != ctx.Err() {
+						log.Error("Unable to open checker for %s. Error: %v", afterCommitID, err)
+					}
+					cancel()
+				}()
+			}
+			defer func() {
+				cancel()
+			}()
+		}
+	}
+
 	for _, diffFile := range diff.Files {
+
+		gotVendor := false
+		gotGenerated := false
+		if checker != nil {
+			attrs, err := checker.CheckPath(diffFile.Name)
+			if err == nil {
+				if vendored, has := attrs["linguist-vendored"]; has {
+					if vendored == "set" || vendored == "true" {
+						diffFile.IsVendored = true
+						gotVendor = true
+					} else {
+						gotVendor = vendored == "false"
+					}
+				}
+				if generated, has := attrs["linguist-generated"]; has {
+					if generated == "set" || generated == "true" {
+						diffFile.IsGenerated = true
+						gotGenerated = true
+					} else {
+						gotGenerated = generated == "false"
+					}
+				}
+			} else {
+				log.Error("Unexpected error: %v", err)
+			}
+		}
+
+		if !gotVendor {
+			diffFile.IsVendored = analyze.IsVendor(diffFile.Name)
+		}
+		if !gotGenerated {
+			diffFile.IsGenerated = analyze.IsGenerated(diffFile.Name)
+		}
+
 		tailSection := diffFile.GetTailSection(gitRepo, beforeCommitID, afterCommitID)
 		if tailSection != nil {
 			diffFile.Sections = append(diffFile.Sections, tailSection)
diff --git a/templates/repo/diff/box.tmpl b/templates/repo/diff/box.tmpl
index 4f8f7260976..8c4b972bbc9 100644
--- a/templates/repo/diff/box.tmpl
+++ b/templates/repo/diff/box.tmpl
@@ -49,11 +49,15 @@
 			{{$isImage := or (call $.IsBlobAnImage $blobBase) (call $.IsBlobAnImage $blobHead)}}
 			{{$isCsv := (call $.IsCsvFile $file)}}
 			{{$showFileViewToggle := or $isImage (and (not $file.IsIncomplete) $isCsv)}}
-			<div class="diff-file-box diff-box file-content {{TabSizeClass $.Editorconfig $file.Name}} mt-3" id="diff-{{.Index}}">
+			<div class="diff-file-box diff-box file-content {{TabSizeClass $.Editorconfig $file.Name}} mt-3" id="diff-{{.Index}}" {{if $file.IsGenerated}}data-folded="true"{{end}}>
 				<h4 class="diff-file-header sticky-2nd-row ui top attached normal header df ac sb">
-					<div class="df ac">
-						<a role="button" class="fold-file muted mr-2">
-							{{svg "octicon-chevron-down" 18}}
+					<div class="fold-file df ac">
+						<a role="button" class="chevron muted mr-2">
+							{{if $file.IsGenerated}}
+								{{svg "octicon-chevron-right" 18}}
+							{{else}}
+								{{svg "octicon-chevron-down" 18}}
+							{{end}}
 						</a>
 						<div class="bold df ac">
 							{{if $file.IsBin}}
@@ -65,6 +69,12 @@
 							{{end}}
 						</div>
 						<span class="file mono">{{if $file.IsRenamed}}{{$file.OldName}} &rarr; {{end}}{{$file.Name}}{{if .IsLFSFile}} ({{$.i18n.Tr "repo.stored_lfs"}}){{end}}</span>
+						{{if $file.IsGenerated}}
+							<span class="ui label ml-3">{{$.i18n.Tr "repo.diff.generated"}}</span>
+						{{end}}
+						{{if $file.IsVendored}}
+							<span class="ui label ml-3">{{$.i18n.Tr "repo.diff.vendored"}}</span>
+						{{end}}
 					</div>
 					<div class="diff-file-header-actions df ac">
 						{{if $showFileViewToggle}}
diff --git a/web_src/js/index.js b/web_src/js/index.js
index 5ea16f44f83..78caa51fd65 100644
--- a/web_src/js/index.js
+++ b/web_src/js/index.js
@@ -2349,8 +2349,9 @@ function initCodeView() {
   }
   $(document).on('click', '.fold-file', ({currentTarget}) => {
     const box = currentTarget.closest('.file-content');
+    const chevron = currentTarget.querySelector('a.chevron');
     const folded = box.dataset.folded !== 'true';
-    currentTarget.innerHTML = svg(`octicon-chevron-${folded ? 'right' : 'down'}`, 18);
+    chevron.innerHTML = svg(`octicon-chevron-${folded ? 'right' : 'down'}`, 18);
     box.dataset.folded = String(folded);
   });
   $(document).on('click', '.blob-excerpt', async ({currentTarget}) => {