Scoped labels (#22585)

Add a new "exclusive" option per label. This makes it so that when the
label is named `scope/name`, no other label with the same `scope/`
prefix can be set on an issue.

The scope is determined by the last occurence of `/`, so for example
`scope/alpha/name` and `scope/beta/name` are considered to be in
different scopes and can coexist.

Exclusive scopes are not enforced by any database rules, however they
are enforced when editing labels at the models level, automatically
removing any existing labels in the same scope when either attaching a
new label or replacing all labels.

In menus use a circle instead of checkbox to indicate they function as
radio buttons per scope. Issue filtering by label ensures that only a
single scoped label is selected at a time. Clicking with alt key can be
used to remove a scoped label, both when editing individual issues and
batch editing.

Label rendering refactor for consistency and code simplification:

* Labels now consistently have the same shape, emojis and tooltips
everywhere. This includes the label list and label assignment menus.
* In label list, show description below label same as label menus.
* Don't use exactly black/white text colors to look a bit nicer.
* Simplify text color computation. There is no point computing luminance
in linear color space, as this is a perceptual problem and sRGB is
closer to perceptually linear.
* Increase height of label assignment menus to show more labels. Showing
only 3-4 labels at a time leads to a lot of scrolling.
* Render all labels with a new RenderLabel template helper function.

Label creation and editing in multiline modal menu:

* Change label creation to open a modal menu like label editing.
* Change menu layout to place name, description and colors on separate
lines.
* Don't color cancel button red in label editing modal menu.
* Align text to the left in model menu for better readability and
consistent with settings layout elsewhere.

Custom exclusive scoped label rendering:

* Display scoped label prefix and suffix with slightly darker and
lighter background color respectively, and a slanted edge between them
similar to the `/` symbol.
* In menus exclusive labels are grouped with a divider line.

---------

Co-authored-by: Yarden Shoham <hrsi88@gmail.com>
Co-authored-by: Lauris BH <lauris@nix.lv>

models/fixtures/issue.yml

@@ -287,3 +287,20 @@
   created_unix: 1602935696
   updated_unix: 1602935696
   is_locked: false
+
+-
+  id: 18
+  repo_id: 55
+  index: 1
+  poster_id: 2
+  original_author_id: 0
+  name: issue for scoped labels
+  content: content
+  milestone_id: 0
+  priority: 0
+  is_closed: false
+  is_pull: false
+  num_comments: 0
+  created_unix: 946684830
+  updated_unix: 978307200
+  is_locked: false

models/fixtures/label.yml

@@ -4,6 +4,7 @@
   org_id: 0
   name: label1
   color: '#abcdef'
+  exclusive: false
   num_issues: 2
   num_closed_issues: 0
 
@@ -13,6 +14,7 @@
   org_id: 0
   name: label2
   color: '#000000'
+  exclusive: false
   num_issues: 1
   num_closed_issues: 1
 
@@ -22,6 +24,7 @@
   org_id: 3
   name: orglabel3
   color: '#abcdef'
+  exclusive: false
   num_issues: 0
   num_closed_issues: 0
 
@@ -31,6 +34,7 @@
   org_id: 3
   name: orglabel4
   color: '#000000'
+  exclusive: false
   num_issues: 1
   num_closed_issues: 0
 
@@ -40,5 +44,46 @@
   org_id: 0
   name: pull-test-label
   color: '#000000'
+  exclusive: false
+  num_issues: 0
+  num_closed_issues: 0
+
+-
+  id: 6
+  repo_id: 55
+  org_id: 0
+  name: unscoped_label
+  color: '#000000'
+  exclusive: false
+  num_issues: 0
+  num_closed_issues: 0
+
+-
+  id: 7
+  repo_id: 55
+  org_id: 0
+  name: scope/label1
+  color: '#000000'
+  exclusive: true
+  num_issues: 0
+  num_closed_issues: 0
+
+-
+  id: 8
+  repo_id: 55
+  org_id: 0
+  name: scope/label2
+  color: '#000000'
+  exclusive: true
+  num_issues: 0
+  num_closed_issues: 0
+
+-
+  id: 9
+  repo_id: 55
+  org_id: 0
+  name: scope/subscope/label2
+  color: '#000000'
+  exclusive: true
   num_issues: 0
   num_closed_issues: 0

models/fixtures/repository.yml

@@ -1622,3 +1622,15 @@
   is_archived: false
   is_private: true
   status: 0
+
+-
+  id: 55
+  owner_id: 2
+  owner_name: user2
+  lower_name: scoped_label
+  name: scoped_label
+  is_empty: false
+  is_archived: false
+  is_private: true
+  num_issues: 1
+  status: 0

models/fixtures/user.yml

@@ -66,7 +66,7 @@
   num_followers: 2
   num_following: 1
   num_stars: 2
-  num_repos: 10
+  num_repos: 11
   num_teams: 0
   num_members: 0
   visibility: 0

models/issues/issue.go

@@ -538,6 +538,31 @@ func (ts labelSorter) Swap(i, j int) {
 	[]*Label(ts)[i], []*Label(ts)[j] = []*Label(ts)[j], []*Label(ts)[i]
 }
 
+// Ensure only one label of a given scope exists, with labels at the end of the
+// array getting preference over earlier ones.
+func RemoveDuplicateExclusiveLabels(labels []*Label) []*Label {
+	validLabels := make([]*Label, 0, len(labels))
+
+	for i, label := range labels {
+		scope := label.ExclusiveScope()
+		if scope != "" {
+			foundOther := false
+			for _, otherLabel := range labels[i+1:] {
+				if otherLabel.ExclusiveScope() == scope {
+					foundOther = true
+					break
+				}
+			}
+			if foundOther {
+				continue
+			}
+		}
+		validLabels = append(validLabels, label)
+	}
+
+	return validLabels
+}
+
 // ReplaceIssueLabels removes all current labels and add new labels to the issue.
 // Triggers appropriate WebHooks, if any.
 func ReplaceIssueLabels(issue *Issue, labels []*Label, doer *user_model.User) (err error) {
@@ -555,6 +580,8 @@ func ReplaceIssueLabels(issue *Issue, labels []*Label, doer *user_model.User) (e
 		return err
 	}
 
+	labels = RemoveDuplicateExclusiveLabels(labels)
+
 	sort.Sort(labelSorter(labels))
 	sort.Sort(labelSorter(issue.Labels))
 

models/issues/issue_test.go

@@ -25,7 +25,7 @@ import (
 func TestIssue_ReplaceLabels(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
-	testSuccess := func(issueID int64, labelIDs []int64) {
+	testSuccess := func(issueID int64, labelIDs, expectedLabelIDs []int64) {
 		issue := unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: issueID})
 		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: issue.RepoID})
 		doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
@@ -35,15 +35,20 @@ func TestIssue_ReplaceLabels(t *testing.T) {
 			labels[i] = unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: labelID, RepoID: repo.ID})
 		}
 		assert.NoError(t, issues_model.ReplaceIssueLabels(issue, labels, doer))
-		unittest.AssertCount(t, &issues_model.IssueLabel{IssueID: issueID}, len(labelIDs))
-		for _, labelID := range labelIDs {
+		unittest.AssertCount(t, &issues_model.IssueLabel{IssueID: issueID}, len(expectedLabelIDs))
+		for _, labelID := range expectedLabelIDs {
 			unittest.AssertExistsAndLoadBean(t, &issues_model.IssueLabel{IssueID: issueID, LabelID: labelID})
 		}
 	}
 
-	testSuccess(1, []int64{2})
-	testSuccess(1, []int64{1, 2})
-	testSuccess(1, []int64{})
+	testSuccess(1, []int64{2}, []int64{2})
+	testSuccess(1, []int64{1, 2}, []int64{1, 2})
+	testSuccess(1, []int64{}, []int64{})
+
+	// mutually exclusive scoped labels 7 and 8
+	testSuccess(18, []int64{6, 7}, []int64{6, 7})
+	testSuccess(18, []int64{7, 8}, []int64{8})
+	testSuccess(18, []int64{6, 8, 7}, []int64{6, 7})
 }
 
 func Test_GetIssueIDsByRepoID(t *testing.T) {
@@ -523,5 +528,5 @@ func TestCountIssues(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	count, err := issues_model.CountIssues(db.DefaultContext, &issues_model.IssuesOptions{})
 	assert.NoError(t, err)
-	assert.EqualValues(t, 17, count)
+	assert.EqualValues(t, 18, count)
 }

models/issues/label.go

@@ -7,8 +7,6 @@ package issues
 import (
 	"context"
 	"fmt"
-	"html/template"
-	"math"
 	"regexp"
 	"strconv"
 	"strings"
@@ -89,6 +87,7 @@ type Label struct {
 	RepoID          int64 `xorm:"INDEX"`
 	OrgID           int64 `xorm:"INDEX"`
 	Name            string
+	Exclusive       bool
 	Description     string
 	Color           string `xorm:"VARCHAR(7)"`
 	NumIssues       int
@@ -128,20 +127,24 @@ func (label *Label) CalOpenOrgIssues(ctx context.Context, repoID, labelID int64)
 }
 
 // LoadSelectedLabelsAfterClick calculates the set of selected labels when a label is clicked
-func (label *Label) LoadSelectedLabelsAfterClick(currentSelectedLabels []int64) {
+func (label *Label) LoadSelectedLabelsAfterClick(currentSelectedLabels []int64, currentSelectedExclusiveScopes []string) {
 	var labelQuerySlice []string
 	labelSelected := false
 	labelID := strconv.FormatInt(label.ID, 10)
-	for _, s := range currentSelectedLabels {
+	labelScope := label.ExclusiveScope()
+	for i, s := range currentSelectedLabels {
 		if s == label.ID {
 			labelSelected = true
 		} else if -s == label.ID {
 			labelSelected = true
 			label.IsExcluded = true
 		} else if s != 0 {
+			// Exclude other labels in the same scope from selection
+			if s < 0 || labelScope == "" || labelScope != currentSelectedExclusiveScopes[i] {
 				labelQuerySlice = append(labelQuerySlice, strconv.FormatInt(s, 10))
 			}
 		}
+	}
 	if !labelSelected {
 		labelQuerySlice = append(labelQuerySlice, labelID)
 	}
@@ -159,49 +162,43 @@ func (label *Label) BelongsToRepo() bool {
 	return label.RepoID > 0
 }
 
-// SrgbToLinear converts a component of an sRGB color to its linear intensity
-// See: https://en.wikipedia.org/wiki/SRGB#The_reverse_transformation_(sRGB_to_CIE_XYZ)
-func SrgbToLinear(color uint8) float64 {
-	flt := float64(color) / 255
-	if flt <= 0.04045 {
-		return flt / 12.92
-	}
-	return math.Pow((flt+0.055)/1.055, 2.4)
+// Get color as RGB values in 0..255 range
+func (label *Label) ColorRGB() (float64, float64, float64, error) {
+	color, err := strconv.ParseUint(label.Color[1:], 16, 64)
+	if err != nil {
+		return 0, 0, 0, err
 	}
 
-// Luminance returns the luminance of an sRGB color
-func Luminance(color uint32) float64 {
-	r := SrgbToLinear(uint8(0xFF & (color >> 16)))
-	g := SrgbToLinear(uint8(0xFF & (color >> 8)))
-	b := SrgbToLinear(uint8(0xFF & color))
-
-	// luminance ratios for sRGB
-	return 0.2126*r + 0.7152*g + 0.0722*b
+	r := float64(uint8(0xFF & (uint32(color) >> 16)))
+	g := float64(uint8(0xFF & (uint32(color) >> 8)))
+	b := float64(uint8(0xFF & uint32(color)))
+	return r, g, b, nil
 }
 
-// LuminanceThreshold is the luminance at which white and black appear to have the same contrast
-// i.e. x such that 1.05 / (x + 0.05) = (x + 0.05) / 0.05
-// i.e. math.Sqrt(1.05*0.05) - 0.05
-const LuminanceThreshold float64 = 0.179
-
-// ForegroundColor calculates the text color for labels based
-// on their background color.
-func (label *Label) ForegroundColor() template.CSS {
+// Determine if label text should be light or dark to be readable on background color
+func (label *Label) UseLightTextColor() bool {
 	if strings.HasPrefix(label.Color, "#") {
-		if color, err := strconv.ParseUint(label.Color[1:], 16, 64); err == nil {
-			// NOTE: see web_src/js/components/ContextPopup.vue for similar implementation
-			luminance := Luminance(uint32(color))
-
-			// prefer white or black based upon contrast
-			if luminance < LuminanceThreshold {
-				return template.CSS("#fff")
-			}
-			return template.CSS("#000")
+		if r, g, b, err := label.ColorRGB(); err == nil {
+			// Perceived brightness from: https://www.w3.org/TR/AERT/#color-contrast
+			// In the future WCAG 3 APCA may be a better solution
+			brightness := (0.299*r + 0.587*g + 0.114*b) / 255
+			return brightness < 0.35
 		}
 	}
 
-	// default to black
-	return template.CSS("#000")
+	return false
+}
+
+// Return scope substring of label name, or empty string if none exists
+func (label *Label) ExclusiveScope() string {
+	if !label.Exclusive {
+		return ""
+	}
+	lastIndex := strings.LastIndex(label.Name, "/")
+	if lastIndex == -1 || lastIndex == 0 || lastIndex == len(label.Name)-1 {
+		return ""
+	}
+	return label.Name[:lastIndex]
 }
 
 // NewLabel creates a new label
@@ -253,7 +250,7 @@ func UpdateLabel(l *Label) error {
 	if !LabelColorPattern.MatchString(l.Color) {
 		return fmt.Errorf("bad color code: %s", l.Color)
 	}
-	return updateLabelCols(db.DefaultContext, l, "name", "description", "color")
+	return updateLabelCols(db.DefaultContext, l, "name", "description", "color", "exclusive")
 }
 
 // DeleteLabel delete a label
@@ -620,6 +617,29 @@ func newIssueLabel(ctx context.Context, issue *Issue, label *Label, doer *user_m
 	return updateLabelCols(ctx, label, "num_issues", "num_closed_issue")
 }
 
+// Remove all issue labels in the given exclusive scope
+func RemoveDuplicateExclusiveIssueLabels(ctx context.Context, issue *Issue, label *Label, doer *user_model.User) (err error) {
+	scope := label.ExclusiveScope()
+	if scope == "" {
+		return nil
+	}
+
+	var toRemove []*Label
+	for _, issueLabel := range issue.Labels {
+		if label.ID != issueLabel.ID && issueLabel.ExclusiveScope() == scope {
+			toRemove = append(toRemove, issueLabel)
+		}
+	}
+
+	for _, issueLabel := range toRemove {
+		if err = deleteIssueLabel(ctx, issue, issueLabel, doer); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // NewIssueLabel creates a new issue-label relation.
 func NewIssueLabel(issue *Issue, label *Label, doer *user_model.User) (err error) {
 	if HasIssueLabel(db.DefaultContext, issue.ID, label.ID) {
@@ -641,6 +661,10 @@ func NewIssueLabel(issue *Issue, label *Label, doer *user_model.User) (err error
 		return nil
 	}
 
+	if err = RemoveDuplicateExclusiveIssueLabels(ctx, issue, label, doer); err != nil {
+		return nil
+	}
+
 	if err = newIssueLabel(ctx, issue, label, doer); err != nil {
 		return err
 	}

models/issues/label_test.go

@@ -4,7 +4,6 @@
 package issues_test
 
 import (
-	"html/template"
 	"testing"
 
 	"code.gitea.io/gitea/models/db"
@@ -25,13 +24,22 @@ func TestLabel_CalOpenIssues(t *testing.T) {
 	assert.EqualValues(t, 2, label.NumOpenIssues)
 }
 
-func TestLabel_ForegroundColor(t *testing.T) {
+func TestLabel_TextColor(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	label := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 1})
-	assert.Equal(t, template.CSS("#000"), label.ForegroundColor())
+	assert.False(t, label.UseLightTextColor())
 
 	label = unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 2})
-	assert.Equal(t, template.CSS("#fff"), label.ForegroundColor())
+	assert.True(t, label.UseLightTextColor())
+}
+
+func TestLabel_ExclusiveScope(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	label := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 7})
+	assert.Equal(t, "scope", label.ExclusiveScope())
+
+	label = unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 9})
+	assert.Equal(t, "scope/subscope", label.ExclusiveScope())
 }
 
 func TestNewLabels(t *testing.T) {
@@ -266,6 +274,7 @@ func TestUpdateLabel(t *testing.T) {
 		Color:       "#ffff00",
 		Name:        "newLabelName",
 		Description: label.Description,
+		Exclusive:   false,
 	}
 	label.Color = update.Color
 	label.Name = update.Name
@@ -323,6 +332,34 @@ func TestNewIssueLabel(t *testing.T) {
 	unittest.CheckConsistencyFor(t, &issues_model.Issue{}, &issues_model.Label{})
 }
 
+func TestNewIssueExclusiveLabel(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	issue := unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: 18})
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+
+	otherLabel := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 6})
+	exclusiveLabelA := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 7})
+	exclusiveLabelB := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 8})
+
+	// coexisting regular and exclusive label
+	assert.NoError(t, issues_model.NewIssueLabel(issue, otherLabel, doer))
+	assert.NoError(t, issues_model.NewIssueLabel(issue, exclusiveLabelA, doer))
+	unittest.AssertExistsAndLoadBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: otherLabel.ID})
+	unittest.AssertExistsAndLoadBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: exclusiveLabelA.ID})
+
+	// exclusive label replaces existing one
+	assert.NoError(t, issues_model.NewIssueLabel(issue, exclusiveLabelB, doer))
+	unittest.AssertExistsAndLoadBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: otherLabel.ID})
+	unittest.AssertExistsAndLoadBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: exclusiveLabelB.ID})
+	unittest.AssertNotExistsBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: exclusiveLabelA.ID})
+
+	// exclusive label replaces existing one again
+	assert.NoError(t, issues_model.NewIssueLabel(issue, exclusiveLabelA, doer))
+	unittest.AssertExistsAndLoadBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: otherLabel.ID})
+	unittest.AssertExistsAndLoadBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: exclusiveLabelA.ID})
+	unittest.AssertNotExistsBean(t, &issues_model.IssueLabel{IssueID: issue.ID, LabelID: exclusiveLabelB.ID})
+}
+
 func TestNewIssueLabels(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	label1 := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 1})

models/migrations/fixtures/Test_DeleteOrphanedIssueLabels/label.yml

@@ -4,6 +4,7 @@
   org_id: 0
   name: label1
   color: '#abcdef'
+  exclusive: false
   num_issues: 2
   num_closed_issues: 0
 
@@ -13,6 +14,7 @@
   org_id: 0
   name: label2
   color: '#000000'
+  exclusive: false
   num_issues: 1
   num_closed_issues: 1
 -
@@ -21,6 +23,7 @@
   org_id:  3
   name: orglabel3
   color: '#abcdef'
+  exclusive: false
   num_issues: 0
   num_closed_issues: 0
 
@@ -30,6 +33,7 @@
   org_id: 3
   name: orglabel4
   color: '#000000'
+  exclusive: false
   num_issues: 1
   num_closed_issues: 0
 
@@ -39,5 +43,6 @@
   org_id: 0
   name: pull-test-label
   color: '#000000'
+  exclusive: false
   num_issues: 0
   num_closed_issues: 0

models/migrations/migrations.go

@@ -459,6 +459,8 @@ var migrations = []Migration{
 	NewMigration("Add card_type column to project table", v1_19.AddCardTypeToProjectTable),
 	// v242 -> v243
 	NewMigration("Alter gpg_key_import content TEXT field to MEDIUMTEXT", v1_19.AlterPublicGPGKeyImportContentFieldToMediumText),
+	// v243 -> v244
+	NewMigration("Add exclusive label", v1_19.AddExclusiveLabel),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v1_19/v244.go

@@ -0,0 +1,16 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_19 //nolint
+
+import (
+	"xorm.io/xorm"
+)
+
+func AddExclusiveLabel(x *xorm.Engine) error {
+	type Label struct {
+		Exclusive bool
+	}
+
+	return x.Sync(new(Label))
+}

modules/migration/label.go

@@ -9,4 +9,5 @@ type Label struct {
 	Name        string `json:"name"`
 	Color       string `json:"color"`
 	Description string `json:"description"`
+	Exclusive   bool   `json:"exclusive"`
 }

modules/structs/issue_label.go

@@ -9,6 +9,8 @@ package structs
 type Label struct {
 	ID   int64  `json:"id"`
 	Name string `json:"name"`
+	// example: false
+	Exclusive bool `json:"exclusive"`
 	// example: 00aabb
 	Color       string `json:"color"`
 	Description string `json:"description"`
@@ -19,6 +21,8 @@ type Label struct {
 type CreateLabelOption struct {
 	// required:true
 	Name string `json:"name" binding:"Required"`
+	// example: false
+	Exclusive bool `json:"exclusive"`
 	// required:true
 	// example: #00aabb
 	Color       string `json:"color" binding:"Required"`
@@ -28,6 +32,9 @@ type CreateLabelOption struct {
 // EditLabelOption options for editing a label
 type EditLabelOption struct {
 	Name *string `json:"name"`
+	// example: false
+	Exclusive *bool `json:"exclusive"`
+	// example: #00aabb
 	Color       *string `json:"color"`
 	Description *string `json:"description"`
 }

modules/templates/helper.go

@@ -7,10 +7,12 @@ package templates
 import (
 	"bytes"
 	"context"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"html"
 	"html/template"
+	"math"
 	"mime"
 	"net/url"
 	"path/filepath"
@@ -382,6 +384,9 @@ func NewFuncMap() []template.FuncMap {
 			// the table is NOT sorted with this header
 			return ""
 		},
+		"RenderLabel": func(label *issues_model.Label) template.HTML {
+			return template.HTML(RenderLabel(label))
+		},
 		"RenderLabels": func(labels []*issues_model.Label, repoLink string) template.HTML {
 			htmlCode := `<span class="labels-list">`
 			for _, label := range labels {
@@ -389,8 +394,8 @@ func NewFuncMap() []template.FuncMap {
 				if label == nil {
 					continue
 				}
-				htmlCode += fmt.Sprintf("<a href='%s/issues?labels=%d' class='ui label' style='color: %s !important; background-color: %s !important' title='%s'>%s</a> ",
-					repoLink, label.ID, label.ForegroundColor(), label.Color, html.EscapeString(label.Description), RenderEmoji(label.Name))
+				htmlCode += fmt.Sprintf("<a href='%s/issues?labels=%d'>%s</a> ",
+					repoLink, label.ID, RenderLabel(label))
 			}
 			htmlCode += "</span>"
 			return template.HTML(htmlCode)
@@ -801,6 +806,67 @@ func RenderIssueTitle(ctx context.Context, text, urlPrefix string, metas map[str
 	return template.HTML(renderedText)
 }
 
+// RenderLabel renders a label
+func RenderLabel(label *issues_model.Label) string {
+	labelScope := label.ExclusiveScope()
+
+	textColor := "#111"
+	if label.UseLightTextColor() {
+		textColor = "#eee"
+	}
+
+	description := emoji.ReplaceAliases(template.HTMLEscapeString(label.Description))
+
+	if labelScope == "" {
+		// Regular label
+		return fmt.Sprintf("<div class='ui label' style='color: %s !important; background-color: %s !important' title='%s'>%s</div>",
+			textColor, label.Color, description, RenderEmoji(label.Name))
+	}
+
+	// Scoped label
+	scopeText := RenderEmoji(labelScope)
+	itemText := RenderEmoji(label.Name[len(labelScope)+1:])
+
+	itemColor := label.Color
+	scopeColor := label.Color
+	if r, g, b, err := label.ColorRGB(); err == nil {
+		// Make scope and item background colors slightly darker and lighter respectively.
+		// More contrast needed with higher luminance, empirically tweaked.
+		luminance := (0.299*r + 0.587*g + 0.114*b) / 255
+		contrast := 0.01 + luminance*0.06
+		// Ensure we add the same amount of contrast also near 0 and 1.
+		darken := contrast + math.Max(luminance+contrast-1.0, 0.0)
+		lighten := contrast + math.Max(contrast-luminance, 0.0)
+		// Compute factor to keep RGB values proportional.
+		darkenFactor := math.Max(luminance-darken, 0.0) / math.Max(luminance, 1.0/255.0)
+		lightenFactor := math.Min(luminance+lighten, 1.0) / math.Max(luminance, 1.0/255.0)
+
+		scopeBytes := []byte{
+			uint8(math.Min(math.Round(r*darkenFactor), 255)),
+			uint8(math.Min(math.Round(g*darkenFactor), 255)),
+			uint8(math.Min(math.Round(b*darkenFactor), 255)),
+		}
+		itemBytes := []byte{
+			uint8(math.Min(math.Round(r*lightenFactor), 255)),
+			uint8(math.Min(math.Round(g*lightenFactor), 255)),
+			uint8(math.Min(math.Round(b*lightenFactor), 255)),
+		}
+
+		itemColor = "#" + hex.EncodeToString(itemBytes)
+		scopeColor = "#" + hex.EncodeToString(scopeBytes)
+	}
+
+	return fmt.Sprintf("<span class='ui label scope-parent' title='%s'>"+
+		"<div class='ui label scope-left' style='color: %s !important; background-color: %s !important'>%s</div>"+
+		"<div class='ui label scope-middle' style='background: linear-gradient(-80deg, %s 48%%, %s 52%% 0%%);'>&nbsp;</div>"+
+		"<div class='ui label scope-right' style='color: %s !important; background-color: %s !important''>%s</div>"+
+		"</span>",
+		description,
+		textColor, scopeColor, scopeText,
+		itemColor, scopeColor,
+		textColor, itemColor, itemText)
+}
+
 // RenderEmoji renders html text with emoji post processors
 func RenderEmoji(text string) template.HTML {
 	renderedText, err := markup.RenderEmoji(template.HTMLEscapeString(text))

options/locale/locale_en-US.ini

@@ -1395,9 +1395,12 @@ issues.sign_in_require_desc = <a href="%s">Sign in</a> to join this conversation
 issues.edit = Edit
 issues.cancel = Cancel
 issues.save = Save
-issues.label_title = Label name
-issues.label_description = Label description
-issues.label_color = Label color
+issues.label_title = Name
+issues.label_description = Description
+issues.label_color = Color
+issues.label_exclusive = Exclusive
+issues.label_exclusive_desc = Name the label <code>scope/item</code> to make it mutually exclusive with other <code>scope/</code> labels.
+issues.label_exclusive_warning = Any conflicting scoped labels will be removed when editing the labels of an issue or pull request.
 issues.label_count = %d labels
 issues.label_open_issues = %d open issues/pull requests
 issues.label_edit = Edit

routers/api/v1/org/label.go

@@ -94,6 +94,7 @@ func CreateLabel(ctx *context.APIContext) {
 
 	label := &issues_model.Label{
 		Name:        form.Name,
+		Exclusive:   form.Exclusive,
 		Color:       form.Color,
 		OrgID:       ctx.Org.Organization.ID,
 		Description: form.Description,
@@ -195,6 +196,9 @@ func EditLabel(ctx *context.APIContext) {
 	if form.Name != nil {
 		label.Name = *form.Name
 	}
+	if form.Exclusive != nil {
+		label.Exclusive = *form.Exclusive
+	}
 	if form.Color != nil {
 		label.Color = strings.Trim(*form.Color, " ")
 		if len(label.Color) == 6 {

routers/api/v1/repo/label.go

@@ -156,6 +156,7 @@ func CreateLabel(ctx *context.APIContext) {
 
 	label := &issues_model.Label{
 		Name:        form.Name,
+		Exclusive:   form.Exclusive,
 		Color:       form.Color,
 		RepoID:      ctx.Repo.Repository.ID,
 		Description: form.Description,
@@ -218,6 +219,9 @@ func EditLabel(ctx *context.APIContext) {
 	if form.Name != nil {
 		label.Name = *form.Name
 	}
+	if form.Exclusive != nil {
+		label.Exclusive = *form.Exclusive
+	}
 	if form.Color != nil {
 		label.Color = strings.Trim(*form.Color, " ")
 		if len(label.Color) == 6 {

routers/web/org/org_labels.go

@@ -45,6 +45,7 @@ func NewLabel(ctx *context.Context) {
 	l := &issues_model.Label{
 		OrgID:       ctx.Org.Organization.ID,
 		Name:        form.Title,
+		Exclusive:   form.Exclusive,
 		Description: form.Description,
 		Color:       form.Color,
 	}
@@ -70,6 +71,7 @@ func UpdateLabel(ctx *context.Context) {
 	}
 
 	l.Name = form.Title
+	l.Exclusive = form.Exclusive
 	l.Description = form.Description
 	l.Color = form.Color
 	if err := issues_model.UpdateLabel(l); err != nil {

routers/web/repo/issue.go

@@ -332,8 +332,24 @@ func issues(ctx *context.Context, milestoneID, projectID int64, isPullOption uti
 		labels = append(labels, orgLabels...)
 	}
 
+	// Get the exclusive scope for every label ID
+	labelExclusiveScopes := make([]string, 0, len(labelIDs))
+	for _, labelID := range labelIDs {
+		foundExclusiveScope := false
+		for _, label := range labels {
+			if label.ID == labelID || label.ID == -labelID {
+				labelExclusiveScopes = append(labelExclusiveScopes, label.ExclusiveScope())
+				foundExclusiveScope = true
+				break
+			}
+		}
+		if !foundExclusiveScope {
+			labelExclusiveScopes = append(labelExclusiveScopes, "")
+		}
+	}
+
 	for _, l := range labels {
-		l.LoadSelectedLabelsAfterClick(labelIDs)
+		l.LoadSelectedLabelsAfterClick(labelIDs, labelExclusiveScopes)
 	}
 	ctx.Data["Labels"] = labels
 	ctx.Data["NumLabels"] = len(labels)

routers/web/repo/issue_label.go

@@ -113,6 +113,7 @@ func NewLabel(ctx *context.Context) {
 	l := &issues_model.Label{
 		RepoID:      ctx.Repo.Repository.ID,
 		Name:        form.Title,
+		Exclusive:   form.Exclusive,
 		Description: form.Description,
 		Color:       form.Color,
 	}
@@ -138,6 +139,7 @@ func UpdateLabel(ctx *context.Context) {
 	}
 
 	l.Name = form.Title
+	l.Exclusive = form.Exclusive
 	l.Description = form.Description
 	l.Color = form.Color
 	if err := issues_model.UpdateLabel(l); err != nil {
@@ -175,7 +177,7 @@ func UpdateIssueLabel(ctx *context.Context) {
 				return
 			}
 		}
-	case "attach", "detach", "toggle":
+	case "attach", "detach", "toggle", "toggle-alt":
 		label, err := issues_model.GetLabelByID(ctx, ctx.FormInt64("id"))
 		if err != nil {
 			if issues_model.IsErrRepoLabelNotExist(err) {
@@ -189,6 +191,7 @@ func UpdateIssueLabel(ctx *context.Context) {
 		if action == "toggle" {
 			// detach if any issues already have label, otherwise attach
 			action = "attach"
+			if label.ExclusiveScope() == "" {
 				for _, issue := range issues {
 					if issues_model.HasIssueLabel(ctx, issue.ID, label.ID) {
 						action = "detach"
@@ -196,6 +199,11 @@ func UpdateIssueLabel(ctx *context.Context) {
 					}
 				}
 			}
+		} else if action == "toggle-alt" {
+			// always detach with alt key pressed, to be able to remove
+			// scoped labels
+			action = "detach"
+		}
 
 		if action == "attach" {
 			for _, issue := range issues {

services/convert/issue.go

@@ -182,6 +182,7 @@ func ToLabel(label *issues_model.Label, repo *repo_model.Repository, org *user_m
 	result := &api.Label{
 		ID:          label.ID,
 		Name:        label.Name,
+		Exclusive:   label.Exclusive,
 		Color:       strings.TrimLeft(label.Color, "#"),
 		Description: label.Description,
 	}

services/forms/repo_form.go

@@ -564,6 +564,7 @@ func (f *CreateMilestoneForm) Validate(req *http.Request, errs binding.Errors) b
 type CreateLabelForm struct {
 	ID          int64
 	Title       string `binding:"Required;MaxSize(50)" locale:"repo.issues.label_title"`
+	Exclusive   bool   `form:"exclusive"`
 	Description string `binding:"MaxSize(200)" locale:"repo.issues.label_description"`
 	Color       string `binding:"Required;MaxSize(7)" locale:"repo.issues.label_color"`
 }

services/migrations/main_test.go

@@ -59,6 +59,7 @@ func assertCommentsEqual(t *testing.T, expected, actual []*base.Comment) {
 
 func assertLabelEqual(t *testing.T, expected, actual *base.Label) {
 	assert.Equal(t, expected.Name, actual.Name)
+	assert.Equal(t, expected.Exclusive, actual.Exclusive)
 	assert.Equal(t, expected.Color, actual.Color)
 	assert.Equal(t, expected.Description, actual.Description)
 }

services/repository/template.go

@@ -31,6 +31,7 @@ func GenerateIssueLabels(ctx context.Context, templateRepo, generateRepo *repo_m
 		newLabels = append(newLabels, &issues_model.Label{
 			RepoID:      generateRepo.ID,
 			Name:        templateLabel.Name,
+			Exclusive:   templateLabel.Exclusive,
 			Description: templateLabel.Description,
 			Color:       templateLabel.Color,
 		})

templates/projects/view.tmpl

@@ -234,7 +234,7 @@
 						{{if or .Labels .Assignees}}
 						<div class="extra content labels-list gt-p-0 gt-pt-2">
 							{{range .Labels}}
-								<a class="ui label" target="_blank" href="{{$.RepoLink}}/issues?labels={{.ID}}" style="color: {{.ForegroundColor}}; background-color: {{.Color}};" title="{{.Description | RenderEmojiPlain}}">{{.Name | RenderEmoji}}</a>
+								<a target="_blank" href="{{$.RepoLink}}/issues?labels={{.ID}}">{{RenderLabel .}}</a>
 							{{end}}
 							<div class="right floated">
 								{{range .Assignees}}

templates/repo/issue/labels/edit_delete_label.tmpl

@@ -26,31 +26,45 @@
 		<form class="ui edit-label form ignore-dirty" action="{{$.Link}}/edit" method="post">
 			{{.CsrfTokenHtml}}
 			<input id="label-modal-id" name="id" type="hidden">
-			<div class="ui grid">
-				<div class="three wide column">
+			<div class="required field">
+				<label for="name">{{.locale.Tr "repo.issues.label_title"}}</label>
 				<div class="ui small input">
-						<input class="new-label-input emoji-input" name="title" placeholder="{{.locale.Tr "repo.issues.new_label_placeholder"}}" autofocus required maxlength="50">
+					<input class="label-name-input emoji-input" name="title" placeholder="{{.locale.Tr "repo.issues.new_label_placeholder"}}" autofocus required maxlength="50">
 				</div>
 			</div>
-				<div class="five wide column">
+			<div class="field label-exclusive-input-field">
+				<div class="ui checkbox">
+					<input class="label-exclusive-input" name="exclusive" type="checkbox">
+					<label>{{.locale.Tr "repo.issues.label_exclusive"}}</label>
+				</div>
+				<br/>
+				<small class="desc">{{.locale.Tr "repo.issues.label_exclusive_desc" | Safe}}</small>
+				<div class="desc gt-ml-2 gt-mt-3 gt-hidden label-exclusive-warning">
+					{{svg "octicon-alert"}} {{.locale.Tr "repo.issues.label_exclusive_warning" | Safe}}
+				</div>
+			</div>
+			<div class="field">
+				<label for="description">{{.locale.Tr "repo.issues.label_description"}}</label>
 				<div class="ui small fluid input">
-						<input class="new-label-desc-input" name="description" placeholder="{{.locale.Tr "repo.issues.new_label_desc_placeholder"}}" maxlength="200">
+					<input class="label-desc-input" name="description" placeholder="{{.locale.Tr "repo.issues.new_label_desc_placeholder"}}" maxlength="200">
 				</div>
 			</div>
+			<div class="field color-field">
+				<label for="color">{{$.locale.Tr "repo.issues.label_color"}}</label>
 				<div class="color picker column">
 					<input class="color-picker" name="color" value="#70c24a" required maxlength="7">
-				</div>
 					<div class="column precolors">
 						{{template "repo/issue/label_precolors"}}
 					</div>
 				</div>
+			</div>
 		</form>
 	</div>
 	<div class="actions">
-		<div class="ui negative button">
+		<div class="ui secondary small basic cancel button">
 			{{.locale.Tr "cancel"}}
 		</div>
-		<div class="ui positive button">
+		<div class="ui primary small approve button">
 			{{.locale.Tr "save"}}
 		</div>
 	</div>

templates/repo/issue/labels/label.tmpl

@@ -1,9 +1,7 @@
 <a
-	class="ui label item {{if not .label.IsChecked}}hide{{end}}"
+	class="item {{if not .label.IsChecked}}hide{{end}}"
 	id="label_{{.label.ID}}"
 	href="{{.root.RepoLink}}/{{if or .root.IsPull .root.Issue.IsPull}}pulls{{else}}issues{{end}}?labels={{.label.ID}}"{{/* FIXME: use .root.Issue.Link or create .root.Link */}}
-	style="color: {{.label.ForegroundColor}}; background-color: {{.label.Color}}"
-	title="{{.label.Description | RenderEmojiPlain}}"
 >
-	{{.label.Name | RenderEmoji}}
+	{{RenderLabel .label}}
 </a>

templates/repo/issue/labels/label_list.tmpl

@@ -30,28 +30,24 @@
 		{{range .Labels}}
 			<li class="item">
 			<div class="ui grid middle aligned">
+				<div class="nine wide column">
+					{{RenderLabel .}}
+					{{if .Description}}<br><small class="desc">{{.Description | RenderEmoji}}</small>{{end}}
+				</div>
 				<div class="four wide column">
-					<div class="ui label" style="color: {{.ForegroundColor}}; background-color: {{.Color}}">{{svg "octicon-tag"}} {{.Name | RenderEmoji}}</div>
-				</div>
-				<div class="six wide column">
-					<div class="ui">
-					{{.Description | RenderEmoji}}
-					</div>
-				</div>
-				<div class="three wide column">
 					{{if $.PageIsOrgSettingsLabels}}
-						<a class="ui right open-issues" href="{{AppSubUrl}}/issues?labels={{.ID}}">{{svg "octicon-issue-opened"}} {{$.locale.Tr "repo.issues.label_open_issues" .NumOpenIssues}}</a>
+						<a class="ui left open-issues" href="{{AppSubUrl}}/issues?labels={{.ID}}">{{svg "octicon-issue-opened"}} {{$.locale.Tr "repo.issues.label_open_issues" .NumOpenIssues}}</a>
 					{{else}}
-						<a class="ui right open-issues" href="{{$.RepoLink}}/issues?labels={{.ID}}">{{svg "octicon-issue-opened"}} {{$.locale.Tr "repo.issues.label_open_issues" .NumOpenIssues}}</a>
+						<a class="ui left open-issues" href="{{$.RepoLink}}/issues?labels={{.ID}}">{{svg "octicon-issue-opened"}} {{$.locale.Tr "repo.issues.label_open_issues" .NumOpenIssues}}</a>
 					{{end}}
 				</div>
 				<div class="three wide column">
 					{{if and (not $.PageIsOrgSettingsLabels ) (not $.Repository.IsArchived) (or $.CanWriteIssues $.CanWritePulls)}}
 						<a class="ui right delete-button" href="#" data-url="{{$.Link}}/delete" data-id="{{.ID}}">{{svg "octicon-trash"}} {{$.locale.Tr "repo.issues.label_delete"}}</a>
-						<a class="ui right edit-label-button" href="#" data-id="{{.ID}}" data-title="{{.Name}}" data-description="{{.Description}}" data-color={{.Color}}>{{svg "octicon-pencil"}} {{$.locale.Tr "repo.issues.label_edit"}}</a>
+						<a class="ui right edit-label-button" href="#" data-id="{{.ID}}" data-title="{{.Name}}" {{if .Exclusive}}data-exclusive{{end}} data-num-issues="{{.NumIssues}}" data-description="{{.Description}}" data-color={{.Color}}>{{svg "octicon-pencil"}} {{$.locale.Tr "repo.issues.label_edit"}}</a>
 					{{else if $.PageIsOrgSettingsLabels}}
 						<a class="ui right delete-button" href="#" data-url="{{$.Link}}/delete" data-id="{{.ID}}">{{svg "octicon-trash"}} {{$.locale.Tr "repo.issues.label_delete"}}</a>
-						<a class="ui right edit-label-button" href="#" data-id="{{.ID}}" data-title="{{.Name}}" data-description="{{.Description}}" data-color={{.Color}}>{{svg "octicon-pencil"}} {{$.locale.Tr "repo.issues.label_edit"}}</a>
+						<a class="ui right edit-label-button" href="#" data-id="{{.ID}}" data-title="{{.Name}}" {{if .Exclusive}}data-exclusive{{end}} data-num-issues="{{.NumIssues}}" data-description="{{.Description}}" data-color={{.Color}}>{{svg "octicon-pencil"}} {{$.locale.Tr "repo.issues.label_edit"}}</a>
 					{{end}}
 				</div>
 			</div>
@@ -73,16 +69,12 @@
 					{{range .OrgLabels}}
 					<li class="item">
 					<div class="ui grid middle aligned">
-						<div class="three wide column">
-							<div class="ui label" style="color: {{.ForegroundColor}}; background-color: {{.Color}}">{{svg "octicon-tag"}} {{.Name | RenderEmoji}}</div>
+						<div class="nine wide column">
+							{{RenderLabel .}}
+							{{if .Description}}<br><small class="desc">{{.Description | RenderEmoji}}</small>{{end}}
 						</div>
-						<div class="seven wide column">
-							<div class="ui">
-							{{.Description | RenderEmoji}}
-							</div>
-						</div>
-						<div class="three wide column">
-								<a class="ui right open-issues" href="{{$.RepoLink}}/issues?labels={{.ID}}">{{svg "octicon-issue-opened"}} {{$.locale.Tr "repo.issues.label_open_issues" .NumOpenRepoIssues}}</a>
+						<div class="four wide column">
+							<a class="ui left open-issues" href="{{$.RepoLink}}/issues?labels={{.ID}}">{{svg "octicon-issue-opened"}} {{$.locale.Tr "repo.issues.label_open_issues" .NumOpenRepoIssues}}</a>
 						</div>
 						<div class="three wide column">
 						</div>

templates/repo/issue/labels/label_new.tmpl

@@ -1,27 +1,47 @@
-<div class="ui new-label segment hide">
-	<form class="ui form" action="{{$.Link}}/new" method="post">
+<div class="ui small new-label modal">
+	<div class="header">
+		{{.locale.Tr "repo.issues.new_label"}}
+	</div>
+	<div class="content">
+		<form class="ui new-label form ignore-dirty" action="{{$.Link}}/new" method="post">
 			{{.CsrfTokenHtml}}
-		<div class="ui grid">
-			<div class="three wide column">
+			<div class="required field">
+				<label for="name">{{.locale.Tr "repo.issues.label_title"}}</label>
 				<div class="ui small input">
-					<input class="new-label-input emoji-input" name="title" placeholder="{{.locale.Tr "repo.issues.new_label_placeholder"}}" autofocus required maxlength="50">
+					<input class="label-name-input emoji-input" name="title" placeholder="{{.locale.Tr "repo.issues.new_label_placeholder"}}" autofocus required maxlength="50">
 				</div>
 			</div>
-			<div class="three wide column">
+			<div class="field label-exclusive-input-field">
+				<div class="ui checkbox">
+					<input class="label-exclusive-input" name="exclusive" type="checkbox">
+					<label>{{.locale.Tr "repo.issues.label_exclusive"}}</label>
+				</div>
+				<br/>
+				<small class="desc">{{.locale.Tr "repo.issues.label_exclusive_desc" | Safe}}</small>
+			</div>
+			<div class="field">
+				<label for="description">{{.locale.Tr "repo.issues.label_description"}}</label>
 				<div class="ui small fluid input">
-					<input class="new-label-desc-input" name="description" placeholder="{{.locale.Tr "repo.issues.new_label_desc_placeholder"}}" maxlength="200">
+					<input class="label-desc-input" name="description" placeholder="{{.locale.Tr "repo.issues.new_label_desc_placeholder"}}" maxlength="200">
 				</div>
 			</div>
+			<div class="field color-field">
+				<label for="color">{{$.locale.Tr "repo.issues.label_color"}}</label>
 				<div class="color picker column">
 					<input class="color-picker" name="color" value="#70c24a" required maxlength="7">
-			</div>
 					<div class="column precolors">
 						{{template "repo/issue/label_precolors"}}
 					</div>
-			<div class="buttons">
-				<div class="ui secondary small basic cancel button">{{.locale.Tr "repo.milestones.cancel"}}</div>
-				<button class="ui primary small button">{{.locale.Tr "repo.issues.create_label"}}</button>
 				</div>
 			</div>
 		</form>
 	</div>
+	<div class="actions">
+		<div class="ui secondary small basic cancel button">
+			{{.locale.Tr "cancel"}}
+		</div>
+		<div class="ui primary small approve button">
+			{{.locale.Tr "repo.issues.create_label"}}
+		</div>
+	</div>
+</div>

templates/repo/issue/list.tmpl

@@ -50,8 +50,14 @@
 							</div>
 							<span class="info">{{.locale.Tr "repo.issues.filter_label_exclude" | Safe}}</span>
 							<a class="item" href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&sort={{$.SortType}}&state={{$.State}}&milestone={{$.MilestoneID}}&project={{$.ProjectID}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}">{{.locale.Tr "repo.issues.filter_label_no_select"}}</a>
+							{{$previousExclusiveScope := "_no_scope"}}
 							{{range .Labels}}
-								<a class="item label-filter-item" href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&sort={{$.SortType}}&state={{$.State}}&labels={{.QueryString}}&milestone={{$.MilestoneID}}&project={{$.ProjectID}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}" data-label-id="{{.ID}}">{{if .IsExcluded}}{{svg "octicon-circle-slash"}}{{else if .IsSelected}}{{svg "octicon-check"}}{{end}}<span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}</a>
+								{{$exclusiveScope := .ExclusiveScope}}
+								{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
+									<div class="ui divider"></div>
+								{{end}}
+								{{$previousExclusiveScope = $exclusiveScope}}
+								<a class="item label-filter-item" href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&sort={{$.SortType}}&state={{$.State}}&labels={{.QueryString}}&milestone={{$.MilestoneID}}&project={{$.ProjectID}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}" data-label-id="{{.ID}}">{{if .IsExcluded}}{{svg "octicon-circle-slash"}}{{else if .IsSelected}}{{if $exclusiveScope}}{{svg "octicon-dot-fill"}}{{else}}{{svg "octicon-check"}}{{end}}{{end}} {{RenderLabel .}}</a>
 							{{end}}
 						</div>
 					</div>
@@ -217,9 +223,15 @@
 							{{svg "octicon-triangle-down" 14 "dropdown icon"}}
 						</span>
 						<div class="menu">
+							{{$previousExclusiveScope := "_no_scope"}}
 							{{range .Labels}}
+								{{$exclusiveScope := .ExclusiveScope}}
+								{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
+									<div class="ui divider"></div>
+								{{end}}
+								{{$previousExclusiveScope = $exclusiveScope}}
 								<div class="item issue-action" data-action="toggle" data-element-id="{{.ID}}" data-url="{{$.RepoLink}}/issues/labels">
-									{{if contain $.SelLabelIDs .ID}}{{svg "octicon-check"}}{{end}}<span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}
+									{{if contain $.SelLabelIDs .ID}}{{if $exclusiveScope}}{{svg "octicon-dot-fill"}}{{else}}{{svg "octicon-check"}}{{end}}{{end}} {{RenderLabel .}}
 								</div>
 							{{end}}
 						</div>

templates/repo/issue/milestone_issues.tmpl

@@ -58,7 +58,7 @@
 							<span class="info">{{.locale.Tr "repo.issues.filter_label_exclude" | Safe}}</span>
 							<a class="item" href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&sort={{$.SortType}}&state={{$.State}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}">{{.locale.Tr "repo.issues.filter_label_no_select"}}</a>
 							{{range .Labels}}
-								<a class="item label-filter-item" href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&sort={{$.SortType}}&state={{$.State}}&labels={{.QueryString}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}" data-label-id="{{.ID}}">{{if .IsExcluded}}{{svg "octicon-circle-slash"}}{{else if contain $.SelLabelIDs .ID}}{{svg "octicon-check"}}{{end}}<span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}</a>
+								<a class="item label-filter-item" href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&sort={{$.SortType}}&state={{$.State}}&labels={{.QueryString}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}" data-label-id="{{.ID}}">{{if .IsExcluded}}{{svg "octicon-circle-slash"}}{{else if contain $.SelLabelIDs .ID}}{{svg "octicon-check"}}{{end}} {{RenderLabel .}}</a>
 							{{end}}
 						</div>
 					</div>
@@ -161,7 +161,7 @@
 						<div class="menu">
 							{{range .Labels}}
 								<div class="item issue-action" data-action="toggle" data-element-id="{{.ID}}" data-url="{{$.RepoLink}}/issues/labels">
-									{{if contain $.SelLabelIDs .ID}}{{svg "octicon-check"}}{{end}}<span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}
+									{{if contain $.SelLabelIDs .ID}}{{svg "octicon-check"}}{{end}} {{RenderLabel .}}
 								</div>
 							{{end}}
 						</div>

templates/repo/issue/new_form.tmpl

@@ -53,14 +53,26 @@
 					{{end}}
 					<div class="no-select item">{{.locale.Tr "repo.issues.new.clear_labels"}}</div>
 					{{if or .Labels .OrgLabels}}
+						{{$previousExclusiveScope := "_no_scope"}}
 						{{range .Labels}}
-							<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{svg "octicon-check"}}</span><span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}
+							{{$exclusiveScope := .ExclusiveScope}}
+							{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
+								<div class="ui divider"></div>
+							{{end}}
+							{{$previousExclusiveScope = $exclusiveScope}}
+							<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}" data-scope="{{$exclusiveScope}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{if $exclusiveScope}}{{svg "octicon-dot-fill"}}{{else}}{{svg "octicon-check"}}{{end}}</span>&nbsp;&nbsp;{{RenderLabel .}}
 							{{if .Description}}<br><small class="desc">{{.Description | RenderEmoji}}</small>{{end}}</a>
 						{{end}}
 
 						<div class="ui divider"></div>
+						{{$previousExclusiveScope := "_no_scope"}}
 						{{range .OrgLabels}}
-							<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{svg "octicon-check"}}</span><span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}
+							{{$exclusiveScope := .ExclusiveScope}}
+							{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
+								<div class="ui divider"></div>
+							{{end}}
+							{{$previousExclusiveScope = $exclusiveScope}}
+							<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}" data-scope="{{$exclusiveScope}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{if $exclusiveScope}}{{svg "octicon-dot-fill"}}{{else}}{{svg "octicon-check"}}{{end}}</span>&nbsp;&nbsp;{{RenderLabel .}}
 							{{if .Description}}<br><small class="desc">{{.Description | RenderEmoji}}</small>{{end}}</a>
 						{{end}}
 					{{else}}

templates/repo/issue/view_content/sidebar.tmpl

@@ -123,13 +123,25 @@
 				{{end}}
 				<div class="no-select item">{{.locale.Tr "repo.issues.new.clear_labels"}}</div>
 				{{if or .Labels .OrgLabels}}
+					{{$previousExclusiveScope := "_no_scope"}}
 					{{range .Labels}}
-						<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{svg "octicon-check"}}</span><span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}
+						{{$exclusiveScope := .ExclusiveScope}}
+						{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
+							<div class="ui divider"></div>
+						{{end}}
+						{{$previousExclusiveScope = $exclusiveScope}}
+						<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}" data-scope="{{$exclusiveScope}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{if $exclusiveScope}}{{svg "octicon-dot-fill"}}{{else}}{{svg "octicon-check"}}{{end}}</span>&nbsp;&nbsp;{{RenderLabel .}}
 						{{if .Description}}<br><small class="desc">{{.Description | RenderEmoji}}</small>{{end}}</a>
 					{{end}}
 					<div class="ui divider"></div>
+					{{$previousExclusiveScope := "_no_scope"}}
 					{{range .OrgLabels}}
-						<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{svg "octicon-check"}}</span><span class="label color" style="background-color: {{.Color}}"></span> {{.Name | RenderEmoji}}
+						{{$exclusiveScope := .ExclusiveScope}}
+						{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
+							<div class="ui divider"></div>
+						{{end}}
+						{{$previousExclusiveScope = $exclusiveScope}}
+						<a class="{{if .IsChecked}}checked{{end}} item" href="#" data-id="{{.ID}}" data-id-selector="#label_{{.ID}}" data-scope="{{$exclusiveScope}}"><span class="octicon-check {{if not .IsChecked}}invisible{{end}}">{{if $exclusiveScope}}{{svg "octicon-dot-fill"}}{{else}}{{svg "octicon-check"}}{{end}}</span>&nbsp;&nbsp;{{RenderLabel .}}
 						{{if .Description}}<br><small class="desc">{{.Description | RenderEmoji}}</small>{{end}}</a>
 					{{end}}
 				{{else}}

templates/repo/projects/view.tmpl

@@ -245,7 +245,7 @@
 						{{if or .Labels .Assignees}}
 						<div class="extra content labels-list gt-p-0 gt-pt-2">
 							{{range .Labels}}
-								<a class="ui label" target="_blank" href="{{$.RepoLink}}/issues?labels={{.ID}}" style="color: {{.ForegroundColor}}; background-color: {{.Color}};" title="{{.Description | RenderEmojiPlain}}">{{.Name | RenderEmoji}}</a>
+								<a target="_blank" href="{{$.RepoLink}}/issues?labels={{.ID}}">{{RenderLabel .}}</a>
 							{{end}}
 							<div class="right floated">
 								{{range .Assignees}}

templates/shared/issuelist.tmpl

@@ -42,7 +42,7 @@
 					{{end}}
 					<span class="labels-list gt-ml-2">
 						{{range .Labels}}
-							<a class="ui label" href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&state={{$.State}}&labels={{.ID}}{{if ne $.listType "milestone"}}&milestone={{$.MilestoneID}}{{end}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}" style="color: {{.ForegroundColor}}; background-color: {{.Color}}" title="{{.Description | RenderEmojiPlain}}">{{.Name | RenderEmoji}}</a>
+							<a href="{{$.Link}}?q={{$.Keyword}}&type={{$.ViewType}}&state={{$.State}}&labels={{.ID}}{{if ne $.listType "milestone"}}&milestone={{$.MilestoneID}}{{end}}&assignee={{$.AssigneeID}}&poster={{$.PosterID}}">{{RenderLabel .}}</a>
 						{{end}}
 					</span>
 				</div>

templates/swagger/v1_json.tmpl

@@ -15348,6 +15348,11 @@
           "type": "string",
           "x-go-name": "Description"
         },
+        "exclusive": {
+          "type": "boolean",
+          "x-go-name": "Exclusive",
+          "example": false
+        },
         "name": {
           "type": "string",
           "x-go-name": "Name"
@@ -16283,12 +16288,18 @@
       "properties": {
         "color": {
           "type": "string",
-          "x-go-name": "Color"
+          "x-go-name": "Color",
+          "example": "#00aabb"
         },
         "description": {
           "type": "string",
           "x-go-name": "Description"
         },
+        "exclusive": {
+          "type": "boolean",
+          "x-go-name": "Exclusive",
+          "example": false
+        },
         "name": {
           "type": "string",
           "x-go-name": "Name"
@@ -17615,6 +17626,11 @@
           "type": "string",
           "x-go-name": "Description"
         },
+        "exclusive": {
+          "type": "boolean",
+          "x-go-name": "Exclusive",
+          "example": false
+        },
         "id": {
           "type": "integer",
           "format": "int64",

tests/integration/api_issue_test.go

@@ -174,7 +174,7 @@ func TestAPISearchIssues(t *testing.T) {
 	token := getUserToken(t, "user2")
 
 	// as this API was used in the frontend, it uses UI page size
-	expectedIssueCount := 15 // from the fixtures
+	expectedIssueCount := 16 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}
@@ -198,7 +198,7 @@ func TestAPISearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 8)
+	assert.Len(t, apiIssues, 9)
 	query.Del("since")
 	query.Del("before")
 
@@ -214,15 +214,15 @@ func TestAPISearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "17", resp.Header().Get("X-Total-Count"))
-	assert.Len(t, apiIssues, 17)
+	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
+	assert.Len(t, apiIssues, 18)
 
 	query.Add("limit", "10")
 	link.RawQuery = query.Encode()
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "17", resp.Header().Get("X-Total-Count"))
+	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
 	assert.Len(t, apiIssues, 10)
 
 	query = url.Values{"assigned": {"true"}, "state": {"all"}, "token": {token}}
@@ -251,7 +251,7 @@ func TestAPISearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 6)
+	assert.Len(t, apiIssues, 7)
 
 	query = url.Values{"owner": {"user3"}, "token": {token}} // organization
 	link.RawQuery = query.Encode()
@@ -272,7 +272,7 @@ func TestAPISearchIssuesWithLabels(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
 	// as this API was used in the frontend, it uses UI page size
-	expectedIssueCount := 15 // from the fixtures
+	expectedIssueCount := 16 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}

tests/integration/api_nodeinfo_test.go

@@ -34,7 +34,7 @@ func TestNodeinfo(t *testing.T) {
 		assert.True(t, nodeinfo.OpenRegistrations)
 		assert.Equal(t, "gitea", nodeinfo.Software.Name)
 		assert.Equal(t, 24, nodeinfo.Usage.Users.Total)
-		assert.Equal(t, 17, nodeinfo.Usage.LocalPosts)
+		assert.Equal(t, 18, nodeinfo.Usage.LocalPosts)
 		assert.Equal(t, 2, nodeinfo.Usage.LocalComments)
 	})
 }

tests/integration/issue_test.go

@@ -356,7 +356,7 @@ func TestSearchIssues(t *testing.T) {
 
 	session := loginUser(t, "user2")
 
-	expectedIssueCount := 15 // from the fixtures
+	expectedIssueCount := 16 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}
@@ -377,7 +377,7 @@ func TestSearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 8)
+	assert.Len(t, apiIssues, 9)
 	query.Del("since")
 	query.Del("before")
 
@@ -393,15 +393,15 @@ func TestSearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "17", resp.Header().Get("X-Total-Count"))
-	assert.Len(t, apiIssues, 17)
+	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
+	assert.Len(t, apiIssues, 18)
 
 	query.Add("limit", "5")
 	link.RawQuery = query.Encode()
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "17", resp.Header().Get("X-Total-Count"))
+	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
 	assert.Len(t, apiIssues, 5)
 
 	query = url.Values{"assigned": {"true"}, "state": {"all"}}
@@ -430,7 +430,7 @@ func TestSearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 6)
+	assert.Len(t, apiIssues, 7)
 
 	query = url.Values{"owner": {"user3"}} // organization
 	link.RawQuery = query.Encode()
@@ -450,7 +450,7 @@ func TestSearchIssues(t *testing.T) {
 func TestSearchIssuesWithLabels(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
-	expectedIssueCount := 15 // from the fixtures
+	expectedIssueCount := 16 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}

web_src/js/components/ContextPopup.vue

@@ -26,25 +26,10 @@
 <script>
 import $ from 'jquery';
 import {SvgIcon} from '../svg.js';
+import {useLightTextOnBackground} from '../utils.js';
 
 const {appSubUrl, i18n} = window.config;
 
-// NOTE: see models/issue_label.go for similar implementation
-const srgbToLinear = (color) => {
-  color /= 255;
-  if (color <= 0.04045) {
-    return color / 12.92;
-  }
-  return ((color + 0.055) / 1.055) ** 2.4;
-};
-const luminance = (colorString) => {
-  const r = srgbToLinear(parseInt(colorString.substring(0, 2), 16));
-  const g = srgbToLinear(parseInt(colorString.substring(2, 4), 16));
-  const b = srgbToLinear(parseInt(colorString.substring(4, 6), 16));
-  return 0.2126 * r + 0.7152 * g + 0.0722 * b;
-};
-const luminanceThreshold = 0.179;
-
 export default {
   components: {SvgIcon},
   data: () => ({
@@ -92,10 +77,10 @@ export default {
     labels() {
       return this.issue.labels.map((label) => {
         let textColor;
-        if (luminance(label.color) < luminanceThreshold) {
-          textColor = '#ffffff';
+        if (useLightTextOnBackground(label.color)) {
+          textColor = '#eeeeee';
         } else {
-          textColor = '#000000';
+          textColor = '#111111';
         }
         return {name: label.name, color: `#${label.color}`, textColor};
       });

web_src/js/features/common-issue.js

@@ -32,7 +32,7 @@ export function initCommonIssue() {
     syncIssueSelectionState();
   });
 
-  $('.issue-action').on('click', async function () {
+  $('.issue-action').on('click', async function (e) {
     let action = this.getAttribute('data-action');
     let elementId = this.getAttribute('data-element-id');
     const url = this.getAttribute('data-url');
@@ -43,6 +43,9 @@ export function initCommonIssue() {
       elementId = '';
       action = 'clear';
     }
+    if (action === 'toggle' && e.altKey) {
+      action = 'toggle-alt';
+    }
     updateIssuesMeta(
       url,
       action,

web_src/js/features/comp/LabelEdit.js

@@ -1,26 +1,64 @@
 import $ from 'jquery';
 import {initCompColorPicker} from './ColorPicker.js';
 
+function isExclusiveScopeName(name) {
+  return /.*[^/]\/[^/].*/.test(name);
+}
+
+function updateExclusiveLabelEdit(form) {
+  const nameInput = $(`${form} .label-name-input`);
+  const exclusiveField = $(`${form} .label-exclusive-input-field`);
+  const exclusiveCheckbox = $(`${form} .label-exclusive-input`);
+  const exclusiveWarning = $(`${form} .label-exclusive-warning`);
+
+  if (isExclusiveScopeName(nameInput.val())) {
+    exclusiveField.removeClass('muted');
+    if (exclusiveCheckbox.prop('checked') && exclusiveCheckbox.data('exclusive-warn')) {
+      exclusiveWarning.removeClass('gt-hidden');
+    } else {
+      exclusiveWarning.addClass('gt-hidden');
+    }
+  } else {
+    exclusiveField.addClass('muted');
+    exclusiveWarning.addClass('gt-hidden');
+  }
+}
+
 export function initCompLabelEdit(selector) {
   if (!$(selector).length) return;
-  // Create label
-  const $newLabelPanel = $('.new-label.segment');
-  $('.new-label.button').on('click', () => {
-    $newLabelPanel.show();
-  });
-  $('.new-label.segment .cancel').on('click', () => {
-    $newLabelPanel.hide();
-  });
-
   initCompColorPicker();
 
+  // Create label
+  $('.new-label.button').on('click', () => {
+    updateExclusiveLabelEdit('.new-label');
+    $('.new-label.modal').modal({
+      onApprove() {
+        $('.new-label.form').trigger('submit');
+      }
+    }).modal('show');
+    return false;
+  });
+
+  // Edit label
   $('.edit-label-button').on('click', function () {
     $('.edit-label .color-picker').minicolors('value', $(this).data('color'));
     $('#label-modal-id').val($(this).data('id'));
-    $('.edit-label .new-label-input').val($(this).data('title'));
-    $('.edit-label .new-label-desc-input').val($(this).data('description'));
+
+    const nameInput = $('.edit-label .label-name-input');
+    nameInput.val($(this).data('title'));
+
+    const exclusiveCheckbox = $('.edit-label .label-exclusive-input');
+    exclusiveCheckbox.prop('checked', this.hasAttribute('data-exclusive'));
+    // Warn when label was previously not exclusive and used in issues
+    exclusiveCheckbox.data('exclusive-warn',
+      $(this).data('num-issues') > 0 &&
+      (!this.hasAttribute('data-exclusive') || !isExclusiveScopeName(nameInput.val())));
+    updateExclusiveLabelEdit('.edit-label');
+
+    $('.edit-label .label-desc-input').val($(this).data('description'));
     $('.edit-label .color-picker').val($(this).data('color'));
     $('.edit-label .minicolors-swatch-color').css('background-color', $(this).data('color'));
+
     $('.edit-label.modal').modal({
       onApprove() {
         $('.edit-label.form').trigger('submit');
@@ -28,4 +66,17 @@ export function initCompLabelEdit(selector) {
     }).modal('show');
     return false;
   });
+
+  $('.new-label .label-name-input').on('input', () => {
+    updateExclusiveLabelEdit('.new-label');
+  });
+  $('.new-label .label-exclusive-input').on('change', () => {
+    updateExclusiveLabelEdit('.new-label');
+  });
+  $('.edit-label .label-name-input').on('input', () => {
+    updateExclusiveLabelEdit('.edit-label');
+  });
+  $('.edit-label .label-exclusive-input').on('change', () => {
+    updateExclusiveLabelEdit('.edit-label');
+  });
 }

web_src/js/features/repo-legacy.js

@@ -110,6 +110,29 @@ export function initRepoCommentForm() {
       }
 
       hasUpdateAction = $listMenu.data('action') === 'update'; // Update the var
+
+      const clickedItem = $(this);
+      const scope = $(this).attr('data-scope');
+      const canRemoveScope = e.altKey;
+
+      $(this).parent().find('.item').each(function () {
+        if (scope) {
+          // Enable only clicked item for scoped labels
+          if ($(this).attr('data-scope') !== scope) {
+            return true;
+          }
+          if ($(this).is(clickedItem)) {
+            if (!canRemoveScope && $(this).hasClass('checked')) {
+              return true;
+            }
+          } else if (!$(this).hasClass('checked')) {
+            return true;
+          }
+        } else if (!$(this).is(clickedItem)) {
+          // Toggle for other labels
+          return true;
+        }
+
         if ($(this).hasClass('checked')) {
           $(this).removeClass('checked');
           $(this).find('.octicon-check').addClass('invisible');
@@ -139,6 +162,7 @@ export function initRepoCommentForm() {
             }
           }
         }
+      });
 
       // TODO: Which thing should be done for choosing review requests
       // to make chosen items be shown on time here?

web_src/js/features/repo-projects.js

@@ -1,4 +1,5 @@
 import $ from 'jquery';
+import {useLightTextOnBackground} from '../utils.js';
 
 const {csrfToken} = window.config;
 
@@ -183,26 +184,13 @@ export function initRepoProject() {
 }
 
 function setLabelColor(label, color) {
-  const red = getRelativeColor(parseInt(color.slice(1, 3), 16));
-  const green = getRelativeColor(parseInt(color.slice(3, 5), 16));
-  const blue = getRelativeColor(parseInt(color.slice(5, 7), 16));
-  const luminance = 0.2126 * red + 0.7152 * green + 0.0722 * blue;
-
-  if (luminance > 0.179) {
-    label.removeClass('light-label').addClass('dark-label');
-  } else {
+  if (useLightTextOnBackground(color)) {
     label.removeClass('dark-label').addClass('light-label');
+  } else {
+    label.removeClass('light-label').addClass('dark-label');
   }
 }
 
-/**
- * Inspired by W3C recommendation https://www.w3.org/TR/WCAG20/#relativeluminancedef
- */
-function getRelativeColor(color) {
-  color /= 255;
-  return color <= 0.03928 ? color / 12.92 : ((color + 0.055) / 1.055) ** 2.4;
-}
-
 function rgbToHex(rgb) {
   rgb = rgb.match(/^rgba?\((\d+),\s*(\d+),\s*(\d+).*\)$/);
   return `#${hex(rgb[1])}${hex(rgb[2])}${hex(rgb[3])}`;

web_src/js/utils.js

@@ -146,3 +146,18 @@ export function toAbsoluteUrl(url) {
   }
   return `${window.location.origin}${url}`;
 }
+
+// determine if light or dark text color should be used on a given background color
+// NOTE: see models/issue_label.go for similar implementation
+export function useLightTextOnBackground(backgroundColor) {
+  if (backgroundColor[0] === '#') {
+    backgroundColor = backgroundColor.substring(1);
+  }
+  // Perceived brightness from: https://www.w3.org/TR/AERT/#color-contrast
+  // In the future WCAG 3 APCA may be a better solution.
+  const r = parseInt(backgroundColor.substring(0, 2), 16);
+  const g = parseInt(backgroundColor.substring(2, 4), 16);
+  const b = parseInt(backgroundColor.substring(4, 6), 16);
+  const brightness = (0.299 * r + 0.587 * g + 0.114 * b) / 255;
+  return brightness < 0.35;
+}

web_src/less/_base.less

@@ -1116,6 +1116,7 @@ a.ui.card:hover,
 
 .ui.modal > .content {
   background: var(--color-body);
+  text-align: left !important;
 }
 
 .ui.modal > .actions {
@@ -1364,6 +1365,10 @@ a.ui.card:hover,
   -webkit-text-fill-color: var(--color-black) !important;
 }
 
+.ui.form .field.muted {
+  opacity: var(--opacity-disabled);
+}
+
 .ui.loading.loading.input > i.icon svg {
   visibility: hidden;
 }
@@ -2568,8 +2573,7 @@ table th[data-sortt-desc] {
     border-top: none;
 
     a {
-      font-size: 15px;
-      padding-top: 5px;
+      font-size: 12px;
       padding-right: 10px;
       color: var(--color-text-light);
 
@@ -2581,10 +2585,6 @@ table th[data-sortt-desc] {
         margin-right: 30px;
       }
     }
-
-    .ui.label {
-      font-size: 1em;
-    }
   }
 
   .item:last-child {

web_src/less/_repository.less

@@ -92,7 +92,7 @@
   .metas {
     .menu {
       overflow-x: auto;
-      max-height: 300px;
+      max-height: 500px;
     }
 
     .ui.list {
@@ -155,12 +155,6 @@
   }
 
   .filter.menu {
-    .label.color {
-      border-radius: 3px;
-      margin-left: 15px;
-      padding: 0 8px;
-    }
-
     &.labels {
       .label-filter .menu .info {
         display: inline-block;
@@ -181,7 +175,7 @@
     }
 
     .menu {
-      max-height: 300px;
+      max-height: 500px;
       overflow-x: auto;
       right: 0 !important;
       left: auto !important;
@@ -190,7 +184,7 @@
 
   .select-label {
     .desc {
-      padding-left: 16px;
+      padding-left: 23px;
     }
   }
 
@@ -607,7 +601,7 @@
         min-width: 220px;
 
         .filter.menu {
-          max-height: 300px;
+          max-height: 500px;
           overflow-x: auto;
         }
       }
@@ -2774,7 +2768,7 @@
 }
 
 .edit-label.modal,
-.new-label.segment {
+.new-label.modal {
   .form {
     .column {
       padding-right: 0;
@@ -2786,12 +2780,9 @@
     }
 
     .color.picker.column {
-      width: auto;
-
-      .color-picker {
-        height: 35px;
-        width: auto;
-        padding-left: 30px;
+      display: flex;
+      .minicolors {
+        flex: 1;
       }
     }
 
@@ -2872,6 +2863,35 @@
   line-height: 1.3em; // there is a `font-size: 1.25em` for inside emoji, so here the line-height needs to be larger slightly
 }
 
+// Scoped labels with different colors on left and right, and slanted divider in the middle
+.scope-parent {
+  background: none !important;
+  padding: 0 !important;
+}
+
+.ui.label.scope-left {
+  border-bottom-right-radius: 0;
+  border-top-right-radius: 0;
+  padding-right: 0;
+  margin-right: 0;
+}
+
+.ui.label.scope-middle {
+  width: 12px;
+  border-radius: 0;
+  padding-left: 0;
+  padding-right: 0;
+  margin-left: 0;
+  margin-right: 0;
+}
+
+.ui.label.scope-right {
+  border-bottom-left-radius: 0;
+  border-top-left-radius: 0;
+  padding-left: 0;
+  margin-left: 0;
+}
+
 .repo-button-row {
   margin-bottom: 10px;
 }