Allow multiple projects per issue and pull requests (#36784)

Add ability to add and remove multiple projects per issue
and pull request.

Resolve #12974

---------

Signed-off-by: Icy Avocado <avocado@ovacoda.com>
Co-authored-by: Tyrone Yeh <siryeh@gmail.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: OpenCode (gpt-5.2-codex) <opencode@openai.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

modules/indexer/issues/bleve/bleve.go

@@ -27,7 +27,7 @@ import (
 const (
 	issueIndexerAnalyzer      = "issueIndexer"
 	issueIndexerDocType       = "issueIndexerDocType"
-	issueIndexerLatestVersion = 5
+	issueIndexerLatestVersion = 6
 )
 
 const unicodeNormalizeName = "unicodeNormalize"
@@ -83,8 +83,8 @@ func generateIssueIndexMapping() (mapping.IndexMapping, error) {
 	docMapping.AddFieldMappingsAt("label_ids", numberFieldMapping)
 	docMapping.AddFieldMappingsAt("no_label", boolFieldMapping)
 	docMapping.AddFieldMappingsAt("milestone_id", numberFieldMapping)
-	docMapping.AddFieldMappingsAt("project_id", numberFieldMapping)
-	docMapping.AddFieldMappingsAt("project_board_id", numberFieldMapping)
+	docMapping.AddFieldMappingsAt("project_ids", numberFieldMapping)
+	docMapping.AddFieldMappingsAt("no_project", boolFieldMapping)
 	docMapping.AddFieldMappingsAt("poster_id", numberFieldMapping)
 	docMapping.AddFieldMappingsAt("assignee_id", numberFieldMapping)
 	docMapping.AddFieldMappingsAt("mention_ids", numberFieldMapping)
@@ -241,11 +241,15 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		queries = append(queries, bleve.NewDisjunctionQuery(milestoneQueries...))
 	}
 
-	if options.ProjectID.Has() {
-		queries = append(queries, inner_bleve.NumericEqualityQuery(options.ProjectID.Value(), "project_id"))
-	}
-	if options.ProjectColumnID.Has() {
-		queries = append(queries, inner_bleve.NumericEqualityQuery(options.ProjectColumnID.Value(), "project_board_id"))
+	if options.NoProjectOnly {
+		queries = append(queries, inner_bleve.BoolFieldQuery(true, "no_project"))
+	} else if len(options.ProjectIDs) > 0 {
+		var projectQueries []query.Query
+		for _, projectID := range options.ProjectIDs {
+			projectQueries = append(projectQueries, inner_bleve.NumericEqualityQuery(projectID, "project_ids"))
+		}
+		// FIXME: ISSUE-MULTIPLE-PROJECTS-FILTER: this logic is not right, it should use "AND" but not "OR"
+		queries = append(queries, bleve.NewDisjunctionQuery(projectQueries...))
 	}
 
 	if options.PosterID != "" {

modules/indexer/issues/db/options.go

@@ -13,6 +13,7 @@ import (
 	"code.gitea.io/gitea/modules/container"
 	"code.gitea.io/gitea/modules/indexer/issues/internal"
 	"code.gitea.io/gitea/modules/optional"
+	"code.gitea.io/gitea/modules/util"
 )
 
 func ToDBOptions(ctx context.Context, options *internal.SearchOptions) (*issue_model.IssuesOptions, error) {
@@ -65,8 +66,7 @@ func ToDBOptions(ctx context.Context, options *internal.SearchOptions) (*issue_m
 		ReviewRequestedID:  convertID(options.ReviewRequestedID),
 		ReviewedID:         convertID(options.ReviewedID),
 		SubscriberID:       convertID(options.SubscriberID),
-		ProjectID:          convertID(options.ProjectID),
-		ProjectColumnID:    convertID(options.ProjectColumnID),
+		ProjectIDs:         util.Iif(options.NoProjectOnly, []int64{db.NoConditionID}, options.ProjectIDs),
 		IsClosed:           options.IsClosed,
 		IsPull:             options.IsPull,
 		IncludedLabelNames: nil,

modules/indexer/issues/dboptions.go

@@ -46,10 +46,10 @@ func ToSearchOptions(keyword string, opts *issues_model.IssuesOptions) *SearchOp
 		searchOpt.MilestoneIDs = opts.MilestoneIDs
 	}
 
-	if opts.ProjectID > 0 {
-		searchOpt.ProjectID = optional.Some(opts.ProjectID)
-	} else if opts.ProjectID == db.NoConditionID { // FIXME: this is inconsistent from other places
-		searchOpt.ProjectID = optional.Some[int64](0) // Those issues with no project(projectid==0)
+	if len(opts.ProjectIDs) == 1 && opts.ProjectIDs[0] == db.NoConditionID {
+		searchOpt.NoProjectOnly = true
+	} else {
+		searchOpt.ProjectIDs = opts.ProjectIDs
 	}
 
 	searchOpt.AssigneeID = opts.AssigneeID
@@ -65,7 +65,6 @@ func ToSearchOptions(keyword string, opts *issues_model.IssuesOptions) *SearchOp
 		return nil
 	}
 
-	searchOpt.ProjectColumnID = convertID(opts.ProjectColumnID)
 	searchOpt.PosterID = opts.PosterID
 	searchOpt.MentionID = convertID(opts.MentionedID)
 	searchOpt.ReviewedID = convertID(opts.ReviewedID)

modules/indexer/issues/elasticsearch/elasticsearch.go

@@ -19,7 +19,7 @@ import (
 )
 
 const (
-	issueIndexerLatestVersion = 2
+	issueIndexerLatestVersion = 3
 	// multi-match-types, currently only 2 types are used
 	// Reference: https://www.elastic.co/guide/en/elasticsearch/reference/7.0/query-dsl-multi-match-query.html#multi-match-types
 	esMultiMatchTypeBestFields   = "best_fields"
@@ -68,8 +68,8 @@ const (
 			"label_ids": { "type": "integer", "index": true },
 			"no_label": { "type": "boolean", "index": true },
 			"milestone_id": { "type": "integer", "index": true },
-			"project_id": { "type": "integer", "index": true },
-			"project_board_id": { "type": "integer", "index": true },
+			"project_ids": { "type": "integer", "index": true },
+			"no_project": { "type": "boolean", "index": true },
 			"poster_id": { "type": "integer", "index": true },
 			"assignee_id": { "type": "integer", "index": true },
 			"mention_ids": { "type": "integer", "index": true },
@@ -204,11 +204,11 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		query.Must(elastic.NewTermsQuery("milestone_id", toAnySlice(options.MilestoneIDs)...))
 	}
 
-	if options.ProjectID.Has() {
-		query.Must(elastic.NewTermQuery("project_id", options.ProjectID.Value()))
-	}
-	if options.ProjectColumnID.Has() {
-		query.Must(elastic.NewTermQuery("project_board_id", options.ProjectColumnID.Value()))
+	if options.NoProjectOnly {
+		query.Must(elastic.NewTermQuery("no_project", true))
+	} else if len(options.ProjectIDs) > 0 {
+		// FIXME: ISSUE-MULTIPLE-PROJECTS-FILTER: this logic is not right, it should use "AND" but not "OR"
+		query.Must(elastic.NewTermsQuery("project_ids", toAnySlice(options.ProjectIDs)...))
 	}
 
 	if options.PosterID != "" {

modules/indexer/issues/indexer_test.go

@@ -416,28 +416,42 @@ func searchIssueInProject(t *testing.T) {
 	}{
 		{
 			SearchOptions{
-				ProjectID: optional.Some(int64(1)),
+				ProjectIDs: []int64{1},
 			},
 			[]int64{5, 3, 2, 1},
 		},
-		{
-			SearchOptions{
-				ProjectColumnID: optional.Some(int64(1)),
-			},
-			[]int64{1},
-		},
-		{
-			SearchOptions{
-				ProjectColumnID: optional.Some(int64(0)), // issue with in default column
-			},
-			[]int64{2},
-		},
 	}
 	for _, test := range tests {
 		issueIDs, _, err := SearchIssues(t.Context(), &test.opts)
 		require.NoError(t, err)
 		assert.Equal(t, test.expectedIDs, issueIDs)
 	}
+
+	// Test filtering for issues with no project assigned using dynamic validation
+	t.Run("no project assigned", func(t *testing.T) {
+		issueIDs, total, err := SearchIssues(t.Context(), &SearchOptions{
+			ProjectIDs: []int64{db.NoConditionID},
+		})
+		require.NoError(t, err)
+		assert.NotEmpty(t, issueIDs)
+		assert.Equal(t, total, int64(len(issueIDs)))
+
+		// Verify each returned issue actually has no project
+		for _, issueID := range issueIDs {
+			issue, err := issues.GetIssueByID(t.Context(), issueID)
+			require.NoError(t, err)
+			err = issue.LoadProjects(t.Context())
+			require.NoError(t, err)
+			assert.Empty(t, issue.Projects, "Issue %d should have no projects", issueID)
+		}
+
+		// Count total issues with no project to verify we got them all
+		allIssues, err := issues.Issues(t.Context(), &issues.IssuesOptions{
+			ProjectIDs: []int64{db.NoConditionID},
+		})
+		require.NoError(t, err)
+		assert.Len(t, issueIDs, len(allIssues), "Should return all issues with no project")
+	})
 }
 
 func searchIssueWithPaginator(t *testing.T) {

modules/indexer/issues/internal/model.go

@@ -30,8 +30,9 @@ type IndexerData struct {
 	LabelIDs           []int64            `json:"label_ids"`
 	NoLabel            bool               `json:"no_label"` // True if LabelIDs is empty
 	MilestoneID        int64              `json:"milestone_id"`
-	ProjectID          int64              `json:"project_id"`
-	ProjectColumnID    int64              `json:"project_board_id"` // the key should be kept as project_board_id to keep compatible
+	ProjectIDs         []int64            `json:"project_ids"`
+	NoProject          bool               `json:"no_project"`                   // True if ProjectIDs is empty
+	ProjectColumnMap   map[int64]int64    `json:"project_column_map,omitempty"` // Maps project ID to column ID for each project the issue is in
 	PosterID           int64              `json:"poster_id"`
 	AssigneeID         int64              `json:"assignee_id"`
 	MentionIDs         []int64            `json:"mention_ids"`
@@ -94,8 +95,8 @@ type SearchOptions struct {
 
 	MilestoneIDs []int64 // milestones the issues have
 
-	ProjectID       optional.Option[int64] // project the issues belong to
-	ProjectColumnID optional.Option[int64] // project column the issues belong to
+	ProjectIDs    []int64 // project the issues belong to. FIXME: ISSUE-MULTIPLE-PROJECTS-FILTER: no multiple project filter support yet. Search logic is wrong.
+	NoProjectOnly bool    // if the issues have no project, if true, ProjectIDs will be ignored
 
 	PosterID   string // poster of the issues, "(none)" or "(any)" or a user ID
 	AssigneeID string // assignee of the issues, "(none)" or "(any)" or a user ID

modules/indexer/issues/internal/tests/tests.go

@@ -301,75 +301,41 @@ var cases = []*testIndexerCase{
 		},
 	},
 	{
-		Name: "ProjectID",
+		Name: "ProjectIDs",
 		SearchOptions: &internal.SearchOptions{
 			Paginator: &db.ListOptions{
 				PageSize: 5,
 			},
-			ProjectID: optional.Some(int64(1)),
+			ProjectIDs: []int64{1},
 		},
 		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
 			assert.Len(t, result.Hits, 5)
 			for _, v := range result.Hits {
-				assert.Equal(t, int64(1), data[v.ID].ProjectID)
+				assert.Contains(t, data[v.ID].ProjectIDs, int64(1))
 			}
 			assert.Equal(t, countIndexerData(data, func(v *internal.IndexerData) bool {
-				return v.ProjectID == 1
+				return slices.Contains(v.ProjectIDs, int64(1))
 			}), result.Total)
 		},
 	},
 	{
-		Name: "no ProjectID",
+		Name: "no ProjectIDs (empty array)",
 		SearchOptions: &internal.SearchOptions{
 			Paginator: &db.ListOptions{
-				PageSize: 5,
+				PageSize: 50,
 			},
-			ProjectID: optional.Some(int64(0)),
+			NoProjectOnly: true,
 		},
 		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
-			assert.Len(t, result.Hits, 5)
+			// Verify only issues with no projects are returned
 			for _, v := range result.Hits {
-				assert.Equal(t, int64(0), data[v.ID].ProjectID)
+				assert.Empty(t, data[v.ID].ProjectIDs, "Issue %d should have no projects", v.ID)
 			}
-			assert.Equal(t, countIndexerData(data, func(v *internal.IndexerData) bool {
-				return v.ProjectID == 0
-			}), result.Total)
-		},
-	},
-	{
-		Name: "ProjectColumnID",
-		SearchOptions: &internal.SearchOptions{
-			Paginator: &db.ListOptions{
-				PageSize: 5,
-			},
-			ProjectColumnID: optional.Some(int64(1)),
-		},
-		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
-			assert.Len(t, result.Hits, 5)
-			for _, v := range result.Hits {
-				assert.Equal(t, int64(1), data[v.ID].ProjectColumnID)
-			}
-			assert.Equal(t, countIndexerData(data, func(v *internal.IndexerData) bool {
-				return v.ProjectColumnID == 1
-			}), result.Total)
-		},
-	},
-	{
-		Name: "no ProjectColumnID",
-		SearchOptions: &internal.SearchOptions{
-			Paginator: &db.ListOptions{
-				PageSize: 5,
-			},
-			ProjectColumnID: optional.Some(int64(0)),
-		},
-		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
-			assert.Len(t, result.Hits, 5)
-			for _, v := range result.Hits {
-				assert.Equal(t, int64(0), data[v.ID].ProjectColumnID)
-			}
-			assert.Equal(t, countIndexerData(data, func(v *internal.IndexerData) bool {
-				return v.ProjectColumnID == 0
-			}), result.Total)
+			// Verify we got ALL issues with no projects
+			expectedCount := countIndexerData(data, func(v *internal.IndexerData) bool {
+				return len(v.ProjectIDs) == 0
+			})
+			assert.Equal(t, expectedCount, result.Total, "Should return all %d issues with no project", expectedCount)
 		},
 	},
 	{
@@ -706,6 +672,10 @@ func generateDefaultIndexerData() []*internal.IndexerData {
 			for i := range subscriberIDs {
 				subscriberIDs[i] = int64(i) + 1 // SubscriberID should not be 0
 			}
+			projectIDs := make([]int64, id%5)
+			for i := range projectIDs {
+				projectIDs[i] = int64(i) + 1 // projectID should not be 0
+			}
 
 			data = append(data, &internal.IndexerData{
 				ID:                 id,
@@ -719,8 +689,8 @@ func generateDefaultIndexerData() []*internal.IndexerData {
 				LabelIDs:           labelIDs,
 				NoLabel:            len(labelIDs) == 0,
 				MilestoneID:        issueIndex % 4,
-				ProjectID:          issueIndex % 5,
-				ProjectColumnID:    issueIndex % 6,
+				ProjectIDs:         projectIDs,
+				NoProject:          len(projectIDs) == 0,
 				PosterID:           id%10 + 1, // PosterID should not be 0
 				AssigneeID:         issueIndex % 10,
 				MentionIDs:         mentionIDs,

modules/indexer/issues/meilisearch/meilisearch.go

@@ -20,7 +20,7 @@ import (
 )
 
 const (
-	issueIndexerLatestVersion = 4
+	issueIndexerLatestVersion = 5
 
 	// TODO: make this configurable if necessary
 	maxTotalHits = 10000
@@ -71,8 +71,8 @@ func NewIndexer(url, apiKey, indexerName string) *Indexer {
 			"label_ids",
 			"no_label",
 			"milestone_id",
-			"project_id",
-			"project_board_id",
+			"project_ids",
+			"no_project",
 			"poster_id",
 			"assignee_id",
 			"mention_ids",
@@ -182,11 +182,11 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		query.And(inner_meilisearch.NewFilterIn("milestone_id", options.MilestoneIDs...))
 	}
 
-	if options.ProjectID.Has() {
-		query.And(inner_meilisearch.NewFilterEq("project_id", options.ProjectID.Value()))
-	}
-	if options.ProjectColumnID.Has() {
-		query.And(inner_meilisearch.NewFilterEq("project_board_id", options.ProjectColumnID.Value()))
+	if options.NoProjectOnly {
+		query.And(inner_meilisearch.NewFilterEq("no_project", true))
+	} else if len(options.ProjectIDs) > 0 {
+		// FIXME: ISSUE-MULTIPLE-PROJECTS-FILTER: this logic is not right, it should use "AND" but not "OR"
+		query.And(inner_meilisearch.NewFilterIn("project_ids", options.ProjectIDs...))
 	}
 
 	if options.PosterID != "" {

modules/indexer/issues/util.go

@@ -87,14 +87,9 @@ func getIssueIndexerData(ctx context.Context, issueID int64) (*internal.IndexerD
 		return nil, false, err
 	}
 
-	var projectID int64
-	if issue.Project != nil {
-		projectID = issue.Project.ID
-	}
-
-	projectColumnID, err := issue.ProjectColumnID(ctx)
-	if err != nil {
-		return nil, false, err
+	projectIDs := make([]int64, 0, len(issue.Projects))
+	for _, project := range issue.Projects {
+		projectIDs = append(projectIDs, project.ID)
 	}
 
 	if err := issue.Repo.LoadOwner(ctx); err != nil {
@@ -114,8 +109,8 @@ func getIssueIndexerData(ctx context.Context, issueID int64) (*internal.IndexerD
 		LabelIDs:           labels,
 		NoLabel:            len(labels) == 0,
 		MilestoneID:        issue.MilestoneID,
-		ProjectID:          projectID,
-		ProjectColumnID:    projectColumnID,
+		ProjectIDs:         projectIDs,
+		NoProject:          len(projectIDs) == 0,
 		PosterID:           issue.PosterID,
 		AssigneeID:         issue.AssigneeID,
 		MentionIDs:         mentionIDs,

modules/structs/issue.go

@@ -60,6 +60,7 @@ type Issue struct {
 	Attachments      []*Attachment `json:"assets"`
 	Labels           []*Label      `json:"labels"`
 	Milestone        *Milestone    `json:"milestone"`
+	Projects         []*Project    `json:"projects"`
 	// deprecated
 	Assignee  *User     `json:"assignee"`
 	Assignees []*User   `json:"assignees"`
@@ -100,7 +101,9 @@ type CreateIssueOption struct {
 	Milestone int64 `json:"milestone"`
 	// list of label ids
 	Labels []int64 `json:"labels"`
-	Closed bool    `json:"closed"`
+	// list of project ids
+	Projects []int64 `json:"projects"`
+	Closed   bool    `json:"closed"`
 }
 
 // EditIssueOption options for editing an issue
@@ -112,7 +115,9 @@ type EditIssueOption struct {
 	Assignee  *string  `json:"assignee"`
 	Assignees []string `json:"assignees"`
 	Milestone *int64   `json:"milestone"`
-	State     *string  `json:"state"`
+	// list of project ids to set (replaces existing projects)
+	Projects *[]int64 `json:"projects"`
+	State    *string  `json:"state"`
 	// swagger:strfmt date-time
 	Deadline       *time.Time `json:"due_date"`
 	RemoveDeadline *bool      `json:"unset_due_date"`

modules/structs/project.go

@@ -0,0 +1,33 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package structs
+
+import (
+	"time"
+)
+
+// Project represents a project
+// swagger:model
+type Project struct {
+	// ID is the unique identifier for the project
+	ID int64 `json:"id"`
+	// Title is the title of the project
+	Title string `json:"title"`
+	// Description provides details about the project
+	Description string `json:"description"`
+	// OwnerID is the owner of the project (for org-level projects)
+	OwnerID int64 `json:"owner_id,omitempty"`
+	// RepoID is the repository this project belongs to (for repo-level projects)
+	RepoID int64 `json:"repo_id,omitempty"`
+	// CreatorID is the user who created the project
+	CreatorID int64 `json:"creator_id"`
+	// IsClosed indicates if the project is closed
+	IsClosed bool `json:"is_closed"`
+	// swagger:strfmt date-time
+	Created time.Time `json:"created_at"`
+	// swagger:strfmt date-time
+	Updated time.Time `json:"updated_at"`
+	// swagger:strfmt date-time
+	Closed *time.Time `json:"closed_at,omitempty"`
+}

modules/templates/page.go

@@ -5,6 +5,7 @@ package templates
 
 import (
 	"context"
+	"fmt"
 	"html/template"
 	"io"
 	"net/http"
@@ -36,7 +37,11 @@ func (r *pageRenderer) funcMapDummy() template.FuncMap {
 }
 
 func (r *pageRenderer) TemplateLookup(tmpl string, templateCtx context.Context) (TemplateExecutor, error) { //nolint:revive // we don't use ctx, only pass it to the template executor
-	return r.tmplRenderer.Templates().Executor(tmpl, r.funcMap(templateCtx))
+	tmpls := r.tmplRenderer.Templates()
+	if tmpls == nil {
+		return nil, fmt.Errorf("no templates defined for %s", tmpl)
+	}
+	return tmpls.Executor(tmpl, r.funcMap(templateCtx))
 }
 
 func (r *pageRenderer) HTML(w io.Writer, status int, tplName TplName, data any, templateCtx context.Context) error { //nolint:revive // we don't use ctx, only pass it to the template executor

modules/templates/util_slice.go

@@ -6,6 +6,11 @@ package templates
 import (
 	"fmt"
 	"reflect"
+	"slices"
+	"strconv"
+	"strings"
+
+	"code.gitea.io/gitea/modules/util"
 )
 
 type SliceUtils struct{}
@@ -33,3 +38,29 @@ func (su *SliceUtils) Contains(s, v any) bool {
 	}
 	return false
 }
+
+// JoinInt64 joins a slice of int64 values into a comma-separated string.
+func (su *SliceUtils) JoinInt64(values []int64) string {
+	if len(values) == 0 {
+		return ""
+	}
+	strs := make([]string, len(values))
+	for i, v := range values {
+		strs[i] = strconv.FormatInt(v, 10)
+	}
+	return strings.Join(strs, ",")
+}
+
+func (su *SliceUtils) JoinToggleIDs(values []int64, target int64) (ret struct {
+	IsIncluded bool
+	ToggledIDs string
+},
+) {
+	ret.IsIncluded = slices.Contains(values, target)
+	if ret.IsIncluded {
+		ret.ToggledIDs = su.JoinInt64(util.SliceRemoveAll(slices.Clone(values), target))
+	} else {
+		ret.ToggledIDs = su.JoinInt64(append(values, target))
+	}
+	return ret
+}

modules/templates/util_test.go

@@ -70,6 +70,16 @@ func TestUtils(t *testing.T) {
 	actual = execTmpl("{{StringUtils.Contains .String .Value}}", map[string]any{"String": "abc", "Value": "x"})
 	assert.Equal(t, "false", actual)
 
+	// Test JoinInt64
+	actual = execTmpl("{{SliceUtils.JoinInt64 .Values}}", map[string]any{"Values": []int64{1, 2, 3}})
+	assert.Equal(t, "1,2,3", actual)
+
+	actual = execTmpl("{{SliceUtils.JoinInt64 .Values}}", map[string]any{"Values": []int64{}})
+	assert.Empty(t, actual)
+
+	actual = execTmpl("{{SliceUtils.JoinInt64 .Values}}", map[string]any{"Values": []int64{42}})
+	assert.Equal(t, "42", actual)
+
 	tmpl := template.New("test")
 	tmpl.Funcs(template.FuncMap{"SliceUtils": NewSliceUtils, "StringUtils": NewStringUtils})
 	template.Must(tmpl.Parse("{{SliceUtils.Contains .Slice .Value}}"))

modules/util/diff_slice_test.go

@@ -0,0 +1,74 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDiffSliceBasic(t *testing.T) {
+	// Typical integer cases
+	t.Run("additions", func(t *testing.T) {
+		added, removed := DiffSlice([]int{1, 2}, []int{1, 2, 3})
+		assert.Equal(t, []int{3}, added)
+		assert.Empty(t, removed)
+	})
+
+	t.Run("removals", func(t *testing.T) {
+		added, removed := DiffSlice([]int{1, 2, 3}, []int{1, 2})
+		assert.Empty(t, added)
+		assert.Equal(t, []int{3}, removed)
+	})
+
+	t.Run("no changes", func(t *testing.T) {
+		added, removed := DiffSlice([]int{1, 2}, []int{1, 2})
+		assert.Empty(t, added)
+		assert.Empty(t, removed)
+	})
+
+	t.Run("empty slices", func(t *testing.T) {
+		added, removed := DiffSlice([]int{}, []int{})
+		assert.Empty(t, added)
+		assert.Empty(t, removed)
+	})
+
+	t.Run("overlapping elements", func(t *testing.T) {
+		added, removed := DiffSlice([]int{1, 2, 4}, []int{2, 3, 4})
+		assert.Equal(t, []int{3}, added)
+		assert.Equal(t, []int{1}, removed)
+	})
+}
+
+func TestDiffSliceOrderAndDuplicates(t *testing.T) {
+	oldSlice := []int{1, 2, 2, 3}
+	newSlice := []int{2, 4, 2, 5}
+
+	added, removed := DiffSlice(oldSlice, newSlice)
+	assert.Equal(t, []int{4, 5}, added)
+	assert.Equal(t, []int{1, 3}, removed)
+}
+
+func TestDiffSliceDeduplicatesOutput(t *testing.T) {
+	// Test case from issue: newSlice contains [4, 4, 5] and oldSlice is [1]
+	// added should return [4, 5], not [4, 4, 5]
+	t.Run("deduplicates added", func(t *testing.T) {
+		added, removed := DiffSlice([]int{1}, []int{4, 4, 5})
+		assert.Equal(t, []int{4, 5}, added)
+		assert.Equal(t, []int{1}, removed)
+	})
+
+	t.Run("deduplicates removed", func(t *testing.T) {
+		added, removed := DiffSlice([]int{1, 1, 2}, []int{3})
+		assert.Equal(t, []int{3}, added)
+		assert.Equal(t, []int{1, 2}, removed)
+	})
+
+	t.Run("deduplicates both", func(t *testing.T) {
+		added, removed := DiffSlice([]int{1, 1, 2, 2}, []int{3, 3, 4, 4})
+		assert.Equal(t, []int{3, 4}, added)
+		assert.Equal(t, []int{1, 2}, removed)
+	})
+}

modules/util/util.go

@@ -15,6 +15,8 @@ import (
 	"strings"
 	"sync"
 
+	"code.gitea.io/gitea/modules/container"
+
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
 )
@@ -291,3 +293,21 @@ func NormalizeStringEOL(input string) string {
 	// Other than this, we should respect the original content, even leading or trailing spaces.
 	return UnsafeBytesToString(NormalizeEOL(UnsafeStringToBytes(input)))
 }
+
+func DiffSlice[T comparable](oldSlice, newSlice []T) (added, removed []T) {
+	oldSet := container.SetOf(oldSlice...)
+	newSet := container.SetOf(newSlice...)
+
+	addedSet, removedSet := container.Set[T]{}, container.Set[T]{}
+	for _, v := range newSlice {
+		if !oldSet.Contains(v) && addedSet.Add(v) {
+			added = append(added, v)
+		}
+	}
+	for _, v := range oldSlice {
+		if !newSet.Contains(v) && removedSet.Add(v) {
+			removed = append(removed, v)
+		}
+	}
+	return added, removed
+}