Add sub issue list support (#32940)

Just like GitHub, show issue icon/title when the issue number is in a list

modules/markup/html_issue_test.go

@@ -0,0 +1,72 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markup_test
+
+import (
+	"context"
+	"html/template"
+	"strings"
+	"testing"
+
+	"code.gitea.io/gitea/modules/htmlutil"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/markup/markdown"
+	testModule "code.gitea.io/gitea/modules/test"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRender_IssueList(t *testing.T) {
+	defer testModule.MockVariableValue(&markup.RenderBehaviorForTesting.DisableAdditionalAttributes, true)()
+	markup.Init(&markup.RenderHelperFuncs{
+		RenderRepoIssueIconTitle: func(ctx context.Context, opts markup.RenderIssueIconTitleOptions) (template.HTML, error) {
+			return htmlutil.HTMLFormat("<div>issue #%d</div>", opts.IssueIndex), nil
+		},
+	})
+
+	test := func(input, expected string) {
+		rctx := markup.NewTestRenderContext(markup.TestAppURL, map[string]string{
+			"user": "test-user", "repo": "test-repo",
+			"markupAllowShortIssuePattern": "true",
+		})
+		out, err := markdown.RenderString(rctx, input)
+		require.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(out)))
+	}
+
+	t.Run("NormalIssueRef", func(t *testing.T) {
+		test(
+			"#12345",
+			`<p><a href="http://localhost:3000/test-user/test-repo/issues/12345" class="ref-issue" rel="nofollow">#12345</a></p>`,
+		)
+	})
+
+	t.Run("ListIssueRef", func(t *testing.T) {
+		test(
+			"* #12345",
+			`<ul>
+<li><div>issue #12345</div></li>
+</ul>`,
+		)
+	})
+
+	t.Run("ListIssueRefNormal", func(t *testing.T) {
+		test(
+			"* foo #12345 bar",
+			`<ul>
+<li>foo <a href="http://localhost:3000/test-user/test-repo/issues/12345" class="ref-issue" rel="nofollow">#12345</a> bar</li>
+</ul>`,
+		)
+	})
+
+	t.Run("ListTodoIssueRef", func(t *testing.T) {
+		test(
+			"* [ ] #12345",
+			`<ul>
+<li class="task-list-item"><input type="checkbox" disabled="" data-source-position="2"/><div>issue #12345</div></li>
+</ul>`,
+		)
+	})
+}