Add link to user profile in markdown mention only if user exists

contrib/pr/checkout.go

@@ -33,6 +33,7 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/routers"
+	markup_service "code.gitea.io/gitea/services/markup"
 
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/config"
@@ -112,7 +113,7 @@ func runPR() {
 	log.Printf("[PR] Setting up router\n")
 	// routers.GlobalInit()
 	external.RegisterRenderers()
-	markup.Init()
+	markup.Init(markup_service.ProcessorHelper())
 	c := routers.NormalRoutes(graceful.GetManager().HammerContext())
 
 	log.Printf("[PR] Ready for testing !\n")

modules/markup/html.go

@@ -603,8 +603,14 @@ func mentionProcessor(ctx *RenderContext, node *html.Node) {
 			start = loc.End
 			continue
 		}
-		replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(setting.AppURL, mention[1:]), mention, "mention"))
-		node = node.NextSibling.NextSibling
+		mentionedUsername := mention[1:]
+
+		if processorHelper.IsUsernameMentionable != nil && processorHelper.IsUsernameMentionable(ctx.Ctx, mentionedUsername) {
+			replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(setting.AppURL, mentionedUsername), mention, "mention"))
+			node = node.NextSibling.NextSibling
+		} else {
+			node = node.NextSibling
+		}
 		start = 0
 	}
 }

modules/markup/renderer.go

@@ -19,8 +19,18 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 )
 
+type ProcessorHelper struct {
+	IsUsernameMentionable func(ctx context.Context, username string) bool
+}
+
+var processorHelper ProcessorHelper
+
 // Init initialize regexps for markdown parsing
-func Init() {
+func Init(ph *ProcessorHelper) {
+	if ph != nil {
+		processorHelper = *ph
+	}
+
 	NewSanitizer()
 	if len(setting.Markdown.CustomURLSchemes) > 0 {
 		CustomLinkURLSchemes(setting.Markdown.CustomURLSchemes)

routers/api/v1/misc/markdown_test.go

@@ -12,6 +12,7 @@ import (
 	"strings"
 	"testing"
 
+	"code.gitea.io/gitea/models/unittest"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
@@ -51,6 +52,8 @@ func wrap(ctx *context.Context) *context.APIContext {
 func TestAPI_RenderGFM(t *testing.T) {
 	setting.AppURL = AppURL
 
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
 	options := api.MarkdownOption{
 		Mode:    "gfm",
 		Text:    "",

routers/init.go

@@ -41,6 +41,7 @@ import (
 	"code.gitea.io/gitea/services/automerge"
 	"code.gitea.io/gitea/services/cron"
 	"code.gitea.io/gitea/services/mailer"
+	markup_service "code.gitea.io/gitea/services/markup"
 	repo_migrations "code.gitea.io/gitea/services/migrations"
 	mirror_service "code.gitea.io/gitea/services/mirror"
 	pull_service "code.gitea.io/gitea/services/pull"
@@ -123,7 +124,7 @@ func GlobalInitInstalled(ctx context.Context) {
 
 	highlight.NewContext()
 	external.RegisterRenderers()
-	markup.Init()
+	markup.Init(markup_service.ProcessorHelper())
 
 	if setting.EnableSQLite3 {
 		log.Info("SQLite3 support is enabled")

services/markup/processorhelper.go

@@ -0,0 +1,24 @@
+package markup
+
+import (
+	"context"
+
+	"code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/markup"
+)
+
+func ProcessorHelper() *markup.ProcessorHelper {
+	return &markup.ProcessorHelper{
+		IsUsernameMentionable: func(ctx context.Context, username string) bool {
+			// here, you  could also try to cast the ctx to a modules/context.Context
+			// Only link if the user actually exists
+			userExists, err := user.IsUserExist(ctx, 0, username)
+			if err != nil {
+				log.Error("Failed to validate user in mention %q exists, assuming it does", username)
+				userExists = true
+			}
+			return userExists
+		},
+	}
+}

tests/integration/setting_test.go

@@ -26,7 +26,7 @@ func TestSettingShowUserEmailExplore(t *testing.T) {
 	htmlDoc := NewHTMLParser(t, resp.Body)
 	assert.Contains(t,
 		htmlDoc.doc.Find(".ui.user.list").Text(),
-		"user4@example.com",
+		"user10@example.com",
 	)
 
 	setting.UI.ShowUserEmail = false
@@ -36,7 +36,7 @@ func TestSettingShowUserEmailExplore(t *testing.T) {
 	htmlDoc = NewHTMLParser(t, resp.Body)
 	assert.NotContains(t,
 		htmlDoc.doc.Find(".ui.user.list").Text(),
-		"user4@example.com",
+		"user10@example.com",
 	)
 
 	setting.UI.ShowUserEmail = showUserEmail