refactor: replace legacy delete-button with link-action (#38143)

Removes the legacy `delete-button` handler (`initGlobalDeleteButton`)
and migrates all remaining usages to `link-action` and `show-modal` /
`form-fetch-action`.

Two handlers are adjusted for the new request shape: webauthn key delete
reads `id` from the query, and account deletion returns `JSONError` on
validation failure.

A E2E test ist added to cover one of the use cases.

Suggested in
https://github.com/go-gitea/gitea/pull/38046#discussion_r3414936737.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: bircni <bircni@icloud.com>

tests/integration/branches_test.go

@@ -38,13 +38,13 @@ func TestViewBranches(t *testing.T) {
 }
 
 func TestUndoDeleteBranch(t *testing.T) {
-	branchAction := func(t *testing.T, button string) (*HTMLDoc, string) {
+	branchAction := func(t *testing.T, button, attr string) (*HTMLDoc, string) {
 		session := loginUser(t, "user2")
 		req := NewRequest(t, "GET", "/user2/repo1/branches")
 		resp := session.MakeRequest(t, req, http.StatusOK)
 
 		htmlDoc := NewHTMLParser(t, resp.Body)
-		link, exists := htmlDoc.doc.Find(button).Attr("data-url")
+		link, exists := htmlDoc.doc.Find(button).Attr(attr)
 		require.True(t, exists, "The template has changed")
 		linkURL, err := url.Parse(link)
 		require.NoError(t, err)
@@ -58,12 +58,12 @@ func TestUndoDeleteBranch(t *testing.T) {
 	}
 
 	onGiteaRun(t, func(t *testing.T, u *url.URL) {
-		htmlDoc, name := branchAction(t, ".delete-branch-button")
+		htmlDoc, name := branchAction(t, ".delete-branch-button", "data-modal-form.action")
 		assert.Contains(t,
 			htmlDoc.doc.Find(".ui.positive.message").Text(),
 			translation.NewLocale("en-US").TrString("repo.branch.deletion_success", name),
 		)
-		htmlDoc, name = branchAction(t, ".restore-branch-button")
+		htmlDoc, name = branchAction(t, ".restore-branch-button", "data-url")
 		assert.Contains(t,
 			htmlDoc.doc.Find(".ui.positive.message").Text(),
 			translation.NewLocale("en-US").TrString("repo.branch.restore_success", name),

tests/integration/delete_user_test.go

@@ -13,7 +13,10 @@ import (
 	repo_model "gitea.dev/models/repo"
 	"gitea.dev/models/unittest"
 	user_model "gitea.dev/models/user"
+	"gitea.dev/modules/test"
 	"gitea.dev/tests"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func assertUserDeleted(t *testing.T, userID int64) {
@@ -34,7 +37,8 @@ func TestUserDeleteAccount(t *testing.T) {
 	session := loginUser(t, "user8")
 	urlStr := "/user/settings/account/delete?password=" + userPassword
 	req := NewRequest(t, "POST", urlStr)
-	session.MakeRequest(t, req, http.StatusSeeOther)
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	assert.NotEmpty(t, test.ParseJSONRedirect(resp.Body.Bytes()).Redirect)
 
 	assertUserDeleted(t, 8)
 	unittest.CheckConsistencyFor(t, &user_model.User{})
@@ -46,8 +50,8 @@ func TestUserDeleteAccountStillOwnRepos(t *testing.T) {
 	session := loginUser(t, "user2")
 	urlStr := "/user/settings/account/delete?password=" + userPassword
 	req := NewRequest(t, "POST", urlStr)
-	session.MakeRequest(t, req, http.StatusSeeOther)
-
+	resp := session.MakeRequest(t, req, http.StatusBadRequest)
+	assert.NotEmpty(t, test.ParseJSONError(resp.Body.Bytes()).ErrorMessage)
 	// user should not have been deleted, because the user still owns repos
 	unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
 }

tests/integration/html_helper.go

@@ -41,6 +41,7 @@ func (doc *HTMLDoc) Find(selector string) *goquery.Selection {
 
 // AssertHTMLElement check if the element by selector exists or does not exist depending on checkExists
 func AssertHTMLElement[T int | bool](t testing.TB, doc *HTMLDoc, selector string, checkExists T) {
+	t.Helper()
 	sel := doc.doc.Find(selector)
 	switch v := any(checkExists).(type) {
 	case bool:

tests/integration/user_settings_test.go

@@ -70,7 +70,7 @@ func TestUserSettingsAccount(t *testing.T) {
 
 		AssertHTMLElement(t, doc, "#password", true)
 		AssertHTMLElement(t, doc, "#email", true)
-		AssertHTMLElement(t, doc, "#delete-form", true)
+		AssertHTMLElement(t, doc, `form[action="/user/settings/account/delete"]`, true)
 	})
 
 	t.Run("credentials disabled", func(t *testing.T) {
@@ -87,7 +87,7 @@ func TestUserSettingsAccount(t *testing.T) {
 
 		AssertHTMLElement(t, doc, "#password", false)
 		AssertHTMLElement(t, doc, "#email", false)
-		AssertHTMLElement(t, doc, "#delete-form", true)
+		AssertHTMLElement(t, doc, `form[action="/user/settings/account/delete"]`, true)
 	})
 
 	t.Run("deletion disabled", func(t *testing.T) {