fix(actions)!: require merged PR to bypass fork PR approval gate (#38010)

`ifNeedApproval` in `services/actions/notifier_helper.go` decided
whether a
fork PR's workflow run had to wait for maintainer approval. The bypass
clause
counted any prior `approved_by > 0` run for `(repo_id,
trigger_user_id)`, so
the very first Approve-and-run click on a contributor's fork PR
permanently
trusted that user for every future fork PR in the same repository —
including
PRs whose only change is the workflow YAML itself.

Approving a workflow *run* is not the same as merging *code*. This
change
aligns the gate with GitHub Actions' first-time-contributor model: trust
is
granted only after the user has had a pull request merged in the repo.

## Behavior change

- **Before**: one approval = permanent trust for that user in that repo.
- **After**: every fork PR is gated until the contributor has at least
one
  merged PR in the repo.

Existing already-approved runs and merged PRs continue to work; only the
trust criterion for *future* fork PRs changes. Maintainers who rely on
the
implicit "approve once" trust will see the approval banner reappear
until
they merge a PR from that contributor.

services/actions/notifier_helper_test.go

@@ -0,0 +1,102 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	actions_model "gitea.dev/models/actions"
+	repo_model "gitea.dev/models/repo"
+	user_model "gitea.dev/models/user"
+	actions_module "gitea.dev/modules/actions"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestIfNeedApproval(t *testing.T) {
+	alwaysWrite := func(_ context.Context, _ *repo_model.Repository, _ *user_model.User) (bool, error) {
+		return true, nil
+	}
+	neverWrite := func(_ context.Context, _ *repo_model.Repository, _ *user_model.User) (bool, error) {
+		return false, nil
+	}
+	hasMerged := func(_ context.Context, _, _ int64) (bool, error) { return true, nil }
+	noMerged := func(_ context.Context, _, _ int64) (bool, error) { return false, nil }
+	errPerm := errors.New("perm error")
+	errMerge := errors.New("merge error")
+
+	forkRun := &actions_model.ActionRun{IsForkPullRequest: true, TriggerEvent: actions_module.GithubEventPullRequest}
+	nonForkRun := &actions_model.ActionRun{IsForkPullRequest: false, TriggerEvent: actions_module.GithubEventPullRequest}
+	prTargetRun := &actions_model.ActionRun{IsForkPullRequest: true, TriggerEvent: actions_module.GithubEventPullRequestTarget}
+
+	repo := &repo_model.Repository{ID: 1}
+	normalUser := &user_model.User{ID: 10}
+	restrictedUser := &user_model.User{ID: 11, IsRestricted: true}
+
+	t.Run("not a fork PR never needs approval", func(t *testing.T) {
+		need, err := ifNeedApprovalWith(t.Context(), nonForkRun, repo, normalUser, alwaysWrite, hasMerged)
+		require.NoError(t, err)
+		assert.False(t, need)
+	})
+
+	t.Run("pull_request_target never needs approval even when fork", func(t *testing.T) {
+		need, err := ifNeedApprovalWith(t.Context(), prTargetRun, repo, normalUser, alwaysWrite, hasMerged)
+		require.NoError(t, err)
+		assert.False(t, need)
+	})
+
+	t.Run("restricted user always needs approval", func(t *testing.T) {
+		need, err := ifNeedApprovalWith(t.Context(), forkRun, repo, restrictedUser, alwaysWrite, hasMerged)
+		require.NoError(t, err)
+		assert.True(t, need)
+	})
+
+	t.Run("fork PR with write permission does not need approval", func(t *testing.T) {
+		need, err := ifNeedApprovalWith(t.Context(), forkRun, repo, normalUser, alwaysWrite, noMerged)
+		require.NoError(t, err)
+		assert.False(t, need)
+	})
+
+	t.Run("fork PR with merged PR but no write permission does not need approval", func(t *testing.T) {
+		need, err := ifNeedApprovalWith(t.Context(), forkRun, repo, normalUser, neverWrite, hasMerged)
+		require.NoError(t, err)
+		assert.False(t, need)
+	})
+
+	t.Run("fork PR with no write and no merged PR needs approval", func(t *testing.T) {
+		need, err := ifNeedApprovalWith(t.Context(), forkRun, repo, normalUser, neverWrite, noMerged)
+		require.NoError(t, err)
+		assert.True(t, need)
+	})
+
+	t.Run("canWriteActions error is propagated", func(t *testing.T) {
+		failWrite := func(_ context.Context, _ *repo_model.Repository, _ *user_model.User) (bool, error) {
+			return false, errPerm
+		}
+		_, err := ifNeedApprovalWith(t.Context(), forkRun, repo, normalUser, failWrite, noMerged)
+		require.ErrorIs(t, err, errPerm)
+	})
+
+	t.Run("hasMergedPR error is propagated", func(t *testing.T) {
+		failMerge := func(_ context.Context, _, _ int64) (bool, error) { return false, errMerge }
+		_, err := ifNeedApprovalWith(t.Context(), forkRun, repo, normalUser, neverWrite, failMerge)
+		require.ErrorIs(t, err, errMerge)
+	})
+
+	t.Run("restricted user skips permission check entirely", func(t *testing.T) {
+		// The perm and merge functions must not be called for a restricted user.
+		called := false
+		trackWrite := func(_ context.Context, _ *repo_model.Repository, _ *user_model.User) (bool, error) {
+			called = true
+			return true, nil
+		}
+		need, err := ifNeedApprovalWith(t.Context(), forkRun, repo, restrictedUser, trackWrite, noMerged)
+		require.NoError(t, err)
+		assert.True(t, need)
+		assert.False(t, called, "permission check must not run for restricted user")
+	})
+}