Add Pull Request merge options - Ignore white-space for conflict checking, Rebase, Squash merge (#3188)

* Pull request options migration and UI in settings

* Add ignore whitespace functionality

* Fix settings if pull requests are disabled

* Fix migration transaction

* Merge with Rebase functionality

* UI changes and related functionality for pull request merging button

* Implement squash functionality

* Fix rebase merging

* Fix pull request merge tests

* Add squash and rebase tests

* Fix API method to reuse default message functions

* Some refactoring and small fixes

* Remove more hardcoded values from tests

* Remove unneeded check from API method

* Fix variable name and comment typo

* Fix reset commit count after PR merge

2 files changed, 35 insertions, 5 deletions

diff --git a/integrations/pull_merge_test.go b/integrations/pull_merge_test.go
index 65ccc93f95..b123239331 100644
--- a/integrations/pull_merge_test.go
+++ b/integrations/pull_merge_test.go
@@ -11,21 +11,23 @@ import (
 	"strings"
 	"testing"
 
+	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/test"
 
 	"github.com/stretchr/testify/assert"
 )
 
-func testPullMerge(t *testing.T, session *TestSession, user, repo, pullnum string) *httptest.ResponseRecorder {
+func testPullMerge(t *testing.T, session *TestSession, user, repo, pullnum string, mergeStyle models.MergeStyle) *httptest.ResponseRecorder {
 	req := NewRequest(t, "GET", path.Join(user, repo, "pulls", pullnum))
 	resp := session.MakeRequest(t, req, http.StatusOK)
 
 	// Click the little green button to create a pull
 	htmlDoc := NewHTMLParser(t, resp.Body)
-	link, exists := htmlDoc.doc.Find("form.ui.form>button.ui.green.button").Parent().Attr("action")
+	link, exists := htmlDoc.doc.Find(".ui.form." + string(mergeStyle) + "-fields > form").Attr("action")
 	assert.True(t, exists, "The template has changed")
 	req = NewRequestWithValues(t, "POST", link, map[string]string{
 		"_csrf": htmlDoc.GetCSRF(),
+		"do":    string(mergeStyle),
 	})
 	resp = session.MakeRequest(t, req, http.StatusFound)
 
@@ -58,7 +60,34 @@ func TestPullMerge(t *testing.T) {
 
 	elem := strings.Split(test.RedirectURL(resp), "/")
 	assert.EqualValues(t, "pulls", elem[3])
-	testPullMerge(t, session, elem[1], elem[2], elem[4])
+	testPullMerge(t, session, elem[1], elem[2], elem[4], models.MergeStyleMerge)
+}
+
+func TestPullRebase(t *testing.T) {
+	prepareTestEnv(t)
+	session := loginUser(t, "user1")
+	testRepoFork(t, session, "user2", "repo1", "user1", "repo1")
+	testEditFile(t, session, "user1", "repo1", "master", "README.md", "Hello, World (Edited)\n")
+
+	resp := testPullCreate(t, session, "user1", "repo1", "master")
+
+	elem := strings.Split(test.RedirectURL(resp), "/")
+	assert.EqualValues(t, "pulls", elem[3])
+	testPullMerge(t, session, elem[1], elem[2], elem[4], models.MergeStyleRebase)
+}
+
+func TestPullSquash(t *testing.T) {
+	prepareTestEnv(t)
+	session := loginUser(t, "user1")
+	testRepoFork(t, session, "user2", "repo1", "user1", "repo1")
+	testEditFile(t, session, "user1", "repo1", "master", "README.md", "Hello, World (Edited)\n")
+	testEditFile(t, session, "user1", "repo1", "master", "README.md", "Hello, World (Edited!)\n")
+
+	resp := testPullCreate(t, session, "user1", "repo1", "master")
+
+	elem := strings.Split(test.RedirectURL(resp), "/")
+	assert.EqualValues(t, "pulls", elem[3])
+	testPullMerge(t, session, elem[1], elem[2], elem[4], models.MergeStyleSquash)
 }
 
 func TestPullCleanUpAfterMerge(t *testing.T) {
@@ -71,7 +100,7 @@ func TestPullCleanUpAfterMerge(t *testing.T) {
 
 	elem := strings.Split(test.RedirectURL(resp), "/")
 	assert.EqualValues(t, "pulls", elem[3])
-	testPullMerge(t, session, elem[1], elem[2], elem[4])
+	testPullMerge(t, session, elem[1], elem[2], elem[4], models.MergeStyleMerge)
 
 	// Check PR branch deletion
 	resp = testPullCleanUp(t, session, elem[1], elem[2], elem[4])
diff --git a/integrations/repo_activity_test.go b/integrations/repo_activity_test.go
index d3d2de4a2c..40983cbe1a 100644
--- a/integrations/repo_activity_test.go
+++ b/integrations/repo_activity_test.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 	"testing"
 
+	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/test"
 
 	"github.com/stretchr/testify/assert"
@@ -24,7 +25,7 @@ func TestRepoActivity(t *testing.T) {
 	resp := testPullCreate(t, session, "user1", "repo1", "master")
 	elem := strings.Split(test.RedirectURL(resp), "/")
 	assert.EqualValues(t, "pulls", elem[3])
-	testPullMerge(t, session, elem[1], elem[2], elem[4])
+	testPullMerge(t, session, elem[1], elem[2], elem[4], models.MergeStyleMerge)
 
 	testEditFileToNewBranch(t, session, "user1", "repo1", "master", "feat/better_readme", "README.md", "Hello, World (Edited Again)\n")
 	testPullCreate(t, session, "user1", "repo1", "feat/better_readme")