Add commits dropdown in PR files view and allow commit by commit review (#25528)

This PR adds a new dropdown to select a commit or a commit range
(shift-click like github) of a Pull Request.
After selection of a commit only the changes of this commit will be shown.
When selecting a range of commits the diff of this range is shown.

This allows to review a PR commit by commit or by viewing only commit ranges.
The "Show changes since your last review" mechanism github uses is implemented, too.
When reviewing a single commit or a commit range the "Viewed" functionality is disabled.

## Screenshots

### The commit dropdown

![image](https://github.com/go-gitea/gitea/assets/51889757/0db3ae62-1272-436c-be64-4730c5d611e3)

### Selecting a commit range

![image](https://github.com/go-gitea/gitea/assets/51889757/ad81eedb-8437-42b0-8073-2d940c25fe8f)

### Show changes of a single commit only

![image](https://github.com/go-gitea/gitea/assets/51889757/6b1a113b-73ef-4ecc-adf6-bc2340bb8f97)

### Show changes of a commit range

![image](https://github.com/go-gitea/gitea/assets/51889757/6401b358-cd66-4c09-8baa-6cf6177f23a7)


Fixes https://github.com/go-gitea/gitea/issues/20989
Fixes https://github.com/go-gitea/gitea/issues/19263

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>

5 files changed, 76 insertions, 18 deletions

diff --git a/tests/integration/api_issue_test.go b/tests/integration/api_issue_test.go
index 8b02342d88..5f4c1e6a47 100644
--- a/tests/integration/api_issue_test.go
+++ b/tests/integration/api_issue_test.go
@@ -219,7 +219,7 @@ func TestAPISearchIssues(t *testing.T) {
 	token := getUserToken(t, "user2", auth_model.AccessTokenScopeReadIssue)
 
 	// as this API was used in the frontend, it uses UI page size
-	expectedIssueCount := 16 // from the fixtures
+	expectedIssueCount := 17 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}
@@ -243,7 +243,7 @@ func TestAPISearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 9)
+	assert.Len(t, apiIssues, 10)
 	query.Del("since")
 	query.Del("before")
 
@@ -259,15 +259,15 @@ func TestAPISearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
-	assert.Len(t, apiIssues, 18)
+	assert.EqualValues(t, "19", resp.Header().Get("X-Total-Count"))
+	assert.Len(t, apiIssues, 19)
 
 	query.Add("limit", "10")
 	link.RawQuery = query.Encode()
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
+	assert.EqualValues(t, "19", resp.Header().Get("X-Total-Count"))
 	assert.Len(t, apiIssues, 10)
 
 	query = url.Values{"assigned": {"true"}, "state": {"all"}, "token": {token}}
@@ -296,7 +296,7 @@ func TestAPISearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 7)
+	assert.Len(t, apiIssues, 8)
 
 	query = url.Values{"owner": {"user3"}, "token": {token}} // organization
 	link.RawQuery = query.Encode()
@@ -317,7 +317,7 @@ func TestAPISearchIssuesWithLabels(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
 	// as this API was used in the frontend, it uses UI page size
-	expectedIssueCount := 16 // from the fixtures
+	expectedIssueCount := 17 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}
diff --git a/tests/integration/api_nodeinfo_test.go b/tests/integration/api_nodeinfo_test.go
index 158a866091..f8f50bf073 100644
--- a/tests/integration/api_nodeinfo_test.go
+++ b/tests/integration/api_nodeinfo_test.go
@@ -33,7 +33,7 @@ func TestNodeinfo(t *testing.T) {
 		assert.True(t, nodeinfo.OpenRegistrations)
 		assert.Equal(t, "gitea", nodeinfo.Software.Name)
 		assert.Equal(t, 25, nodeinfo.Usage.Users.Total)
-		assert.Equal(t, 18, nodeinfo.Usage.LocalPosts)
+		assert.Equal(t, 19, nodeinfo.Usage.LocalPosts)
 		assert.Equal(t, 2, nodeinfo.Usage.LocalComments)
 	})
 }
diff --git a/tests/integration/api_repo_test.go b/tests/integration/api_repo_test.go
index fae1415568..3933298f23 100644
--- a/tests/integration/api_repo_test.go
+++ b/tests/integration/api_repo_test.go
@@ -93,9 +93,9 @@ func TestAPISearchRepo(t *testing.T) {
 	}{
 		{
 			name: "RepositoriesMax50", requestURL: "/api/v1/repos/search?limit=50&private=false", expectedResults: expectedResults{
-				nil:   {count: 32},
-				user:  {count: 32},
-				user2: {count: 32},
+				nil:   {count: 33},
+				user:  {count: 33},
+				user2: {count: 33},
 			},
 		},
 		{
diff --git a/tests/integration/issue_test.go b/tests/integration/issue_test.go
index ab2986906b..8fecfa61a4 100644
--- a/tests/integration/issue_test.go
+++ b/tests/integration/issue_test.go
@@ -356,7 +356,7 @@ func TestSearchIssues(t *testing.T) {
 
 	session := loginUser(t, "user2")
 
-	expectedIssueCount := 16 // from the fixtures
+	expectedIssueCount := 17 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}
@@ -377,7 +377,7 @@ func TestSearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 9)
+	assert.Len(t, apiIssues, 10)
 	query.Del("since")
 	query.Del("before")
 
@@ -393,15 +393,15 @@ func TestSearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
-	assert.Len(t, apiIssues, 18)
+	assert.EqualValues(t, "19", resp.Header().Get("X-Total-Count"))
+	assert.Len(t, apiIssues, 19)
 
 	query.Add("limit", "5")
 	link.RawQuery = query.Encode()
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.EqualValues(t, "18", resp.Header().Get("X-Total-Count"))
+	assert.EqualValues(t, "19", resp.Header().Get("X-Total-Count"))
 	assert.Len(t, apiIssues, 5)
 
 	query = url.Values{"assigned": {"true"}, "state": {"all"}}
@@ -430,7 +430,7 @@ func TestSearchIssues(t *testing.T) {
 	req = NewRequest(t, "GET", link.String())
 	resp = session.MakeRequest(t, req, http.StatusOK)
 	DecodeJSON(t, resp, &apiIssues)
-	assert.Len(t, apiIssues, 7)
+	assert.Len(t, apiIssues, 8)
 
 	query = url.Values{"owner": {"user3"}} // organization
 	link.RawQuery = query.Encode()
@@ -450,7 +450,7 @@ func TestSearchIssues(t *testing.T) {
 func TestSearchIssuesWithLabels(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
-	expectedIssueCount := 16 // from the fixtures
+	expectedIssueCount := 17 // from the fixtures
 	if expectedIssueCount > setting.UI.IssuePagingNum {
 		expectedIssueCount = setting.UI.IssuePagingNum
 	}
diff --git a/tests/integration/pull_diff_test.go b/tests/integration/pull_diff_test.go
new file mode 100644
index 0000000000..5411250935
--- /dev/null
+++ b/tests/integration/pull_diff_test.go
@@ -0,0 +1,58 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"net/http"
+	"testing"
+
+	"code.gitea.io/gitea/tests"
+
+	"github.com/PuerkitoBio/goquery"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPullDiff_CompletePRDiff(t *testing.T) {
+	doTestPRDiff(t, "/user2/commitsonpr/pulls/1/files", false, []string{"test1.txt", "test10.txt", "test2.txt", "test3.txt", "test4.txt", "test5.txt", "test6.txt", "test7.txt", "test8.txt", "test9.txt"})
+}
+
+func TestPullDiff_SingleCommitPRDiff(t *testing.T) {
+	doTestPRDiff(t, "/user2/commitsonpr/pulls/1/commits/c5626fc9eff57eb1bb7b796b01d4d0f2f3f792a2", true, []string{"test3.txt"})
+}
+
+func TestPullDiff_CommitRangePRDiff(t *testing.T) {
+	doTestPRDiff(t, "/user2/commitsonpr/pulls/1/files/4ca8bcaf27e28504df7bf996819665986b01c847..23576dd018294e476c06e569b6b0f170d0558705", true, []string{"test2.txt", "test3.txt", "test4.txt"})
+}
+
+func TestPullDiff_StartingFromBaseToCommitPRDiff(t *testing.T) {
+	doTestPRDiff(t, "/user2/commitsonpr/pulls/1/files/c5626fc9eff57eb1bb7b796b01d4d0f2f3f792a2", true, []string{"test1.txt", "test2.txt", "test3.txt"})
+}
+
+func doTestPRDiff(t *testing.T, prDiffURL string, reviewBtnDisabled bool, expectedFilenames []string) {
+	defer tests.PrepareTestEnv(t)()
+
+	session := loginUser(t, "user2")
+
+	req := NewRequest(t, "GET", "/user2/commitsonpr/pulls")
+	session.MakeRequest(t, req, http.StatusOK)
+
+	// Get the given PR diff url
+	req = NewRequest(t, "GET", prDiffURL)
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	doc := NewHTMLParser(t, resp.Body)
+
+	// Assert all files are visible.
+	fileContents := doc.doc.Find(".file-content")
+	numberOfFiles := fileContents.Length()
+
+	assert.Equal(t, len(expectedFilenames), numberOfFiles)
+
+	fileContents.Each(func(i int, s *goquery.Selection) {
+		filename, _ := s.Attr("data-old-filename")
+		assert.Equal(t, expectedFilenames[i], filename)
+	})
+
+	// Ensure the review button is enabled for full PR reviews
+	assert.Equal(t, reviewBtnDisabled, doc.doc.Find(".js-btn-review").HasClass("disabled"))
+}