Add commits dropdown in PR files view and allow commit by commit revi…

…ew (#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 #20989
Fixes #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>

models/fixtures/issue.yml

@@ -304,3 +304,20 @@
   created_unix: 946684830
   updated_unix: 978307200
   is_locked: false
+
+-
+  id: 19
+  repo_id: 58
+  index: 1
+  poster_id: 2
+  original_author_id: 0
+  name: issue for pr
+  content: content
+  milestone_id: 0
+  priority: 0
+  is_closed: false
+  is_pull: true
+  num_comments: 0
+  created_unix: 946684830
+  updated_unix: 978307200
+  is_locked: false

models/fixtures/pull_request.yml

@@ -76,3 +76,16 @@
   base_branch: master
   merge_base: 2a47ca4b614a9f5a
   has_merged: false
+
+-
+  id: 7
+  type: 0 # gitea pull request
+  status: 2 # mergable
+  issue_id: 19
+  index: 1
+  head_repo_id: 58
+  base_repo_id: 58
+  head_branch: branch1
+  base_branch: main
+  merge_base: cbff181af4c9c7fee3cf6c106699e07d9a3f54e6
+  has_merged: false

models/fixtures/repo_unit.yml

@@ -607,3 +607,33 @@
   repo_id: 52
   type: 1
   created_unix: 946684810
+
+-
+  id: 91
+  repo_id: 58
+  type: 1
+  created_unix: 946684810
+
+-
+  id: 92
+  repo_id: 58
+  type: 2
+  created_unix: 946684810
+
+-
+  id: 93
+  repo_id: 58
+  type: 3
+  created_unix: 946684810
+
+-
+  id: 94
+  repo_id: 58
+  type: 4
+  created_unix: 946684810
+
+-
+  id: 95
+  repo_id: 58
+  type: 5
+  created_unix: 946684810

models/fixtures/repository.yml

@@ -1662,3 +1662,34 @@
   is_private: false
   status: 0
   num_issues: 0
+
+-
+  id: 58 # org public repo
+  owner_id: 2
+  owner_name: user2
+  lower_name: commitsonpr
+  name: commitsonpr
+  default_branch: main
+  num_watches: 0
+  num_stars: 0
+  num_forks: 0
+  num_issues: 0
+  num_closed_issues: 0
+  num_pulls: 1
+  num_closed_pulls: 0
+  num_milestones: 0
+  num_closed_milestones: 0
+  num_projects: 0
+  num_closed_projects: 0
+  is_private: false
+  is_empty: false
+  is_archived: false
+  is_mirror: false
+  status: 0
+  is_fork: false
+  fork_id: 0
+  is_template: false
+  template_id: 0
+  size: 0
+  is_fsck_enabled: true
+  close_issues_via_commit_in_any_branch: false

models/fixtures/user.yml

@@ -66,7 +66,7 @@
   num_followers: 2
   num_following: 1
   num_stars: 2
-  num_repos: 13
+  num_repos: 14
   num_teams: 0
   num_members: 0
   visibility: 0

models/issues/issue_test.go

@@ -538,7 +538,7 @@ func TestCountIssues(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	count, err := issues_model.CountIssues(db.DefaultContext, &issues_model.IssuesOptions{})
 	assert.NoError(t, err)
-	assert.EqualValues(t, 18, count)
+	assert.EqualValues(t, 19, count)
 }
 
 func TestIssueLoadAttributes(t *testing.T) {

models/issues/review_list.go

@@ -114,7 +114,7 @@ func FindLatestReviews(ctx context.Context, opts FindReviewOptions) (ReviewList,
 	}
 
 	sess.In("id", builder.
-		Select("max ( id ) ").
+		Select("max(id)").
 		From("review").
 		Where(cond).
 		GroupBy("reviewer_id"))

models/repo/repo_list_test.go

@@ -235,12 +235,12 @@ func TestSearchRepository(t *testing.T) {
 		{
 			name:  "AllPublic/PublicRepositoriesOfUserIncludingCollaborative",
 			opts:  &repo_model.SearchRepoOptions{ListOptions: db.ListOptions{Page: 1, PageSize: 10}, OwnerID: 15, AllPublic: true, Template: util.OptionalBoolFalse},
-			count: 30,
+			count: 31,
 		},
 		{
 			name:  "AllPublic/PublicAndPrivateRepositoriesOfUserIncludingCollaborative",
 			opts:  &repo_model.SearchRepoOptions{ListOptions: db.ListOptions{Page: 1, PageSize: 10}, OwnerID: 15, Private: true, AllPublic: true, AllLimited: true, Template: util.OptionalBoolFalse},
-			count: 35,
+			count: 36,
 		},
 		{
 			name:  "AllPublic/PublicAndPrivateRepositoriesOfUserIncludingCollaborativeByName",
@@ -255,7 +255,7 @@ func TestSearchRepository(t *testing.T) {
 		{
 			name:  "AllPublic/PublicRepositoriesOfOrganization",
 			opts:  &repo_model.SearchRepoOptions{ListOptions: db.ListOptions{Page: 1, PageSize: 10}, OwnerID: 17, AllPublic: true, Collaborate: util.OptionalBoolFalse, Template: util.OptionalBoolFalse},
-			count: 30,
+			count: 31,
 		},
 		{
 			name:  "AllTemplates",

options/locale/locale_en-US.ini

@@ -1662,6 +1662,13 @@ pulls.switch_comparison_type = Switch comparison type
 pulls.switch_head_and_base = Switch head and base
 pulls.filter_branch = Filter branch
 pulls.no_results = No results found.
+pulls.show_all_commits = Show all commits
+pulls.show_changes_since_your_last_review = Show changes since your last review
+pulls.showing_only_single_commit = Showing only changes of commit %[1]s
+pulls.showing_specified_commit_range = Showing only changes between %[1]s..%[2]s
+pulls.select_commit_hold_shift_for_range = Select commit. Hold shift + click to select a range
+pulls.review_only_possible_for_full_diff = Review is only possible when viewing the full diff
+pulls.filter_changes_by_commit = Filter by commit
 pulls.nothing_to_compare = These branches are equal. There is no need to create a pull request.
 pulls.nothing_to_compare_and_allow_empty_pr = These branches are equal. This PR will be empty.
 pulls.has_pull_request = `A pull request between these branches already exists: <a href="%[1]s">%[2]s#%[3]d</a>`

routers/web/repo/pull.go

@@ -694,6 +694,42 @@ func PrepareViewPullInfo(ctx *context.Context, issue *issues_model.Issue) *git.C
 	return compareInfo
 }
 
+type pullCommitList struct {
+	Commits             []pull_service.CommitInfo `json:"commits"`
+	LastReviewCommitSha string                    `json:"last_review_commit_sha"`
+	Locale              map[string]string         `json:"locale"`
+}
+
+// GetPullCommits get all commits for given pull request
+func GetPullCommits(ctx *context.Context) {
+	issue := checkPullInfo(ctx)
+	if ctx.Written() {
+		return
+	}
+	resp := &pullCommitList{}
+
+	commits, lastReviewCommitSha, err := pull_service.GetPullCommits(ctx, issue)
+	if err != nil {
+		ctx.JSON(http.StatusInternalServerError, err)
+		return
+	}
+
+	// Get the needed locale
+	resp.Locale = map[string]string{
+		"lang":                                ctx.Locale.Language(),
+		"filter_changes_by_commit":            ctx.Tr("repo.pulls.filter_changes_by_commit"),
+		"show_all_commits":                    ctx.Tr("repo.pulls.show_all_commits"),
+		"stats_num_commits":                   ctx.TrN(len(commits), "repo.activity.git_stats_commit_1", "repo.activity.git_stats_commit_n", len(commits)),
+		"show_changes_since_your_last_review": ctx.Tr("repo.pulls.show_changes_since_your_last_review"),
+		"select_commit_hold_shift_for_range":  ctx.Tr("repo.pulls.select_commit_hold_shift_for_range"),
+	}
+
+	resp.Commits = commits
+	resp.LastReviewCommitSha = lastReviewCommitSha
+
+	ctx.JSON(http.StatusOK, resp)
+}
+
 // ViewPullCommits show commits for a pull request
 func ViewPullCommits(ctx *context.Context) {
 	ctx.Data["PageIsPullList"] = true
@@ -739,7 +775,7 @@ func ViewPullCommits(ctx *context.Context) {
 }
 
 // ViewPullFiles render pull request changed files list page
-func ViewPullFiles(ctx *context.Context) {
+func viewPullFiles(ctx *context.Context, specifiedStartCommit, specifiedEndCommit string, willShowSpecifiedCommitRange, willShowSpecifiedCommit bool) {
 	ctx.Data["PageIsPullList"] = true
 	ctx.Data["PageIsPullFiles"] = true
 
@@ -762,6 +798,33 @@ func ViewPullFiles(ctx *context.Context) {
 		prInfo = PrepareViewPullInfo(ctx, issue)
 	}
 
+	// Validate the given commit sha to show (if any passed)
+	if willShowSpecifiedCommit || willShowSpecifiedCommitRange {
+
+		foundStartCommit := len(specifiedStartCommit) == 0
+		foundEndCommit := len(specifiedEndCommit) == 0
+
+		if !(foundStartCommit && foundEndCommit) {
+			for _, commit := range prInfo.Commits {
+				if commit.ID.String() == specifiedStartCommit {
+					foundStartCommit = true
+				}
+				if commit.ID.String() == specifiedEndCommit {
+					foundEndCommit = true
+				}
+
+				if foundStartCommit && foundEndCommit {
+					break
+				}
+			}
+		}
+
+		if !(foundStartCommit && foundEndCommit) {
+			ctx.NotFound("Given SHA1 not found for this PR", nil)
+			return
+		}
+	}
+
 	if ctx.Written() {
 		return
 	} else if prInfo == nil {
@@ -775,12 +838,30 @@ func ViewPullFiles(ctx *context.Context) {
 		return
 	}
 
-	startCommitID = prInfo.MergeBase
-	endCommitID = headCommitID
+	ctx.Data["IsShowingOnlySingleCommit"] = willShowSpecifiedCommit
+
+	if willShowSpecifiedCommit || willShowSpecifiedCommitRange {
+		if len(specifiedEndCommit) > 0 {
+			endCommitID = specifiedEndCommit
+		} else {
+			endCommitID = headCommitID
+		}
+		if len(specifiedStartCommit) > 0 {
+			startCommitID = specifiedStartCommit
+		} else {
+			startCommitID = prInfo.MergeBase
+		}
+		ctx.Data["IsShowingAllCommits"] = false
+	} else {
+		endCommitID = headCommitID
+		startCommitID = prInfo.MergeBase
+		ctx.Data["IsShowingAllCommits"] = true
+	}
 
 	ctx.Data["Username"] = ctx.Repo.Owner.Name
 	ctx.Data["Reponame"] = ctx.Repo.Repository.Name
 	ctx.Data["AfterCommitID"] = endCommitID
+	ctx.Data["BeforeCommitID"] = startCommitID
 
 	fileOnly := ctx.FormBool("file-only")
 
@@ -789,8 +870,8 @@ func ViewPullFiles(ctx *context.Context) {
 	if fileOnly && (len(files) == 2 || len(files) == 1) {
 		maxLines, maxFiles = -1, -1
 	}
+
 	diffOptions := &gitdiff.DiffOptions{
-		BeforeCommitID:     startCommitID,
 		AfterCommitID:      endCommitID,
 		SkipTo:             ctx.FormString("skip-to"),
 		MaxLines:           maxLines,
@@ -799,9 +880,18 @@ func ViewPullFiles(ctx *context.Context) {
 		WhitespaceBehavior: gitdiff.GetWhitespaceFlag(ctx.Data["WhitespaceBehavior"].(string)),
 	}
 
+	if !willShowSpecifiedCommit {
+		diffOptions.BeforeCommitID = startCommitID
+	}
+
 	var methodWithError string
 	var diff *gitdiff.Diff
-	if !ctx.IsSigned {
+
+	// if we're not logged in or only a single commit (or commit range) is shown we
+	// have to load only the diff and not get the viewed information
+	// as the viewed information is designed to be loaded only on latest PR
+	// diff and if you're signed in.
+	if !ctx.IsSigned || willShowSpecifiedCommit || willShowSpecifiedCommitRange {
 		diff, err = gitdiff.GetDiff(gitRepo, diffOptions, files...)
 		methodWithError = "GetDiff"
 	} else {
@@ -908,6 +998,22 @@ func ViewPullFiles(ctx *context.Context) {
 	ctx.HTML(http.StatusOK, tplPullFiles)
 }
 
+func ViewPullFilesForSingleCommit(ctx *context.Context) {
+	viewPullFiles(ctx, "", ctx.Params("sha"), true, true)
+}
+
+func ViewPullFilesForRange(ctx *context.Context) {
+	viewPullFiles(ctx, ctx.Params("shaFrom"), ctx.Params("shaTo"), true, false)
+}
+
+func ViewPullFilesStartingFromCommit(ctx *context.Context) {
+	viewPullFiles(ctx, "", ctx.Params("sha"), true, false)
+}
+
+func ViewPullFilesForAllCommitsOfPr(ctx *context.Context) {
+	viewPullFiles(ctx, "", "", false, false)
+}
+
 // UpdatePullRequest merge PR's baseBranch into headBranch
 func UpdatePullRequest(ctx *context.Context) {
 	issue := checkPullInfo(ctx)

routers/web/user/home_test.go

@@ -75,7 +75,7 @@ func TestPulls(t *testing.T) {
 	Pulls(ctx)
 	assert.EqualValues(t, http.StatusOK, ctx.Resp.Status())
 
-	assert.Len(t, ctx.Data["Issues"], 4)
+	assert.Len(t, ctx.Data["Issues"], 5)
 }
 
 func TestMilestones(t *testing.T) {

routers/web/web.go

@@ -1279,14 +1279,20 @@ func registerRoutes(m *web.Route) {
 			m.Get("", repo.SetWhitespaceBehavior, repo.GetPullDiffStats, repo.ViewIssue)
 			m.Get(".diff", repo.DownloadPullDiff)
 			m.Get(".patch", repo.DownloadPullPatch)
-			m.Get("/commits", context.RepoRef(), repo.SetWhitespaceBehavior, repo.GetPullDiffStats, repo.ViewPullCommits)
+			m.Group("/commits", func() {
+				m.Get("", context.RepoRef(), repo.SetWhitespaceBehavior, repo.GetPullDiffStats, repo.ViewPullCommits)
+				m.Get("/list", context.RepoRef(), repo.GetPullCommits)
+				m.Get("/{sha:[a-f0-9]{7,40}}", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.SetShowOutdatedComments, repo.ViewPullFilesForSingleCommit)
+			})
 			m.Post("/merge", context.RepoMustNotBeArchived(), web.Bind(forms.MergePullRequestForm{}), repo.MergePullRequest)
 			m.Post("/cancel_auto_merge", context.RepoMustNotBeArchived(), repo.CancelAutoMergePullRequest)
 			m.Post("/update", repo.UpdatePullRequest)
 			m.Post("/set_allow_maintainer_edit", web.Bind(forms.UpdateAllowEditsForm{}), repo.SetAllowEdits)
 			m.Post("/cleanup", context.RepoMustNotBeArchived(), context.RepoRef(), repo.CleanUpPullRequest)
 			m.Group("/files", func() {
-				m.Get("", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.SetShowOutdatedComments, repo.ViewPullFiles)
+				m.Get("", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.SetShowOutdatedComments, repo.ViewPullFilesForAllCommitsOfPr)
+				m.Get("/{sha:[a-f0-9]{7,40}}", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.SetShowOutdatedComments, repo.ViewPullFilesStartingFromCommit)
+				m.Get("/{shaFrom:[a-f0-9]{7,40}}..{shaTo:[a-f0-9]{7,40}}", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.SetShowOutdatedComments, repo.ViewPullFilesForRange)
 				m.Group("/reviews", func() {
 					m.Get("/new_comment", repo.RenderNewCodeCommentForm)
 					m.Post("/comments", web.Bind(forms.CodeCommentForm{}), repo.SetShowOutdatedComments, repo.CreateCodeComment)