Compare branches, commits and tags with each other (#6991)

* Supports tags when comparing commits or branches

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Hide headline when only comparing and don't load unused data

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Merges compare logics to allow comparing branches, commits and tags with eachother

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Display branch or tag instead of commit when used for comparing

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Show pull request form after click on button

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Transfers relevant pull.go changes from master to compare.go

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Fixes error when comparing forks against a commit or tag

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Removes console.log from JavaScript file

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Show icon next to commit reference when comparing branch or tag

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Updates css file

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Fixes import order

* Renames template variable

* Update routers/repo/compare.go

Co-Authored-By: zeripath <art27@cantab.net>

* Update from master

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Allow short-shas in compare

* Renames prInfo to compareInfo

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Check PR permissions only if compare is pull request

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Adjusts comment

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Use compareInfo instead of prInfo

5 files changed, 360 insertions, 337 deletions

diff --git a/routers/api/v1/repo/pull.go b/routers/api/v1/repo/pull.go
index f53ab4b8f3..0e1db144b1 100644
--- a/routers/api/v1/repo/pull.go
+++ b/routers/api/v1/repo/pull.go
@@ -188,7 +188,7 @@ func CreatePullRequest(ctx *context.APIContext, form api.CreatePullRequestOption
 	)
 
 	// Get repo/branch information
-	headUser, headRepo, headGitRepo, prInfo, baseBranch, headBranch := parseCompareInfo(ctx, form)
+	headUser, headRepo, headGitRepo, compareInfo, baseBranch, headBranch := parseCompareInfo(ctx, form)
 	if ctx.Written() {
 		return
 	}
@@ -240,7 +240,7 @@ func CreatePullRequest(ctx *context.APIContext, form api.CreatePullRequestOption
 		milestoneID = milestone.ID
 	}
 
-	patch, err := headGitRepo.GetPatch(prInfo.MergeBase, headBranch)
+	patch, err := headGitRepo.GetPatch(compareInfo.MergeBase, headBranch)
 	if err != nil {
 		ctx.Error(500, "GetPatch", err)
 		return
@@ -277,7 +277,7 @@ func CreatePullRequest(ctx *context.APIContext, form api.CreatePullRequestOption
 		BaseBranch:   baseBranch,
 		HeadRepo:     headRepo,
 		BaseRepo:     repo,
-		MergeBase:    prInfo.MergeBase,
+		MergeBase:    compareInfo.MergeBase,
 		Type:         models.PullRequestGitea,
 	}
 
@@ -600,7 +600,7 @@ func MergePullRequest(ctx *context.APIContext, form auth.MergePullRequestForm) {
 	ctx.Status(200)
 }
 
-func parseCompareInfo(ctx *context.APIContext, form api.CreatePullRequestOption) (*models.User, *models.Repository, *git.Repository, *git.PullRequestInfo, string, string) {
+func parseCompareInfo(ctx *context.APIContext, form api.CreatePullRequestOption) (*models.User, *models.Repository, *git.Repository, *git.CompareInfo, string, string) {
 	baseRepo := ctx.Repo.Repository
 
 	// Get compared branches information
@@ -712,11 +712,11 @@ func parseCompareInfo(ctx *context.APIContext, form api.CreatePullRequestOption)
 		return nil, nil, nil, nil, "", ""
 	}
 
-	prInfo, err := headGitRepo.GetPullRequestInfo(models.RepoPath(baseRepo.Owner.Name, baseRepo.Name), baseBranch, headBranch)
+	compareInfo, err := headGitRepo.GetCompareInfo(models.RepoPath(baseRepo.Owner.Name, baseRepo.Name), baseBranch, headBranch)
 	if err != nil {
-		ctx.Error(500, "GetPullRequestInfo", err)
+		ctx.Error(500, "GetCompareInfo", err)
 		return nil, nil, nil, nil, "", ""
 	}
 
-	return headUser, headRepo, headGitRepo, prInfo, baseBranch, headBranch
+	return headUser, headRepo, headGitRepo, compareInfo, baseBranch, headBranch
 }
diff --git a/routers/repo/commit.go b/routers/repo/commit.go
index 870ff568f3..dde6d8f321 100644
--- a/routers/repo/commit.go
+++ b/routers/repo/commit.go
@@ -19,9 +19,9 @@ import (
 )
 
 const (
-	tplCommits base.TplName = "repo/commits"
-	tplGraph   base.TplName = "repo/graph"
-	tplDiff    base.TplName = "repo/diff/page"
+	tplCommits    base.TplName = "repo/commits"
+	tplGraph      base.TplName = "repo/graph"
+	tplCommitPage base.TplName = "repo/commit_page"
 )
 
 // RefCommits render commits page
@@ -261,7 +261,7 @@ func Diff(ctx *context.Context) {
 	}
 	ctx.Data["RawPath"] = setting.AppSubURL + "/" + path.Join(userName, repoName, "raw", "commit", commitID)
 	ctx.Data["BranchName"], err = commit.GetBranchName()
-	ctx.HTML(200, tplDiff)
+	ctx.HTML(200, tplCommitPage)
 }
 
 // RawDiff dumps diff results of repository in given commit ID to io.Writer
@@ -276,54 +276,3 @@ func RawDiff(ctx *context.Context) {
 		return
 	}
 }
-
-// CompareDiff show different from one commit to another commit
-func CompareDiff(ctx *context.Context) {
-	ctx.Data["IsRepoToolbarCommits"] = true
-	ctx.Data["IsDiffCompare"] = true
-	userName := ctx.Repo.Owner.Name
-	repoName := ctx.Repo.Repository.Name
-	beforeCommitID := ctx.Params(":before")
-	afterCommitID := ctx.Params(":after")
-
-	commit, err := ctx.Repo.GitRepo.GetCommit(afterCommitID)
-	if err != nil {
-		ctx.NotFound("GetCommit", err)
-		return
-	}
-
-	diff, err := models.GetDiffRange(models.RepoPath(userName, repoName), beforeCommitID,
-		afterCommitID, setting.Git.MaxGitDiffLines,
-		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles)
-	if err != nil {
-		ctx.NotFound("GetDiffRange", err)
-		return
-	}
-
-	commits, err := commit.CommitsBeforeUntil(beforeCommitID)
-	if err != nil {
-		ctx.ServerError("CommitsBeforeUntil", err)
-		return
-	}
-	commits = models.ValidateCommitsWithEmails(commits)
-	commits = models.ParseCommitsWithSignature(commits)
-	commits = models.ParseCommitsWithStatus(commits, ctx.Repo.Repository)
-
-	ctx.Data["CommitRepoLink"] = ctx.Repo.RepoLink
-	ctx.Data["Commits"] = commits
-	ctx.Data["CommitCount"] = commits.Len()
-	ctx.Data["BeforeCommitID"] = beforeCommitID
-	ctx.Data["AfterCommitID"] = afterCommitID
-	ctx.Data["Username"] = userName
-	ctx.Data["Reponame"] = repoName
-	ctx.Data["IsImageFile"] = commit.IsImageFile
-	ctx.Data["Title"] = "Comparing " + base.ShortSha(beforeCommitID) + "..." + base.ShortSha(afterCommitID) + " · " + userName + "/" + repoName
-	ctx.Data["Commit"] = commit
-	ctx.Data["Diff"] = diff
-	ctx.Data["DiffNotAvailable"] = diff.NumFiles() == 0
-	ctx.Data["SourcePath"] = setting.AppSubURL + "/" + path.Join(userName, repoName, "src", "commit", afterCommitID)
-	ctx.Data["BeforeSourcePath"] = setting.AppSubURL + "/" + path.Join(userName, repoName, "src", "commit", beforeCommitID)
-	ctx.Data["RawPath"] = setting.AppSubURL + "/" + path.Join(userName, repoName, "raw", "commit", afterCommitID)
-	ctx.Data["RequireHighlightJS"] = true
-	ctx.HTML(200, tplDiff)
-}
diff --git a/routers/repo/compare.go b/routers/repo/compare.go
new file mode 100644
index 0000000000..a85084791d
--- /dev/null
+++ b/routers/repo/compare.go
@@ -0,0 +1,337 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package repo
+
+import (
+	"path"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+const (
+	tplCompare base.TplName = "repo/diff/compare"
+)
+
+// ParseCompareInfo parse compare info between two commit for preparing comparing references
+func ParseCompareInfo(ctx *context.Context) (*models.User, *models.Repository, *git.Repository, *git.CompareInfo, string, string) {
+	baseRepo := ctx.Repo.Repository
+
+	// Get compared branches information
+	// format: <base branch>...[<head repo>:]<head branch>
+	// base<-head: master...head:feature
+	// same repo: master...feature
+
+	var (
+		headUser   *models.User
+		headBranch string
+		isSameRepo bool
+		infoPath   string
+		err        error
+	)
+	infoPath = ctx.Params("*")
+	infos := strings.Split(infoPath, "...")
+	if len(infos) != 2 {
+		log.Trace("ParseCompareInfo[%d]: not enough compared branches information %s", baseRepo.ID, infos)
+		ctx.NotFound("CompareAndPullRequest", nil)
+		return nil, nil, nil, nil, "", ""
+	}
+
+	baseBranch := infos[0]
+	ctx.Data["BaseBranch"] = baseBranch
+
+	// If there is no head repository, it means compare between same repository.
+	headInfos := strings.Split(infos[1], ":")
+	if len(headInfos) == 1 {
+		isSameRepo = true
+		headUser = ctx.Repo.Owner
+		headBranch = headInfos[0]
+
+	} else if len(headInfos) == 2 {
+		headUser, err = models.GetUserByName(headInfos[0])
+		if err != nil {
+			if models.IsErrUserNotExist(err) {
+				ctx.NotFound("GetUserByName", nil)
+			} else {
+				ctx.ServerError("GetUserByName", err)
+			}
+			return nil, nil, nil, nil, "", ""
+		}
+		headBranch = headInfos[1]
+		isSameRepo = headUser.ID == ctx.Repo.Owner.ID
+	} else {
+		ctx.NotFound("CompareAndPullRequest", nil)
+		return nil, nil, nil, nil, "", ""
+	}
+	ctx.Data["HeadUser"] = headUser
+	ctx.Data["HeadBranch"] = headBranch
+	ctx.Repo.PullRequest.SameRepo = isSameRepo
+
+	// Check if base branch is valid.
+	baseIsCommit := ctx.Repo.GitRepo.IsCommitExist(baseBranch)
+	baseIsBranch := ctx.Repo.GitRepo.IsBranchExist(baseBranch)
+	baseIsTag := ctx.Repo.GitRepo.IsTagExist(baseBranch)
+	if !baseIsCommit && !baseIsBranch && !baseIsTag {
+		// Check if baseBranch is short sha commit hash
+		if baseCommit, _ := ctx.Repo.GitRepo.GetCommit(baseBranch); baseCommit != nil {
+			baseBranch = baseCommit.ID.String()
+			ctx.Data["BaseBranch"] = baseBranch
+			baseIsCommit = true
+		} else {
+			ctx.NotFound("IsRefExist", nil)
+			return nil, nil, nil, nil, "", ""
+		}
+	}
+	ctx.Data["BaseIsCommit"] = baseIsCommit
+	ctx.Data["BaseIsBranch"] = baseIsBranch
+	ctx.Data["BaseIsTag"] = baseIsTag
+
+	// Check if current user has fork of repository or in the same repository.
+	headRepo, has := models.HasForkedRepo(headUser.ID, baseRepo.ID)
+	if !has && !isSameRepo {
+		ctx.Data["PageIsComparePull"] = false
+	}
+
+	var headGitRepo *git.Repository
+	if isSameRepo {
+		headRepo = ctx.Repo.Repository
+		headGitRepo = ctx.Repo.GitRepo
+		ctx.Data["BaseName"] = headUser.Name
+	} else {
+		headGitRepo, err = git.OpenRepository(models.RepoPath(headUser.Name, headRepo.Name))
+		ctx.Data["BaseName"] = baseRepo.OwnerName
+		if err != nil {
+			ctx.ServerError("OpenRepository", err)
+			return nil, nil, nil, nil, "", ""
+		}
+	}
+
+	// user should have permission to read baseRepo's codes and pulls, NOT headRepo's
+	permBase, err := models.GetUserRepoPermission(baseRepo, ctx.User)
+	if err != nil {
+		ctx.ServerError("GetUserRepoPermission", err)
+		return nil, nil, nil, nil, "", ""
+	}
+	if !permBase.CanRead(models.UnitTypeCode) {
+		if log.IsTrace() {
+			log.Trace("Permission Denied: User: %-v cannot read code in Repo: %-v\nUser in baseRepo has Permissions: %-+v",
+				ctx.User,
+				baseRepo,
+				permBase)
+		}
+		ctx.NotFound("ParseCompareInfo", nil)
+		return nil, nil, nil, nil, "", ""
+	}
+
+	// user should have permission to read headrepo's codes
+	permHead, err := models.GetUserRepoPermission(headRepo, ctx.User)
+	if err != nil {
+		ctx.ServerError("GetUserRepoPermission", err)
+		return nil, nil, nil, nil, "", ""
+	}
+	if !permHead.CanRead(models.UnitTypeCode) {
+		if log.IsTrace() {
+			log.Trace("Permission Denied: User: %-v cannot read code in Repo: %-v\nUser in headRepo has Permissions: %-+v",
+				ctx.User,
+				headRepo,
+				permHead)
+		}
+		ctx.NotFound("ParseCompareInfo", nil)
+		return nil, nil, nil, nil, "", ""
+	}
+
+	// Check if head branch is valid.
+	headIsCommit := ctx.Repo.GitRepo.IsCommitExist(headBranch)
+	headIsBranch := headGitRepo.IsBranchExist(headBranch)
+	headIsTag := headGitRepo.IsTagExist(headBranch)
+	if !headIsCommit && !headIsBranch && !headIsTag {
+		// Check if headBranch is short sha commit hash
+		if headCommit, _ := ctx.Repo.GitRepo.GetCommit(headBranch); headCommit != nil {
+			headBranch = headCommit.ID.String()
+			ctx.Data["HeadBranch"] = headBranch
+			headIsCommit = true
+		} else {
+			ctx.NotFound("IsRefExist", nil)
+			return nil, nil, nil, nil, "", ""
+		}
+	}
+	ctx.Data["HeadIsCommit"] = headIsCommit
+	ctx.Data["HeadIsBranch"] = headIsBranch
+	ctx.Data["HeadIsTag"] = headIsTag
+
+	// Treat as pull request if both references are branches
+	if ctx.Data["PageIsComparePull"] == nil {
+		ctx.Data["PageIsComparePull"] = headIsBranch && baseIsBranch
+	}
+
+	if ctx.Data["PageIsComparePull"] == true && !permBase.CanReadIssuesOrPulls(true) {
+		if log.IsTrace() {
+			log.Trace("Permission Denied: User: %-v cannot create/read pull requests in Repo: %-v\nUser in baseRepo has Permissions: %-+v",
+				ctx.User,
+				baseRepo,
+				permBase)
+		}
+		ctx.NotFound("ParseCompareInfo", nil)
+		return nil, nil, nil, nil, "", ""
+	}
+
+	compareInfo, err := headGitRepo.GetCompareInfo(models.RepoPath(baseRepo.Owner.Name, baseRepo.Name), baseBranch, headBranch)
+	if err != nil {
+		ctx.ServerError("GetCompareInfo", err)
+		return nil, nil, nil, nil, "", ""
+	}
+	ctx.Data["BeforeCommitID"] = compareInfo.MergeBase
+
+	return headUser, headRepo, headGitRepo, compareInfo, baseBranch, headBranch
+}
+
+// PrepareCompareDiff renders compare diff page
+func PrepareCompareDiff(
+	ctx *context.Context,
+	headUser *models.User,
+	headRepo *models.Repository,
+	headGitRepo *git.Repository,
+	compareInfo *git.CompareInfo,
+	baseBranch, headBranch string) bool {
+
+	var (
+		repo  = ctx.Repo.Repository
+		err   error
+		title string
+	)
+
+	// Get diff information.
+	ctx.Data["CommitRepoLink"] = headRepo.Link()
+
+	headCommitID := headBranch
+	if ctx.Data["HeadIsCommit"] == false {
+		if ctx.Data["HeadIsTag"] == true {
+			headCommitID, err = headGitRepo.GetTagCommitID(headBranch)
+		} else {
+			headCommitID, err = headGitRepo.GetBranchCommitID(headBranch)
+		}
+		if err != nil {
+			ctx.ServerError("GetRefCommitID", err)
+			return false
+		}
+	}
+
+	ctx.Data["AfterCommitID"] = headCommitID
+
+	if headCommitID == compareInfo.MergeBase {
+		ctx.Data["IsNothingToCompare"] = true
+		return true
+	}
+
+	diff, err := models.GetDiffRange(models.RepoPath(headUser.Name, headRepo.Name),
+		compareInfo.MergeBase, headCommitID, setting.Git.MaxGitDiffLines,
+		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles)
+	if err != nil {
+		ctx.ServerError("GetDiffRange", err)
+		return false
+	}
+	ctx.Data["Diff"] = diff
+	ctx.Data["DiffNotAvailable"] = diff.NumFiles() == 0
+
+	headCommit, err := headGitRepo.GetCommit(headCommitID)
+	if err != nil {
+		ctx.ServerError("GetCommit", err)
+		return false
+	}
+
+	compareInfo.Commits = models.ValidateCommitsWithEmails(compareInfo.Commits)
+	compareInfo.Commits = models.ParseCommitsWithSignature(compareInfo.Commits)
+	compareInfo.Commits = models.ParseCommitsWithStatus(compareInfo.Commits, headRepo)
+	ctx.Data["Commits"] = compareInfo.Commits
+	ctx.Data["CommitCount"] = compareInfo.Commits.Len()
+	if ctx.Data["CommitCount"] == 0 {
+		ctx.Data["PageIsComparePull"] = false
+	}
+
+	if compareInfo.Commits.Len() == 1 {
+		c := compareInfo.Commits.Front().Value.(models.SignCommitWithStatuses)
+		title = strings.TrimSpace(c.UserCommit.Summary())
+
+		body := strings.Split(strings.TrimSpace(c.UserCommit.Message()), "\n")
+		if len(body) > 1 {
+			ctx.Data["content"] = strings.Join(body[1:], "\n")
+		}
+	} else {
+		title = headBranch
+	}
+
+	ctx.Data["title"] = title
+	ctx.Data["Username"] = headUser.Name
+	ctx.Data["Reponame"] = headRepo.Name
+	ctx.Data["IsImageFile"] = headCommit.IsImageFile
+
+	headTarget := path.Join(headUser.Name, repo.Name)
+	ctx.Data["SourcePath"] = setting.AppSubURL + "/" + path.Join(headTarget, "src", "commit", headCommitID)
+	ctx.Data["BeforeSourcePath"] = setting.AppSubURL + "/" + path.Join(headTarget, "src", "commit", compareInfo.MergeBase)
+	ctx.Data["RawPath"] = setting.AppSubURL + "/" + path.Join(headTarget, "raw", "commit", headCommitID)
+	return false
+}
+
+// CompareDiff show different from one commit to another commit
+func CompareDiff(ctx *context.Context) {
+	headUser, headRepo, headGitRepo, compareInfo, baseBranch, headBranch := ParseCompareInfo(ctx)
+	if ctx.Written() {
+		return
+	}
+
+	nothingToCompare := PrepareCompareDiff(ctx, headUser, headRepo, headGitRepo, compareInfo, baseBranch, headBranch)
+	if ctx.Written() {
+		return
+	}
+
+	if ctx.Data["PageIsComparePull"] == true {
+		pr, err := models.GetUnmergedPullRequest(headRepo.ID, ctx.Repo.Repository.ID, headBranch, baseBranch)
+		if err != nil {
+			if !models.IsErrPullRequestNotExist(err) {
+				ctx.ServerError("GetUnmergedPullRequest", err)
+				return
+			}
+		} else {
+			ctx.Data["HasPullRequest"] = true
+			ctx.Data["PullRequest"] = pr
+			ctx.HTML(200, tplCompareDiff)
+			return
+		}
+
+		if !nothingToCompare {
+			// Setup information for new form.
+			RetrieveRepoMetas(ctx, ctx.Repo.Repository)
+			if ctx.Written() {
+				return
+			}
+		}
+
+		headBranches, err := headGitRepo.GetBranches()
+		if err != nil {
+			ctx.ServerError("GetBranches", err)
+			return
+		}
+		ctx.Data["HeadBranches"] = headBranches
+	}
+	beforeCommitID := ctx.Data["BeforeCommitID"].(string)
+	afterCommitID := ctx.Data["AfterCommitID"].(string)
+
+	ctx.Data["Title"] = "Comparing " + base.ShortSha(beforeCommitID) + "..." + base.ShortSha(afterCommitID)
+
+	ctx.Data["IsRepoToolbarCommits"] = true
+	ctx.Data["IsDiffCompare"] = true
+	ctx.Data["RequireHighlightJS"] = true
+	ctx.Data["RequireTribute"] = true
+	ctx.Data["PullRequestWorkInProgressPrefixes"] = setting.Repository.PullRequest.WorkInProgressPrefixes
+	setTemplateIfExists(ctx, pullRequestTemplateKey, pullRequestTemplateCandidates)
+	renderAttachmentSettings(ctx)
+
+	ctx.HTML(200, tplCompare)
+}
diff --git a/routers/repo/pull.go b/routers/repo/pull.go
index 412750dd55..182f715545 100644
--- a/routers/repo/pull.go
+++ b/routers/repo/pull.go
@@ -28,7 +28,7 @@ import (
 
 const (
 	tplFork        base.TplName = "repo/pulls/fork"
-	tplComparePull base.TplName = "repo/pulls/compare"
+	tplCompareDiff base.TplName = "repo/diff/compare"
 	tplPullCommits base.TplName = "repo/pulls/commits"
 	tplPullFiles   base.TplName = "repo/pulls/files"
 
@@ -280,13 +280,13 @@ func setMergeTarget(ctx *context.Context, pull *models.PullRequest) {
 }
 
 // PrepareMergedViewPullInfo show meta information for a merged pull request view page
-func PrepareMergedViewPullInfo(ctx *context.Context, issue *models.Issue) *git.PullRequestInfo {
+func PrepareMergedViewPullInfo(ctx *context.Context, issue *models.Issue) *git.CompareInfo {
 	pull := issue.PullRequest
 
 	setMergeTarget(ctx, pull)
 	ctx.Data["HasMerged"] = true
 
-	prInfo, err := ctx.Repo.GitRepo.GetPullRequestInfo(ctx.Repo.Repository.RepoPath(),
+	prInfo, err := ctx.Repo.GitRepo.GetCompareInfo(ctx.Repo.Repository.RepoPath(),
 		pull.MergeBase, pull.GetGitRefName())
 
 	if err != nil {
@@ -298,7 +298,7 @@ func PrepareMergedViewPullInfo(ctx *context.Context, issue *models.Issue) *git.P
 			return nil
 		}
 
-		ctx.ServerError("GetPullRequestInfo", err)
+		ctx.ServerError("GetCompareInfo", err)
 		return nil
 	}
 	ctx.Data["NumCommits"] = prInfo.Commits.Len()
@@ -307,7 +307,7 @@ func PrepareMergedViewPullInfo(ctx *context.Context, issue *models.Issue) *git.P
 }
 
 // PrepareViewPullInfo show meta information for a pull request preview page
-func PrepareViewPullInfo(ctx *context.Context, issue *models.Issue) *git.PullRequestInfo {
+func PrepareViewPullInfo(ctx *context.Context, issue *models.Issue) *git.CompareInfo {
 	repo := ctx.Repo.Repository
 	pull := issue.PullRequest
 
@@ -336,7 +336,7 @@ func PrepareViewPullInfo(ctx *context.Context, issue *models.Issue) *git.PullReq
 		return nil
 	}
 
-	prInfo, err := headGitRepo.GetPullRequestInfo(models.RepoPath(repo.Owner.Name, repo.Name),
+	prInfo, err := headGitRepo.GetCompareInfo(models.RepoPath(repo.Owner.Name, repo.Name),
 		pull.BaseBranch, pull.HeadBranch)
 	if err != nil {
 		if strings.Contains(err.Error(), "fatal: Not a valid object name") {
@@ -347,7 +347,7 @@ func PrepareViewPullInfo(ctx *context.Context, issue *models.Issue) *git.PullReq
 			return nil
 		}
 
-		ctx.ServerError("GetPullRequestInfo", err)
+		ctx.ServerError("GetCompareInfo", err)
 		return nil
 	}
 
@@ -628,266 +628,6 @@ func stopTimerIfAvailable(user *models.User, issue *models.Issue) error {
 	return nil
 }
 
-// ParseCompareInfo parse compare info between two commit for preparing pull request
-func ParseCompareInfo(ctx *context.Context) (*models.User, *models.Repository, *git.Repository, *git.PullRequestInfo, string, string) {
-	baseRepo := ctx.Repo.Repository
-
-	// Get compared branches information
-	// format: <base branch>...[<head repo>:]<head branch>
-	// base<-head: master...head:feature
-	// same repo: master...feature
-
-	var (
-		headUser   *models.User
-		headBranch string
-		isSameRepo bool
-		infoPath   string
-		err        error
-	)
-	infoPath = ctx.Params("*")
-	infos := strings.Split(infoPath, "...")
-	if len(infos) != 2 {
-		log.Trace("ParseCompareInfo[%d]: not enough compared branches information %s", baseRepo.ID, infos)
-		ctx.NotFound("CompareAndPullRequest", nil)
-		return nil, nil, nil, nil, "", ""
-	}
-
-	baseBranch := infos[0]
-	ctx.Data["BaseBranch"] = baseBranch
-
-	// If there is no head repository, it means pull request between same repository.
-	headInfos := strings.Split(infos[1], ":")
-	if len(headInfos) == 1 {
-		isSameRepo = true
-		headUser = ctx.Repo.Owner
-		headBranch = headInfos[0]
-
-	} else if len(headInfos) == 2 {
-		headUser, err = models.GetUserByName(headInfos[0])
-		if err != nil {
-			if models.IsErrUserNotExist(err) {
-				ctx.NotFound("GetUserByName", nil)
-			} else {
-				ctx.ServerError("GetUserByName", err)
-			}
-			return nil, nil, nil, nil, "", ""
-		}
-		headBranch = headInfos[1]
-		isSameRepo = headUser.ID == ctx.Repo.Owner.ID
-	} else {
-		ctx.NotFound("CompareAndPullRequest", nil)
-		return nil, nil, nil, nil, "", ""
-	}
-	ctx.Data["HeadUser"] = headUser
-	ctx.Data["HeadBranch"] = headBranch
-	ctx.Repo.PullRequest.SameRepo = isSameRepo
-
-	// Check if base branch is valid.
-	if !ctx.Repo.GitRepo.IsBranchExist(baseBranch) {
-		ctx.NotFound("IsBranchExist", nil)
-		return nil, nil, nil, nil, "", ""
-	}
-
-	// Check if current user has fork of repository or in the same repository.
-	headRepo, has := models.HasForkedRepo(headUser.ID, baseRepo.ID)
-	if !has && !isSameRepo {
-		log.Trace("ParseCompareInfo[%d]: does not have fork or in same repository", baseRepo.ID)
-		ctx.NotFound("ParseCompareInfo", nil)
-		return nil, nil, nil, nil, "", ""
-	}
-
-	var headGitRepo *git.Repository
-	if isSameRepo {
-		headRepo = ctx.Repo.Repository
-		headGitRepo = ctx.Repo.GitRepo
-		ctx.Data["BaseName"] = headUser.Name
-	} else {
-		headGitRepo, err = git.OpenRepository(models.RepoPath(headUser.Name, headRepo.Name))
-		ctx.Data["BaseName"] = baseRepo.OwnerName
-		if err != nil {
-			ctx.ServerError("OpenRepository", err)
-			return nil, nil, nil, nil, "", ""
-		}
-	}
-
-	// user should have permission to read baseRepo's codes and pulls, NOT headRepo's
-	permBase, err := models.GetUserRepoPermission(baseRepo, ctx.User)
-	if err != nil {
-		ctx.ServerError("GetUserRepoPermission", err)
-		return nil, nil, nil, nil, "", ""
-	}
-	if !permBase.CanReadIssuesOrPulls(true) || !permBase.CanRead(models.UnitTypeCode) {
-		if log.IsTrace() {
-			log.Trace("Permission Denied: User: %-v cannot create/read pull requests or cannot read code in Repo: %-v\nUser in baseRepo has Permissions: %-+v",
-				ctx.User,
-				baseRepo,
-				permBase)
-		}
-		ctx.NotFound("ParseCompareInfo", nil)
-		return nil, nil, nil, nil, "", ""
-	}
-
-	// user should have permission to read headrepo's codes
-	permHead, err := models.GetUserRepoPermission(headRepo, ctx.User)
-	if err != nil {
-		ctx.ServerError("GetUserRepoPermission", err)
-		return nil, nil, nil, nil, "", ""
-	}
-	if !permHead.CanRead(models.UnitTypeCode) {
-		if log.IsTrace() {
-			log.Trace("Permission Denied: User: %-v cannot read code requests in Repo: %-v\nUser in headRepo has Permissions: %-+v",
-				ctx.User,
-				headRepo,
-				permHead)
-		}
-		ctx.NotFound("ParseCompareInfo", nil)
-		return nil, nil, nil, nil, "", ""
-	}
-
-	// Check if head branch is valid.
-	if !headGitRepo.IsBranchExist(headBranch) {
-		ctx.NotFound("IsBranchExist", nil)
-		return nil, nil, nil, nil, "", ""
-	}
-
-	headBranches, err := headGitRepo.GetBranches()
-	if err != nil {
-		ctx.ServerError("GetBranches", err)
-		return nil, nil, nil, nil, "", ""
-	}
-	ctx.Data["HeadBranches"] = headBranches
-
-	prInfo, err := headGitRepo.GetPullRequestInfo(models.RepoPath(baseRepo.Owner.Name, baseRepo.Name), baseBranch, headBranch)
-	if err != nil {
-		ctx.ServerError("GetPullRequestInfo", err)
-		return nil, nil, nil, nil, "", ""
-	}
-	ctx.Data["BeforeCommitID"] = prInfo.MergeBase
-
-	return headUser, headRepo, headGitRepo, prInfo, baseBranch, headBranch
-}
-
-// PrepareCompareDiff render pull request preview diff page
-func PrepareCompareDiff(
-	ctx *context.Context,
-	headUser *models.User,
-	headRepo *models.Repository,
-	headGitRepo *git.Repository,
-	prInfo *git.PullRequestInfo,
-	baseBranch, headBranch string) bool {
-
-	var (
-		repo  = ctx.Repo.Repository
-		err   error
-		title string
-	)
-
-	// Get diff information.
-	ctx.Data["CommitRepoLink"] = headRepo.Link()
-
-	headCommitID, err := headGitRepo.GetBranchCommitID(headBranch)
-	if err != nil {
-		ctx.ServerError("GetBranchCommitID", err)
-		return false
-	}
-	ctx.Data["AfterCommitID"] = headCommitID
-
-	if headCommitID == prInfo.MergeBase {
-		ctx.Data["IsNothingToCompare"] = true
-		return true
-	}
-
-	diff, err := models.GetDiffRange(models.RepoPath(headUser.Name, headRepo.Name),
-		prInfo.MergeBase, headCommitID, setting.Git.MaxGitDiffLines,
-		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles)
-	if err != nil {
-		ctx.ServerError("GetDiffRange", err)
-		return false
-	}
-	ctx.Data["Diff"] = diff
-	ctx.Data["DiffNotAvailable"] = diff.NumFiles() == 0
-
-	headCommit, err := headGitRepo.GetCommit(headCommitID)
-	if err != nil {
-		ctx.ServerError("GetCommit", err)
-		return false
-	}
-
-	prInfo.Commits = models.ValidateCommitsWithEmails(prInfo.Commits)
-	prInfo.Commits = models.ParseCommitsWithSignature(prInfo.Commits)
-	prInfo.Commits = models.ParseCommitsWithStatus(prInfo.Commits, headRepo)
-	ctx.Data["Commits"] = prInfo.Commits
-	ctx.Data["CommitCount"] = prInfo.Commits.Len()
-
-	if prInfo.Commits.Len() == 1 {
-		c := prInfo.Commits.Front().Value.(models.SignCommitWithStatuses)
-		title = strings.TrimSpace(c.UserCommit.Summary())
-
-		body := strings.Split(strings.TrimSpace(c.UserCommit.Message()), "\n")
-		if len(body) > 1 {
-			ctx.Data["content"] = strings.Join(body[1:], "\n")
-		}
-	} else {
-		title = headBranch
-	}
-
-	ctx.Data["title"] = title
-	ctx.Data["Username"] = headUser.Name
-	ctx.Data["Reponame"] = headRepo.Name
-	ctx.Data["IsImageFile"] = headCommit.IsImageFile
-
-	headTarget := path.Join(headUser.Name, repo.Name)
-	ctx.Data["SourcePath"] = setting.AppSubURL + "/" + path.Join(headTarget, "src", "commit", headCommitID)
-	ctx.Data["BeforeSourcePath"] = setting.AppSubURL + "/" + path.Join(headTarget, "src", "commit", prInfo.MergeBase)
-	ctx.Data["RawPath"] = setting.AppSubURL + "/" + path.Join(headTarget, "raw", "commit", headCommitID)
-	return false
-}
-
-// CompareAndPullRequest render pull request preview page
-func CompareAndPullRequest(ctx *context.Context) {
-	ctx.Data["Title"] = ctx.Tr("repo.pulls.compare_changes")
-	ctx.Data["PageIsComparePull"] = true
-	ctx.Data["IsDiffCompare"] = true
-	ctx.Data["RequireHighlightJS"] = true
-	ctx.Data["RequireTribute"] = true
-	ctx.Data["PullRequestWorkInProgressPrefixes"] = setting.Repository.PullRequest.WorkInProgressPrefixes
-	setTemplateIfExists(ctx, pullRequestTemplateKey, pullRequestTemplateCandidates)
-	renderAttachmentSettings(ctx)
-
-	headUser, headRepo, headGitRepo, prInfo, baseBranch, headBranch := ParseCompareInfo(ctx)
-	if ctx.Written() {
-		return
-	}
-
-	pr, err := models.GetUnmergedPullRequest(headRepo.ID, ctx.Repo.Repository.ID, headBranch, baseBranch)
-	if err != nil {
-		if !models.IsErrPullRequestNotExist(err) {
-			ctx.ServerError("GetUnmergedPullRequest", err)
-			return
-		}
-	} else {
-		ctx.Data["HasPullRequest"] = true
-		ctx.Data["PullRequest"] = pr
-		ctx.HTML(200, tplComparePull)
-		return
-	}
-
-	nothingToCompare := PrepareCompareDiff(ctx, headUser, headRepo, headGitRepo, prInfo, baseBranch, headBranch)
-	if ctx.Written() {
-		return
-	}
-
-	if !nothingToCompare {
-		// Setup information for new form.
-		RetrieveRepoMetas(ctx, ctx.Repo.Repository)
-		if ctx.Written() {
-			return
-		}
-	}
-
-	ctx.HTML(200, tplComparePull)
-}
-
 // CompareAndPullRequestPost response for creating pull request
 func CompareAndPullRequestPost(ctx *context.Context, form auth.CreateIssueForm) {
 	ctx.Data["Title"] = ctx.Tr("repo.pulls.compare_changes")
@@ -926,7 +666,7 @@ func CompareAndPullRequestPost(ctx *context.Context, form auth.CreateIssueForm)
 			return
 		}
 
-		ctx.HTML(200, tplComparePull)
+		ctx.HTML(200, tplCompareDiff)
 		return
 	}
 
@@ -936,7 +676,7 @@ func CompareAndPullRequestPost(ctx *context.Context, form auth.CreateIssueForm)
 			return
 		}
 
-		ctx.RenderWithErr(ctx.Tr("repo.issues.new.title_empty"), tplComparePull, form)
+		ctx.RenderWithErr(ctx.Tr("repo.issues.new.title_empty"), tplCompareDiff, form)
 		return
 	}
 
diff --git a/routers/routes/routes.go b/routers/routes/routes.go
index eb5f73768e..4c736f63ed 100644
--- a/routers/routes/routes.go
+++ b/routers/routes/routes.go
@@ -732,9 +732,9 @@ func RegisterRoutes(m *macaron.Macaron) {
 		m.Group("/milestone", func() {
 			m.Get("/:id", repo.MilestoneIssuesAndPulls)
 		}, reqRepoIssuesOrPullsReader, context.RepoRef())
-		m.Combo("/compare/*", context.RepoMustNotBeArchived(), reqRepoCodeReader, reqRepoPullsReader, repo.MustAllowPulls, repo.SetEditorconfigIfExists).
-			Get(repo.SetDiffViewStyle, repo.CompareAndPullRequest).
-			Post(bindIgnErr(auth.CreateIssueForm{}), repo.CompareAndPullRequestPost)
+		m.Combo("/compare/*", repo.MustBeNotEmpty, reqRepoCodeReader, repo.SetEditorconfigIfExists).
+			Get(repo.SetDiffViewStyle, repo.CompareDiff).
+			Post(context.RepoMustNotBeArchived(), reqRepoPullsReader, repo.MustAllowPulls, bindIgnErr(auth.CreateIssueForm{}), repo.CompareAndPullRequestPost)
 
 		m.Group("", func() {
 			m.Group("", func() {
@@ -906,9 +906,6 @@ func RegisterRoutes(m *macaron.Macaron) {
 		}, context.RepoRef(), reqRepoCodeReader)
 		m.Get("/commit/:sha([a-f0-9]{7,40})\\.:ext(patch|diff)",
 			repo.MustBeNotEmpty, reqRepoCodeReader, repo.RawDiff)
-
-		m.Get("/compare/:before([a-z0-9]{40})\\.\\.\\.:after([a-z0-9]{40})", repo.SetEditorconfigIfExists,
-			repo.SetDiffViewStyle, repo.MustBeNotEmpty, reqRepoCodeReader, repo.CompareDiff)
 	}, ignSignIn, context.RepoAssignment(), context.UnitTypes())
 	m.Group("/:username/:reponame", func() {
 		m.Get("/stars", repo.Stars)