Fix protected branch files detection on pre_receive hook (#31778) (#31796)

Backport #31778 by @lunny

Fix #31738

When pushing a new branch, the old commit is zero. Most git commands
cannot recognize the zero commit id. To get the changed files in the
push, we need to get the first diverge commit of this branch. In most
situations, we could check commits one by one until one commit is
contained by another branch. Then we will think that commit is the
diverge point.

And in a pre-receive hook, this will be more difficult because all
commits haven't been merged and they actually stored in a temporary
place by git. So we need to bring some envs to let git know the commit
exist.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/git/commit_test.go

@@ -4,6 +4,8 @@
 package git
 
 import (
+	"context"
+	"os"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -345,3 +347,18 @@ func TestGetCommitFileStatusMerges(t *testing.T) {
 	assert.Equal(t, commitFileStatus.Removed, expected.Removed)
 	assert.Equal(t, commitFileStatus.Modified, expected.Modified)
 }
+
+func Test_GetCommitBranchStart(t *testing.T) {
+	bareRepo1Path := filepath.Join(testReposDir, "repo1_bare")
+	repo, err := OpenRepository(context.Background(), bareRepo1Path)
+	assert.NoError(t, err)
+	defer repo.Close()
+	commit, err := repo.GetBranchCommit("branch1")
+	assert.NoError(t, err)
+	assert.EqualValues(t, "2839944139e0de9737a044f78b0e4b40d989a9e3", commit.ID.String())
+
+	startCommitID, err := repo.GetCommitBranchStart(os.Environ(), "branch1", commit.ID.String())
+	assert.NoError(t, err)
+	assert.NotEmpty(t, startCommitID)
+	assert.EqualValues(t, "9c9aef8dd84e02bc7ec12641deb4c930a7c30185", startCommitID)
+}

modules/git/diff.go

@@ -271,7 +271,17 @@ func CutDiffAroundLine(originalDiff io.Reader, line int64, old bool, numbersOfLi
 }
 
 // GetAffectedFiles returns the affected files between two commits
-func GetAffectedFiles(repo *Repository, oldCommitID, newCommitID string, env []string) ([]string, error) {
+func GetAffectedFiles(repo *Repository, branchName, oldCommitID, newCommitID string, env []string) ([]string, error) {
+	if oldCommitID == emptySha1ObjectID.String() || oldCommitID == emptySha256ObjectID.String() {
+		startCommitID, err := repo.GetCommitBranchStart(env, branchName, newCommitID)
+		if err != nil {
+			return nil, err
+		}
+		if startCommitID == "" {
+			return nil, fmt.Errorf("cannot find the start commit of %s", newCommitID)
+		}
+		oldCommitID = startCommitID
+	}
 	stdoutReader, stdoutWriter, err := os.Pipe()
 	if err != nil {
 		log.Error("Unable to create os.Pipe for %s", repo.Path)

modules/git/repo_commit.go

@@ -7,6 +7,7 @@ package git
 import (
 	"bytes"
 	"io"
+	"os"
 	"strconv"
 	"strings"
 
@@ -414,7 +415,7 @@ func (repo *Repository) commitsBefore(id ObjectID, limit int) ([]*Commit, error)
 
 	commits := make([]*Commit, 0, len(formattedLog))
 	for _, commit := range formattedLog {
-		branches, err := repo.getBranches(commit, 2)
+		branches, err := repo.getBranches(os.Environ(), commit.ID.String(), 2)
 		if err != nil {
 			return nil, err
 		}
@@ -437,12 +438,15 @@ func (repo *Repository) getCommitsBeforeLimit(id ObjectID, num int) ([]*Commit,
 	return repo.commitsBefore(id, num)
 }
 
-func (repo *Repository) getBranches(commit *Commit, limit int) ([]string, error) {
+func (repo *Repository) getBranches(env []string, commitID string, limit int) ([]string, error) {
 	if DefaultFeatures().CheckVersionAtLeast("2.7.0") {
 		stdout, _, err := NewCommand(repo.Ctx, "for-each-ref", "--format=%(refname:strip=2)").
 			AddOptionFormat("--count=%d", limit).
-			AddOptionValues("--contains", commit.ID.String(), BranchPrefix).
+			AddOptionValues("--contains", commitID, BranchPrefix).
-			RunStdString(&RunOpts{Dir: repo.Path})
+			RunStdString(&RunOpts{
+				Dir: repo.Path,
+				Env: env,
+			})
 		if err != nil {
 			return nil, err
 		}
@@ -451,7 +455,10 @@ func (repo *Repository) getBranches(commit *Commit, limit int) ([]string, error)
 		return branches, nil
 	}
 
-	stdout, _, err := NewCommand(repo.Ctx, "branch").AddOptionValues("--contains", commit.ID.String()).RunStdString(&RunOpts{Dir: repo.Path})
+	stdout, _, err := NewCommand(repo.Ctx, "branch").AddOptionValues("--contains", commitID).RunStdString(&RunOpts{
+		Dir: repo.Path,
+		Env: env,
+	})
 	if err != nil {
 		return nil, err
 	}
@@ -513,3 +520,35 @@ func (repo *Repository) AddLastCommitCache(cacheKey, fullName, sha string) error
 	}
 	return nil
 }
+
+func (repo *Repository) GetCommitBranchStart(env []string, branch, endCommitID string) (string, error) {
+	cmd := NewCommand(repo.Ctx, "log", prettyLogFormat)
+	cmd.AddDynamicArguments(endCommitID)
+
+	stdout, _, runErr := cmd.RunStdBytes(&RunOpts{
+		Dir: repo.Path,
+		Env: env,
+	})
+	if runErr != nil {
+		return "", runErr
+	}
+
+	parts := bytes.Split(bytes.TrimSpace(stdout), []byte{'\n'})
+
+	var startCommitID string
+	for _, commitID := range parts {
+		branches, err := repo.getBranches(env, string(commitID), 2)
+		if err != nil {
+			return "", err
+		}
+		for _, b := range branches {
+			if b != branch {
+				return startCommitID, nil
+			}
+		}
+
+		startCommitID = string(commitID)
+	}
+
+	return "", nil
+}

modules/git/repo_commit_test.go

@@ -4,6 +4,7 @@
 package git
 
 import (
+	"os"
 	"path/filepath"
 	"testing"
 
@@ -31,7 +32,7 @@ func TestRepository_GetCommitBranches(t *testing.T) {
 	for _, testCase := range testCases {
 		commit, err := bareRepo1.GetCommit(testCase.CommitID)
 		assert.NoError(t, err)
-		branches, err := bareRepo1.getBranches(commit, 2)
+		branches, err := bareRepo1.getBranches(os.Environ(), commit.ID.String(), 2)
 		assert.NoError(t, err)
 		assert.Equal(t, testCase.ExpectedBranches, branches)
 	}

routers/private/hook_pre_receive.go

@@ -229,7 +229,7 @@ func preReceiveBranch(ctx *preReceiveContext, oldCommitID, newCommitID string, r
 
 	globs := protectBranch.GetProtectedFilePatterns()
 	if len(globs) > 0 {
-		_, err := pull_service.CheckFileProtection(gitRepo, oldCommitID, newCommitID, globs, 1, ctx.env)
+		_, err := pull_service.CheckFileProtection(gitRepo, branchName, oldCommitID, newCommitID, globs, 1, ctx.env)
 		if err != nil {
 			if !models.IsErrFilePathProtected(err) {
 				log.Error("Unable to check file protection for commits from %s to %s in %-v: %v", oldCommitID, newCommitID, repo, err)
@@ -278,7 +278,7 @@ func preReceiveBranch(ctx *preReceiveContext, oldCommitID, newCommitID string, r
 			// Allow commits that only touch unprotected files
 			globs := protectBranch.GetUnprotectedFilePatterns()
 			if len(globs) > 0 {
-				unprotectedFilesOnly, err := pull_service.CheckUnprotectedFiles(gitRepo, oldCommitID, newCommitID, globs, ctx.env)
+				unprotectedFilesOnly, err := pull_service.CheckUnprotectedFiles(gitRepo, branchName, oldCommitID, newCommitID, globs, ctx.env)
 				if err != nil {
 					log.Error("Unable to check file protection for commits from %s to %s in %-v: %v", oldCommitID, newCommitID, repo, err)
 					ctx.JSON(http.StatusInternalServerError, private.Response{

services/pull/patch.go

@@ -503,11 +503,11 @@ func checkConflicts(ctx context.Context, pr *issues_model.PullRequest, gitRepo *
 }
 
 // CheckFileProtection check file Protection
-func CheckFileProtection(repo *git.Repository, oldCommitID, newCommitID string, patterns []glob.Glob, limit int, env []string) ([]string, error) {
+func CheckFileProtection(repo *git.Repository, branchName, oldCommitID, newCommitID string, patterns []glob.Glob, limit int, env []string) ([]string, error) {
 	if len(patterns) == 0 {
 		return nil, nil
 	}
-	affectedFiles, err := git.GetAffectedFiles(repo, oldCommitID, newCommitID, env)
+	affectedFiles, err := git.GetAffectedFiles(repo, branchName, oldCommitID, newCommitID, env)
 	if err != nil {
 		return nil, err
 	}
@@ -533,11 +533,11 @@ func CheckFileProtection(repo *git.Repository, oldCommitID, newCommitID string,
 }
 
 // CheckUnprotectedFiles check if the commit only touches unprotected files
-func CheckUnprotectedFiles(repo *git.Repository, oldCommitID, newCommitID string, patterns []glob.Glob, env []string) (bool, error) {
+func CheckUnprotectedFiles(repo *git.Repository, branchName, oldCommitID, newCommitID string, patterns []glob.Glob, env []string) (bool, error) {
 	if len(patterns) == 0 {
 		return false, nil
 	}
-	affectedFiles, err := git.GetAffectedFiles(repo, oldCommitID, newCommitID, env)
+	affectedFiles, err := git.GetAffectedFiles(repo, branchName, oldCommitID, newCommitID, env)
 	if err != nil {
 		return false, err
 	}
@@ -574,7 +574,7 @@ func checkPullFilesProtection(ctx context.Context, pr *issues_model.PullRequest,
 		return nil
 	}
 
-	pr.ChangedProtectedFiles, err = CheckFileProtection(gitRepo, pr.MergeBase, "tracking", pb.GetProtectedFilePatterns(), 10, os.Environ())
+	pr.ChangedProtectedFiles, err = CheckFileProtection(gitRepo, pr.HeadBranch, pr.MergeBase, "tracking", pb.GetProtectedFilePatterns(), 10, os.Environ())
 	if err != nil && !models.IsErrFilePathProtected(err) {
 		return err
 	}