forgejo/services/pull/patch.go
zeripath 1eebbf23f0
When conflicts have been previously detected ensure that they can be resolved (#19247)
There is yet another problem with conflicted files not being reset when
the test patch resolves them.

This PR adjusts the code for checkConflicts to reset the ConflictedFiles
field immediately at the top. It also adds a reset to conflictedFiles
for the manuallyMerged and a shortcut for the empty status in
protectedfiles.

Signed-off-by: Andrew Thornton <art27@cantab.net>
2022-03-29 18:42:34 +02:00

538 lines
18 KiB
Go

// 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 pull
import (
"bufio"
"context"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"code.gitea.io/gitea/models"
"code.gitea.io/gitea/models/unit"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/graceful"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/process"
"code.gitea.io/gitea/modules/util"
"github.com/gobwas/glob"
)
// DownloadDiffOrPatch will write the patch for the pr to the writer
func DownloadDiffOrPatch(ctx context.Context, pr *models.PullRequest, w io.Writer, patch, binary bool) error {
if err := pr.LoadBaseRepo(); err != nil {
log.Error("Unable to load base repository ID %d for pr #%d [%d]", pr.BaseRepoID, pr.Index, pr.ID)
return err
}
gitRepo, closer, err := git.RepositoryFromContextOrOpen(ctx, pr.BaseRepo.RepoPath())
if err != nil {
return fmt.Errorf("OpenRepository: %v", err)
}
defer closer.Close()
if err := gitRepo.GetDiffOrPatch(pr.MergeBase, pr.GetGitRefName(), w, patch, binary); err != nil {
log.Error("Unable to get patch file from %s to %s in %s Error: %v", pr.MergeBase, pr.HeadBranch, pr.BaseRepo.FullName(), err)
return fmt.Errorf("Unable to get patch file from %s to %s in %s Error: %v", pr.MergeBase, pr.HeadBranch, pr.BaseRepo.FullName(), err)
}
return nil
}
var patchErrorSuffices = []string{
": already exists in index",
": patch does not apply",
": already exists in working directory",
"unrecognized input",
}
// TestPatch will test whether a simple patch will apply
func TestPatch(pr *models.PullRequest) error {
ctx, _, finished := process.GetManager().AddContext(graceful.GetManager().HammerContext(), fmt.Sprintf("TestPatch: Repo[%d]#%d", pr.BaseRepoID, pr.Index))
defer finished()
// Clone base repo.
tmpBasePath, err := createTemporaryRepo(ctx, pr)
if err != nil {
log.Error("CreateTemporaryPath: %v", err)
return err
}
defer func() {
if err := models.RemoveTemporaryPath(tmpBasePath); err != nil {
log.Error("Merge: RemoveTemporaryPath: %s", err)
}
}()
gitRepo, err := git.OpenRepositoryCtx(ctx, tmpBasePath)
if err != nil {
return fmt.Errorf("OpenRepository: %v", err)
}
defer gitRepo.Close()
// 1. update merge base
pr.MergeBase, err = git.NewCommand(ctx, "merge-base", "--", "base", "tracking").RunInDir(tmpBasePath)
if err != nil {
var err2 error
pr.MergeBase, err2 = gitRepo.GetRefCommitID(git.BranchPrefix + "base")
if err2 != nil {
return fmt.Errorf("GetMergeBase: %v and can't find commit ID for base: %v", err, err2)
}
}
pr.MergeBase = strings.TrimSpace(pr.MergeBase)
// 2. Check for conflicts
if conflicts, err := checkConflicts(ctx, pr, gitRepo, tmpBasePath); err != nil || conflicts || pr.Status == models.PullRequestStatusEmpty {
return err
}
// 3. Check for protected files changes
if err = checkPullFilesProtection(pr, gitRepo); err != nil {
return fmt.Errorf("pr.CheckPullFilesProtection(): %v", err)
}
if len(pr.ChangedProtectedFiles) > 0 {
log.Trace("Found %d protected files changed", len(pr.ChangedProtectedFiles))
}
pr.Status = models.PullRequestStatusMergeable
return nil
}
type errMergeConflict struct {
filename string
}
func (e *errMergeConflict) Error() string {
return fmt.Sprintf("conflict detected at: %s", e.filename)
}
func attemptMerge(ctx context.Context, file *unmergedFile, tmpBasePath string, gitRepo *git.Repository) error {
switch {
case file.stage1 != nil && (file.stage2 == nil || file.stage3 == nil):
// 1. Deleted in one or both:
//
// Conflict <==> the stage1 !SameAs to the undeleted one
if (file.stage2 != nil && !file.stage1.SameAs(file.stage2)) || (file.stage3 != nil && !file.stage1.SameAs(file.stage3)) {
// Conflict!
return &errMergeConflict{file.stage1.path}
}
// Not a genuine conflict and we can simply remove the file from the index
return gitRepo.RemoveFilesFromIndex(file.stage1.path)
case file.stage1 == nil && file.stage2 != nil && (file.stage3 == nil || file.stage2.SameAs(file.stage3)):
// 2. Added in ours but not in theirs or identical in both
//
// Not a genuine conflict just add to the index
if err := gitRepo.AddObjectToIndex(file.stage2.mode, git.MustIDFromString(file.stage2.sha), file.stage2.path); err != nil {
return err
}
return nil
case file.stage1 == nil && file.stage2 != nil && file.stage3 != nil && file.stage2.sha == file.stage3.sha && file.stage2.mode != file.stage3.mode:
// 3. Added in both with the same sha but the modes are different
//
// Conflict! (Not sure that this can actually happen but we should handle)
return &errMergeConflict{file.stage2.path}
case file.stage1 == nil && file.stage2 == nil && file.stage3 != nil:
// 4. Added in theirs but not ours:
//
// Not a genuine conflict just add to the index
return gitRepo.AddObjectToIndex(file.stage3.mode, git.MustIDFromString(file.stage3.sha), file.stage3.path)
case file.stage1 == nil:
// 5. Created by new in both
//
// Conflict!
return &errMergeConflict{file.stage2.path}
case file.stage2 != nil && file.stage3 != nil:
// 5. Modified in both - we should try to merge in the changes but first:
//
if file.stage2.mode == "120000" || file.stage3.mode == "120000" {
// 5a. Conflicting symbolic link change
return &errMergeConflict{file.stage2.path}
}
if file.stage2.mode == "160000" || file.stage3.mode == "160000" {
// 5b. Conflicting submodule change
return &errMergeConflict{file.stage2.path}
}
if file.stage2.mode != file.stage3.mode {
// 5c. Conflicting mode change
return &errMergeConflict{file.stage2.path}
}
// Need to get the objects from the object db to attempt to merge
root, err := git.NewCommand(ctx, "unpack-file", file.stage1.sha).RunInDir(tmpBasePath)
if err != nil {
return fmt.Errorf("unable to get root object: %s at path: %s for merging. Error: %w", file.stage1.sha, file.stage1.path, err)
}
root = strings.TrimSpace(root)
defer func() {
_ = util.Remove(filepath.Join(tmpBasePath, root))
}()
base, err := git.NewCommand(ctx, "unpack-file", file.stage2.sha).RunInDir(tmpBasePath)
if err != nil {
return fmt.Errorf("unable to get base object: %s at path: %s for merging. Error: %w", file.stage2.sha, file.stage2.path, err)
}
base = strings.TrimSpace(filepath.Join(tmpBasePath, base))
defer func() {
_ = util.Remove(base)
}()
head, err := git.NewCommand(ctx, "unpack-file", file.stage3.sha).RunInDir(tmpBasePath)
if err != nil {
return fmt.Errorf("unable to get head object:%s at path: %s for merging. Error: %w", file.stage3.sha, file.stage3.path, err)
}
head = strings.TrimSpace(head)
defer func() {
_ = util.Remove(filepath.Join(tmpBasePath, head))
}()
// now git merge-file annoyingly takes a different order to the merge-tree ...
_, conflictErr := git.NewCommand(ctx, "merge-file", base, root, head).RunInDir(tmpBasePath)
if conflictErr != nil {
return &errMergeConflict{file.stage2.path}
}
// base now contains the merged data
hash, err := git.NewCommand(ctx, "hash-object", "-w", "--path", file.stage2.path, base).RunInDir(tmpBasePath)
if err != nil {
return err
}
hash = strings.TrimSpace(hash)
return gitRepo.AddObjectToIndex(file.stage2.mode, git.MustIDFromString(hash), file.stage2.path)
default:
if file.stage1 != nil {
return &errMergeConflict{file.stage1.path}
} else if file.stage2 != nil {
return &errMergeConflict{file.stage2.path}
} else if file.stage3 != nil {
return &errMergeConflict{file.stage3.path}
}
}
return nil
}
// AttemptThreeWayMerge will attempt to three way merge using git read-tree and then follow the git merge-one-file algorithm to attempt to resolve basic conflicts
func AttemptThreeWayMerge(ctx context.Context, gitPath string, gitRepo *git.Repository, base, ours, theirs, description string) (bool, []string, error) {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
// First we use read-tree to do a simple three-way merge
if _, err := git.NewCommand(ctx, "read-tree", "-m", base, ours, theirs).RunInDir(gitPath); err != nil {
log.Error("Unable to run read-tree -m! Error: %v", err)
return false, nil, fmt.Errorf("unable to run read-tree -m! Error: %v", err)
}
// Then we use git ls-files -u to list the unmerged files and collate the triples in unmergedfiles
unmerged := make(chan *unmergedFile)
go unmergedFiles(ctx, gitPath, unmerged)
defer func() {
cancel()
for range unmerged {
// empty the unmerged channel
}
}()
numberOfConflicts := 0
conflict := false
conflictedFiles := make([]string, 0, 5)
for file := range unmerged {
if file == nil {
break
}
if file.err != nil {
cancel()
return false, nil, file.err
}
// OK now we have the unmerged file triplet attempt to merge it
if err := attemptMerge(ctx, file, gitPath, gitRepo); err != nil {
if conflictErr, ok := err.(*errMergeConflict); ok {
log.Trace("Conflict: %s in %s", conflictErr.filename, description)
conflict = true
if numberOfConflicts < 10 {
conflictedFiles = append(conflictedFiles, conflictErr.filename)
}
numberOfConflicts++
continue
}
return false, nil, err
}
}
return conflict, conflictedFiles, nil
}
func checkConflicts(ctx context.Context, pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath string) (bool, error) {
// 1. checkConflicts resets the conflict status - therefore - reset the conflict status
pr.ConflictedFiles = nil
// 2. AttemptThreeWayMerge first - this is much quicker than plain patch to base
description := fmt.Sprintf("PR[%d] %s/%s#%d", pr.ID, pr.BaseRepo.OwnerName, pr.BaseRepo.Name, pr.Index)
conflict, _, err := AttemptThreeWayMerge(ctx,
tmpBasePath, gitRepo, pr.MergeBase, "base", "tracking", description)
if err != nil {
return false, err
}
if !conflict {
treeHash, err := git.NewCommand(ctx, "write-tree").RunInDir(tmpBasePath)
if err != nil {
return false, err
}
treeHash = strings.TrimSpace(treeHash)
baseTree, err := gitRepo.GetTree("base")
if err != nil {
return false, err
}
if treeHash == baseTree.ID.String() {
log.Debug("PullRequest[%d]: Patch is empty - ignoring", pr.ID)
pr.Status = models.PullRequestStatusEmpty
}
return false, nil
}
// 3. OK read-tree has failed so we need to try a different thing - this might actually succeed where the above fails due to whitespace handling.
// 3a. Create a plain patch from head to base
tmpPatchFile, err := os.CreateTemp("", "patch")
if err != nil {
log.Error("Unable to create temporary patch file! Error: %v", err)
return false, fmt.Errorf("unable to create temporary patch file! Error: %v", err)
}
defer func() {
_ = util.Remove(tmpPatchFile.Name())
}()
if err := gitRepo.GetDiffBinary(pr.MergeBase, "tracking", tmpPatchFile); err != nil {
tmpPatchFile.Close()
log.Error("Unable to get patch file from %s to %s in %s Error: %v", pr.MergeBase, pr.HeadBranch, pr.BaseRepo.FullName(), err)
return false, fmt.Errorf("unable to get patch file from %s to %s in %s Error: %v", pr.MergeBase, pr.HeadBranch, pr.BaseRepo.FullName(), err)
}
stat, err := tmpPatchFile.Stat()
if err != nil {
tmpPatchFile.Close()
return false, fmt.Errorf("unable to stat patch file: %v", err)
}
patchPath := tmpPatchFile.Name()
tmpPatchFile.Close()
// 3b. if the size of that patch is 0 - there can be no conflicts!
if stat.Size() == 0 {
log.Debug("PullRequest[%d]: Patch is empty - ignoring", pr.ID)
pr.Status = models.PullRequestStatusEmpty
return false, nil
}
log.Trace("PullRequest[%d].testPatch (patchPath): %s", pr.ID, patchPath)
// 4. Read the base branch in to the index of the temporary repository
_, err = git.NewCommand(gitRepo.Ctx, "read-tree", "base").RunInDir(tmpBasePath)
if err != nil {
return false, fmt.Errorf("git read-tree %s: %v", pr.BaseBranch, err)
}
// 5. Now get the pull request configuration to check if we need to ignore whitespace
prUnit, err := pr.BaseRepo.GetUnit(unit.TypePullRequests)
if err != nil {
return false, err
}
prConfig := prUnit.PullRequestsConfig()
// 6. Prepare the arguments to apply the patch against the index
args := []string{"apply", "--check", "--cached"}
if prConfig.IgnoreWhitespaceConflicts {
args = append(args, "--ignore-whitespace")
}
is3way := false
if git.CheckGitVersionAtLeast("2.32.0") == nil {
args = append(args, "--3way")
is3way = true
}
args = append(args, patchPath)
// 7. Prep the pipe:
// - Here we could do the equivalent of:
// `git apply --check --cached patch_file > conflicts`
// Then iterate through the conflicts. However, that means storing all the conflicts
// in memory - which is very wasteful.
// - alternatively we can do the equivalent of:
// `git apply --check ... | grep ...`
// meaning we don't store all of the conflicts unnecessarily.
stderrReader, stderrWriter, err := os.Pipe()
if err != nil {
log.Error("Unable to open stderr pipe: %v", err)
return false, fmt.Errorf("unable to open stderr pipe: %v", err)
}
defer func() {
_ = stderrReader.Close()
_ = stderrWriter.Close()
}()
// 8. Run the check command
conflict = false
err = git.NewCommand(gitRepo.Ctx, args...).
RunWithContext(&git.RunContext{
Timeout: -1,
Dir: tmpBasePath,
Stderr: stderrWriter,
PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {
// Close the writer end of the pipe to begin processing
_ = stderrWriter.Close()
defer func() {
// Close the reader on return to terminate the git command if necessary
_ = stderrReader.Close()
}()
const prefix = "error: patch failed:"
const errorPrefix = "error: "
const threewayFailed = "Failed to perform three-way merge..."
const appliedPatchPrefix = "Applied patch to '"
const withConflicts = "' with conflicts."
conflictMap := map[string]bool{}
// Now scan the output from the command
scanner := bufio.NewScanner(stderrReader)
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, prefix) {
conflict = true
filepath := strings.TrimSpace(strings.Split(line[len(prefix):], ":")[0])
conflictMap[filepath] = true
} else if is3way && line == threewayFailed {
conflict = true
} else if strings.HasPrefix(line, errorPrefix) {
conflict = true
for _, suffix := range patchErrorSuffices {
if strings.HasSuffix(line, suffix) {
filepath := strings.TrimSpace(strings.TrimSuffix(line[len(errorPrefix):], suffix))
if filepath != "" {
conflictMap[filepath] = true
}
break
}
}
} else if is3way && strings.HasPrefix(line, appliedPatchPrefix) && strings.HasSuffix(line, withConflicts) {
conflict = true
filepath := strings.TrimPrefix(strings.TrimSuffix(line, withConflicts), appliedPatchPrefix)
if filepath != "" {
conflictMap[filepath] = true
}
}
// only list 10 conflicted files
if len(conflictMap) >= 10 {
break
}
}
if len(conflictMap) > 0 {
pr.ConflictedFiles = make([]string, 0, len(conflictMap))
for key := range conflictMap {
pr.ConflictedFiles = append(pr.ConflictedFiles, key)
}
}
return nil
},
})
// 9. If there is a conflict the `git apply` command will return a non-zero error code - so there will be a positive error.
if err != nil {
if conflict {
pr.Status = models.PullRequestStatusConflict
log.Trace("Found %d files conflicted: %v", len(pr.ConflictedFiles), pr.ConflictedFiles)
return true, nil
}
return false, fmt.Errorf("git apply --check: %v", err)
}
return false, nil
}
// CheckFileProtection check file Protection
func CheckFileProtection(repo *git.Repository, 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)
if err != nil {
return nil, err
}
changedProtectedFiles := make([]string, 0, limit)
for _, affectedFile := range affectedFiles {
lpath := strings.ToLower(affectedFile)
for _, pat := range patterns {
if pat.Match(lpath) {
changedProtectedFiles = append(changedProtectedFiles, lpath)
break
}
}
if len(changedProtectedFiles) >= limit {
break
}
}
if len(changedProtectedFiles) > 0 {
err = models.ErrFilePathProtected{
Path: changedProtectedFiles[0],
}
}
return changedProtectedFiles, err
}
// CheckUnprotectedFiles check if the commit only touches unprotected files
func CheckUnprotectedFiles(repo *git.Repository, 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)
if err != nil {
return false, err
}
for _, affectedFile := range affectedFiles {
lpath := strings.ToLower(affectedFile)
unprotected := false
for _, pat := range patterns {
if pat.Match(lpath) {
unprotected = true
break
}
}
if !unprotected {
return false, nil
}
}
return true, nil
}
// checkPullFilesProtection check if pr changed protected files and save results
func checkPullFilesProtection(pr *models.PullRequest, gitRepo *git.Repository) error {
if pr.Status == models.PullRequestStatusEmpty {
pr.ChangedProtectedFiles = nil
return nil
}
if err := pr.LoadProtectedBranch(); err != nil {
return err
}
if pr.ProtectedBranch == nil {
pr.ChangedProtectedFiles = nil
return nil
}
var err error
pr.ChangedProtectedFiles, err = CheckFileProtection(gitRepo, pr.MergeBase, "tracking", pr.ProtectedBranch.GetProtectedFilePatterns(), 10, os.Environ())
if err != nil && !models.IsErrFilePathProtected(err) {
return err
}
return nil
}