githaven-fork/services/repository/files/cherry_pick.go
Mihir Joshi b8270240bf
Fix reverting a merge commit failing (#28794)
Fixes #22236

---
Error occurring currently while trying to revert commit using read-tree
-m approach:
> 2022/12/26 16:04:43 ...rvices/pull/patch.go:240:AttemptThreeWayMerge()
[E] [63a9c61a] Unable to run read-tree -m! Error: exit status 128 -
fatal: this operation must be run in a work tree
> 	 - fatal: this operation must be run in a work tree

We need to clone a non-bare repository for `git read-tree -m` to work.

bb371aee6e
adds support to create a non-bare cloned temporary upload repository.

After cloning a non-bare temporary upload repository, we [set default
index](https://github.com/go-gitea/gitea/blob/main/services/repository/files/cherry_pick.go#L37)
(`git read-tree HEAD`).
This operation ends up resetting the git index file (see investigation
details below), due to which, we need to call `git update-index
--refresh` afterward.


Here's the diff of the index file before and after we execute
SetDefaultIndex: https://www.diffchecker.com/hyOP3eJy/

Notice the **ctime**, **mtime** are set to 0 after SetDefaultIndex.

You can reproduce the same behavior using these steps:
```bash
$ git clone https://try.gitea.io/me-heer/test.git -s -b main
$ cd test
$ git read-tree HEAD
$ git read-tree -m 1f085d7ed8 1f085d7ed8 9933caed00
error: Entry '1' not uptodate. Cannot merge.
```

After which, we can fix like this:
```
$ git update-index --refresh
$ git read-tree -m 1f085d7ed8 1f085d7ed8 9933caed00
```
2024-01-16 15:06:51 +00:00

129 lines
3.5 KiB
Go

// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package files
import (
"context"
"fmt"
"strings"
"code.gitea.io/gitea/models"
repo_model "code.gitea.io/gitea/models/repo"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/structs"
"code.gitea.io/gitea/services/pull"
)
// CherryPick cherrypicks or reverts a commit to the given repository
func CherryPick(ctx context.Context, repo *repo_model.Repository, doer *user_model.User, revert bool, opts *ApplyDiffPatchOptions) (*structs.FileResponse, error) {
if err := opts.Validate(ctx, repo, doer); err != nil {
return nil, err
}
message := strings.TrimSpace(opts.Message)
author, committer := GetAuthorAndCommitterUsers(opts.Author, opts.Committer, doer)
t, err := NewTemporaryUploadRepository(ctx, repo)
if err != nil {
log.Error("%v", err)
}
defer t.Close()
if err := t.Clone(opts.OldBranch, false); err != nil {
return nil, err
}
if err := t.SetDefaultIndex(); err != nil {
return nil, err
}
if err := t.RefreshIndex(); err != nil {
return nil, err
}
// Get the commit of the original branch
commit, err := t.GetBranchCommit(opts.OldBranch)
if err != nil {
return nil, err // Couldn't get a commit for the branch
}
// Assigned LastCommitID in opts if it hasn't been set
if opts.LastCommitID == "" {
opts.LastCommitID = commit.ID.String()
} else {
lastCommitID, err := t.gitRepo.ConvertToGitID(opts.LastCommitID)
if err != nil {
return nil, fmt.Errorf("CherryPick: Invalid last commit ID: %w", err)
}
opts.LastCommitID = lastCommitID.String()
if commit.ID.String() != opts.LastCommitID {
return nil, models.ErrCommitIDDoesNotMatch{
GivenCommitID: opts.LastCommitID,
CurrentCommitID: opts.LastCommitID,
}
}
}
commit, err = t.GetCommit(strings.TrimSpace(opts.Content))
if err != nil {
return nil, err
}
parent, err := commit.ParentID(0)
if err != nil {
parent = git.ObjectFormatFromName(repo.ObjectFormatName).EmptyTree()
}
base, right := parent.String(), commit.ID.String()
if revert {
right, base = base, right
}
description := fmt.Sprintf("CherryPick %s onto %s", right, opts.OldBranch)
conflict, _, err := pull.AttemptThreeWayMerge(ctx,
t.basePath, t.gitRepo, base, opts.LastCommitID, right, description)
if err != nil {
return nil, fmt.Errorf("failed to three-way merge %s onto %s: %w", right, opts.OldBranch, err)
}
if conflict {
return nil, fmt.Errorf("failed to merge due to conflicts")
}
treeHash, err := t.WriteTree()
if err != nil {
// likely non-sensical tree due to merge conflicts...
return nil, err
}
// Now commit the tree
var commitHash string
if opts.Dates != nil {
commitHash, err = t.CommitTreeWithDate("HEAD", author, committer, treeHash, message, opts.Signoff, opts.Dates.Author, opts.Dates.Committer)
} else {
commitHash, err = t.CommitTree("HEAD", author, committer, treeHash, message, opts.Signoff)
}
if err != nil {
return nil, err
}
// Then push this tree to NewBranch
if err := t.Push(doer, commitHash, opts.NewBranch); err != nil {
return nil, err
}
commit, err = t.GetCommit(commitHash)
if err != nil {
return nil, err
}
fileCommitResponse, _ := GetFileCommitResponse(repo, commit) // ok if fails, then will be nil
verification := GetPayloadCommitVerification(ctx, commit)
fileResponse := &structs.FileResponse{
Commit: fileCommitResponse,
Verification: verification,
}
return fileResponse, nil
}