bench-forgejo/services/pull/patch_unmerged.go
zeripath f1e85622da
Improve TestPatch to use git read-tree -m and implement git-merge-one-file functionality (#18004)
The current TestPatch conflict code uses a plain git apply which does not properly
account for 3-way merging. However, we can improve things using `git read-tree -m` to
do a three-way merge then follow the algorithm used in merge-one-file. We can also use 
`--patience` and/or `--histogram` to generate a nicer diff for applying patches too.

Fix #13679
Fix #6417

Signed-off-by: Andrew Thornton <art27@cantab.net>
2021-12-19 05:19:25 +01:00

180 lines
5 KiB
Go

// Copyright 2021 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"
"strconv"
"strings"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
)
// lsFileLine is a Quadruplet struct (+error) representing a partially parsed line from ls-files
type lsFileLine struct {
mode string
sha string
stage int
path string
err error
}
// SameAs checks if two lsFileLines are referring to the same path, sha and mode (ignoring stage)
func (line *lsFileLine) SameAs(other *lsFileLine) bool {
if line == nil || other == nil {
return false
}
if line.err != nil || other.err != nil {
return false
}
return line.mode == other.mode &&
line.sha == other.sha &&
line.path == other.path
}
// readUnmergedLsFileLines calls git ls-files -u -z and parses the lines into mode-sha-stage-path quadruplets
// it will push these to the provided channel closing it at the end
func readUnmergedLsFileLines(ctx context.Context, tmpBasePath string, outputChan chan *lsFileLine) {
defer func() {
// Always close the outputChan at the end of this function
close(outputChan)
}()
lsFilesReader, lsFilesWriter, err := os.Pipe()
if err != nil {
log.Error("Unable to open stderr pipe: %v", err)
outputChan <- &lsFileLine{err: fmt.Errorf("unable to open stderr pipe: %v", err)}
return
}
defer func() {
_ = lsFilesWriter.Close()
_ = lsFilesReader.Close()
}()
stderr := &strings.Builder{}
err = git.NewCommandContext(ctx, "ls-files", "-u", "-z").
RunInDirTimeoutEnvFullPipelineFunc(
nil, -1, tmpBasePath,
lsFilesWriter, stderr, nil,
func(_ context.Context, _ context.CancelFunc) error {
_ = lsFilesWriter.Close()
defer func() {
_ = lsFilesReader.Close()
}()
bufferedReader := bufio.NewReader(lsFilesReader)
for {
line, err := bufferedReader.ReadString('\000')
if err != nil {
if err == io.EOF {
return nil
}
return err
}
toemit := &lsFileLine{}
split := strings.SplitN(line, " ", 3)
if len(split) < 3 {
return fmt.Errorf("malformed line: %s", line)
}
toemit.mode = split[0]
toemit.sha = split[1]
if len(split[2]) < 4 {
return fmt.Errorf("malformed line: %s", line)
}
toemit.stage, err = strconv.Atoi(split[2][0:1])
if err != nil {
return fmt.Errorf("malformed line: %s", line)
}
toemit.path = split[2][2 : len(split[2])-1]
outputChan <- toemit
}
})
if err != nil {
outputChan <- &lsFileLine{err: fmt.Errorf("git ls-files -u -z: %v", git.ConcatenateError(err, stderr.String()))}
}
}
// unmergedFile is triple (+error) of lsFileLines split into stages 1,2 & 3.
type unmergedFile struct {
stage1 *lsFileLine
stage2 *lsFileLine
stage3 *lsFileLine
err error
}
// unmergedFiles will collate the output from readUnstagedLsFileLines in to file triplets and send them
// to the provided channel, closing at the end.
func unmergedFiles(ctx context.Context, tmpBasePath string, unmerged chan *unmergedFile) {
defer func() {
// Always close the channel
close(unmerged)
}()
ctx, cancel := context.WithCancel(ctx)
lsFileLineChan := make(chan *lsFileLine, 10) // give lsFileLineChan a buffer
go readUnmergedLsFileLines(ctx, tmpBasePath, lsFileLineChan)
defer func() {
cancel()
for range lsFileLineChan {
// empty channel
}
}()
next := &unmergedFile{}
for line := range lsFileLineChan {
if line.err != nil {
log.Error("Unable to run ls-files -u -z! Error: %v", line.err)
unmerged <- &unmergedFile{err: fmt.Errorf("unable to run ls-files -u -z! Error: %v", line.err)}
return
}
// stages are always emitted 1,2,3 but sometimes 1, 2 or 3 are dropped
switch line.stage {
case 0:
// Should not happen as this represents successfully merged file - we will tolerate and ignore though
case 1:
if next.stage1 != nil {
// We need to handle the unstaged file stage1,stage2,stage3
unmerged <- next
}
next = &unmergedFile{stage1: line}
case 2:
if next.stage3 != nil || next.stage2 != nil || (next.stage1 != nil && next.stage1.path != line.path) {
// We need to handle the unstaged file stage1,stage2,stage3
unmerged <- next
next = &unmergedFile{}
}
next.stage2 = line
case 3:
if next.stage3 != nil || (next.stage1 != nil && next.stage1.path != line.path) || (next.stage2 != nil && next.stage2.path != line.path) {
// We need to handle the unstaged file stage1,stage2,stage3
unmerged <- next
next = &unmergedFile{}
}
next.stage3 = line
default:
log.Error("Unexpected stage %d for path %s in run ls-files -u -z!", line.stage, line.path)
unmerged <- &unmergedFile{err: fmt.Errorf("unexpected stage %d for path %s in git ls-files -u -z", line.stage, line.path)}
return
}
}
// We need to handle the unstaged file stage1,stage2,stage3
if next.stage1 != nil || next.stage2 != nil || next.stage3 != nil {
unmerged <- next
}
}